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Some Thoughts on Lenses: A Different Perspective?


I recently arrived at what I think is a worthwhile insight into the lenses I use. The material that follows should become instantly obvious once read, but the several photographers I discussed this with all commented that they had never thought of the matter that way and that it was worth some thought. Those comments inspired me to share my viewpoint here.

A lot of my shots are taken with relatively long focal lengths, typically from 60mm to 135mm on an APS-C camera. I have always tried to obtain maximum sharpness in my pictures, and whenever I evaluate a lens I pay particular attention to center sharpness. Up to a point, center sharpness is actually one of the easier goals of almost any lens design. That said, in testing perhaps a dozen different longer focal length lenses, two delivered outstanding central sharpness, another 4 or 5 good sharpness, and several were downright disappointing.

I came to realize that I use a longer lens because I am primarily interested in what lies in the center of the image. This seems likely to be true for most photographers. Such being the case, sharp resolution on axis of a longer lens is a very sensible desire and attribute. Also, many photographers using longer lenses are doing to so for enhanced bokeh and could care less if there is a resolution fall-off outside the portion of interest in the photograph.

Recognition of this led me then to consider then what would be the desirable characteristics of the so-called “normal” lens? Understanding that we live in an imperfect world and that super sharpness across the entire designed image field remains more of a desire than a reality, none the less we generally expect excellent center-weighted sharpness but still very good performance into the corners, and please, no vignetting, and little or no distortion. Generally, we also want a larger maximum aperture to give us more flexibility in different shooting situations.

Wide-angle lenses are where this gets interesting. We want such lenses to be inclusive! This is not a political statement in this case, but rather a selection criterion for making a shot. Almost always, we want a wide-angle lens to offer sharp definition into the corners of the picture, more so than we require of longer focal length lenses. Yes, we want good resolution at the center, but with wide-angle lenses we also need items in the corners to be sharp; otherwise, we would not select a lens that includes such elements.

Developing a good wide-angle lens is the most difficult assignment for prime lenses. While not desirable, barrel and pincushion distortions if reasonably controlled can be dealt with either in the camera or in post-processing. Vignetting is always a factor, especially at larger apertures, thanks to the geometry of wide-angle lens ray paths. And this is also true in holding sharpness into the corners. Most of these problems are reduced or eliminated at smaller apertures.

Better modern wide-angle lenses typically have many lens elements, usually including both aspheric and low dispersion components. Requirements for larger apertures magnify the design issues. These factors are the reason that many wide-angle lenses cost more than longer lenses. Producing a wide-angle lens for a mirrorless camera involves less compromise, thanks to the reduced flange distance having done away with the flipping mirror, and this factor is leading to improved designs.

For some static shots, a wide-angle photographic panorama can be achieved with multiple pictures, taken either handheld or with a tripod, and usually with a normal lens, then stitched together in post-processing. This technique can achieve superior results, but of course with a different aspect ratio if only one plane is used. Also, there is less of the geometric distortion that necessarily accompanies photos taken with extremely wide-angle lenses. But again, this technique only can be used for static shots. Good wide-angle lenses are still an important part of a photographer’s kit.

Thinking along these lines led me also to the following:

Some Self-Analysis

A useful exercise for any photographer is this: make a selection of perhaps 50 pictures that represent your better work. Now, sort them based on several different criteria. For one, what focal length was the lens used for the shot? Make a chart showing this.

Whatever the result, you should ask yourself if you are comfortable with the outcome. If you are, fine — consider any ways to optimize that focal length area. If you are not, and feel you are missing some aspect you want to improve, start using the lenses that cover the area of your perceived weakness more.

If most of your fifty pictures were taken outdoors, what time of day were these pictures taken? Log the times and the season, and again make a chart. And again, ask yourself some questions. Were your best pictures taken at a time of day when you usually are not shooting? Like maybe you should be getting out of bed earlier? Or maybe your best shots were in poor weather?

Another worthwhile exercise is to study each of these pictures, and ask yourself how you would change it if you had the chance to do it over? Write your answers down, then look at the answers for consistent patterns. Finding them is certain to give you direction on where you can improve.

This sort of analysis will better identify your strengths and weaknesses, and evaluate them. Then decide: should you work to polish your strengths? Or strengthen your weaknesses? Or both? You may very well not be bothered at all about your weaknesses, considering them to be in areas you have no real interest in improvement. No problem — in that case go with what you are good at and work to improve yourself.

Hopefully, the above thoughts will lead you to a better understanding of your own work, and to improve on it, whether you are a professional or an amateur. Have fun!

About the author: Bob Locher certainly makes no claim to being a great photographer; rather, he considers himself to not be a very good one. He is not much of a speaker either, and does not have his own YouTube Channel, nor does he do Photographic Tours. But, he has been in the photographic hardware industry most of his life, fancies himself as something of a writer, has opinions and is not afraid to express them. He loves photography, values technical quality and is indeed a pixel-peeper. The opinions expressed in this article are solely those of the author. Locher has written over 50 magazine articles as well as two books. You can find more of his work and writing on his website.