Diseases That Plague Photographers

Photography is an art meant to invigorate our creative side and facilitate our ability to see our world in new and interesting ways. Many books, articles, tutorials, and blogs focus on various aspects of the artistic and technical merits of photography. Rarely discussed, however, are some of the strange maladies that afflict photographers. There are the occasional whispers and, “Did you hear about Joe?” types of exchanges, but all too often, such problems are rarely acknowledged and dealt with openly.

In an effort to bring such diseases to light, Dr. E.X. Posur, a leading psychiatrist that specializes in treating photographers, highlights a number of common illnesses he has encountered, and their associated symptoms and treatment. Although described individually, they are all part of a common illness labeled “photographus excessivitis”. Rarely will a photographer exhibit symptoms a single disease. Close examination almost always reveals multiple afflictions.

Diseases that plague photographers

It is important to point out that professional photographers rarely deal with these illnesses, but those that wear the label, “serious amateur” bear the brunt of these diseases. Because professionals have been inoculated by the need to earn a living, they seem to have built up a strong immunity to the diseases outlined in this article. Though they appreciate the merits of their equipment, professional photographers see their equipment as tools to achieve an end, not an end unto itself. This subtle, but critical, difference between the professional and the serious amateur prevents the former from acquiring many of illnesses outlined below. Professionals are not totally immune, however, and can succumb as quickly as any serious amateur if they are not careful.

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Photographing What You Love

Eyes wide open! ©B.S. Yesterday, I spent some time looking at the infamous “Stages of a photographer” chart again. The graph starts out with a blue line – the one that marks “How good you think you are” – at the top of the scale. It mentions that the photographer, at an early stage of his/her photography career shoots mostly flowers and cats (or anything else that’s pretty, cute or more or less easily accessible). The green line marks the actual quality of the photos, which is at the very bottom of the chart. It all makes sense – at one point, we all thought our work was, well, pretty.

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Tips on Photographing Wedding Formals and Group Portraits

Photographing formals during weddings can be very tiresome and stressful to all parties involved. It’s the part of the day both the guests and the photographer often want to get past as quickly as possible. Friends and family want to enjoy the cocktail with others. Bride and Groom are tired from standing far too long and a looking forward to get some rest before the reception. Could anyone blame them?

Family Portrait

On some occasions, I have been even asked to skip the formals in hopes of avoiding guests from stress and chaos, which sometimes can happen during the formal session. While not everyone might enjoy this experience, it is also understood that taking formal pictures is an essential part of wedding photography. This is how the memories are preserved. This is a precious way for a bride to remember her family for many, many years to come; in her happy state. So, the challenge remains for the photographer to make sure that the time allocated for the formal portraits is spent efficiently and as quickly as possible. In the eyes of the wedding guests, a photographer is a miracle worker, control freak and a very sweet person who can turn a very difficult session into something magical. So, my dear magician friends, let’s get on to it. You are the expert and what do you do next?

There are steps you can take to achieve your goal and have everyone happy on your watch. Your first step would be to make sure that the watch doesn’t go over 30 minutes for any formal session.

Bride with her mom

1. Talk to the bride and groom before the wedding. Do your research and get to know your subjects earlier. Let’s admit that there is no way for you to get to know so many people at once. So, start early and talk it up with the bride and groom during the consultation session. Find out what their expectations are towards the formal portraits and how many people might participate in those. Sometimes it is easier to get a list of the family members who ought to be photographed alongside the bride and the groom. Ask the bride to inform her relatives that there will be a point during the wedding (if the exact timing is known, that would be more helpful) when they will be asked to get photographed. Keeping everyone informed will help you gather people around efficiently. Always make sure to ask the couple if there is anything you need to know about their families and have a strategy worked out to take care of any potential problems.

Usually, close family make it obvious for you to notice them. Walk around them, be a regular guest and interact with them before the formals, so that you are “familiar” to them. Let the guests talk and meet and have fun while you steal a few of them to get photographed. This way, everyone can be engaged all the time by either you or by other guests. It will only help you get those sincere emotions naturally, with much ease.

Also, keep in mind that you do not have to fit every single guest into a formal session. Friends and distant family members can be photographed all along the wedding reception and cocktail hour.

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Don’t Get Stuck with Your Gear – Pursue Your Passion

A lot has changed since digital came around in 1999. Film has always been about quality – all kinds of it, too. It was about resolving power – we have Fujichrome Velvia for that now; it was about color accuracy, which also suits the former as well as, say, Fujicolor Superia Reala; or, for those who want sharp and vivid, there‘s always the beautiful Kodak Ektar. Now, however, there’s one kind of film for all those purposes. Just as film was finally providing the quality, the age of digital sensors came. And, some think, wiped film‘s quality ambitions off the table as if it were dust. We now have one film that can do everything – low light, color accuracy or vividness, sharpness and endless manipulation possibilities. One film that fits all.

Engagement session

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Defining Photography

Once, I came upon a thought provoking comment on some local online photography community in Lithuania. It was posted under an apparently heavily, yet skillfully manipulated image, and in fact it was done so well that, at first glance, it was rather hard to believe it was a manipulation. The text was posted by an elderly photographer who is known to write very argument-rich comments under many works on that particular website. From what I’ve noticed before, he was usually intrigued by a lot of different images in different styles made by different photographers and he seemed to be very objective with his evaluation, if slightly conservative with his approach to photography as a form of art and expression. Still, given his age, experience and especially taking into account post-soviet influence in understanding of what art is, it was only natural. However, this time the respected online critic (as strange as it may sound to some) was strongly bewildered by the author’s approach to photography and how much digital manipulation (Photoshop in particular) was part of the work. “Where does photography end and digital art begin?”, he wondered. I wondered too.

Manipulation Example

It seems the understanding of what photography is (and art photography in particular) has changed during the last few years. Few? It’s a been over a decade now since we had the launch of Nikon D1, a camera seen by many as the first big step towards the revolution brought by DSLRs. Not only was it usable and offered decent at the time resolution, it was quick and as robust as the film SLR it was largely based on, the Nikon F5. And artists – not only photographers, but all kinds – must have burst with excitement. “New ways to express ourselves”, they’d think. The beginning of the real, readily available digital imaging offered artists new ways to deceive, and trick, and provoke the viewer.

I’m an artist. At least I should be – I study at the faculty of arts, and not the kind you would think of first. We, sadly, don’t talk much about Henri Cartier-Bresson, Ansel Adams or Salvador Dali – they are too ordinary, as funny as it may sound. Too known. Too legendary and too classic. We do talk about the likes of Leigh Bowery and Marina Abramović, who, while just as known to some, are much less acceptable, at least in a country as conservative as Lithuania. And so it is good – we are taught to be less conservative, to evaluate not purely with emotions, but with our minds. To try and understand before becoming judgmental. We are taught to expand our understanding of art. Not to necessarily like, no – this remains our freedom, but to understand why artists do what they do even when it seems to be the strangest and silliest thing in the world.

And then there are lines that, not so long ago by some standards, were not to be crossed. They defined where photography ends and, for example, videography begins. But now, now we have sculpture, but also installations. Now we have theaters and video art, but also performances and video performances. We have conceptual art and art that has yet to be named and defined only to lose the definition in a year, or five, or ten. What does Vik Muniz do? Is he a sculpturer, or a master of installations, or a photographer, or a painter? He’s everything.

And we crossed the lines. Art is becoming just that, art. It’s harder and harder, sometimes, to define it and frame it. But the process of evaluation is no easier because of this, and harder still. Where does photography end? I believe it’s hard to compare such different things. A portrait made by Irving Penn can hardly be compared to a modern photographic manipulation, even though they are or can be both great works. It’s also hard to compare Irving Penn to someone like, say, Magda Berny, although they both do portraits. Too different. Both good, yet different in their purposes and thus incomparable. As long as we keep that in mind and accept photography as a way (or part of it, however small or big) to express ourselves, we should have no problems evaluating different works differently.

Keep an open mind, they teach us at the University. It’s what we all should try to do.

A Window of Opportunity

When photographing various places and landscapes, I sometimes make a note of a location or a spot that I particularly like, so that I could come back and take pictures later. Often times you will find a really beautiful scene, but poor lighting conditions, bad timing, lack of proper equipment or other circumstances might prevent you from capturing the perfect shot. There are numerous locations that I saved as my “favorites”, which I try to go back to and recapture when I have a chance. Sometimes I come back with nothing, other times I might get lucky and come back with a picture I actually like. I might even visit the same place in different seasons to get a completely new look, like in this set of pictures.

Here is a picture of a cool-looking entrance at Castillo de San Cristóbal that I photographed in 2010:

Castillo de San Cristóbal - 2010

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How to Avoid Moiré

In this quick article, I will talk about how to avoid moiré if your camera is not equipped with a low-pass / anti-aliasing filter, or if it has a special low-pass filter like the Nikon D800E that is also prone to moire. Moiré can be quite painful to deal with in post-processing, so it is best to avoid it in first place. Below you will find a list of steps you can take to avoid moiré while shooting patterns.

  1. Analyze patterns in your images on your camera’s LCD at 100% view – while looking at your images on the camera LCD at 100% view can be very inefficient and time-consuming (especially on the Nikon D800E with its massive 36.3 megapixel images), if you are shooting anything with repeating patterns, you need to know whether there is moiré in your images or not. Looking at the thumbnail on the LCD might not reveal moiré, so you will have to zoom in to see it. Very strong / nasty moiré might be visible even at 50% view or less, while you will only spot mild moiré at 100% pixel level view. If you see moiré and want to avoid it, proceed to step #2 below.
    Quick useful tip: if you own an advanced Nikon DSLR like Nikon D300s or higher, you can set the multi-selector center button on the back of the camera to instantly show 100% view without having to press the zoom button several times. You have to enable this feature here: Custom Settings Menu->Controls->Multi selector center button->Playback mode->Zoom on/off->High magnification. Once set, you will be able to zoom in to your images at 100% by simply pressing this button in playback mode.
  2. Change camera to subject distance or adjust focal length – if moiré is visible in your image, the best thing you can do is change the distance to your subject. You can either physically move closer or away from your subject, or you can zoom in/out with your lens. Remember, moiré only happens when the pattern you are photographing exceeds sensor resolution, so all you have to do is move to a safer distance. Sometimes this means moving just inches away from your subject.
  3. Adjust focus to a different area – while this is not always practical, adjusting the focus a little away from the patterns will remove moiré.
  4. Change the angle of the camera – simply changing the angle of the camera a little can completely eliminate even very strong moiré patterns.
  5. Stop down the lens to f/11-f/16 – when lenses are stopped down beyond a certain aperture (depending on the lens and the sensor size), an optical phenomenon known as “diffraction” kicks in. Diffraction effectively reduces resolution, which also eliminates moiré. While I would personally avoid doing this, if you cannot change your subject to camera distance or adjust your focal length for whatever reason, this technique surely works.

If you did not do any of the above and ended up with an image that has visible moiré, then your only option is to try to fix it in post-processing.

Why Downsampling an Image Reduces Noise

One of our readers, Mike Baker, sent the below email to me today. I thought it was a great and interesting analysis of why downsampling an an image reduces noise, so I decided to share it with you (with his permission, of course). Trying to digest this stuff makes my head spin, but it is a great read. You might need to read it several times to understand what he means, especially with all the mathematical formulas (I had to):

You recently commented about downsizing a high-resolution image to a lower-resolution in order to reduce the apparent noise. While I knew that this is an effective way to reduce noise visible in the images, I had not thought in much detail about the technical reasons why this works.

After a long evening’s thought on the subject, and running a few questions past my friend and fellow engineer, I believe I have a (reasonable, though perhaps not perfect!) handle on the subject…

If the image signal and the image noise had similar properties, averaging neighboring pixels in order to reduce the resolution would not improve the signal-to-noise ratio. However, signal and noise have different properties.

There is (in general) no relationship between the noise in neighboring pixels. Technical junkies call this “no correlation”.

Correlation is the long-term average of the product of two signals N1 x N2. If two signals have no correlation, then the mean of their product is zero.

The signal in neighboring pixels has a high degree of correlation. If you add uncorrelated signals, then their “power” is added, meaning the combined signal is the square root of the combined power.

N_comb = sqrt(N1^2+N2^2) and for N1 = N2 = N we get N_comb = sqrt(2)*N, where N1, N2 are root-mean-square (RMS) values of the noise.

However, if signals are highly correlated, then their sum is effectively the sum of their magnitudes:

S_comb = S1+S2 and for S1=S2=S we get S_comb = 2*S

So, if we add the content of two neighboring pixels, we get:

SNR_comb = S_comb/N_comb = sqrt(2)*(S/N)

So, the signal-to-noise increases by square root of two, which is about 40%.

Now, you may say that the signal in neighboring pixels is not always 100% correlated. The correlation between the signals depends on the image content. If the image content is very smooth, the correlation is high. If the image content varies very fast, the correlation is low. Of course, noise will be more noticeable in smooth areas and the effect of resampling the image will be stronger.

Adaptive noise filters take into account the absolute signal-to-noise and the image content. They reduce the resolution more in areas that are smooth and have poor signal-to-noise and keep the original resolution in areas that have strongly varying image content and high signal-to-noise. You can think of it as a joint optimization of SNR and resolution.

Now, we also need to look into the different sources of noise:

  1. The first source of noise is dark current which is caused by electrons that accumulate in the individual pixel well, even if there are no photons entering (lens cover on). Dark current becomes dominant for very long exposures. For normal exposures the errors from trapped electrons are negligible.
  2. The second source of noise is the read-out noise. This is essentially generated by two sources: A) Noise added by the amplifier and B) Noise generated by the analog-to-digital converter. It is a fixed amount of noise that is added to each image during read-out. When you choose the ISO setting on your camera, you essentially set the read-out gain and therefore the read-out noise. The higher the ISO, the higher the read-out gain and the less read-out noise. Of course if you pick an ISO which is too high you will get signal saturation. So for low-light situations always pick an ISO that is no higher than needed to capture the image you want.
  3. The third source of noise is called “quantization noise” and is a bit harder to understand. It has to do with the fact that (in low-light conditions) we don’t sample a smooth, continuous flow of photons but rather discrete bunches of photons. The problem is, that a source of light does not produce a stream of photons that are spaced equally in time. So, if you image a low light source that sends out (on average) 100 photons per second, you may receive 90 photons for the first second, 105 for the second etc.. The average error will be on the order of the square-root of the number of photons (or electrons in the pixel sensor well). A typical sensor well contains between 20,000 and 60,000 electrons when fully charged. The maximum amount depends on the pixel size. A sensor well with 20,000 electrons has an error of approx +/-141 electrons when fully charged or +/-0.7%. A well with 60,000 electrons has an error of approx +/-245 electrons when fully charged or +/-0.4%. While we may be able to reduce dark current and read-out noise by cooling the sensor, there is essentially nothing we can do about it. If we keep on shrinking the pixels, we will have smaller and smaller electron wells and less and less electrons trapped.

    The above errors of 0.7% or 0.4% appear rather small and we would not be able to notice them. However, in low-light situations, sensor wells will be only partially filled. If we only manage to trap 1000 electrons, the error becomes 3%. If we only trap 100 electrons, the error becomes 10%.

    Notice that the term “quantization noise” has nothing to do with the signal quantization by the analog-to-digital converter. It has to do with the fact that your signal actually arrives in quantums of energy.

What do you guys think? Anyone wants to challenge Mike’s analysis? :)

What is Moiré?

Moiré pattern occurs when a scene or an object that is being photographed contains repetitive details (such as lines, dots, etc) that exceed the sensor resolution. As a result, the camera produces a strange-looking wavy pattern as seen below:

Moiré

(Image courtesy of photo.net)

See how noticeable the moiré pattern is on the jacket? That’s moiré for you, at its worst. Moiré is almost never seen in nature, but is very common in everyday objects and items around us – you might see it in all kinds of fabric, straight hair, architecture, etc. You might have even seen it on your television. In photography, moiré happens mostly because of the way light reaches the sensor and how the sensor interprets the light through the bayer interpolation filter.

While there are methods to effectively reduce moiré, there is no easy way to completely remove it in post-processing software. Lightroom 4 will ship with a moiré reduction tool and Nikon will also ship its next version of Capture NX with built-in moiré reduction functionality, but neither one will be able to fully get rid of the worst moiré pattern occurrences.

Here is a comparison between the Nikon D800 and D800E (the latter is prone to moire), which clearly shows Moiré on the Nikon D800E (Image courtesy of Nikon):
Nikon D800 vs D800E Moire

See “How to Avoid Moiré

Case Study: Skin Color Problems

Another case study was submitted on Nikon D7000′s handling of colors. Here is what our reader writes:

Hello Nasim, 2 months ago I bought my first Nikon camera – D7000. I’ve read much about it and decided that this is best camera for me, but recently I am noticing that in certain lighting conditions colors are inadequate. There is an awfull yellow-green color, especially noticeable on people’s faces. Skin on pictures is also has strange color. Changing wb temperature is hardly helping. As an owner of the D7000 could you tell me if this is the problem of all D7000 cameras or is it malfunction of mine? What can i do to fix this?

And here is a sample image that was attached to the case study:
Skin Color Problem

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