Pentax-FA 50mm F1.4 v Pentax-A 50mm F1.7 @F2
It is an illusion that photos are made with the camera… they are made with the eye, heart and head. Henri Cartier-Bresson
Lots of film bodies, a couple of digital ones, too many lenses (mainly older glass) and a Horseman LE 5x4.
My website
Apparently.
http://www.pentaxforums.com/forums/pentax-slr-lens-discussion/81528-fa50mm-f1-4-...
Where a FA 1.7 is compared to the FA 1.4. I had thought that the A and FA lenses were optically identical? Indeed, Dimitrov's website seems to indicate that this is the case.
Yup! the 1.4 gets my vote!......but could it be down to manual focussing!.....my 1.7 is extremley sharp when I get it spot on......Ken
My manual focusing perhaps could have been a touch better, but I did try about 8 times with this subject. Started at infinity, take a shot, move the ring a tiny bit, take another shot, and so on. Then I chose the sharpest. Out in the real world, I'm unlikely to often focus it better than this (despite having a Katz Eye screen).
Also with other subjects, no matter what I do, I can't get the 1.7 lens quite as sharp as the 1.4 at f2. It's pretty good, yes, but not quite as sharp and contrasty.
I was wondering which of these two lenses to take next time I go on holiday. The 1.7 is lighter and would be Łess to Łoose, but the 1.4 does seem better at f2 - which is a setting I really would use. For smaller apertures, I tend to stick with my zooms for convenience.
The only caveat I would have for interpreting the results from this test (apart from preferring tripod mounted shots and no SR to remove those two variables) would be that we are only comparing one example of each lens. These could be typical or not, but we have no way of knowing.
We only really know a lens after regular use unless we are in the optical lab, and the nicest Pentax 50mm I have every had was actually a SMC Pentax-M 50mm f1.7 - perhaps it was a really good example of its type.
I see that you are comparing the A 1.7 with the FA 1.4. You might like to check out this link:
http://www.pentaxforums.com/forums/pentax-slr-lens-discussion/81528-fa50mm-f1-4-...
Where a FA 1.7 is compared to the FA 1.4. I had thought that the A and FA lenses were optically identical? Indeed, Dimitrov's website seems to indicate that this is the case.
It's interesting that the test there shows the opposite to what I found. I don't know if that's due to focusing problems (with me or them) or sample variation with the lenses.
All I can say is that I've tried very hard to get as good results with my 1.7 as my 1.4 at f2, and have failed. The 1.7 lens looks to be in good condition, and I'm the only owner. (Got it back in 1984 with a P30).
The only caveat I would have for interpreting the results from this test (apart from preferring tripod mounted shots and no SR to remove those two variables) would be that we are only comparing one example of each lens. These could be typical or not, but we have no way of knowing.
Agreed, and it's possible that my 1.7 is substandard.
Tripod test are preferable, but I'm confident that those varables are not playing a part as the results have been consistent over many shots.
On an unrelated note, your FA results are considerably superior to my old Super Takumar 50mm 1.4 at f2, and are still a little better that the Tak at f2.8.
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On an unrelated note, your FA results are considerably superior to my old Super Takumar 50mm 1.4 at f2, and are still a little better that the Tak at f2.8.
There was an optical re-design of the 50mm between the M and A series, so A, F and FA 50's should be better than M, K, and Super Taks in this case. I believe this is supposed to be most obviously true of the 1.4s.
but it does help
I'm sorry my test above was somewhat misleading. I won't bore you with more images unless I do a more scientfic test.
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I've chosen to compare at f2 because that's when the FA begins to have a decent level of sharpness (in my opinion), and this aperture may be used when you want a significant speed advantage over a more ordinary lens.
The following results are consistent with other tests I've done. I made several attempts at focus with each lens and chose the sharpest results. It's possible that I could have focused more accurately still, but only a tiny bit, if at all.
Handheld, but shutter fast enough to freeze any camera shake (1/400 and 1/250 sec, respectively). SR on. ISO 100. RAW + Silkypix, same settings for each image.
Uncropped:
Pentax-A 50mm F1.7 @ F2:
Pentax-FA 50mm F1.4 @ F2:
100% crops:
Near centre:
Pentax-A 50mm F1.7 @ F2:
Pentax-FA 50mm F1.4 @ F2:
Border:
Pentax-A 50mm F1.7 @ F2:
Pentax-FA 50mm F1.4 @ F2: