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02-06-2014, 01:06 AM   #1
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DA-50 f1.8 or F-50 f1.7?

Is one better than the other in IQ or focus speed/accuracy? I have new DA in box and have avoided opening because I was intending to sell it and keep my F that I have had for years. Now wondering if I should go the other way after reading such great things about DA. F has some obvious advantages such as metal mount, distance scale, full frame (for future-but almost given up on Pentax for that) and better build. But what about newer coatings, optical advances etc? I also have a A-50 f1.4 but think I'll keep it either way and sell one of other two.

02-06-2014, 01:26 AM   #2
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i believe the older F-50mm is much stick with that one if i were you.If your F is ok, meaning no fungus,haze etc etc i would definitely keep it
02-06-2014, 01:31 AM   #3

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Well, I don't have Da 50/1.8. I have DA*55/1.4. But my friend bought 50/1.8. And it is quite good. Colors are great and compares well even wit 55. Sharpness is from 2.2 almost as good, and by 2.8, as good. (Shot with K-3). Rounded blades are clearly showing in Oof when stopping down.

I think that F50/1.7 is sharp from f1.7. And tones are more personal than modern lenses. So that one is up to your taste. About FF and metal bajonet, it is also personal thing.

While I'm not saying that you should open that box, just to find out, you might have to think that how much you can have from 1.8 after opening the box, and/or how much you might get from F50/1.7 instead.? You might end up keeping both or selling other one.

Just my 2 cents.
02-06-2014, 05:23 AM   #4
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I think you already know the differences.
DA 50mm f1.8: -full automation, optimized for digital APSC
-new coatings (though, not the newest HD ones)
-light and small
-rounded aperture blades?
-52mm filter size
-probably has shorter focus throw, so faster AF

F 50mm f1.7 - aperture ring
- automation (AF, aperture)
- DoF scales
- arguably better build (DA 50mm has plastic mount, but there were next to no problems with those, its not really a drawback)
- full frame image circle (though, the DA 50mm might also cover FF, has anyone confirmed on film camera?)
-49mm filter size
-f1.7 vs f1.8 is a negligible difference

With fast 50mm lenses you almost can't go wrong. I would choose the DA because it is newer and comes with warranty. Only reason why I would choose F is if it was significantly cheaper or if i needed the DoF scales or aperture ring (if using bellows, for example). Or if I had a good filter collection that fits only one. Either way you can (and probably should) buy a lens hood for it. Then again, when it comes to 50mm, I primarily use the Pentax M 50mm f1.7. Don't even need the auto-aperture

02-06-2014, 05:44 AM   #5

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It has 7 rounded aperture blades. And AF is quite fast too.
02-06-2014, 06:49 AM   #6
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I had the same dilemma. I usually carry an FA50/1.4, but received a DA50/1.8 with my new K-3. Like you, I kept it in the box for days thinking I would sell it. In the end, I decided to open it and take a look. I found I really like the light weight, and will probably make it part of my light business travel kit. I think I will keep both (LBA strikes again).
02-06-2014, 07:07 AM   #7
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I have tried both and I'm going to tell you why I'm going to keep my DA 50mm.

For me, the only reason that I should keep F 50mm is because it is sharper at 1.7 than DA 50mm at 1.8. That is the only reason that might tip me to keeping my F 50mm. But it was definitely loud, literally. You should know if you have one. And all this talk about F 50mm is compatible with FF, well, DA 50mm is compatible too, and I have tried it with my Pz1-p. DA 50mm is not loud, at all, compared to F 50mm and I can accept the level of sharpness at 1.8. Some people might have different reasons, but for me, it is enough for me to keep my DA 50mm and sell my F 50mm.

Sample shots from Pz1-p with DA 50mm 1.8. Both at 1.8

02-06-2014, 11:59 AM   #8
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I'm sure both are great and I haven't tried the DA50. But I would take the F50/1.7 because it's super sharp, has amazing rendering and micro contrast, and is just a joy to use. However if you can't find one cheaper than the DA50 then that makes it a little harder.


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