Quote:
Originally Posted by slodave
Bumping the aperture up to f11 or f16 is better. Sweet spot for focus on almost all lenses, in the middle.
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No argument that most lenses are sharpest a few stops down from wide open. For fine detail with extreme enlargement there is a small difference. With a picture of the moon the difference is insignificant.
An interesting side note about the lens for our aerial camera: It is a 6 inch focal length (about 150mm) that covers a 9x9 negative. The lens weighs about 250 pounds and is huge. It has a built in rotating shutter.
This is not our particular camera but our is just like this one. The lens is the round thing on the right side. The circular handle is a removable cover used to remove the lens from the camera mount. It is a chore to lift it out. The film magazines hold a 433 ft long 9 inch wide roll of film.
The entire point of all of this is that lens is designed to be the sharpest and most accurate at wide open, F4.5 We virtually never stop it down to F8. The shutter speed adjusts automatically. It can be set to manual but that is pointless.