Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
11-01-2018, 02:18 AM   #16
Junior Member




Join Date: Aug 2018
Posts: 36
I have mixed feelings about this lens. First one had quality control issues with "scratched" inner barrel surface which showed as white dots. Second one is free of those, but it seems it has decentered issue with the left side. It starts to become visible when going below F5.6. That is shame because it is really sharp lens even at F1.4 and any softness will be more visible. Pentax suppose to check each DFA*50 lens manually and I would be suprised if they have that high tolerance for decentering. There is also lots of purple and green CA especially in out of focus areas and high contrast edges. Basically only true APO lens are free of those or they have very little of it what I have checked from the Leica APO lens. Still, I shake my head when some reviews say this lens barely has any CA.

11-01-2018, 03:57 AM   #17
Veteran Member
Medex's Avatar

Join Date: May 2013
Posts: 333
Original Poster
QuoteOriginally posted by Pikselisiirto Quote
Second one is free of those, but it seems it has decentered issue with the left side. It starts to become visible when going below F5.6. That is shame because it is really sharp lens even at F1.4 and any softness will be more visible.

Still, I shake my head when some reviews say this lens barely has any CA.
Check you other lenses for decentering as well. I thought my 15-30 is slightly decentered in left lower corner. The same with samyang 14 and pentax dfa50. I did not check other lenses. But i tried another k-1 body in the store and there was no decentering signs.
So... maybe sensor block is a little missaligned.

About CAs. In case of not ideal focus they are more pronounced at open aperture. But according to ephotozine test, CAs are less than 1 pixel even at edges and max 0.3 pixel in the center at f16

Last edited by Medex; 11-01-2018 at 04:06 AM.
11-01-2018, 08:21 AM   #18
Pentaxian




Join Date: May 2016
Photos: Albums
Posts: 2,122
QuoteOriginally posted by Medex Quote
Check you other lenses for decentering as well. I thought my 15-30 is slightly decentered in left lower corner. The same with samyang 14 and pentax dfa50. I did not check other lenses. But i tried another k-1 body in the store and there was no decentering signs.
So... maybe sensor block is a little missaligned.

About CAs. In case of not ideal focus they are more pronounced at open aperture. But according to ephotozine test, CAs are less than 1 pixel even at edges and max 0.3 pixel in the center at f16
same, i went through 3 copies of 15-30, and still don't have a copy with even sharpness. I basically just use around f16 to have even sharpness. Not sure what to do with it, lens was already serviced, with no notable change (except a shattered lens cap). I'm thinking to ask Precision to send both K-1 and 15-30 to Japan for mount calibration, maybe it's my mount that causes the issues and not the 3 separate copies of a pro lens..
11-01-2018, 08:31 AM   #19
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 14,522
QuoteOriginally posted by awscreo Quote
same, i went through 3 copies of 15-30, and still don't have a copy with even sharpness. I basically just use around f16 to have even sharpness. Not sure what to do with it, lens was already serviced, with no notable change (except a shattered lens cap). I'm thinking to ask Precision to send both K-1 and 15-30 to Japan for mount calibration, maybe it's my mount that causes the issues and not the 3 separate copies of a pro lens..
Unless your other lenses are having the problem I would still suspect the lens. Can you find anyone else with a Pentax body to do a test?

11-01-2018, 09:40 AM   #20
Pentaxian




Join Date: May 2016
Photos: Albums
Posts: 2,122
QuoteOriginally posted by UncleVanya Quote
Unless your other lenses are having the problem I would still suspect the lens. Can you find anyone else with a Pentax body to do a test?
Might be easier to find a pot of gold under my porch lol. I haven't seen another Pentax user since I saw a guy with a 645n or z two years ago lol (I live in the middle of nowhere though).

Thing is, I don't have another UWA to test it against. I sold the SY 14 2.8, I checked through the photos I took with it, it's hard to saw whether it was soft in the same places as I didn't use it wide open that much.

If it's the 15-30 that has the issue, then I'm really not confident in QC for these products

PS: although, i have looked at photos from other members with 15-30, and seems a lot of them have soft sides as well (either right or left side), so I don't know if it's just how the lens is, and I have too high expectations for this universally praised (in both Pentax and Tamron forms) lens.
11-01-2018, 10:35 AM   #21
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 14,522
QuoteOriginally posted by awscreo Quote
Might be easier to find a pot of gold under my porch lol. I haven't seen another Pentax user since I saw a guy with a 645n or z two years ago lol (I live in the middle of nowhere though).

Thing is, I don't have another UWA to test it against. I sold the SY 14 2.8, I checked through the photos I took with it, it's hard to saw whether it was soft in the same places as I didn't use it wide open that much.

If it's the 15-30 that has the issue, then I'm really not confident in QC for these products

PS: although, i have looked at photos from other members with 15-30, and seems a lot of them have soft sides as well (either right or left side), so I don't know if it's just how the lens is, and I have too high expectations for this universally praised (in both Pentax and Tamron forms) lens.
Are you sure it isn't field curvature? Check in with Sandy Hancock to see if he can shed light on this. I know he loves his 15-30.
11-01-2018, 10:45 AM   #22
Pentaxian




Join Date: May 2016
Photos: Albums
Posts: 2,122
QuoteOriginally posted by UncleVanya Quote
Are you sure it isn't field curvature? Check in with Sandy Hancock to see if he can shed light on this. I know he loves his 15-30.
well, it just seems strange - focused in the center of the frame, I can clearly see much softer right edge. Left edge is a bit soft, but overall it's very good for 2.8, the right edge is bad.
And it's consistently showing throughout the aperture range, it's just harder to notice at f8 onwards. I also see it in my astro shots, the right edge shows more coma and out of focus
stars than left edge, that should be a pretty good indication since it's focused on infinity right?

I'll pm Sandy Hancock, maybe he can show me that I'm wrong)

For reference - my last test series after 2nd servicing of the lens: https://drive.google.com/open?id=1RGOOXsLb081ir3KkmBF4oMACvbchMLY3
11-01-2018, 10:47 AM   #23
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 14,522
QuoteOriginally posted by awscreo Quote
I'll pm Sandy Hancock, maybe he can show me that I'm wrong)
Or confirm your worst fears!

11-01-2018, 10:52 AM   #24
Pentaxian




Join Date: May 2016
Photos: Albums
Posts: 2,122
QuoteOriginally posted by UncleVanya Quote
Or confirm your worst fears!
Well, i better do that before my warranty runs out
11-01-2018, 11:07 AM   #25
Loyal Site Supporter
Loyal Site Supporter




Join Date: Mar 2012
Location: Rochester, NY
Photos: Gallery
Posts: 3,163
QuoteOriginally posted by awscreo Quote
Might be easier to find a pot of gold under my porch lol. I haven't seen another Pentax user since I saw a guy with a 645n or z two years ago lol (I live in the middle of nowhere though).

Thing is, I don't have another UWA to test it against. I sold the SY 14 2.8, I checked through the photos I took with it, it's hard to saw whether it was soft in the same places as I didn't use it wide open that much.

If it's the 15-30 that has the issue, then I'm really not confident in QC for these products

PS: although, i have looked at photos from other members with 15-30, and seems a lot of them have soft sides as well (either right or left side), so I don't know if it's just how the lens is, and I have too high expectations for this universally praised (in both Pentax and Tamron forms) lens.
I live in Rochester and I am retired so I have time to meet up somewhere. I have a K1 and a K1-II if you want to test the images from those cameras against yours. That would be a sample size of three and therefore statistically significant. Driving is not a problem with me. I have met up with a few fellow Pentaxians in Yellowstone the last few years.


There was a tear in the fabric of space at Yellowstone today. Pentax stirkes back! - PentaxForums.com


Send me a PM if you want to meet up for a side by side test.
11-01-2018, 11:08 AM   #26
Pentaxian




Join Date: Dec 2011
Posts: 2,035
QuoteOriginally posted by UncleVanya Quote
To be clear - Pentax Pixel Shift produces a still 36mp file but one with higher color accuracy - right?
The Pentax Pixelshift feature does add details (correct color information instead of Debayer-Software-guessing does add details).
Best case in practise it adds enough detail to the equivalent of about a 50 MPx normal non-pxshift Bayer sensor.

I have to say though that beyond the 30-36 MPx count in real world photos I consider it "impossible" to see advantages of even higher resolutions (remember, our eyes resolve no more than "6 MPx" using the normal FA 43mm field of view = viewing distance equals image diagonal). So I do not care if the lens can resolve 36, 40, 50 or 100 MPx equivalents. And it is far easier to see a difference between 24 and 36 Mpx than 36 and 54.
11-01-2018, 11:19 AM   #27
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 14,522
QuoteOriginally posted by beholder3 Quote
The Pentax Pixelshift feature does add details (correct color information instead of Debayer-Software-guessing does add details).
Best case in practise it adds enough detail to the equivalent of about a 50 MPx normal non-pxshift Bayer sensor.

I have to say though that beyond the 30-36 MPx count in real world photos I consider it "impossible" to see advantages of even higher resolutions (remember, our eyes resolve no more than "6 MPx" using the normal FA 43mm field of view = viewing distance equals image diagonal). So I do not care if the lens can resolve 36, 40, 50 or 100 MPx equivalents. And it is far easier to see a difference between 24 and 36 Mpx than 36 and 54.
That makes sense to me. I recall earlier digital perceptual studies done showing that a 2x increase in MP level was needed for a blind AB/X test to generate consistent results of people realizing there was more detail - this was not at the pixel peeping level of course. I suspect with better screens we are better at consistently seeing it when we look for it - but I suspect our brains still fill in the details enough to keep us from noticing unless the difference is large - at least at casual glance etc.

---------- Post added 11-01-18 at 02:22 PM ----------

QuoteOriginally posted by gaweidert Quote
I live in Rochester and I am retired so I have time to meet up somewhere. I have a K1 and a K1-II if you want to test the images from those cameras against yours. That would be a sample size of three and therefore statistically significant. Driving is not a problem with me. I have met up with a few fellow Pentaxians in Yellowstone the last few years.


There was a tear in the fabric of space at Yellowstone today. Pentax stirkes back! - PentaxForums.com


Send me a PM if you want to meet up for a side by side test.
Heck if you are ever down south any I live in NC near Charlotte. I would love to see a K1 in person (either one) and get a feel for it. I have a K-3 and I would be happy to reciprocate if there is anything I have you wanted to try. (FA 31, F 50 f1.7, FA 50 1.4, FA 77, DFA 100, DA* 200, DA* 60-250 - not yet modified, FA* 300 are some of my FF lenses...)
11-01-2018, 11:51 AM   #28
Pentaxian




Join Date: May 2016
Photos: Albums
Posts: 2,122
QuoteOriginally posted by gaweidert Quote
I live in Rochester and I am retired so I have time to meet up somewhere. I have a K1 and a K1-II if you want to test the images from those cameras against yours. That would be a sample size of three and therefore statistically significant. Driving is not a problem with me. I have met up with a few fellow Pentaxians in Yellowstone the last few years.


There was a tear in the fabric of space at Yellowstone today. Pentax stirkes back! - PentaxForums.com


Send me a PM if you want to meet up for a side by side test.
dang, I was just in Rochester area two weeks ago, visiting Watkins Glen and going further to Niagara. It's about 4.5 hours from me, I'll see if I can get up there again (brother studies in Buffalo, so not out of the question).
Thank you for the offer!

---------- Post added 11-01-18 at 11:52 AM ----------

QuoteOriginally posted by UncleVanya Quote
Heck if you are ever down south any I live in NC near Charlotte. I would love to see a K1 in person (either one) and get a feel for it. I have a K-3 and I would be happy to reciprocate if there is anything I have you wanted to try. (FA 31, F 50 f1.7, FA 50 1.4, FA 77, DFA 100, DA* 200, DA* 60-250 - not yet modified, FA* 300 are some of my FF lenses...)
NC is a tad far from me for a casual drive, but if I ever go on a NY - Florida drive like last year, I'll make sure to stop and say hello Would love to test the FA 77 actually)
11-01-2018, 12:20 PM   #29
Site Supporter
Site Supporter
IgorZ's Avatar

Join Date: Aug 2015
Location: Ottawa
Posts: 1,525
QuoteOriginally posted by awscreo Quote
well, it just seems strange - focused in the center of the frame, I can clearly see much softer right edge. Left edge is a bit soft, but overall it's very good for 2.8, the right edge is bad.
And it's consistently showing throughout the aperture range, it's just harder to notice at f8 onwards. I also see it in my astro shots, the right edge shows more coma and out of focus
stars than left edge, that should be a pretty good indication since it's focused on infinity right?

I'll pm Sandy Hancock, maybe he can show me that I'm wrong)

For reference - my last test series after 2nd servicing of the lens: https://drive.google.com/open?id=1RGOOXsLb081ir3KkmBF4oMACvbchMLY3
I think you are right, the right side looks worse to me...
11-01-2018, 12:23 PM   #30
Pentaxian




Join Date: May 2016
Photos: Albums
Posts: 2,122
QuoteOriginally posted by IgorZ Quote
I think you are right, the right side looks worse to me...
Yup, and it's my 3rd copy, and it's been serviced twice. So I'm wondering if it's my mount. I do notice slight softness with my dfa 28-105 on the right side as well, I wonder if the issue is worse with 15-30 because it's much wider.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
body, camera, da*, details, drive, dslr, f1.4, fa, full frame, full-frame, hd, k-1, k1, lens, mpx, nc, pentax k-1, resolution, rochester, sdm, sigma, test, yellowstone, zeiss
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Aperture control with Leica R and Zeiss Milvus, Otus on Pentax tduell Pentax SLR Lens Discussion 2 12-01-2017 02:48 PM
Nature Red Kite (Milvus Milvus) Over and Over Again ... Ian.morgan Post Your Photos! 8 11-19-2017 04:29 PM
Lightroom profile for Zeiss Milvus 18mm f2.8 peterh337 Pentax SLR Lens Discussion 4 11-17-2017 09:39 AM
New Zeiss Milvus 50mm f/1.4 lens on my Pentax K1 Fenwoodian Pentax SLR Lens Discussion 36 07-10-2017 09:03 PM
Zeiss anounces Milvus 35mm 1.4 for canon and Nikon D1N0 Non-Pentax Cameras: Canon, Nikon, etc. 7 06-21-2017 05:19 PM



All times are GMT -7. The time now is 12:23 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top