Everyone probably recalls my negative reaction to the design and build
of this lens when I received it on Wednesday. Uncertain whether to keep
it, I got an FA 50 F2.8 macro from the lab where I used to work, and
tested them systematically at all apertures from F2.8 to F22.
The test subject was some black text on a white background, printed on a
rigid box. I set both lenses for 1:2, and used a macro focusing rail to
focus. Since I do not have the equipment to ensure that the subject
distance was the same for all four corners, I could compare only the
center of the image. The edges and corners could not be compared.
The results:
Viewing at actual pixels, the FA is very slightly sharper than the D FA
at F5.6 and F8. Emphasis on the qualifier: very slightly. It took
extreme magnification to see the difference. For all other F-stops, the
D FA was slightly sharper than the FA. For all comparisons, the
differences were so small that I may have been seeing nothing more than
sample variation.
In short, the D FA 50 Macro is a worthy successor to the FA 50 Macro.
As for the D FA 50 itself, it is actually a bit sharper in the center at
F2.8 than at F4, although it is sharper in the corners at F4. Otherwise,
sharpness increases slightly with each smaller aperture up to F11. F11
is the lens's sharpest aperture. Sharpness diminishes slightly at F16,
and slightly again at F22. Emphasis on slightly. This lens is superb
across the entire aperture range.
In short: I guess I'll keep it. It is certainly easy to shoot macro with
a lens this light, and it is so light that it will travel well. Plus the
rebate was why I bought it now.
Here's an early photo:
http://www.fotocommunity.com/pc/pc/cat/3537/display/5022625
Joe
