Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
02-23-2017, 01:42 PM   #1
New Member




Join Date: Feb 2017
Posts: 5
MU43 with vintage Pentax Glass

I started mounting old pentax lenses on a Pana G2 I picked up when they were dumping them at steep discount in 2011. I had the Pentax S1a that I gave my father for XMas in the early 70s. So I mounted 55mm ST f1.8 on the G2 and had lots of fun. I also had a vivatar 135mm f3.5 in m42 mount. Both lenses were tolerable at 12mp G2. The Vivatar didn't improve with stopping down. At F4 it was as gook as it was going to get. The ST55mm f1.8 wide open was soft and dreamy which I liked for some applications. At F2 it cut CA's some and helped contrast and from 2.9-5.6 in improved.

In 2013 an old friend gave me his Pentax gear. All of it. Two bodies seven lenses. Most of it was late 1970s gear and had been toted all over europe and middle east under unfavorable circumstances. I found this fourm when I started looking for comments on lens performance for the lens in his kit. I ended up keeping all but lens which was not a pentax and was worthless for digital. I am now shooting with them on an OLY E-M5 MK1. Most of reviews I found on the lenses seemed somewhat weighted toward optimism on issue of resolution. The reviewers don't always tell you what body they were testing the lens with and this makes for diffiuclties since. One I read which really supprised me was a fellow who had mounted a SMC 35mm F3.5 on a Sony A7 and reported that it worked well. The lenses I have tested include Pentax-M 200 F4, Pentax-M 85mm F2, Pentax-M 50 F2, Pentax-M 55mm F1.7, F4, ST 150mm f4, SMC 35mm F3.5. The last in the series is the most problematic since I was unable to get any kind of resoution in corners even at f8. The lens is in pristine conditon, looks brand new. No dust, no mould, flawless glass. On MU43 cameras it is soft at f8-f3.5 getter softer as you open up.

Perhaps something happend to this looks like new lens while it was toted through the Sinai in 1979. The other lenses which were along for the ride work as expected. The Pentax-M 85mm F2 has spots of mould on the internal surfaces but it doesn't cause any problems on 4/3 sensor. It is soft with hugh CA's wide open but from f2.8 to 5.6 or even f8 it is very usable. I mention it since it is most damaged lens in the lot and the SMC 35mm F3.5 is the most undammage, virtually mint condtion lens.

Anyway,

I did film photograpy in 1970, worked for studios, labs, freelance. From 1980-2005 didn't own a camera. Been shooting 4/3 cameras since 2006.

Stirling Bartholomew

02-23-2017, 02:04 PM   #2
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 15,781
@DCShooter
DCShooter has mentioned before that a reversed element can cause the kind of problem you report where you can't get sharpness outside of the center but that may be unrelated here. Post some pics of the 35mm and the corner softness for some input.

I use M43 and APSC K-3 with m43 native and K mount lenses used on the M43. I'm using a Panasonic GX-1 and sometimes borrowing my old camera back from my dad a Panasonic GX-7. Both are 16mp sensors but the GX-7 has some in body image stabilization and better manual focus aids which work better for me with adapted lenses.

I don't think your copy of the 35 is indicative of the rest based on the reviews out there but as you say some can be rather optimistic. In m43 you are only using the center portion of the image circle which generally has a higher quality. The fact that you have such poor corners makes me suspect the reversed element or something along those lines.

---------- Post added 02-23-17 at 04:12 PM ----------

Case in point:
http://nappycafe.com/pentax/construction-western.jpg

Posted in the review section for the lens and shot on a K-3.
Looks pretty sharp to me all over but I'm not pixel peeping it. I could be missing something.

Last edited by UncleVanya; 02-23-2017 at 02:13 PM.
02-23-2017, 02:19 PM   #3
PEG Moderator
Loyal Site Supporter
Kerrowdown's Avatar

Join Date: Aug 2008
Location: Hielands o' Scootlund
Photos: Gallery
Posts: 41,967
Welcome to the forum, an interesting intro and I'm sure folk here may have some suggestions on some your issues.
02-23-2017, 09:51 PM   #4
pjv
Otis Memorial Pentaxian
Loyal Site Supporter
Loyal Site Supporter
pjv's Avatar

Join Date: Mar 2015
Location: Melbourne, Australia
Photos: Gallery
Posts: 6,251
Hi from Australia Stirling. Welcome to the Pentax forums. I am not qualified ( don't know enough !! ) to respond to your issues, so I will just say Hi and good to have you aboard.

02-24-2017, 11:09 AM   #5
New Member




Join Date: Feb 2017
Posts: 5
Original Poster
Thank you for the replies. This is a friendly forum.

I took the SMC 35mm F3.5 for another field test. I find shooting charts in my living room tedious and I have already done that. Look at what I shot yesterday I can see how someone shooting film and printing 8x10s or even 11x14s might find this lens usable. But pixel peeping and comparing the results to the Oly E1 "kit lens" aka Zuiko 14-54mm f2.8-3.5 the digital zoom lens at 35mm is better at f4 than the Pentax at any aperture. This shouldn't surprise anyone. The digital lens was designed for digital sensors which put demands on a lens somewhat different than film.

I do a lot of shooting of flat surfaces at 90 degrees, the brick wall shot, so any kind of field curvature would be notable at wide apertures. But f4-5.6 on 4/3 sensor equal to two stops smaller in 35mm film. So DOF isn't the issue. I also specifically tested using charts for field curvature and it turns out the corners are soft even when you focus on the corner. So perhaps the lens is damaged from heat but not vioiably. It was hauled all over Israel for 8 months in a backpack which was left sitting in the sun.

I would like a to use a smaller lens than Zuiko 14-54mm f2.8-3.5 for street shooting. But it is my best option under the circumstances. I had a 28mm prime with a Pentax K mount but it was some off brand and optically it was worthless. SMC 35mm F3.5 delivers decent medium size images. But when you shooing complex and high contrast texture the gradual softening toward the corners isn't acceptable.

I saw one review of the SMC 35mm F3.5 which had resolution charts showing three zones: middle 2/3 and extreme corner resolutions. The charts mirrored my test results. The extream corners were soft to marginally acceptable at all apertures. Again, I didn't run the test for these charts and know nothing about how they were done. My own living room tests were done at a distance of 3 meters shooting at five US AIRFORCE charts vintave 1951. After running these tests my experience in the field shooting side by side with the Zuiko 14-54mm resulted in retireing the old prime.
02-24-2017, 12:39 PM   #6
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 15,781
Given the 2x crop factor I can't fathom how the results would mirror. You should only be seeing the central resolution. I'm also unclear how so many others see the lens as edge to edge sharp - but that's what you see.

Oddly many of those are shots on a k-3 at 24mp and a 1.5x crop. So they are including parts of the image circle that are outside what you are seeing.
02-24-2017, 08:39 PM   #7
Pentaxian




Join Date: Jan 2010
Location: Michigan
Photos: Gallery
Posts: 2,207
Hi SB,
What adapter are you using, and is it on register, and parallel, and with high emissivity bore?
I took these tonight with the E_PL_1 ( camera jpgs 1600 x 1200)

M.ZUIKO DIGITAL 14~42mm 1:3.5~5.6 set at ~ 35mm
https://app.box.com/s/f09lhvhrdvvh6o7qespodd65th6a4w6w

with my home machined adaptor and the SMC Pentax-M 1:2.8 35mm
https://app.box.com/s/n6e6t81y540q5npn4ywhofurqicl7jd6


https://app.box.com/s/db2d50c7edecf721ca74
02-25-2017, 08:52 AM   #8
New Member




Join Date: Feb 2017
Posts: 5
Original Poster
QuoteOriginally posted by UncleVanya Quote
Given the 2x crop factor I can't fathom how the results would mirror. You should only be seeing the central resolution. I'm also unclear how so many others see the lens as edge to edge sharp - but that's what you see.

Oddly many of those are shots on a k-3 at 24mp and a 1.5x crop. So they are including parts of the image circle that are outside what you are seeing.
I agree. The general pattern of the results are typical of many lenses. Its like seeing a radial gradient in Lightroom. The center out performs the edges by a significant amount. In the case of the test i saw the drop between the center and the mid-postion was radical so that would mirror what you would seen on 4/3 crop. Doesn't really matter how it performs on other sensors. I am using the same adapter for three other lenses and it works fine. This was a topic for introduction to the forum not some big problem that needs to be solved. My tests on the other vintage lenses produced results you would expect. The pentax-m 200mm f4 isn't steller but usable. The ST 150mm f4 is better than the 200mm. The ST 55mm f1.8 and Pentax M-55m f1.7 are both very good, with the later showing sligt edge over the older at f2. The Pentax M-50mm F2 isn't in the same ball park so it ghathes dust. I keep in permanently mounted on a pentax K1000 body which will probably never be used.

Thanks for all the replies.

02-25-2017, 09:53 AM   #9
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 15,781
QuoteOriginally posted by Stirling Bartholomew Quote
I agree. The general pattern of the results are typical of many lenses. Its like seeing a radial gradient in Lightroom. The center out performs the edges by a significant amount. In the case of the test i saw the drop between the center and the mid-postion was radical so that would mirror what you would seen on 4/3 crop. Doesn't really matter how it performs on other sensors. I am using the same adapter for three other lenses and it works fine. This was a topic for introduction to the forum not some big problem that needs to be solved. My tests on the other vintage lenses produced results you would expect. The pentax-m 200mm f4 isn't steller but usable. The ST 150mm f4 is better than the 200mm. The ST 55mm f1.8 and Pentax M-55m f1.7 are both very good, with the later showing sligt edge over the older at f2. The Pentax M-50mm F2 isn't in the same ball park so it ghathes dust. I keep in permanently mounted on a pentax K1000 body which will probably never be used.

Thanks for all the replies.
Understood. But my point is that if other sensors are showing different results - and you don't have another sensor to test your copy against - then the problem of determining if your copy is representative (which you seem to assert) or non-representative (which photographic output from other photographers seems to assert) is the question that needs to be answered. Your results are not in question. What's in question is what we should make of this. Even if you had an APSC sensor or FF sensor to test against - if the results were atypical we could still be at a loss as to the source - it might be that your copy is bad - it might be that a lot of copies are bad. It's a mess since there is very little science applied because of small sample sizes.
02-25-2017, 03:23 PM   #10
New Member




Join Date: Feb 2017
Posts: 5
Original Poster
QuoteOriginally posted by UncleVanya Quote
Understood. But my point is that if other sensors are showing different results - and you don't have another sensor to test your copy against - then the problem of determining if your copy is representative (which you seem to assert) or non-representative (which photographic output from other photographers seems to assert) is the question that needs to be answered. Your results are not in question. What's in question is what we should make of this. Even if you had an APSC sensor or FF sensor to test against - if the results were atypical we could still be at a loss as to the source - it might be that your copy is bad - it might be that a lot of copies are bad. It's a mess since there is very little science applied because of small sample sizes.
I am really not assuming that my lens is typical. The resolution charts were small and not really readable where I saw them posted. It looked like the fall off in resolution from center to 2/3 was pretty dramatic but if people are getting good shots on 24mp FX cameras with this lens I am willing to accept the fact that damage to lens might not be visible. Under extreme heat the surfaces between the lens elements might undergo irreversible changes which would throw everything out of alignment without it being visible looking into the glass.

What defies imagination is why I have a Pentax-M 85mm f2 lens with visible mould in dozen places on internal surfaces and find it quite usable and other hand have a spotless pristine lens SMC 35mm f3.5 which the more I look at it with strong light at various angles I am convinced it has no internal defects, not even a tiny dust spots. This perfectly spotless lens is not behaving as it should. I can see using the 10x focus enlargement in the Oly EM-5 that the whole image is soft and doesn't improve much stopping down. Most of my field test shots look decent at 1:2 in Lightroom. It is only at 1:1 you see the difference between the different lenses.

I like to experiment with lenses that have faults like flare and CAs to see what sort atmospheric affect can be gained. Recently read the autobiography of Sally Mann titled "Hold Still" which got started on playing around with all the old lenses again.

Thank you for the replies.

Last edited by Stirling Bartholomew; 02-25-2017 at 03:56 PM.
02-26-2017, 06:58 AM   #11
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 15,781
I do still wonder if an element could be reversed.
02-26-2017, 06:11 PM   #12
New Member




Join Date: Feb 2017
Posts: 5
Original Poster
corner shot magnifed 2:1

I know this doesn't matter but I did quick living room shot focusing on the left hand corner and did a comparison of Zuiko 14-54mm at 35mm, with 1/3 stop increments from f3.2-f5.6 and then the SMC 35mm f3.5 same setup with half stop increments when possible. The wide open f3.2 Zuiko shot was better than the best I could get from SMC 35MM at f6.3 or f8. Here are screen captures of images in Lightroom at a ratio of 2:1. First Zuiko 14-54mm at 35mm at F4. Next is the SMC 35mm at f6.3 which was best of the lot. (Not much change from f5.6-f8, however f6.3 is a lot better than f3.5. You can see that plainly in field tests. It isn't the <acronym title="Out of Focus"><acronym title="Out of Focus">OOF</acronym></acronym> that bothers me, its the qulaity of OFF, the bokeh is ugly in a number of my field tests. It isn't far enough <acronym title="Out of Focus"><acronym title="Out of Focus">OOF</acronym></acronym>, just enough to look jagged. These screen shots at 2:1 make bokeh look smoother than what I was bringing home in the field tests. I would post field tests but they subject matter wasn't thrilling and it would waste storage.

The third shot is the SMC 35mm F3.5 wide open at f3.5.
Attached Images
     

Last edited by Stirling Bartholomew; 02-26-2017 at 06:35 PM.
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!
35mm, center, element, f2, f3.5, f4, g2, image, lens, lenses, m43, panasonic, pentax, pentax-m, post, smc
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
New glass - old glass. Which lenses should Pentax revisit? HopelessTogger Pentax Full Frame 204 09-07-2017 05:12 AM
Pentax K-1 with Takumar glass pentaxbuff Pentax K-1 2 11-03-2016 08:26 PM
Having a K1, now is the time to shop for vintage glass biz-engineer Pentax K-1 24 06-20-2016 06:35 PM
People Vintage Glass back in Time Rense Post Your Photos! 6 07-15-2011 05:07 AM



All times are GMT -7. The time now is 04:31 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