What Is Diffraction in Photography?

When photographers talk about diffraction, they are referring to the fact that a photograph grows progressively less sharp at small aperture values – f/16, f/22, and so on. As you stop down your lens to such small apertures, the finest detail in your photographs will begin to blur. With good reason, this effect can worry beginning photographers. However, if you understand how diffraction impacts your photographs, you can make educated decisions and take the sharpest possible photographs in the field.

The effects of diffraction – that your sharpness decreases at smaller and smaller apertures – are shown in the comparison below. Keep in mind that these are fairly extreme crops:

(To see the sharpness differences more clearly, click on the image. Pay particular attention to the pattern of colored dots on the woman’s face.)

The reason that this occurs is based upon the principles of physics; in short, as the aperture gets smaller and smaller, light waves spread out and interfere with one another increasingly more. This causes small details of your photographs to blur.

However, this explanation is overly simple, and it still can be confusing to beginning photographers. What, physically, causes diffraction? At what point does diffraction begin to blur your photographs? Is there anything you can do to prevent diffraction? Are expensive lenses better at controlling diffraction? The answers to all of these questions will be explained in-depth below.

1) The Physics of Diffraction

In explaining diffraction, it can be difficult to straddle the line between avoiding and embracing references to optical physics. Most photographers are interested in day-to-day knowledge rather than comprehensive background information, but it is impossible to talk about diffraction without describing how it works at a fundamental level. That said, this section is meant to be understandable even if you are not a physicist; we recommend reading it, since it will provide a more solid foundation for your understanding of diffraction.

At its most basic, diffraction is the concept that waves – including light waves – can interfere with one another. In fact, every time that waves pass through a slit, they will interfere. To make this easy to visualize, consider waves of water. If you drop a rock into a perfectly still lake, you will cause a ripple of small waves to form. These waves spread out in concentric circles, just like the image below:

(Image adapted from Wikimedia Commons)

What happens if you create a barrier to block the path of these waves? Quite simply, you would stop their movement. This is boring:

(The waves on the left-hand side, of course, would continue to bounce around; that isn’t shown in this diagram.)

To make it interesting, then, you cut a hole in the barrier so that water can pass. Now, what sorts of patterns would the waves create?

The waves look similar to how you might expect, although there are a few additional patterns that form aside from the primary wave:

These additional patterns are artifacts from the wave bending around the corners. They arise because the two corners act, essentially, as individual sources of waves – waves which can collide with one another. In certain areas of collision, the waves cancel each other out (destructive interference); that is why some areas of the diagram look completely still. In other places, though, the waves add together (constructive interference), which causes an additional pattern to form off to the sides.

To visualize this, let’s say that there is a sensor along the far-right edge of the diagram. This sensor measures the intensity of the waves at a given point, which increases with the amplitude of the wave. A graph of the intensity is shown below:

Clearly, the central pattern is the most significant. The patterns off to the side are still present, but they don’t have nearly the same intensity as the one in the center. This means that the central pattern is most significant in photography, as we will cover in a moment. For now, though, let’s see what happens with a large versus a narrow opening in the barrier. Note that the images below have been simplified, and only the central wave pattern is included:

The main difference between these two images is that the smaller opening results in a larger spread of waves, while the large opening causes much less spreading.

Take a look at a comparison between the graphs of the two waves:

Although it may initially seem unusual that a small opening leads to a larger spread of waves, the illustrations above should show that it makes logical sense. Essentially, larger openings allow the waves to pass without much interference. Since the waves are not particularly disturbed, they follow a relatively straight path towards the edge of the pool. Smaller openings, though, affect a wave more significantly, causing it to bend at harsher angles. (This is a slight simplification; for more technical information, I recommend reading the Wikipedia page on the Huygens principle.)

Finally, note that a “small” opening is relative. In fact, the opening only causes diffraction when it is similar in size to the wavelength that passes through it. This is why light, which has a tiny wavelength, will not diffract significantly if it passes through a ten-foot wide opening – even though the ocean does.

Congratulations! You now understand the physics of diffraction. At its most basic, a small opening causes waves to bend and interfere with one another; this, in turn, spreads out their signal.

2) In Photography

Clearly, diffraction is an important concept in physics. In fact, a similar experiment (with two slits rather than one) played a major role in proving that light can behave as a wave – one of the most important discoveries in scientific history. But how does this impact your everyday photography?

(Image from Wikimedia Commons)

It all comes down to the aperture of a lens. Shown in the photograph above, the aperture blades in a lens act as a single slit that passes waves of light. A pattern of the light’s intensity is exactly what you would expect to see:

This looks familiar! That’s because light, similar to water, travels in waves. (Image from Wikimedia Commons.)

This, though, is a two-dimensional graph. In the real world, a pinpoint of light projects in three dimensions. So, a more accurate graph appears below:

(Image from Wikimedia Commons.)

This three-dimensional pattern occurs every time that light shines through the aperture in your camera lens. When projected onto the sensor of your camera, it looks like this:

(Image from Wikimedia Commons.)

The figure above shows what is known as an airy disk. This is, quite simply, the appearance of a diffraction pattern when it hits your camera sensor. The central region is the brightest, and it has the largest effect on your photographs.

It isn’t difficult to tell why this airy disk can cause a photograph to blur. We already know that a small opening – or, a small aperture – causes waves to spread out. This means that, at small apertures, the airy disk becomes much larger. If you can envision the airy disk as hitting your camera sensor, you get a picture that looks like this, where the grid represents the pixels on your sensor:

(Note that, in reality, the airy disk grows dimmer as the aperture grows narrower; to simplify the diagram, this effect is not shown here.)

Now, think of a scene as being composed of countless tiny sources of light. Every pinpoint of light travels through the aperture of your lens; as a result, each part of your photograph projects onto your sensor as an airy disk. These, as shown above, become blurrier with small aperture values. This is the reason that you see diffraction!

3) High- Versus Low-Megapixel Cameras

The comparison above, showing an airy disk hitting the pixels of your sensor, might prompt a question: if the pixels were larger, wouldn’t the airy disk be less likely to bleed over?

In fact, that is completely true! Large pixels – those which are bigger than the airy disk – do not show diffraction at the same apertures that a small-pixel camera would. Perhaps I can stop down to f/11 on the 12-megapixel Nikon D700 before noticing any diffraction, while the 36-megapixel D800/D810 would show visible diffraction at any aperture smaller than f/5.6. These numbers aren’t set in stone, though; I recommend testing your own camera to see when diffraction begins to grow noticeable (and, more importantly, when it begins to grow objectionable).

However, this isn’t a problem with high-resolution sensors. In fact, if all your settings are the same, a high-resolution sensor will always capture more detail than a low-resolution sensor of the same size. More pixels will never lead to lower detail, even at the tiniest of apertures. This means that, if you print your photos at the same size, a Nikon D800/D810 photo will always have more detail than a Nikon D700 photo, all else equal.

That said, if you buy the Nikon D800/D810, chances are good that you want to print large or pixel-peep. If this is the case for you, diffraction absolutely is a bigger issue than it would have been with a low-resolution sensor! To get the best possible sharpness from a D800/D810, you should pay attention if your aperture is smaller than about f/8. Again, I recommend testing the exact boundaries of your camera yourself.

NIKON D800E + 105mm f/2.8 @ 105mm, ISO 100, 1/3, f/7.1

4) Small Versus Large Sensors

It is often said that crop-sensor cameras (i.e., DX Nikon cameras) show diffraction more easily than full-frame cameras (FX Nikon). Is this a myth, or does it hold true?

Let’s start with what we know. At a given aperture on a lens, the airy disk will always be the same physical size. It doesn’t matter what sensor you use; this is a property of physics that only depends upon the aperture itself. For example, whether I put a 50mm f/1.8 lens on the full-frame D750 or the crop-sensor D3300, the size of its airy disk projection will be identical (assuming the same aperture).

So, where’s the confusion? The issue irises from the fact that the same airy disk takes up a larger percentage of a crop-sensor camera than a full-frame camera. Take a look at the example below:

In fact, at an equal print size, a DX camera will show more diffraction than an FX camera. This is because the DX sensor is essentially a crop of the FX sensor; in other words, it magnifies everything in your photograph – including the diffraction – just like cropping in post-production.

The amount of additional diffraction is the same as your crop factor. So, for a 1.5x crop-sensor camera, multiply your aperture by 1.5 in order to see the equivalent diffraction on a full-frame camera. For example, the airy disk at f/11 on a DX camera takes up roughly the same percentage of your sensor as the airy disk at f/16 would on a full-frame camera.

Of course, if you use a DX camera, you may not print quite as large as you would with an FX camera. For many photographers, then, there is no practical difference; the smaller prints from a DX camera cancel out the additional diffraction. If you do print at large sizes with a DX camera, be aware that diffraction will be more significant at a given aperture.

NIKON D7000 + 24mm f/1.4 @ 24mm, ISO 100, 1/250, f/5.6

5) Diffraction and Depth of Field

Diffraction decreases a photograph’s sharpness at small apertures. Yet, at the same time, small apertures increase the amount of depth of field in a photograph. This is not a contradiction, although it can be confusing at first. Look, for example, at the comparison below:

As you can tell, the f/22 photo has much more of the scene within its depth of field. If I want this entire subject to be sharp, it is far better than the photograph at f/5.6. However, let’s look at the point of focus more closely:

As you can see, the f/5.6 photo is significantly sharper. (Click on the image to see it more clearly.)

This, of course, does not mean that you should shoot every photograph at f/5.6. If you need a large depth of field, feel free to use smaller apertures; sometimes, it’s worth the slight reduction in sharpness from diffraction.

6) Choosing the Sharpest Aperture

There is always diffraction at every single aperture of your lens. This has to be true; light always needs to bend through an aperture, even if it is very large. However, at wide apertures like f/2.8 or f/4, the airy disk is much smaller than the pixels in your photograph. This means that diffraction is essentially impossible to see at such small apertures.

However, this doesn’t mean that large apertures are the sharpest on a given lens. As you likely know, a lens tends to be at its sharpest when its aperture is slightly stopped-down. For example, my 20mm f/1.8 lens is sharpest in the center at f/4. Below is a sharpness chart for such a lens:

So, why is the peak at an aperture of f/4 rather than f/1.8? That is slightly beyond the scope of this article, but the essence is that – at larger apertures – more light travels through the edges of a lens. Since the center of a lens is the best-corrected region, this decreases the sharpness of the photograph (and increases its spherical aberration). A smaller aperture actually blocks light that has traveled through the edges of a lens, which improves the sharpness of a photograph.

This effect, balanced with the decrease of sharpness from diffraction, is the reason that f/4 gives the greatest sharpness on a lens like the 20mm f/1.8.

How do you tell which aperture is sharpest on your lens? Simply look at the tested results online. However, don’t stress too much about always shooting at the “perfect” aperture. For one, even these test results can be ambiguous. In the chart above, for example, the corners of the lens are actually sharpest at f/8. So, depending upon your subject, you may prefer sharper corners rather than the sharpest possible center.

At the same time, even suboptimal apertures aren’t horribly blurry. I have made a few large prints from photographs taken at f/16, and their quality is more than enough for my needs. If you need an aperture like this – generally to increase your depth of field – don’t be afraid to use it.

NIKON D800E + 24mm f/1.4 @ 24mm, ISO 100, 6/10, f/16.0

7) Avoiding Diffraction

Now that you understand diffraction, how do you make sure to avoid it in your photographs? Unfortunately, the simple answer is that you can’t. Diffraction is a result of physics. It doesn’t matter how good your lens is; diffraction will rob sharpness at smaller apertures no matter what.

Even though you cannot circumvent the laws of physics, there is one way to avoid diffraction in your photographs: use a larger aperture. If you need the absolute sharpest photograph, this is the only way to avoid the effects of diffraction. Are you photographing a scene that needs a large depth of field? Try focus stacking at an aperture of f/5.6 or f/8, where diffraction is minimal.

At the same time, if you did use a small aperture (say, f/16 or f/22), you can improve a photograph’s apparent detail by sharpening in post-processing. This doesn’t actually eliminate the effects of diffraction, but it is a simple way to improve photos taken at small apertures.

In theory, it is possible to correct for diffraction through a sharpening process known as deconvolution sharpening. This type of sharpening is most effective when one has a perfect model of the lens in question, including its exact optical characteristics. For this reason, generic deconvolution sharpening does not reduce the effects of diffraction to a meaningful degree; NASA, however, is known to use such a method to improve the sharpness of Hubble Telescope photographs. (Some camera manufacturers, including Pentax, may have a diffraction-reduction menu option; however, this is nothing more than a standard unsharp mask cooked into your RAW file.) If you want to test deconvolution sharpening, increase the “Detail” slider as much as possible in either Lightroom or Camera Raw. Of course, it will not be specific to your lens, which would be necessary for true diffraction reduction.

However, although you can sharpen your photographs in post-processing, the best way to decrease diffraction is simply to use a larger aperture.

NIKON D7000 + 105mm f/2.8 @ 105mm, ISO 100, 1/40, f/6.3

8) Extra Information

Aperture is a technical topic; so is the interaction between light and your camera sensor. Some of the information above is presented as a best-case scenario, and the reality can be slightly more complex. Most of the following information will not affect the actual appearance of your photographs, but it is worth covering some of these special cases.

For example, light with large wavelengths will diffract more readily than light with shorter wavelengths; this means that red light (with a wavelength of about 650 nm) leads to a larger airy disk than blue light (about 475 nm) at the same aperture. So, in theory, you will see slightly less blur from diffraction if you are working in extremely blue light; in practice, this effect is small enough that it has little impact on your photographs.

Also, in most cameras, the pixels that combine to make a photograph do not all detect the same wavelengths of light. For sensors with a Bayer array of pixels (including Nikon, Canon, and Sony DSLR/mirrorless cameras), the number of green-sensing pixels is twice the number of red and blue pixels. This means that the pixel diagram presented earlier is a slight simplification; however, this does not change the fact that blur from diffraction increases due to the size of the airy disk.

Finally, the depiction of the airy disk in this article is bit simpler than it would appear in the real world. Above, I showed it as a series of concentric rings; in reality, though, that would only occur if the aperture were perfectly circular. Most lenses have seven, eight, or nine aperture blades, which (even when curved) are not quite circles. So, the “airy disk” becomes an “airy octagon.” However, there is no practical difference in the appearance of diffraction in your photographs; your photos will be just as blurry as you stop down the lens.

If you have any questions about the finer points of diffraction, please feel free to ask a question in the comments section; a single article is too short to explain everything that there is to know about such a complex topic.

NIKON D7000 + 17-55mm f/2.8 @ 55mm, ISO 100, 1/250, f/5.6

9) Conclusions

Given all of these technical caveats, diffraction can seem like an out-there, unusual topic to be discussing. However, its effects are clear and significant in your photographs, and they are well worth considering while you are taking pictures. Especially for landscape and architectural photographers – or anyone who wants to take sharp photos with a large depth of field – it is important to understand the tradeoffs that come from shooting at a small aperture.

Diffraction is present in all your photographs, and – if you aren’t careful – it can rob some sharpness from your favorite images. However, once you see its effects in practice, diffraction will become second nature.

The post What Is Diffraction in Photography? appeared first on Photography Life.

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How to photograph a fruit splash using off-camera flash

Dive into the world of high-speed photography as we show you how you can capture a fruity splash with your flash.

High-speed photography is a fantastic way to capture some spectacular effects. Freezing the moment an object breaks the water’s surface makes for stunning splash photography.

The setup may look complex, but all that’s required is a bit of preparation beforehand, some photography and flash know-how, and a great deal of patience! We used a macro lens but a standard zoom will do the job.

We’ll show you how to create your own tabletop studio and set up your camera and flash to capture some high-speed action. Our aim is to capture the cherry just after it’s broken the surface of the water, but before it sinks to the bottom of the container.

In order to freeze the action at the exact moment the cherry splashes into the water we’ll be using off-camera flash. By lighting the splash from the side we’ll get more depth and avoid capturing nasty looking shadows.

This isn’t an exact science, so getting the timing right is a bit of an experiment. So what are you waiting for? Grab some fruit and let’s get started.

01 Manual for full control
In manual mode, set shutter speed to the maximum flash sync speed (1/180-1/250 sec, depending on your EOS). Set a narrow aperture (eg f/8) for a good depth of field and set ISO low for noise-free shots.

 

02 Master flash
To set the pop-up flash as Master, go to Flash Control Settings and enable Flash Firing. Select Built-in Flash Func, scroll down to Wireless Func, press Set. Select the option to trigger the off-camera flash only.

 

03 Set the Slave
Set your flashgun to the Slave wireless setting and the same channel as camera. Select Manual flash power and you can adjust the output via the camera’s Flash Settings menu. We started off with 1/4 power.

 

04 Pre-focus
Grab a spoon and submerge it in the water, roughly where your subject will fall, and pre-focus, then switch your lens to MF to lock the focus. It may take a couple of attempts to achieve accurate results.

Final Tips

Diffuse the light
Clear surfaces, like glass, can be a challenge to shoot as they’re so reflective. If you fire a burst of flash in the direction of the glass container, you’ll capture lots of imperfections in the glass – and plenty of fingerprints and dust, despite cleaning it before you started. Position your reflector’s translucent diffuser panel between the setup and off-camera flash to soften the light.

Flash and exposure
To capture splash photography without motion blur we need to use flash as this can capture much faster movement than your camera’s fastest shutter speed. For best results you’ll need to shoot in a fairly dark room, so turn off the lights and close the curtains. Manually set your flashgun to 1/4 power, take some test shots, then fine-tune the exposure by adjusting the aperture to darken or brighten the image.

The post How to photograph a fruit splash using off-camera flash appeared first on Digital Camera World.

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How to Expose Film Correctly at Night

I wrote this article for my darkroom photography students and for others who want to shoot photos at night using film but have no idea how to do it. I know that few people these days are creating images with film and the ones that are, are either very savvy or are totally lost. Taking pictures with film is very different than using a digital camera. With film, you want to expose properly so you end up with very good negatives to print.

Night Photography with Film

The information included here is what I normally do when I expose film at night or indoors with very little light. I do this to capture enough light and end up with very good negatives. Nowadays not many people know that film has a greater capability to capture light than digital sensors. What I mean by that is that the range of tones is greater in film when exposed properly. So, to capture enough light on film and have the range you are looking for, you have to do it well.

A digital camera helps you to create an image with an extended range by creating multiple images using HDR photography, and then stitching them together in Photoshop. This means that you have to take many steps to obtain the same range of tones than you can obtain in one well exposed negative. With the number of apps and editing programs out there, your options are unlimited! I appreciate that. But, even with all these advantages, many people with very expensive cameras are unfamiliar with the fundamentals of photography and will have just “nice” images on their Facebook wall. Film gives you a deeper understanding of the multiple processes that go into making a solid print suitable for framing. These instructions are designed to help you render consistent high quality negatives.

One of the difficulties for many photographers who use film is exposing it correctly at night. Shutters are different in every camera, so you have to do your own testing to get good results. You have to expose the film correctly and make sure that you expose for the shadows and develop for the highlights. This has been the motto of many great photographers for many years. Film can capture great detail in the shadows and highlights, but if you do not control the developing process, the highlights will end up as white patches with no detail. By controlling the developing process you control the highlights. This will give you images with great tonality.

How to Shoot Photos at Night

Since film cameras will not record everything you do in the field, bring a notebook to document everything you do in the camera. Also, bring a tripod, cable release, flashlight and lots and lots of patience. Patience is probably the most important part in the process of using film. Also, don’t just shoot willy nilly; be selective of what you photograph. Remember that a roll of film is only 24 or 36 exposures; make everyone count as if it was the last photo you were ever going to create. This will make you a very good, or better yet, a great photographer.

First of all, film does not respond to artificial light the same way as digital camera sensors. I suggest that if you want a type of film that responds to all types of light, you use panchromatic film. What is panchromatic you ask? Panchromatic film is a normal black-and-white film sensitive to light of all visible colors (electromagnetic wavelengths between 400 nm and 700 nm). There are other types of film, for example, orthochromatic film, which is not sensitive to all waves (colors) of light.

If you’re interested in knowing more about panchromatic film, here is a link with more information: http://ift.tt/1SRj3qu

I strongly recommend Ilford films. I use Ilford HP5 most of the time as it has very little grain (if you expose it correctly). The second film that I recommend is Kodak Tri-X; this is a legendary film. A little too grainy for my taste, but a great film nevertheless.

Chicago at Night

Before you have the film in the camera, make sure everything is in working order: Apertures, shutter speeds and light meter. Since we are trying to expose film correctly, do not set the ASA in the camera to 400, which is what the film is rated. This number will give you okay negatives but not very good negatives. So, set your ASA to 200 and follow the light meter! What I mean by this, is to make sure that you do not over or under expose each shot. Of course, you do not have to do this all the time, only when you want very good negatives! Some students overexposed their negatives on top of the ASA sensitivity compensation and then want to under develop the roll based on something they read on the internet! Wrong! Develop the film normally, at the correct time. You want one stop of over exposure in your negatives, otherwise, if you under-develop, you undo this compensation and will screw up the rest of the images in the roll which were properly exposed.

So the camera is set, the film is in, everything is working correctly. You are ready to go and expose film. But, when shooting film at night it actually loses speed and the actual film speed or ASA is not valid. So, you must take that into account and compensate for Reciprocity Failure or ‘reciprocity law’ (what happens to film at night, or indoors with artificial light and very long exposure).

Go to a dark (and safe) area of your street, it doesn’t matter what you photograph; your concern right now is on learning before creating. Set your camera in the tripod, screw in the cable release, and set the ASA in the dial as high as it will go. Older cameras can go to 1600 or 3200 ASA; set it there. Now set your lens to the biggest aperture—let’s say f/2.8. Look at your light meter and read the shutter speed. What is it? If you are in a very dark place, your light meter will probably give you a long exposure even with the ASA at 1600. Let’s assume that the correct time that you read in the light meter is 2 seconds. If you had 1600 ASA film in the camera this will be half okay, but you don’t have that. Remember, we are shooting with Ilford HP5 400 at 200 ASA. Copy this sample chart in your notebook so you remember it for next time:

Equivalent Exposures

Of course you are not going to have the same aperture and shutter speeds as in this sample, this chart is simply a calculation reference. Start cutting the ASA in half, each time you cut the ASA in half that corresponds to one full stop of exposure, so just double the shutter speed and the exposure time will be correct.

So, with the film that you have in the camera your exposure is 16 seconds but, this is before compensating for reciprocity failure or a different aperture of the lens. I know that using the lens fully open is a good idea but maybe you want to use a smaller aperture, let’s say f/8. The chart is correct for the film with the ASA you have in the camera, but not for an aperture of f/8. For that aperture, keep adjusting. Please notice that now that we found the correct exposure for 200 ASA film, we keep that ASA and change the aperture of the lens only! Since we are cutting the amount of light in half every time we close the aperture of the lens, we double the exposure time to compensate. ALL these combinations will give us exactly the same amount of light in the film; this is called reciprocal exposures.

Can you imagine an exposure of 256 seconds? And this is without compensating for reciprocity failure.

So, what is reciprocity? Why is it necessary to compensate the exposure on film? Before we continue with the chart, let me tell you about the Reciprocity Law or the Schwarzschild Effect.

Reciprocity Failure

For most photographic materials, reciprocity is valid with good accuracy over a range of values of exposure duration, but becomes increasingly inaccurate as we depart from this range. As the light level decreases out of range, the increase in duration, and hence of total exposure, required to produce an equivalent response becomes higher than the formula states. For example, at half the light required for a normal exposure, the duration must be more than doubled for the same result. Multipliers used to correct for this effect are called reciprocity factors.

Long Exposure

At very low light levels, film is less responsive. Light can be considered to be a stream of discrete photons, and a light-sensitive emulsion is composed of discrete light-sensitive grains, usually silver halide crystals. Each grain must absorb a certain number of photons in order for the light-driven reaction to occur and the latent image to form. In particular, if the surface of the silver halide crystal has a cluster of approximately four or more reduced silver atoms, resulting from absorption of a sufficient number of photons (usually a few dozen photons are required), it is rendered developable. At low light levels, i.e. few photons per unit time, photons impinge upon each grain relatively infrequently; if the four photons required arrive over a long enough interval, the partial change due to the first one or two is not stable enough to survive before enough photons arrive to make a permanent latent image center.

This breakdown in the usual tradeoff between aperture and shutter speed is known as reciprocity failure. Each different film type has a different response at low light levels. Some films are very susceptible to reciprocity failure, and others much less so. Some films that are very light sensitive at normal illumination levels and normal exposure times lose much of their sensitivity at low light levels, becoming effectively “slow” films for long exposures. Conversely some films that are “slow” under normal exposure duration retain their light sensitivity better at low light levels.

Another example: For a given film, if a light meter indicates a required EV of 5 and the photographer sets the aperture to f/11, then ordinarily a 4-second exposure would be required; a reciprocity correction factor of 1.5 would require the exposure to be extended to 6 seconds for the same result. Reciprocity failure generally becomes significant at exposures of longer than about 1 second for film, and above 30 seconds for paper.

Reciprocity also breaks down at extremely high levels of illumination with very short exposures. This is a concern for scientific and technical photography, but rarely to general photographers, as exposures significantly shorter than a millisecond are only required for subjects such as explosions and particle physics experiments, or when taking high-speed motion pictures with very high shutter speeds (1/10,000 of a second or faster).

Finally, here is an additional chart where I use 100 ASA film at a very small aperture of the lens and compensate for reciprocity accordingly. Remember, the longer you expose film the more it loses speed, this is why I compensate to such percentages.

100 ASA film at a very small aperture

Since they did not want people in the picture (below) and this lobby is busy 24 hours a day, I ended up using a small aperture on a Linhoff medium format camera and shot the picture exposing it for 32 minutes after reciprocity correction.

Hilton Towers lobby Hotel on Michigan Ave. Kodak Film 25 ASA shot at 12 ASA

Film photography is a lot more than just a push a button and hope for the best. Can you get beautiful images with digital? Of course! Can you use your digital camera and do the same extra-long exposures? Absolutely! But compare digital to film; nothing will beat the thrill of seeing your first print that you carefully composed, developed, tested, and exposed as it slowly appears in a developer tray.

About the Author:
Ignacio Alvarez is a photography instructor at City Colleges of Chicago.

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Flash Photography Guide at 75% Off

Natural light is beautiful, but it doesn’t always cooperate. That’s why it’s important for photographers to understand how and when flash lighting can be beneficial. And if you don’t know where to begin, reading Ed Verosky’s Guide to Flash Photography is a good starting point. It covers everything from choosing a flash to how light works to setting up classic lighting patterns. We were able to arrange a 75% discount ($ 5 down from $ 20) which ends soon. Deal found here: Guide to Flash Photography at 75% Off

The Guide to Flash Photography at 75% Off

Guide to Flash Photography is a compilation of his best flash instruction from books and tutorials over the last several years and a follow-up to his eBook, 100% Reliable Flash Photography, which was originally written in 2010. Much of the information has been reworked and updated to present a clearer picture of Verosky’s methodology.

The goal is to give you a complete foundational understanding of how light and flash work so that you can produce great flash photography quickly and easily, no matter what the circumstances. The aim of the guide is to present the material in a way that doesn’t waste your time, while it gives you every opportunity to learn and master your technique.

Some of the Many Topics Covered (89 pages)

• Duration of Light
• Constant & Flash Lighting
• Behavior of Light
• Direct & Diffuse Light
• Color of Light
• Aperture, Shutter Speed & ISO
• Shooting Modes
• Manual Mode

Pages from the Flash Photography Guide

• Types of Flash Units
• Remote Flash Triggering
• Light Stands
• Light Metering
• Lighting Ratios
• TTL Flash
• Exposure Compensation
• Off-Camera Flash
• Building a Portable Studio
• Lighting Setups
• Portraiture
• Basic Lighting Patterns

Table of Contents

Depending on your skill level and familiarity with topics like camera settings and exposure, you might have to spend a little more time with certain sections, but stick to it. It will pay off big as time goes on.

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Framing Subjects with Natural Elements

You have probably already read some great articles at Photography Life regarding framing of your subjects and all the rules that are applicable while doing so (if you have not, check out the section on composition in the photography tips for beginners page). This time around, I want to draw your attention to framing subjects with natural elements to create compelling images. For me personally, photographing is like narrating a story, so I often find it important to incorporate the surrounding elements of the scene along with my subjects. While you can certainly take fantastic photos isolating your subjects with creamy bokeh, I believe that decorating your shots with creative framing will help you add some substance and a pleasant visual appeal to enhance the story.

NIKON D750 + 85mm f/1.4 @ 85mm, ISO 250, 1/200, f/2.0

Do Location and Type of Photography Matter When Looking for Natural Frames?

I personally photograph weddings and portraits, so almost all of the images presented in this article come from working in the field with my clients. Although we might not be always free to let our creative juices flow due to time and other constraints, being able to “see” what is around us and being able to integrate surrounding elements into our work can be potentially rewarding. The good news is, you do not have to be in a stunning location to be able to do this – at times, just a limb of a tree or a little corner of a bush will suffice. If you are not sure of what element(s) to incorporate in your shots, you can always blur the background out with a slightly visible natural frame that will caress the outer edges of the photograph. This alone can help add mystery to your story line, which the viewer can relate to or follow.

NIKON D700 + 50mm f/1.4 @ 50mm, ISO 200, 1/1600, f/2.8

Vignetting with Natural Elements

Vignetting (not to be confused with optical vignetting) is a technique that is often used to help draw the viewer’s attention on the subject by weakening the impact of the surrounding elements. When utilized properly and very subtly (even in post-processing) it can be a great technique to use. Generally, we think of vignetting as a darker (or a lighter) halo at the edges of the frame that gradually fades away and softens as it gets closer towards the center of the image. Here, the idea is to try to create a natural vignette using the surrounding elements of the scene. In sample images used in this article, I demonstrate the use of tree branches, leaves and other objects to wrap around my subjects in order to create the vignetting effect. When doing this, you want to make sure that large branches and other distracting elements are not cutting into the middle of the frame and that your subject is positioned in the open area of the naturally occurring frame.

NIKON D700 + 50mm f/1.4 @ 50mm, ISO 200, 1/1000, f/2.5

Creating Gradients With Natural Elements

By now, you might have already practiced adding artificial gradients in Photoshop and Lightroom in order to enhance the look of your images. This trick can be successfully done in the field by just framing one of the edges of the frame with a natural element. It could be a branch of a tree or even a blank wall! In this instance, you are surrounding your subject(s) with negative space, which can be a very effective way to compose your images. Rather than leaving the negative space blank, you can even successfully decorate it with simple surrounding elements, which can be naturally-occurring. The gradient element of the photo does not necessarily have to come from a far element either – you can successfully use a foreground element to give some pop of color or add a little drama to your photo.

NIKON Df + 50mm f/1.8 @ 50mm, ISO 400, 1/25, f/2.8

NIKON D700 + 50mm f/1.4 @ 50mm, ISO 1250, 1/100, f/2.8

Photographing Through Elements to Create a Frame

This method is utilized by a lot of photographers. In my opinion, photographing through natural elements around you adds a little more surrealism to images. It often reminds me of a story of Little Red Riding Hood. As I used to follow a narrative of her in the woods while she picked berries and flowers, I often imagined leaves brushing against my face as I tried looking at her through a frame of lush greenery. This would give me a feeling of being there with her, through a tiny window of visual framing.

Decorating photos with frames like this is pretty easy. If you see tree branches around with enough opening to squeeze through with your lens, give it a shot! Play around with this method a bit to understand how it affects your images. When framing shots like this, you might want to experiment with different focal lengths, apertures, camera to subject distance and framing, since you will get different looks.

NIKON D3S + 50mm f/1.8 @ 50mm, ISO 200, 1/640, f/2.0

NIKON Df + 50mm f/1.8 @ 50mm, ISO 100, 1/500, f/2.5

Creating a Frame Within a Frame

Composing your shot so that you have a frame within a frame can also yield great results. You can create frames using doorways, windows, arches, mirrors and all kinds of other elements that can fit your subject(s). Such composition gives an an excellent opportunity to draw viewers’ attention to your subject(s), because it leads the eye in that particular direction. Using such framing elements also adds a sense of intrigue to images, making them appear much more interesting and engaging.

X-T1 + XF23mmF1.4 R @ 23mm, ISO 200, 1/180, f/1.4

NIKON D3S + 50mm f/1.8 @ 50mm, ISO 400, 1/160, f/2.5

NIKON Df + 50mm f/1.8 @ 50mm, ISO 500, 1/100, f/2.8

NIKON Df + 50mm f/1.8 @ 50mm, ISO 50, 1/200, f/2.8

Next time you go out shooting, give the above techniques a try and let us know what you think in the comments section below!

The post Framing Subjects with Natural Elements appeared first on Photography Life.

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Best multi-rotor drones for photographers

Multi-rotor drones are the latest imaging buzz, enabling photographers to capture stunning aerial scenes. We put four of the top models through their paces…

3DR Solo

www.3drobotics.com
£1,358/$ 1,399 inc gimbal
3D Robotics has taken multi- rotor design to another level with the Solo drone. The very sleek, no-fuss design has been refined for image capture rather than simply catering to the needs of the radio-controlled device enthusiast.

Auto-flight features include Cable Cam, Orbit and Follow Me, which are straightforward to set up through the free 3DR Solo app. All of these features enable you to capture the action without needing to control the craft manually.

The Solo is the only multi-rotor in this test group not to include a gimbal or camera in the box. Instead these need to be purchased in addition to the basic kit. The gimbal is also manufactured by 3D Robotics, and is designed to hold a GoPro Hero4 camera. The price we quote above includes the gimbal, but not the camera.

The Solo offers complete GoPro integration. Once the camera is mounted into the gimbal and the app, for iOS or Android, is loaded to your mobile device, you have fast access to flight features and camera and gimbal operation, as well as a Live View stream.

Video choices
As the Solo uses a Hero4, you have a huge array of video options, from 4K at 30fps to 1080p at 120fps. The Hero4’s image quality is excellent, but the camera suffers from pronounced fish-eye distortion.

The Solo costs more than the competition, especially once the essential extras are taken into account, but there is no arguing about the overall quality of this product, or with the ease of set-up and use. There’s also the significant advantage that its auto-flight features offer for capturing aerial imagery.

Score: 5/5

DJI Phantom 3 Professional

www.dji.com
£1,048/$ 1,163
DJI has a proven track record with multi-rotors and is the company that popularised the technology. The third generation of Phantom has refined the design, with the Professional model catering to those wanting to capture aerial footage and stills.

It features a 4K camera capable of 24fps PAL video capture, as well as plenty of other resolutions, including full 1080p at 60fps.

DJI has really worked on the ease of flight and usability of the camera. The DJI Go app, for both iOS and Android, has a clean design and enables quick control over the camera and gimbal, ensuring that you capture the shots you need.

The camera features a Sony Exmor 1/2.3-inch sensor. which captures scenes through the 94 degree or 20mm (35mm equivalent) lens; this offers less distortion than the lens in the Hero4.

Image quality is excellent, and video is bright and crisp, with little sign of significant flare. Noise is handled well, but becomes apparent when the light drops.

Easy to use
Control of the camera and gimbal is through either the mobile app or directly through the handset, which makes it exceptionally easy to use. Auto-flight features include Follow Me, Point of Interest and GPS Waypoint, which are all easy enough to programme and use through the app.

The Phantom is the most responsive multi-rotor of this group. It’s incredibly quick to manoeuvre, although this can be a good and a bad trait. For high-level imaging work, its speed enables the Professional to cover a great distance quickly. For low-level work, however, a little more flying skill is required.

Score: 4/5

Parrot Bebop 2 with Skycontroller

www.parrot.com
£749/$ 799
It would be easy to dismiss the Bebop 2 as just a toy, especially as it weighs so little at just 500g – comfortably the lightest in this test group.

However, the Skycontroller more than makes up for the Bebop 2’s small size: it’s almost twice the size of the controllers supplied with the other multi-rotors.

The Skycontroller is able to operate the Bebop 2 with or without a tablet, and extends the Wi-Fi range up to 2 kilometres (1.2 miles), subject to local regulations.

The Bebop 2 really shouldn’t be underestimated when it comes to speed and durability, though. Even when used in windy conditions, it is able to utilise its GPS features to hold its position well.

The Bebop 2 is the only multi-rotor design here not to rely on an external camera or gimbal: instead it incorporates the camera into the nose cone of the body. The camera is limited to Full HD 1080p at 30fps and has a 180° field of view from its f/2.3 lens.

Video and still quality don’t quite match that of the other three drone cameras on test here, but they have the convenience of three-axis image stabilisation and the ability to tilt the camera from the mobile app or controller.

Good for beginners
The auto-flight features in the Bebop 2 are incredibly well thought out, although you have to make an in-app purchase within the otherwise free-of-charge FreeFlight 3 app in order to plot auto-flight routes through GPS waypoints.

The Bebop 2 is a strong choice if you’re just starting out and need a durable, easy-to-fly drone. It supplies more than you’d expect for its small size.
Score: 3/5

Yuneec Typhoon Q500 4K

www.yuneec.com
£1,237/$ 1,299
Yuneec has a good standing in the enthusiast multi-rotor world. The quality of the company’s multi-rotors has recently been realised with its partnership with Manfrotto.

The Typhoon’s design reflects the hobbyist market in which this drone originated, with a sleek style resembling some type of spacecraft. The Typhoon also comes with more kit than any of the other drones on test here.

It arrives in a decent-quality metal flight case, along with two batteries, a handset with Live View display, a gimbal, a camera and, to top it off, a separate handheld gimbal for ground work.

The contents of the kit are very impressive, and the auto-flight features such as Auto Takeoff and Landing, Watch Me and Follow Me are all well-conceived.

The real winner for videographers, though, is the slow mode, which can be quickly selected directly on the handset. This mode slows the speed of the Typhoon down, enabling easy capture of panning and other usually tricky shots.

All-in-one solution
The image quality from the gimbal-mounted camera is excellent at 4K at 30fps in bright conditions, but unfortunately noise becomes increasingly apparent as the light dips. There are also some issues with image flare.

The CG03 camera features a 1/ 2.3-inch sensor and a lens with a 115° field of view at 14mm (35mm equivalent). The Yuneec Typhoon Q500 4K makes for a good all-in-one solution at an amazing price, considering everything you get; but compared with the others on test, it just isn’t quite as durable or refined.

Score: 3/5

What to look for in a multi-rotor drone

Without a licence from the Civil Aviation Authority, any drone you fly must be under 20kg, fully equipped. This limits you to a drone with a built-in camera or one that can hold a GoPro Hero camera. A video resolution of 1080p and stills capture of 12MP should be the minimum spec you look for. Essentials also include a motorised gimbal, a Live View feed and smart flight controls.

READ MORE

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Fotodiox introduces extra large WonderPana Free Arc system for Canon EF 11-24mm wide zoom

US accessory manufacturer Fotodiox has announced an XL version of its WonderPana Free Arc filter system for wide angle lenses that it says is designed specifically to allow users of the Canon EF 11-24mm F4L USM lens to use filters over the front element. The Canon super-wide zoom has no filter thread of its own and the front element is heavily convex, so fitting filters in the traditional way is impossible. The WonderPana Free Arc system positions a filter holder over the front of the lens that takes 186mm screw-in filters and/or 80mm rectangular filter sheets. The holder is enormous so that large filters can be used to avoid vignetting when the lens is used at its widest setting.

The Free Arc clamps the hood of the lens between its collar and the screw-on filter-holding cone, and provides a 186mm thread for the company’s screw-in filters. A set of brackets can also be attached to the cone that allow two square filters to be fitted as well. The system makes it possible to fit one round filter and one square filter at the same time, and the whole filter stage is rotatable so graduated filters can be positioned to suit the subject.

The Fotodiox WonderPana Free Arc XL costs $ 225.95 and the 183mm filters start at $ 99.95. For more information visit the Free Arc page on the Fotodiox website.

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Wide? Ultra-wide? WonderPana has you covered.

Ultra wide-angle lenses are typically impossible to filter due to their bulbous front lens element, lack of filter threads and potential for severe vignetting. The ALL NEWWonderPana FreeArc XL, however, is the latest in our line of aluminum filter collars that let you to attach our massive 186mm filter options, like ND 4-1000 and circular polarizers, to wide and ultra wide-angle lenses.

Perfect for landscape and architectural photographers and filmmakers, we designed the WonderPana FreeArc XL to suit Canon’s new breed of 11-24mm lens. Durable and lightweight enough for hand-held shooting, it can be ready at a moment’s notice to answer any image challenge that requires filters. You can even keep it installed on your lens as a critical layer of lens protection. Just check out our video below to learn more:

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