I found this on the internet. So is that why my photographs seem so plane?

Optimum Aperture

The ability of a lens to reproduce fine detail in a subject is sometimes referred to as its resolving power and in subjective terms its "sharpness". If one is after the "sharpest" reproduction of a particular subject plane, it is advisable to not stop the lens down too far because resolution of a lens decreases with decreasing apertures due to diffraction.

This fact was treated by Lord Rayleigh in the late 1800's. When a lens is delivering the theoretically sharpest possible image (at whatever aperture) this is an indication that the lens is operating at the Rayleigh limit. In most camera lenses the condition of sharpest performance is _about_ 2 to 3 stops smaller than maximum aperture. Assuming an f/1.4 lens this means that the aperture to use to achieve the highest possible resolution is about f/4. In enlarger lenses it is closer to 1 to 2 stops smaller than maximum.

When a smaller aperture is used resolution suffers due to the effects of diffraction. When a larger aperture is used the lens's performance decreases due to residual aberrations that the lens designers are unable to correct.

This effect can sometimes be easily seen by looking at a magnified image made with an enlarging lens. Note that as the lens is stopped down the grain pattern becomes fuzzier than if the aperture is close to maximum.

-- herbet camerino (hbrasileiro@cihi.ca), April 14, 2000

Answers

Most printed images are seen from a distance that precludes any fuzziness induced by diffration due to a lens being stopped down to far. An image should be about impact and meaning not about sharpness. To many photographers are too concerned with how increadibly sharp an image is and not about what the image is saying to the audience. James

-- james (james_mickelson@hotmail.com), April 15, 2000.

All true, and so is the reply. Don't get hung up on it. If you really want to see what sharpness is all about you need to study some good contact prints made from 8x10 negatives, like those of Edward Weston and others.

And then investigate the truly primitive equipment he used to make those images.

A decent lens on a decent camera (and that includes just about all of them made since about 1940) will produce excellent negatives once you have "tuned" your film, exposure and development techniques. (Check the answers to your other post.)

If you're starting out, use what you have and learn it thoroughly before you go on an equipment buying binge. The camera and lenses you mentioned in your other post will do just fine.

It's also important to make sure your enlarger is "tuned up." Good quality lens, accurately aligned, etc. Once again, use what you have and put the best glass on it you can afford.

Get in there and make some prints. Put your money into enough film and paper to learn with, and don't be afraid to experiment.

Most of all, have fun

-- Tony Brent (ajbrent@mich.com), April 15, 2000.

I can hardly believe that the fact that lenses have a best aperture was news to anyone.

There are many factors that contribute to the overall quality of a print or transparency. First and foremost are probably subject matter, lighting, and composition followed by tonality and contrast. IMHO sharpness, in terms of pure resolution, comes somewhere near the bottom of the list of what goes to make a good picture. The easiest way to end up with a collection of boring photographs is to shoot everything at the optimum aperture of the lens. A fact that Digital camera designers don't seem to have grasped.

-- Pete Andrews (p.l.andrews@bham.ac.uk), April 17, 2000.

Pete, where's a tripod come into your order of things? ;-)

For image sharpness I'd think it should be high on the list. Agree with your reply though :)

-- Nigel Smith (nlandgl@eisa.net.au), April 17, 2000.

Maybe they seem "plane" because they're al areial shots?

-- Sean yates (yatescats@yahoo.com), April 21, 2000.