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06-14-2011, 07:50 PM   #1
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M 50mm F1.4 VS M 50mm F1.7

I have M 50mm F1.7 on hand but I also have a chance to upgrade to M 50mm F1.4 with about $40 bucks more.

Not sure any big difference on these 2 lenses? Image quality? Useful? Potential value?

06-14-2011, 08:02 PM   #2

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I've owned and used both and in terms of IQ and build quality I'd say there's very little difference.

So really, I suppose it comes down to deciding whether the 1-stop faster aperture is worth a slightly bigger lens and $40 extra
06-14-2011, 09:08 PM - 1 Like   #3
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I have an M50/1.7, and ST and FA 50/1.4's, and a K50/1.2. All have legendary optics. AFAIK the main difference between the generations of 50/1.4's are the coatings.

As for aperture -- there are GREAT and noticeable differences between f/1.2, f/1.4, f/1.7, and f/2, even just those half-f-stop increments. Some will claim the M50/1.7 is sharper wide-open than its faster brethren, but that's not surprising, and they're all pretty similar by f/2-2.8.

Much as I love my M50/1.7, it sees much less use than the faster glass. Yes, f/1.4 gives a VERY different effect than f/1.7. (And my various Pentax, Yashica, and Tomioka f/1.4 Fifty's all produce different images.) My recommendation: Do the deal. Move to f/1.4.
06-14-2011, 09:13 PM   #4
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I recommend getting the faster 50 too, it's a nice lens. And yes there is a noticeable difference between f/1.7 and f/1.4.

06-15-2011, 04:57 AM   #5
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1.4 is sharper stopped down, creamier wide open

1.7 is sharper wide open.

i love my 1.4, and I sold a 1.7 to get there. But you have to be interested in *more* than just sharpness. the 1.4 has really wonderful *rendering*.
06-15-2011, 05:14 AM   #6
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Over the last 30+ years I've owned it, I've taken more photos with the M50/1.4 than any other lens. It is the lens that really hooked me on Pentax optics.
06-15-2011, 11:16 AM   #7
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For the price difference I wouldn't do the trade. I own the M50 1.4 but optically the 1.7 is sharp even at 1.7 and you gain less than 1/2 a stop. The 1.4 is good when stopped down. I say stick with the 1.7 since you have it already. The DOF with the 1.4 is very very shallow.

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