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03-27-2011, 07:58 PM   #1
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Lenses that are sharp wide open?

I was wondering, which lenses for Pentax are sharp wide open? I've got the DA * 300mm, I know that one is sharp wide open, but none of the rest I have are. I think I read that the 77mm and 31mm are sharp wide open. Any others? It doesn't have to be prime or Pentax. If you know of any, please list.
Thanks,


Last edited by kbrede; 03-27-2011 at 09:11 PM.
03-27-2011, 08:20 PM   #2
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"Sharp" is a relative term. Most lenses are sharper stopped down than wide open, but some are sharper than others. If you want to see numbers, checked out the reviews on photozone.de and the MTF stats. Or, for older lenses, see the resolution tests at http://www.takinami.com/yoshihiko/photo/lens_test/index.html
03-27-2011, 08:26 PM   #3
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I've tried more lenses that are acceptably sharp wide open than those that are too soft wide open. I would not worry too much about it, to be honest.

The few that are *too* soft are:

FA 50 1.4 (but who cares, it's also faster than any of the other lenses).

Kit lens at 18mm or 55mm.

M 80-200 f4.5.

...

that's it.

Honestly, sharpness is not nearly as important as a lot of other factors.
03-27-2011, 08:26 PM   #4
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Many lenses will differ in border sharpness and center sharpness. Sigma 30 1.4 is an example. It has excellent center sharpness wide open, but not so good corners.

Pentax FA 31 is very good at both borders and center, wide open. DA 15 is f/4, so not really a 'fast' lens, but it is very sharp(center) at 4. DA 70 is very sharp at 2.4.

These are all the ones I have

cheers,

Abhi

03-27-2011, 08:38 PM   #5
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Only a Sigma zoom I have is not sharp wide open and needs to be closed down at least a stop and a half. All my limited primes, the 50-135 and the 12-24 are "sharp enough" wide open. Even the humble 55-300 is "almost sharp enough" wide open and maybe needs 1/2 stop down to be sharp enough.

Technique, appropriate shutter speeds, good PPing, and lighting all greatly influence sharpness or perceived sharpness. 95% of my not sharp images are related to failings in those areas rather than problems with the lens.
03-27-2011, 08:39 PM   #6
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My F 50mm f/1.7 is quite sharp wide open. This was at f/1.7 on regular fuji 200 (focus is on the guy on the right).

03-27-2011, 09:06 PM   #7
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The DA 40mm is very sharp wide open from my experience. Also the DFA 100mm Macro WR
03-27-2011, 09:12 PM   #8
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Original Poster
QuoteOriginally posted by Marc Sabatella Quote
"Sharp" is a relative term.
To put it In other words, lenses that *you* wouldn't hesitate to shoot wide open if you wanted a sharp shot. I'm actually looking for subjective. I never worry about shooting my 300 wide open, the rest of my lenses I do.


Last edited by kbrede; 03-27-2011 at 09:24 PM.
03-27-2011, 09:25 PM   #9
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sharp? DA12-24, FA31, Sigma 30, FA43, FA35, DA35, DAL35, DA40, DA*55, FA50/1.7, 55/1.8, DA70, FA77, FA50 macro, Sigma 70, DA* 16-50, DA* 50-135, Tamron 90, D/FA 100 macro series, Sigma 105, FA135, and so forth and so on.

the thing is, most of the recent Pentax compatible lenses are sharp at wide open and a few of the older lenses, although the degree of sharpness however varies from lens to lens. with today's post-processing softwares and MP resolution, I don't think that sharpness is that as necessary anymore unless you are looking to crop or look at a micro-level especially with longer shots.
03-27-2011, 10:23 PM   #10
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QuoteOriginally posted by kbrede Quote
To put it In other words, lenses that *you* wouldn't hesitate to shoot wide open if you wanted a sharp shot. I'm actually looking for subjective. I never worry about shooting my 300 wide open, the rest of my lenses I do.
If the choice is between getting a fast enough shutter speed or accepting motion blur, I'd shoot anything wide open - it's bound to be sharper than if I stopped down. That include the kit zooms, although of course I'd prefer to shoot something faster to increase shutter speed further.

Bottom line being, whatever you lose in sharpness by shooting wide open on even the worst lenses I've used is more than offset by the increase in shutter speed, at least in the cases where that's the limiting factor. And besides, my choice in lens is primarily determined by focal length, so I don't care how sharp my DA15 is wide open if it's not the right lens for the job.

So I still don't really get the question.
03-27-2011, 11:04 PM   #11
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FA43 is very sharp wide open also.
03-27-2011, 11:13 PM   #12
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I find the Russian lenses to be sharp wide open. Except Jupiter 9, but that's by design.
03-27-2011, 11:20 PM   #13
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QuoteOriginally posted by Laurentiu Cristofor Quote
I find the Russian lenses to be sharp wide open. Except Jupiter 9, but that's by design.
I think in a recent thread about J9 someone said that earlier models are sharper. I've got one from '76 and it's not soft.
03-27-2011, 11:23 PM   #14
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Tamron 17-50, surprisingly so, sharp wide open, throughout the zoom range--even to the borders--even better than its bigger, older brother the 28-75--according to Photozone.
03-27-2011, 11:29 PM   #15
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According to Henry Cartier-Bresson: "sharpness is a bourgeois concept":ugh:
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