Yet another Pancolar 2/50 M42 Star Wars

macheck · Joined: 30 Oct 2013 Posts: 131 Location: Poland

Hello

It is my first post on the forum but previously I have been here and there a lot of times as a guest.
Please help me to evaluate the quality of above mentioned lens.
I think that it produces a sharp distorton free image (Pentax K10D) but I do not have a lot of reference.
First the lens, Pancolar 2/50 M42 with moveable DOF range scale with non locking lever for aperture manual closing (known as Star Wars version):
Front view:

Rear view:

1. Pancolar 2/50 M42 (5.6):

1a. Pancolar 2/50 M42 (5.6) crop 100%:

1b. Pancolar 2/50 M42 (5.6) crop 200%:

2. Pancolar 2/50 M42 (5.6):

2a. Pancolar 2/50 M42 (5.6) crop 100%:

3. Pancolar 2/50 M42 (5.6):

3a. Pancolar 2/50 M42 (5.6) crop 100%:

4. Pancolar 2/50 M42 (2):

Any comments and remarks are very welcome.

Macheck

fuzzywuzzy · Expire: 2013-11-30

Attila · Expire: 2025-11-18

Welcome , nice to see here! Great lens congrats!

Nordentro · Expire: 2015-01-29

Welcome!
Very nice samples you got here from the Star Wars Wink

First time I see 200% crop Very Happy

Why the 200%? Surprised

mo · Expire: 2016-07-30

It's my favorite lens so I am biased,just enjoy it. Very Happy

I know its hard to find for the right price especially in the M42 mount.What serial number is yours?

macheck · Joined: 30 Oct 2013 Posts: 131 Location: Poland

Thank you very much for kind replies.
The main reason for my posting was to ask you for the opinion about the performance of the lens, that is why 200% crop, since 100% was not detailed enough - it is my observation of balcony balustrades.
My opinion is that this lens is better (rather more distinct) at infinity.
Serial number: 7244854
Macheck

mo · Expire: 2016-07-30

Here are some samples from Attila's gallery on this site
http://www.mflenses.com/gallery/v/german/zeiss/pancolar/carl_zeiss_jena_pancolar_50mm_f2/?

Thanks for your serial number,I am collecting them as a hobby. Embarassed

Mos6502 · Joined: 20 Jun 2011 Posts: 961 Location: Austin

The 2/50 is my favorite lens when using my Exakta, I think maybe the best standard lens for the Exakta that was made. Its sharpness and rendering are admirable and classic.

Ray Parkhurst · Posted: Mon Nov 04, 2013 4:03 am Post subject:

With lenses which are capable of resolutions well beyond DSLR or MILC sensors, it's often difficult to make an objective determination of just how good they really are. Your 200% crops are a valiant attempt to do this, but don't actually give any more info than 100% crops since the limiting factor is your camera, not your lens. Your K10 has around 6um pixels, and this results in a DLA of about f10. So any aperture larger than f10 is being "lost" on the camera from a sharpness perspective. In fact, your f2 lens is more than 4 stops better than your camera(!!). The anti-aliasing filter in your camera makes the situation even worse, reducing the effective resolution to an even smaller aperture value. Large apertures of course make sense from a DOF perspective but they are useless for checking lens sharpness.

The simplest way to compare the real capability of large-aperture lenses is to add a teleconverter, or even stacked teleconverters. For instance, if you add a 2x teleconverter to your 50mm f2 lens, it effectively becomes a 100mm f4 lens. The resolution of this system is still well beyond your camera's capabilities, so you'll see little degradation in image quality (except for any distortion caused by the teleconverter itself). In fact, for your case, you could add a cascade of two 2x teleconverters, making an effective 200mm f8 lens, and still not cause image degradation problems due to diffraction(!!). This is because f8 is still larger than the f10 DLA of your camera.

Try a simple experiment with 2 images:
1) Shoot without teleconverter at f2 and take a 100% crop of representative part of the image.
2) Shot with teleconverter (still at f2 on the lens). Take a 100% crop of the same area, but of course it will be 2x the size. Downsize this resulting crop by 2x so it is same size as #1 crop above and compare.

Since you were doing 200% crops, you could also compare a 200% crop from #1 with 100% crop from #2.

In each case, you will see a better result with the teleconverter image than with the bare lens.

Ray

macheck · Joined: 30 Oct 2013 Posts: 131 Location: Poland

Thank you very much for inputs.
Ray, the method you propose is worth trying. I never thought of teleconverter as an aid for assessing lens quality but using it as a magnifying glass might be of some help when lens over resolves the sensor. The drawback is the observation will be more limited to central part of image.
Thank you for the inspiration I promise to produce the testing results.
Pardon me but reading the first paragraph of your post I have a feeling that in two places there it would be better to replace the word "aperture" with phrase "f-stop value".
Departing from the pure diffraction issues, I would also say that moderate f-stop values help to minimize the lens aberrations that are also playing some role in the sharp image creation.

Sincerely
Machcek

Ray Parkhurst · Posted: Tue Nov 05, 2013 5:17 am Post subject:

mo · Expire: 2016-07-30

This isn't the best example but I hope it conveys that sharpness is not always needed.Although I think this lens is sharp enough stopped down.

This is from my Pancolar 2/50 on the Pentax K-01, I think it's either wide open or at least under F4