Pentacon 2.8/29mm

[uddhava]

I took a few shots in Budapest with this lens recently.

#1


#2


#3


#4


#5


#6


#7

[thebbm]

perform far far better than the one i get

[Oldhand]

Very nice results - well done
OH

[uddhava]

Thank you both.
I was fortunate to have some sunny weather.
I have heard many persons have gotten bad copies of this lens.
Mine seems fine.

[Oldhand]

[Attila]

A 'gamble' lens you got best one seems, congrats!

[newst]

I used to have a Zeiss Jena version. An adequate performer but nothing spectacular. Zeiss name but no Zeiss zing.

[Attila]

[newst]

I do believe that back in the day when the DDR merged a number of lens manufacturers Zeiss ended up producing the 29mm Pentacon designed lens.

http://slrlensreview.com/web/reviews/carl-zeiss-lenses-swhorizontalmenu-172/zeiss-wide-angle/397-carl-zeiss-jena-29mm-f28-m42-lens-review

[ManualFocus-G]

Yep, the Pentacon 29/2.8 was also branded Carl Zeiss Jena for the final few years of production. Same lens of course

[kds315*]

Surprisingly good!! I have some sleeping here...hmm should use them!!

[Attila]

[vanylapep]

What's unique about this lens?

[Attila]

Price .. cheap

[thebbm]

[Attila]

[uddhava]

[Gerald]

Regarding the photos in the original post, the colors are well saturated, so we can say the optical lens surfaces must be clean and well polished. The general definition looks good. That lens certainly isn't a lemon. Sadly, the images are 6 MP only, what does not permit a good analysis of sharpness. In addition, an APS-C camera was used, what precludes any analysis of the outer portions of the lens' image circle. Information about the apertures used weren't provided, too, but any decent 28mm lens should work fine with F8 or F11 aperture.

Specific comments on the photos

Photo #1
The right side is a little softer than the left. It looks like the focal plane is slightly inclined due to inaccuracy of adapter, lens mount or camera flange; or maybe there is some decentering of the optical elements. Anyway, the effect is quite small to be ignored in most cases.

Photo #2
The same.

Photo #4
Coma visible in the corners, especially the lower left corner. This is typical of wide angle lenses when working wide open. Solution to cases like this: close the aperture to F11 and corners and edges will be much sharper.

Comments about the Pentacon 29mm F2.8 lens
A clue to this strange focal length is that Modern Photography measured it once and found the value 30.6mm. That is, 29mm is within the usual margin of 5% compared to the actual value of the focal length.

I have a copy of the Pentacon 29mm F2.8 and I can say it is a well-built lens and its performance is typical of many 28mm lenses of its time.

In my opinion, the Pentacon 29mm F2.8 is an underrated lens and the reasons for this are as follows:

1. It was produced in huge quantities at a time when East Germany desperately needed foreign exchange. The Japanese manufacturers were very competitive, so "made in GDR" lenses had to be sold at a very low price.

2. During the Cold War, the products produced in socialist countries were not well regarded in the West, and generally considered of low quality. This bad reputation was not entirely unjustified, however.

3. Collectors are more interested in famous names and rarity than in real technical quality. The Pentacon lenses are genuine Meyer lenses, but the name Meyer is not written on the lens ring. The Pentacon lenses were manufactured by the millions on the wrong side of the Iron Curtain, so it has always been a cheap lens.

4. Pentacon lenses very easy to open, so a lot of unskilled people have "repaired" Pentacon lenses (I just wonder how many Pentacon lenses have been destroyed by those lens "experts"). Hence the widespread opinion you need luck to get a good Pentacon lens.

5. Finally, never underestimate the psychological aspects, in particular the "price factor". Most people find difficult to assess the real quality of a lens, so expensive lenses are usually considered better than cheaper lenses, regardless of their relative technical merits. Leica and Zeiss, for example, know very well how to take advantage of people's ego.

[iangreenhalgh1]

The problem with the Pentacon 2.8/29 is field curvature which makes the outer part of the frame soft until the lens is closed down to f5.6. You can see the softness of the edges even on APS-C. The 2.8/28 that replaced it is a marked improvement.

[Gerald]

According to my observations, the main aberration that affects sharpness in the corners is coma. Coma reduces the contrast of fine details without greatly affecting the ultimate resolution. In contrast field curvature produces the effect of a slight defocusing, which significantly affects the ultimate resolution. Let's take a look at how the Pentacon 29mm F2.8 reproduces fine details for the various apertures. The pictures below are 100% crops of size 400 x 300 pixels. You should multiply the size of these rectangles by 15 to have the size of the full image. The images were converted from RAW without sharpening. Vignetting was corrected, but this doesn't affect resolution.

Upper left corner:



Center:



Upper left corner at F5.6 - Sharpened


The slightly whitening of the black squares' edges is caused by coma. Note how coma reduces the contrast of details, especially for the largest apertures F2.8, F4 and F5.6. Also note that when the lens is closed down from F2.8 to F4, the image quality in the corners is about the same. The quality in the corners only begins to improve noticeably when aperture is closed at least two stops. By the way, this is more or less normal for most lenses.

The corners improve significantly by F8, they are very good at F11, but still there is a small improvement at F16. Note that lateral chromatic aberration is more noticeable for small apertures. Luckily, lateral CA can be easily corrected in post-processing.

Rule of thumb: if you want high sharpness across the image, use F8, or preferably F11 or F16. Use the three widest apertures only in situations where corner sharpness is not important, or when light conditions are precarious and you cannot use a tripod. Out of curiosity I tried to sharpen in PP the corner for F5.6 aperture. Although PP doesn't work miracles, it is possible to greatly enhance the perceived sharpness.

What about the sharpness in the center? As expected the sharpness in the center are much higher than in the corners, especially for wide open. Indeed, sharpness in the center of the field is is already so high wide open that increase in sharpness is not dramatic if the lens is stopped down.

Finally, it is interesting to compare the performance of the Pentacon 29mm F2.8 with the SAL-28F28 Sony 28mm F/2.8. The images below were extracted from the review done by Kurt Munger in:
http://kurtmunger.com/sony_28mm_f_2_8_reviewid238.html




Note how the corner is smeared at F2.8 and F4. In fact, the behavior of the Sony lens is very similar to the Pentacon. To be fair, this kind of behavior is typical of most traditional wide angle lenses. I kept Kurt Munger's comments because they are spot on.

Again, if you want excellence in the center, stop the lens down two stops; if you want excellence at the edges, stop down four stops.