Tag Archives: Technique

Technique

Sharpening Basics: A Primer

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(Minor updates to this article were made in February 2019.)

Sharpening is a very important step for optimizing digital photograph files. If you let your camera save images in the common .jpg format (a compressed image format that is often used on the web) the camera is applying sharpening to the image produced by the camera sensor. If you use the raw format (a high quality format that retains the original sensor data of the exposure) you will find that the photograph looks soft until you apply sharpening during the post production phase.

Sharpening optimizes the visibility of details that are already in your photograph. It is a matter of more clearly revealing what is in the photograph than  a matter of creating detail where there was none. Most sharpening works by increasing the contrast between light and dark areas in the image — what we call sharpening as actually more about adjusting the relative brightness of adjacent portions of the photograph.

Typical sharpening

The image above is an example of a small section of a photograph.[1] It is a “100% magnification crop” of a tiny area from a much larger photograph made with a high megapixel DSLR camera. A “100% magnification crop” is an image displayed so that each pixel — or individual picture element — of the original photograph is displayed using a single pixel on the screen. (Things are a bit more complicated than that when using modern high-resolution monitors, though I’ll let that description stand for now.) 100% magnification crops let us look very closely at what is going on in photographas “at the pixel level.” In this case, the full original image from which these small examples were extracted would be equivalent to prints at a width of roughly 10-12 feet.

The right side of the example shows this tiny section of the photograph before sharpening. The left side shows the results of fairly typical sharpening. Continue reading Sharpening Basics: A Primer →

Morning Musings

Digital Exposure: Some Basic Rules (Morning Musings 1/10/15)

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Earlier this week I read Alan Ross’s fine article about the zone system and the possibility of adapting it for use with digital photography. (“Can the Zone System Go Digital“) It is a fine summary of some very important principles of exposure, and it is one of the most straightforward and readable explanations of the basics concepts of zone system exposure I’ve seen. It also offers a useful way to apply zone system principles to shooting with digital cameras.

Shoreline Reflections, Tenaya Lake
Shoreline Reflections, Tenaya Lake

I don’t use the zone system, but I do expose in ways that often have the same goals, especially when faced with subjects that have a very wide dynamic range (risking a loss of shadow and/or highlight detail) or, oddly, a very narrow dynamic range (where metering systems can try to turn everything neutral gray.) As I read his article I thought it might be fun to try to distill some of my basic principles for exposure down to a very short list. Here it is:

  • Protect the highlights! — Overexposed highlights and bright areas can completely lose detail if they are overexposed with digital photography, and these details may not be recoverable in post.
  • Watch out for dark tones that are too dark — If dark tones go too dark, they may need to be pulled back up in post, and noise, banding, and other artifacts can be the result of radical lightening of dark areas.
  • Consider the most important values in the scene, and adjust exposure to favor them — You may want to compensate for the camera’s tendency to want to make black and white tones end up gray in narrow dynamic range photographs
  • If important, subtle tonal variations are found in the shadows or in the highlights, consider offsetting exposure to protect them — You may want to underexpose just a bit to retain differences among tones in the bright areas. If there are a lot of important details in very dark shadows, you may wish to overexpose a bit.
  • Use the danged histogram — The RGB histogram display quickly tells you a lot of important things about your exposure.
  • Use the camera as the meter — Go ahead and make an exposure to test your settings. While there is a certain historical macho that says you should get it right in a single exposure, or that you should use a handheld meter, modern digital cameras can provide just as much information as external meters.
  • Don’t be afraid to bracket — Sometimes it is simply faster to make several bracketed exposures rather than to figure out one “perfect” one. That may sound like a photographic blasphemy to some… but it works!

Do you have other basic exposure rules that can be applied in a general way?

G Dan Mitchell is a California photographer and visual opportunist whose subjects include the Pacific coast, redwood forests, central California oak/grasslands, the Sierra Nevada, California deserts, urban landscapes, night photography, and more.
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Text, photographs, and other media are © Copyright G Dan Mitchell (or others when indicated) and are not in the public domain and may not be used on websites, blogs, or in other media without advance permission from G Dan Mitchell.

Morning Musings

Testing? Testing? (Morning Musings 12/8/14)

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Aperture Test Image
Aperture Test Image (1)

This morning I saw an article over at The Online Photographer (which you should be following) about a particular camera/lens combination and the process of doing a quick and informal test of that gear… right there in the kitchen.

I read a lot of photography questions about how this or that thing works, which setting is “best” for a particular result, what shutter speed range works for hand-held photography, how much the shadows can be pushed, whether a lens is sharp enough for some particular usage, and much more. Folks are often looking for quick answers — and who wouldn’t in most cases. However, the quick answers often turn out to be less clear than they might like, and sometimes the simplest questions can end up in controversy.

A simple answer is to simply try it out yourself!

The answers to many of the questions that we ask are too complex to lend themselves to absolute answers. Yet, we can often get a very good and quite accurate feeling for these things by just giving them a try. In some cases the “testing” can be very informal, while in others it might require just a bit more care and organization. But in our modern photographic world of digital cameras and computer post-processing and display the testing is much easier than it might have been in the past, and it is well within our grasp to do it ourselves.

I recall one of the first times I put this to good use with a digital camera. Continue reading Testing? Testing? (Morning Musings 12/8/14) →

Equipment, Morning Musings

About Tripods (Morning Musings 11/4/14)

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Friends photographing in Utah's red rock landscape
Friends photographing in Utah’s red rock landscape

Morning Musings are back! Today I have a few general thoughts about tripods — not aimed at those who are already confirmed tripod users, but rather at those who find it hard to bother using them.

To start, let’s admit that one does not always need a tripod. For certain types of photography in which quick response is required and in which being too obviously a photographer can interfere with photographs, it is usually better to not use one. There are exceptions to every rule, but you are unlikely to want to use one for most street photography, for personal and family photography at home and on vacations, for certain kinds of portrait work, casual travel photography, and so on.

Let’s also agree that using a tripod is a burden, especially at first when one hasn’t accepted the extra trouble and when you haven’t yet developed instincts that make tripod use a lot more automatic before long. I’ll readily admit to being less than thrilled on about the 50th time that I must remove my tripod from the car, extend and lock the legs, level the thing, attach the camera, and only then make a photograph… after which I have to reverse the process: remove the camera, collapse the tripod legs, stow the thing once again. The slightly put-upon feeling diminishes as you get used to it, but it perhaps never goes away entirely. (The good news here is that the process of setting up and using the tripod does eventually become much quicker and much more automatic than it first seems.)

So, why use it then? There are more reasons than you might imagine.

Stability is an obvious advantage of the tripod. While you can, with care and practice, often hold a camera quite steadily and produce very sharp images when shooting handheld, you simply cannot eliminate all of the blur that comes when you hold the camera in your hands. And if you do happen to have very steady hands, you still will make mistakes that produce blur — working a bit too fast you may introduce a bit of camera vibration in some shots and you will reduce the number of successful results. A good tripod used correctly can virtually eliminate all camera motion and vibration in most cases. This is especially important when doing some kinds of photography that intrinsically require longer shutter speeds. This obviously includes night photography. Low light, low ISO, long lenses, and small apertures often require landscape photographers to use rather long shutter speeds. Continue reading About Tripods (Morning Musings 11/4/14) →