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09-12-2010, 06:21 AM   #31
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QuoteOriginally posted by Asahiflex Quote
You are forgetting the DA* 55/1.4 SDM from 2009. It IS a DA Star lens, albeit the slowest one to date
The reason I kept my FA 50mm f1.7 even though I bought the DA* 55mm

09-12-2010, 06:24 AM   #32
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QuoteOriginally posted by Asahiflex Quote
You are forgetting the DA* 55/1.4 SDM from 2009.
Or DA* 60-250/4 for that matter

Both aren't APSC lenses.

Below is the upper right 35mm full frame corner (unsharpened 100% crop of an 11MP scan) of the DA*60-250 at 250mm wide open which is the weakest spot for vignetting for this lens on full frame. There is slight vignetting and CA which leads to the slight contour on the B&W film. But still quite usable. Also, it is patented as a 35mm lens by Pentax.

Last edited by falconeye; 06-23-2012 at 03:08 AM.
09-12-2010, 06:32 AM   #33
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60-250mm vignetting

I am not convinced that the 60-250mm is anything more than a lens designed with only APS-C in mind; look at this recent test posted by another forum member of the 60-250mm on film:

?????? DA?60-250mm???????

The vignetting is so severe that it is very unlikely the lens was designed to for a full 35mm image circle.


QuoteOriginally posted by falconeye Quote
Or DA* 60-250/4 for that matter

Both aren't APSC lenses.
09-12-2010, 06:46 AM   #34
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QuoteOriginally posted by Mike.P Quote
The reason I kept my FA 50mm f1.7 even though I bought the DA* 55mm
I sold my FA 50/1.4 after I got the Da* 55 (it's a much better lens) but I kept the F 50/1.7 just in case

09-12-2010, 06:54 AM   #35
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QuoteOriginally posted by Ayoh Quote
The vignetting is so severe that it is very unlikely the lens was designed to for a full 35mm image circle.
Vignetting is difficult to judge with a film camera.

Attached you find the complete photo which represents the worst sample with respect to vignetting with this lens (250mm f/4 own test, the corner above is from this photo -- the dark thing in the lower left is a shadow).

In the sample you cited, the film is scanned to 24x36.3mm which slightly exceeds the full frame image circle. Then, in both my and the referenced sample, film may have a very non-linear response curve dramatically exxagerating the effects of vignetting. This certainly is the effect with the B&W film I used whch has hard gradation.

Overall, the 60-250 may not get the best rating for corner performance but it is a full frame lens. Vignetting is easily corrected in camera nowadays and may not have been a prime objective in designing this lens. Almost all full frame lenses benefit from vignetting correction and unlike distortion, it is fast too. AFAIK, the cos^4 standard vignetting correction is always invisibly done in all digital cameras but missing from film scans. I know for sure that the Pentax firmware contains the corresponding algorithm. Even before the lens correction thing arrived.

BTW, full frame zoom lenses all vignette between 1 and 3 stops in the corner. E.g., the Canon EF 24-105mm f/4 USM L full frame lens vignettes up to 2.5 stops and corner resolution drops into the fair region which is pretty poor actually. I see no sign that the DA*60-250 would perform worse than other Star-category lenses from other vendors.

BTW, why doesn't the sun shade vignette at 60mm on full frame? They even didn't ship the lens with an APSC sun shade ...

Last edited by falconeye; 06-23-2012 at 03:08 AM.
09-12-2010, 07:40 AM   #36
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Full frame coverage

Thank you for your comprehensive reply Falk. Your remarks pointing out the non-linearity of film and the lens shade coverage certainly do make me want to rethink my original sceptical conclusions. I was also not able to see your resolution test shot prior to my earlier posting, however now that I have, the corner resolution certainly also looks acceptable. Perhaps we will in fact see a 35mm sized Pentax DSLR in the near future, I certainly would buy one.


QuoteOriginally posted by falconeye Quote
Vignetting is difficult to judge with a film camera.

Attached you find the complete photo which represents the worst sample with respect to vignetting with this lens (250mm f/4 own test, the corner above is from this photo -- the dark thing in the lower left is a shadow).

In the sample you cited, the film is scanned to 24x36.3mm which slightly exceeds the full frame image circle. Then, in both my and the referenced sample, film may have a very non-linear response curve dramatically exxagerating the effects of vignetting. This certainly is the effect with the B&W film I used whch has hard gradation.

Overall, the 60-250 may not get the best rating for corner performance but it is a full frame lens. Vignetting is easily corrected in camera nowadays and may not have been a prime objective in designing this lens. Almost all full frame lenses benefit from vignetting correction and unlike distortion, it is fast too. AFAIK, the cos^4 standard vignetting correction is always invisibly done in all digital cameras but missing from film scans. I know for sure that the Pentax firmware contains the corresponding algorithm. Even before the lens correction thing arrived.

BTW, full frame zoom lenses all vignette between 1 and 3 stops in the corner. E.g., the Canon EF 24-105mm f/4 USM L full frame lens vignettes up to 2.5 stops and corner resolution drops into the fair region which is pretty poor actually. I see no sign that the DA*60-250 would perform worse than other Star-category lenses from other vendors.

BTW, why doesn't the sun shade vignette at 60mm on full frame? They even didn't ship the lens with an APSC sun shade ...
09-12-2010, 09:15 AM   #37
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QuoteOriginally posted by kevinschoenmakers Quote
They don't put WR on the lens because the DA* line is WR by default.

As for point 3, I was wrong, actually.
you are correct, one of the DA*'s selling points is that they are WR...were WR prior to the specific WR lenses coming out.
10-24-2010, 04:08 PM   #38
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one question for the DA*16-50 owners that also own a k7 or a k5
how does it handle with the body (without the grip)? is the combo to heavy for day to day use? I'm looking for an all in one WR solution in that range

10-24-2010, 04:18 PM   #39
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QuoteOriginally posted by kales Quote
Yeah, but I am not sure whether it's up to K-7/K-5 WR standard.

the DA*16-50's WR is for K10d I think, and K10d seems have a lower WR standard than K-7
more WR means moe bulk. I don't think anyone in Pentaxland wants that
10-24-2010, 04:42 PM   #40
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k10 have the same wr quality like the k-7/5.
the seals are only more coldproof in the newer bodys.
the combination da*lens and k10 till k-5 is absolut longtime weather,dust and dirtproof.
i have seen my k10 and k-7 inside,and the servicechief told me,that he now is knowing,why a sealing is soooo good for my stuff
10-24-2010, 07:12 PM   #41
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QuoteOriginally posted by falconeye Quote
Or discontinue the lens which I hope they don't. It's a stunning performer (for me).
I've heard others praise the lens as well. What does this say about DxOMarks lens tests?

In a comparison against the Tamron 17-50 and Sigma 17-50 the Pentax 16-50 doesn't fare well at all.

EDIT: Some of the relative performance can probably be explained by the fact that one cannot choose one and the same camera for all three lenses. Odd that DxOMark doesn't offer a normalised comparison mode.

Last edited by Class A; 10-24-2010 at 07:30 PM.
10-24-2010, 11:53 PM   #42
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the pentax 16-50 DA* does not fair well optically to any of the competition. Canon have the best lens in this focal length. Their 17-55 is the best around.
10-25-2010, 04:20 AM   #43
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The DA 16-50 is a decent lens. As to whether or not it is better than the competition in this focal length I can't say. It is certainly faster to focus than the 50-135 which struggles mightly in many situations, mainly because of a long focus throw. I think Falconeye is right however, I see Pentax continuing the 16-50 in production, but not changing the design. They had enough trouble taking care of the decentering problems with it. I had my SDM changed on it awhile back and it does seem more reliable (although not faster to focus).
10-25-2010, 04:23 AM   #44
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QuoteOriginally posted by Class A Quote
I've heard others praise the lens as well. What does this say about DxOMarks lens tests?

In a comparison against the Tamron 17-50 and Sigma 17-50 the Pentax 16-50 doesn't fare well at all.

EDIT: Some of the relative performance can probably be explained by the fact that one cannot choose one and the same camera for all three lenses. Odd that DxOMark doesn't offer a normalised comparison mode.
Actually, the DxO MTF curves, center at 16mm and f/5.6, show they all perform equal (that's sort of sweet spot where I often use the lens -- YMMV) and at f/2.8 Pentax and Sigma beat the Tamron. OTOH, Tamron is better stopped down.

The MTFs are measured on K20D for the DA and Canon 7D for the others. Theoretically, MTFs below some lp/mm threshold shouldn't depend much on the camera used, still, that's not a bad result. I agree though that the image quality degrades faster towards the corners and longer focal lengths than with the competition.

Last edited by falconeye; 10-25-2010 at 04:50 AM.
10-25-2010, 08:04 AM   #45
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i am kind of convinced the defect in the 16-50 was updated too. If i were to buy that lens however i would get an extended warranty though lol.
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