Those of us who are interested in photography hear a lot of talk about sharpness so perhaps some discussion of it is appropriate. My first camera was a plastic box that held a roll of 127 film. It had a rotating blade with a hole of some type in it that allowed light to pass through when a small lever was pushed. The lens? Well, I don’t know about it, but it directed light onto the film to create an image. After the film was developed it was possible to see objects in the photos. As a result of experience with that primitive camera, I was astonished at how much better my second camera was. That Kodak Pony 828 did quite well if I estimated distance carefully.
Sharpness of a lens is sometimes given quantitatively in terms of the ability to resolve closely spaced lines on a grid or test target. However, lenses that have maximum apertures of f1.4, 2.0, etc. are almost always sharper when stopped down to f 5.6 or 8. Moreover, most lenses give sharper images in the middle of the field of coverage rather than in the edges and corners. In most practical photography such deficiencies have no discernable effect on the overall picture quality.
It is a mistake to assume that one needs to have recently produced lenses to have excellent photos or that lenses on vintage cameras are not capable of producing excellent photos. It is also a mistake to assume that one must have a medium or large format camera to produce excellent photos. Although resolving closely spaced lines on a surface provides one test of sharpness, most photographs are of subjects such as people, buildings, trees, water, mountains, etc. As a result, other factors are important in lens performance. Contrast, color rendition, and appearance of areas that are out of focus in the photos have a bearing on the performance of the lens. Consequently, a lens that does not have stellar resolving power in terms of resolving closely spaced lines may be perfectly acceptable for general photography. All of these issues are related to lens design and construction.
When a photograph is produced from a negative the photo is almost always enlarged to produce a photo that is larger than the image on the negative. Therefore, the extent of enlargement will affect the apparent sharpness of the photo. Although most lenses of good quality may resolve a similar number of closely spaced lines, a larger negative should result in a sharper image. Most medium format cameras that produce 6X6 cm or 6X7 cm negatives on 120 film will yield sharper images that those produced by 35mm cameras. Similarly, most 35mm cameras should produce sharper photos than do those that use 110 film. Superimposed on all of this is the requirement that the camera is motionless during the exposure. The following graphic illustrates the performance of a lens from the 1950s.
Although the foregoing statements are generally true, do not assume that the smaller formats cannot yield excellent results. It is believed by some that 110 cameras that give 13X17mm negatives must of necessity produce fuzzy photos. Such generalizations give the perception that 110 cameras are toys and, in fact, some may be. However, the better 110 cameras have excellent lenses that can be focused precisely. Quite good photos measuring 8X10 or even 11X14 inches can be produced by 110 cameras. In such cases, the photo may reveal a grainy character, but that is also related to the type of film, processing conditions, etc. Consider these images.
Do not give up on an older camera or one that uses 110 film without some testing. Ken Rockwell is a well-known evaluator of photographic equipment and he has this to say on the subject of sharpness.
“Sharpness is the most overrated aspect of lens performance.”
In another essay written in 2008, Rockwell had this to say.
“In 2008, sharpness is the last thing about which you need to worry when selecting a lens. Even the cheapest SLR and compact cameras lenses are sharper than expensive lenses used to be, and all are sharper than most digital camera’s ability to resolve fine details.”
My thoughts on the subject can be summarized simply as do not think that -you must have-recently designed equipment and strive for perfection. Enjoy taking photos and make memories while striving to make photographs that have greater interest and messages.
-Jim House
