Category Archives: Technique

Reader Question: About Depth of Field

Lupine, Upper Sabrina Basin
Lupine, Upper Sabrina Basin

I recently received an email from David, who has some questions about depth of field:

As you have a lot of experience of using the Fuji X-E1, may I please ask you for some advice regarding landscape focusing.

My aim is to use the 18-55mm kit lens with the majority of shots taken at the widest end. I have in mind setting the lens at Hyperfocal distances, based on a crop factor of 1.5 and a circle of confusion of 0.02. I think the first figure is reliable, but I’m not sure about the second in relation to the X-E1 – perhaps you could confirm.

I have already done some testing at home using the attached table (which come from the well respected DOFmaster site).

In my experiment I carefully measured distances at apertures of f8 and f11 using a tripod and a printed card as the subject. I set the lens manually at the hyperfocal distance, using the EVF distance scale. I was disappointed to find that the closest point of focus was not as sharp as I had hoped. Have you any idea why this may be?

I did a further test on aperture f11 and this time set the distance scale at 4 feet (2/3 of the way between 3 and 5 feet). This resulted in a sharp image from 3.5 feet. This would suggest that the distance scale is not accurate.

Any suggestions you have to overcome the problem would be much appreciated.

Let me preface my response on the depth of field (DOF) issue by congratulating you for taking the time to conduct your own experiments. One of the great things about digital cameras is that we don’t have to trust what we read — we can easily and quickly conduct the experiments ourselves. In addition to getting the answer to the question at hand, we end up knowing our gear at a much deeper and even intuitive level, which is extremely important when we are in the field and we don’t have time to ponder and calculate, but must instead make a photograph in the moment.

The rest of this post is going to be somewhat involved, so let me share a quick thought right at the beginning:

The usefulness of DOF calculators is very limited, as they are based on subjective assumptions that may not match what you are doing with your photographs. The best way to align your expectations with exposure choices is to test them yourself and evaluate images in the form that you most often produce — and not just at 100% magnification on a computer screen.

What is DOF? Essentially the depth of field is the distance range in front of and behind (unless you focus at infinity) the focus point within which subjects are likely to sharp enough to seem in focus when the photograph is viewed at some arbitrary magnification. This size of this range increases as we stop down (for example, going from f/2.8 to f/8 expands the DOF) and decreases as we open the aperture (going from f/8 to f/2.8 contracts DOF). This is a source of creative control for the photographer. A smaller aperture can allow subjects across a greater distance range to appear relatively sharp, while a larger aperture can keep the primary subject in focus while pleasingly “un-focusing” elements in front of and behind the primary focus point. Continue reading Reader Question: About Depth of Field

Lenses for Landscape Photography (Morning Musings 1/12/15)

This isn’t exactly a regular “morning musings” post, but I wanted to share this stuff and it seemed like a good pretext! This post concerns two related articles at the website:

From time to time I share new posts in my “Photographic Myths and Platitudes” series. These articles deal with common ideas about photography that range from “open to question” to quite wrong. I try to look at these issues from a perspective that is both objective and based on actual photographic practice.

I wrote the first of these two articles about lenses for DSLR landscape photography back in 2010 after reading one too many claims that wide-angle lenses are landscape lenses and that longer focal lengths are not good ‘landscape lenses.’  It shouldn’t be a surprise that I disagree. The first article goes over reasons to consider a wide range of focal lengths for photographing landscape.

When I wrote that first article I realized that there was another notion about landscape photography that needed a closer look, a belief that prime lenses are better than zoom lenses for landscape photography. This long-cherished idea probably has its roots back in an earlier period of photography when all photography (not to mention all landscape photography) was done with prime lenses, and in a somewhat later period when early zoom lenses had some serious shortcomings. But things are a lot different today, and most of the excellent contemporary DSLR (and a great deal of medium format) landscape photography that you see and enjoy today was done with zoom lenses.

Knowing what a sensitive issue this is for some photographers, I delayed writing part II for over four years! I’ll acknowledge in advance that there are some reasons to shoot landscape subjects with non-zoom lenses, and that my perspective is not The Truth about landscape photography lenses. However, I’m certain that the majority of landscape photographers will be best served by today’s excellent zoom lenses.

In any case, part II deals with this issue, and it is available now. I hope you’ll enjoy it and perhaps learn something new.

Morning Musings are somewhat irregular posts in which I write about whatever is on my mind at the moment. Connections to photography may be tenuous at times!


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.

A Bit More on Aperture Selection (Morning Musing for 8/23/14)

(Thanks to a reader who posted a follow up comment on an earlier post — “Making Aperture Selection Easy (Morning Musing for 8/22/14)” — I wrote up a response with a quick explanation of why you might want to be careful about stopping down too far if you are trying to maximize image sharpness. I think it might be useful information for others, too, so I’m sharing it here as a new post.)

Aperture selection, among other things, allows us to control depth of field (DOF)— the range of distances in front of and behind (if not focused on infinity) the subject that is the center of the plane of focus. By choosing larger apertures (such as f/1.4) we narrow the DOF and can throw elements beyond or in front of the main subject out of focus, making them soft and diffused. Choosing smaller apertures (such as f/16) will increase the DOF, and subjects further behind or in front of the primary subject will be much sharper.

Some photographers make a logical leap from “increasing DOF with small apertures makes more things in the frame look sharp” to “smaller apertures are sharper.” It doesn’t actually work quite that way! Continue reading A Bit More on Aperture Selection (Morning Musing for 8/23/14)

Making Aperture Selection Easy (Morning Musing for 8/22/14)

From time to time I see questions from photographers trying to figure out exactly which aperture is the “right” one for a particular photograph. Some will go so far as to consult depth of field calculators (or “DOF calculators”) to help them decide whether the should open up a third of a stop from f/11.

There may be times where that sort of precision aperture selection is useful, but in many cases you can make things a lot simpler*, basically selecting from one of three general options:

  1. If depth of field isn’t a big issue — let’s say you are shooting a relatively flat subject — simply use a “middle of the road” aperture that will be sharp on your lens/camera combination. The old rule of thumb about using f/8 is a decent one to follow here, although cropped sensor shooters might go for something more like f/5.6.
  2. If you need very deep depth of field, go straight to the smallest aperture you feel comfortable using. On a full frame camera this is likely to be about f/16, while on a cropped sensor camera it might be a bit larger, perhaps in the f/11 or so range. If your need for extra deep depth of field is strong enough that you are willing to give up a small degree of overall image sharpness — which will be invisible in small images anyway —  you might even go one stop smaller on some occasions to f/22 on full frame and f/16 on crop.
  3. If you need to limit depth of field to throw background elements out of focus, simply try the largest aperture that your lens has — but consider stopping down just a bit if you need just a bit more depth of field.

Basically, for most photographs, especially if you have good light and/or are using a tripod, you could probably get away with considering only three apertures in most cases — the “normal” one, the really small one, and the really big one.

  • Yes, this is a bit of a simplification, though it really does work in the vast majority of the photographs that most people are making. Clearly things can get a bit more complicated if you are, for example, shooting in very low light or need to deal with moving subjects. In the interest of keeping this “Easy” description easy, I’ll simply acknowledge those possibilities here without elaborating.

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.
Blog | About | Flickr | Twitter | FacebookGoogle+ | 500px.com | LinkedIn | Email

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.