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12-08-2009, 03:37 PM   #1
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IQ difference between FA and A 50mm/1.4?

I am a newbie to DLSR's, and have a K20D with the basic kit zoom lens. I have been reading about the joys of fast primes, specifically the FA 50/1.4 Being on a budget, I began wondering about how the IQ of the A series 50/1.4 compares to it. I wouldn't mind manual focusing (based on reading some linked articles) if the IQ is comparable. Any opinions?

12-08-2009, 03:57 PM   #2
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They have the same optical formula, so IQ is probably the same. The FA has later versions of the SMC coating, that might make a small difference.

The A version is better for manual focusing, with a better feel and more precise focus ring. The FA makes manual focusing a little harder, only because it's set up for auto focus.

Both kinds of focus have their quirks with DSLRs at apertures from f1.4 to f2.8. Auto focus might lock on to something behind or in front of your subject, and the extremely narrow depth of field will leave your subject out of focus. The smaller viewfinders and newer focus screens make determining the actual focus point hard. You may find Live View helpful.
12-08-2009, 04:10 PM - 1 Like   #3
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Typically, the "A" version is still pretty expensive. If you're thinking of going that way to save money, you can save a *lot* more by getting either the A50/1.7 (which many actually prefer over the 1.4), M50/1.4 (if you must have the 1.4).
12-08-2009, 07:09 PM   #4
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While all the Pentax 50s are very good, some are better in some areas that others.
I'm a bit of a 50 junkie, and while I haven't formally tested, I can tell you what I've found qualitiatively, if not quantitatively between some of the 50s
Of the two that you mentioned, I like the A better. While the FA isn't bad, it seems to me that it was softer wide open, and never got as sharp as the A. I suspect that this is probably due to more mechanical slop to allow the autofocus to work.

12-10-2009, 03:28 AM   #5
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QuoteOriginally posted by Wheatfield Quote
While all the Pentax 50s are very good, some are better in some areas that others.
I'm a bit of a 50 junkie, and while I haven't formally tested, I can tell you what I've found qualitiatively, if not quantitatively between some of the 50s
Of the two that you mentioned, I like the A better. While the FA isn't bad, it seems to me that it was softer wide open, and never got as sharp as the A. I suspect that this is probably due to more mechanical slop to allow the autofocus to work.
Yes, if manual focus is okay, the A 1.4-version is a great lens. It is also much better made, than the A 1.7 version, which has a lot of plastics inside (I know, I have one fallen apart...) I also prefer the A 1.4 over the M 1.4, because the A-contacts make metering etc. much more reliable.

Ben
11-25-2010, 09:20 PM   #6
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Wow, thanks for all the help.

I think the 1.4 sounds pretty nice. For autofocus, I need FA? or A?

Thanks!
11-25-2010, 09:41 PM   #7
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Fa series is autofocus, A series is manual focus.
11-25-2010, 11:06 PM   #8
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The FA series is likely going to be the best all around.... but the IQ differences are likely to be negligible.

However, a good manual-focuser can be just as good, or better, than autofocus. It's much easier to manual focus a A lens. I wonder is that is why wheatfield noticed a tiny bit of extra sharpness in favour of the A 50 1.4? The DOF is so thin that ANY autofocus errors would really throw the image off.

The A 50 1.7, on the other hand, is an outright steal for the price and performance, so +! on marc's suggestion.

11-26-2010, 08:17 PM   #9
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QuoteOriginally posted by paperbag846 Quote
The FA series is likely going to be the best all around.... but the IQ differences are likely to be negligible.

However, a good manual-focuser can be just as good, or better, than autofocus. It's much easier to manual focus a A lens. I wonder is that is why wheatfield noticed a tiny bit of extra sharpness in favour of the A 50 1.4? The DOF is so thin that ANY autofocus errors would really throw the image off.

The A 50 1.7, on the other hand, is an outright steal for the price and performance, so +! on marc's suggestion.

I checked the FA pretty thoroughly before I sold it, but it's possible. I never compared the two side by side, I just always felt the A was the sharper of the two from random use.
11-26-2010, 10:26 PM   #10
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As an owner of 178 50mm lenses I can say they are optically identical, however the FA does indeed posses updated lens coatings and of course AF. That may or may not be a deal breaker for you.
11-27-2010, 03:14 AM   #11
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QuoteOriginally posted by Digitalis Quote
As an owner of 178 50mm lenses I can say they are optically identical, however the FA does indeed posses updated lens coatings and of course AF. That may or may not be a deal breaker for you.
*jaw hits the deck*

Just one question - Why ?!

Ok another - which are your Top 5 and why ?
11-27-2010, 06:15 AM   #12
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QuoteOriginally posted by Frogfish Quote
which are your Top 5 and why
I collect 50mm lenses, specifically 50mm. Because if I fleshed out to the 43mm to 60mm "normal" lens range my collection would be considerably larger, and substantially costlier.

my top five lenses that I own, that's a bit hard to say but a quick list off the top of my head would go:

1: Leitz - Leica Noctilux 50mm f/0.95 ASPH - the fastest sharpest superspeed lens for 35mm cameras - this lens is currently tied with the Noctilux 50mm f/1.0, and the original classic noctilux 50mm f/1.2 from 1960's - they are all absolutely gorgeous lenses that are really hard to fault.

2: Nikon - Noct nikkor 58mm f/1.2 ASPH - A masterpiece for 35mm SLR cameras, A superb lens for low light work with the Nikon D3s

3: Pentax - SMCP-K(and A) 50mm f/1.2 - one of the first 35mm SLR super-speed lenses and still one of the best.

4: Leitz - Leica Summilux 50mm f/1.4 ASPH (though the pre-ASPH is not slouch) - a great standard lens for the Leica M system

5: Leitz - Leica Summilux-R 50mm f/1.4 ASPH - brilliant lens, very sharp with superb bokeh, it's a bit of a brick though.

Last edited by Digitalis; 11-27-2010 at 07:34 AM.
11-27-2010, 07:19 AM   #13
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QuoteOriginally posted by Digitalis Quote
As an owner of 178 50mm lenses...
Thanks, Dig. I will never again feel remorse for owning multiple lenses of comparable focal lengths.
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