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05-31-2010, 03:15 PM   #16
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QuoteOriginally posted by ManuH Quote
The 12-24 has not been tested by Photozone at 15mm, only 12mm, 18mm and 24mm which makes it hard to make actual comparisons.
True. But interpolation suggests it would come down as I suggested.

QuoteQuote:
But the DA* 16-50mm beats both lens at f/4, by a hair maybe
A hair indeed - and to be fair, that's all the DA15 beats the 16-50 or the DA12-24 by at f/5.6 or f/8. Realistically, there's no point in using sharpness as the main differentiator between these lenses - they are all excellent.

QuoteQuote:
Unfortunately at 16mm, the DA* has a lot of barrel distortion.
And CA is off the scale compared to the DA15. Still, a probably not as big an issue in practice as the more mundane details: DA15 is 15mm only but is a very small lens, the DA12-24 and DA60-50 are zooms but are much larger. That's really all it comes down to.

05-31-2010, 03:25 PM   #17
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QuoteOriginally posted by tokyoso Quote
The DA 15 has gotta be the sharpest in the center. But what do you do when the subject is not in the center?
First, "center" doesn't mean just the absolute dead center. It really covers most of the frame - everything but maybe the 10% along the borders. The vast majority of the time your subject *will* be in the "center" as far as that goes. In the few cases where you might need more detail in those last few pixels in the corners than you can manage at f/4, simply stop down, as one would normally do anyhow when shooting wide open and trying to get the corners in focus. At f/8 the DA15 beats all others.

Really, *far* too big a deal is made of the DA15's allegedly soft wide open corners.
05-31-2010, 03:44 PM   #18
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QuoteOriginally posted by Marc Sabatella Quote
Really, *far* too big a deal is made of the DA15's allegedly soft wide open corners.
i know, the photos posted all look very sharp to me.
05-31-2010, 03:45 PM   #19
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QuoteOriginally posted by Marc Sabatella Quote
First, "center" doesn't mean just the absolute dead center. It really covers most of the frame - everything but maybe the 10% along the borders. The vast majority of the time your subject *will* be in the "center" as far as that goes. In the few cases where you might need more detail in those last few pixels in the corners than you can manage at f/4, simply stop down, as one would normally do anyhow when shooting wide open and trying to get the corners in focus. At f/8 the DA15 beats all others.

Really, *far* too big a deal is made of the DA15's allegedly soft wide open corners.
+1

I was in the same position before buying my wide lens. I was between 12-24mm, 21mm, 15mm, and sigma 10-20. After much research i found out that 15mm the sharpest center IQ of all pentax lenses and superb sharpness thru out the whole frame when stepped to f8. In addition it offers very well controlled CA and Distortion plus it's small convenient size.


Last edited by Alex00; 05-31-2010 at 04:43 PM.
05-31-2010, 04:15 PM   #20
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QuoteOriginally posted by Marc Sabatella Quote
Really, *far* too big a deal is made of the DA15's allegedly soft wide open corners.
Same can be said about the DA* 16-50mm I love the results produced by this lens. The only things I don't like are size and weight. This is where the DA 15mm ltd is a huge winner.
05-31-2010, 04:21 PM   #21
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CA on the 12-24 isn't as bad as many would have you think

QuoteOriginally posted by Marc Sabatella Quote
And CA is off the scale compared to the DA15. Still, a probably not as big an issue in practice as the more mundane details: DA15 is 15mm only but is a very small lens, the DA12-24 and DA60-50 are zooms but are much larger. That's really all it comes down to.
I don't own the DA15mm but I have to say that in the 3 years I've been shooting with the 12-24 I've had very little problem with CA, even in situations where it's expected like tree branches against a bright winter sky. IMO, there are a few bad copies of the 12-24 out there that have generated a massive amout of negative press in regards to CA. Obviously, like all wide angles some CA will be present in some situations. But I've found it to be a very manageable problem.

NaCl(and the 3mm of extra FOV is hard to deny)H2O
05-31-2010, 04:45 PM   #22
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QuoteOriginally posted by NaClH2O Quote
I don't own the DA15mm but I have to say that in the 3 years I've been shooting with the 12-24 I've had very little problem with CA, even in situations where it's expected like tree branches against a bright winter sky. IMO, there are a few bad copies of the 12-24 out there that have generated a massive amout of negative press in regards to CA. Obviously, like all wide angles some CA will be present in some situations. But I've found it to be a very manageable problem.

NaCl(and the 3mm of extra FOV is hard to deny)H2O
Can you post an untouched image with branches ageist bright sky as you mentioned above.
05-31-2010, 04:51 PM   #23
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QuoteOriginally posted by ManuH Quote
Same can be said about the DA* 16-50mm I love the results produced by this lens. The only things I don't like are size and weight. This is where the DA 15mm ltd is a huge winner.
CA on the 16-50 is very bad according to photozone. I wouldn't put it in the same category as the prime 15mm.

05-31-2010, 04:59 PM   #24
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QuoteOriginally posted by Zav Quote
Zeiss Distagon 21mm f2,8 may be the sharpest wide angle available for Pentax.
I think so too......
05-31-2010, 05:02 PM   #25
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BTW, for some reason I only just noticed that this thread was posted in the DSLR forum. it belongs in the Lens forum, so I am moving it there.
05-31-2010, 05:28 PM   #26
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QuoteOriginally posted by Zav Quote
Zeiss Distagon 21mm f2,8 may be the sharpest wide angle available for Pentax.

Zeiss is not the sharpest lens,. Neither does it have the best distortion control. It also isn't automatic. it does however provide steady corner to corner sharpness which is good enough for many of us. CA is also very well controlled.

Zeiss Distagon ZF (ZE) T* 21mm f/2.8 (on Canon EOS) - Review / Lab Test - Analysis
05-31-2010, 05:59 PM   #27
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I can only speak for primes but if you want to beat the DA 15mm, DA 21mm or FA 20mm, you may have to go look at Zeiss 18mm.
05-31-2010, 06:37 PM   #28
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Depending on the RAW converter used, CA correction can soften an image somewhat. So when comparing a lens which has very little CA to one which has a lot, it would make sense to judge sharpness differences after correction.
05-31-2010, 07:32 PM   #29
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QuoteOriginally posted by Blue Quote
I can only speak for primes but if you want to beat the DA 15mm, DA 21mm or FA 20mm, you may have to go look at Zeiss 18mm.
Looking at the Photo Zone tests, is there anything for Pentax that measures higher in center sharpness than the Sigma 30 1.4?
05-31-2010, 07:40 PM   #30
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QuoteOriginally posted by JHD Quote
Looking at the Photo Zone tests, is there anything for Pentax that measures higher in center sharpness than the Sigma 30 1.4?
The FA 43mm Ltd comes so close that the sensor resolution is probably the limiting factor as this point. It would be nice if Photozone was updated for the K20D/K-7 sensors.
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