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03-24-2011, 01:00 PM   #1
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Will I lose IQ going from a M42 50/1.4 to an FA 50/1.4?

Although I'm still relatively new, the more I shoot the more I find the majority of the pics I take are indoors and low light candids. I have an M42 SMC 50/1.4 that I adore: it literally has opened up whole new worlds of photographic possibilities for me.

However (and you knew one of those was coming) I'm getting frustrated by manual focus/aperture. I keep failing to capture a moment or expression because I'm trying to focus. Given the extremely short depth of field (I believe that's the technical term, correct me if I'm wrong) wide open or at f/2, this is even more vexing. Add in that it's a huge pain to swap from the M42 adapter to a K mount (and most of my other lenses are K mounts) and I'm seriously thinking of getting a new lens.

It seems as though my options are the Sigma 50/1.4 EX DG, the DA* 55/1.4, and the classic FA 50/1.4. Given the prices I'm seeing, the FA is my top choice. So what (if any) IQ will I be loosing if I switch to the FA, given my needs (generally f2.8 or wider, low light indoors, moving people as subjects)?

03-24-2011, 04:07 PM   #2
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It wouldn't be IQ that you give up going from an SMC Tak 50/1.4 to an FA 50/1.4, but you will gain autofocus and aperture control. You have to use stop down aperture control on the digital body. That said, the 2 lenses are different beasts. As far as I know, the FA doesn't have Ghostless Coating like the FA 35/2 had. If it did, it would make a big difference. I personally think the tak is better optically, but the FA is a very good lens but the F 50/1.4 may be the best of all the f1.4 50s by Pentax.
03-24-2011, 04:21 PM   #3
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The optical formula is pretty much the same. I might guess the FA coating to be perhaps a little better as SMC is an evolving coating but not a whole lot

Personally I find for some things I like MF more, mainly because as a hobby photography for me is a distraction from other things the more involved I get in photography the more relaxation I get and although MF is demanding by itself it makes you forget more of the day to day BS. Having said that, if I know I won't have a lot of time I wll put AF lenses on
03-24-2011, 04:47 PM   #4
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How does the FA 50/1.4 compare to the DA 35/2.4? Lots slower obviously, and different focal length. Totally different ball game, or in the same class?

03-24-2011, 05:09 PM   #5
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Have you considered the FA43mm f1.9 and FA31mm f1.8? Both lenses are AF and considered optically better than the FA50mm. While they are not as fast as the FA50mm, both the 43mm and 31mm are very competent in low light, and would complement nicely your SMC50 f1.4.

Food for thoughts....
03-24-2011, 05:13 PM   #6
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Hi hcc, I admit I had not looked at those. I will now Thanks for the tip.
03-25-2011, 10:59 AM   #7
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Looks like the 43 and 31 are a bit out of my range for now. I think FA 50/1.4 is the right choice for now, and maybe pick up a da 35/2.4 at some point as well...

03-25-2011, 03:52 PM   #8
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Any difference in optical quality betwen FA and M42 50mm will be moot if you get more in-focus shots with the FA.

Pretty hard to focus such a fast lens on DSLR without a focusing screen.
03-26-2011, 01:11 PM   #9
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Pentax hasn't made a 50mm lens that isn't of sufficient optical quality for my needs. I'd take the AF, aperture control and ability to use P-TTL flash over whatever minute difference there is in IQ.

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