Joseph Tainter <[EMAIL PROTECTED]> wrote:
>I just got this from KEH in "like new" condition, complete with box,
>case, papers, and caps. The lens appears (nearly) unused, but I notice
>that the front tube (filter mount) is looser than on other lenses that I
>have. Is this normal? Slides from a test roll last weekend came back
>very sharp.
Don't think it's normal but if it's just the filter ring it shouldn't affect
picture quality and it should be easy to fix. The inner trim ring should
unscrew, revealing three or four small screws that hold the filter ring. One or
more of these is probably what need tightening.
>With my 1p set for mtf, the meter gives me f5.6 at regular distances,
>and f8 at macro. I thought that macro lenses were designed to give their
>best performance stopped down. How does this lens perform at f16-32? (In
>macro, I shot every stop from f8-32, and my eyes can't detect much
>difference in the slides except depth of field.)
At some point the increase in diffraction as the aperture gets smaller causes a
reduction in sharpness that more than offsets the other benefits of small
apertures (at least as far as sharpness is concerned). This value varues from
one lens to another but with most 50mm lenses it's around f8. Since diffraction
is dependent on the physical size of the aperture in mm (rather than the
relative size in "f" numbers), longer lenses stay sharp down to smaller
apertures than normal lenses. A 100mm shouldn't fall off much until at least f16
but again, this varies from lens to lens. Since, as you've observed, this babty
is razor sharp all over, just choose an aperture as close to f8 as possible that
gives you the DOF you want.
>My 1p hunts more than usual with the lens in macro mode.
Typical of all macro lenses; that's just part of nature of macro photography.
Most people almost never use autofocus for macro.
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