Hello all,
So I spent a bit of time comparing these 2 cheap old AF zooms, looking for the best (or least bad) one to use with my new-to-me K-1, and thought I would share the results since I wasn't able to find any discussion about that anywhere (I didn't want to get the 28-105 right away, for simple budget reasons):
F 35-135, bought used for €25, in correct condition (some dust)
vs
FA 28-70, bought used for €30, in good condition (no dust, no element separation)
I was originally attracted to each lens for different reasons:
F: excellent range for daily family activities, relatively fast aperture, limited weight
FA: tried it before on APS-C and liked it, constant f/4, very small and light
Then I started to wonder if I should keep only one? I must admit that I was quite biased towards the FA, and thought it would outclass the old F based on the images produced in real life conditions before.
However, the results of this quick and dirty test (in my backyard, under natural lighting) showed a more nuanced reality.
The FA is indeed all in all a more balanced lens across the zomm and aperture ranges. It has a more neutral and modern rendering (blueish cast, smooth oof areas).
On the other hand, the old and ugly F lens has more character but hold its own. It has a disctinct old-style yellow cast (similar to M lenses) which is not unpleasing; it seems also slightly more sharp on the focus plan; however, its big issue is with oof rendering. The bokeh is quite harsh, with too much irregularity and too many highlights. It is especially not recommandable at 35mm, better in the 50-70mm range. Note that I have not tested the long end, I just wanted to compare the common range of both zooms (35-70mm).
In summary, I prefer the FA at 35mm and at wider apertures (at least up to 5.6), and tend to prefer the F at 70mm and at smaller apertures (11-16), but even in the ranges where both are "equivalent" the images produced will be well different!
If the topic is of interest to anyone you can look at the pics (35-50-70mm, f/4 to f/16):
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