There seems to have been a fair bit of discussion about these two lenses recently, so I'm posting this message which has been sitting in my 'drafts' folder for a while.
I've recently conducted a fairly unscientific and limited comparison of
these two lenses on the *ist D:
SMC A 70-210mm f4
SMC F 70-210mm f4-5.6
Pretty rudimentary test - photographed my bookshelf from about 6m (20ish
feet?) with both lenses on the tripod mounted *ist D at 70mm, about
120mm (not marked on the F), and 210mm, wide open and at f8 at each FL.
Then as an afterthought I compared both lenses at 210/f5.6.
Shot jpeg, daylight WB, 400 ASA. Unfortunately I didn't make efforts to
fix exposure, so it's slightly variable. I had to guess where 120mm was on the F version, and it was slightly different to the FL of the A at 120mm.
Focussed manually with as much precision as I could using the
refconverter A with viewfinder magnification.
Centre sharpness was examined at 100% and I just had a guess at which
was sharper (from writing on book spines etc.). Shooting RAW may be a
good idea for the future, though it wasn't too hard to see the winner in
most comparisons. No attempt was made to compare sharpness variation of
each lens across the zoom range.
The results:
A vs F [EMAIL PROTECTED] A [EMAIL PROTECTED] ? [EMAIL PROTECTED]/4.5] A [EMAIL PROTECTED] A [EMAIL PROTECTED]/5.6] F [EMAIL PROTECTED] A [EMAIL PROTECTED] F
A aperture comparison (is it better wide open or at f8?) 70 ? 120 8 210 8
F aperture comparison 70 8 120 8 210 5.6
And I was hoping for a clear winner )-: The A appears sharper in most situations, but the F has the advantage of size and AF, as well as that edge it has at 210/5.6. These lenses will probably both be on the market as soon as I locate a F* 300/4.5 at a reasonable price (-:
Hope this has been of interest to some. If anyone bugs me enough I may put up a page with the samples for you to see yourself.
David
