Re GN Topcor 1.8/50 vs Re.Auto-Topcor 1.8/58

[alex ph]

A while ago I was asking how Re GN Topcor 1.8/50 is compared with the most cherished and desired Re.Auto-Topcor 1.8/58. At that moment I did not find any clear statement or side-by-side comparison. I now have an opportunity to compare the GN with a 58mm which is a version with serial 116029.., and the FL written as 5.8cm.

I attest quite a slight difference which considers mostly bokeh. The GN has also a thinner DOF which is visible in the front OOF. But that might be my copy which seems to be dis- and reassembled in a slightly wrong way.

Meanwhile sharpness, colours and flare resistance are the same. What is surprising, I don't really see any difference in focal length between the 50mm and the 58mm lens. All shots are taken from the same position.

The camera is Nex-5N. Moderate contrast adjustment is applied.

#1 Re.Topcor 1.8/58, w/o


#2 Topcor.Re GN 1.8/50, w/o


#3 Re.Topcor 1.8/58, f2.8


#4 Topcor.Re GN 1.8/50, f2.8


#5 Re.Topcor 1.8/58, f2.8


#6 Topcor.Re GN 1.8/50, f2.8


#7 Re.Topcor 1.8/58, f2.8


#8 Topcor.Re GN 1.8/50

[kiddo]

Is it possible that we have a planar vs sonnar version?

[alex ph]

It's hardly possible, kiddo, both for the almost identical image character and for the acknowledgment of Re.Auto-Topcors as a double Gauss lens, for example here.

[tb_a]

[alex ph]

[Lightshow]

[cbass]

Thank you for the comparison. Am I seeing correctly that the 58 mm looks to be wider than the 50mm? Was it just your positioning?

[Ernst Dinkla]

[kiddo]

The GN looks softer at 2.8 that 1.8....thats weird

[alex ph]

My position was the same. And that's what I note as a surprise thing: I cannot see any difference in focal length. But I wouldn't say the 58 being wider. That might be an illusion coming from the mixed character of the objects in-frame. I'll make later a "brick wall" comparison, to be sure.

The GN that is sharper at f1.8 than at f2.8, I wouldn't say neither. If you look at the leaf in the center of #2 and #4, in #4 its edges and small details are better visible. But the 50mm front OOF blur is stronger than the 58mm has, and it is also a strange thing. Once again, might be my copy that has some signs of reassembly.

[cbass]

The GN appears to have softer corners, but better bokeh. I think my preference is the 58 f/1.8 from the pictures you posted.

[y]

Judging from shots #6 + #8 and the fact they were not taken using a FF camera it seems the GN's optics is indeed heavily misaligned. Poor lens

[alex ph]

I was also surprised by this front OOF rendering by the GN on Sony Nex. But those shots were taken with a FF Sony, some of them w/o at low light, and I cannot observe such an effect. I am puzzled indeed. I will make another test with both A7 and Nex, of a plane object, to see the difference.

[kiddo]

I think that we need some more info, generally, the RE 58mm were better spoken of lenses, that's why I didn't bother for the GN, even if can be easier and cheaper to find your samples of GN ,are nice on the oof area, I do prefer it better for portraits, just like I prefer the 1.4 vs 1.8 58mmRE. The same I prefer 1.4 vs 1.7 plannar C/Y.

[alex ph]

Fellows, here is an update about both lenses. I did not have time to find a brick wall, so here is an indoor uniform sequence taken on a tripod fixed at the same position. The shots are taken with Sony A7.

This more consistent test shows a real difference in focal distance. The rendering in-focus seems to be really the same, while bokeh differs slightly, as you already noted in the discussion.

The front OOF does not seem that different, as in the forest shots, the GN does not have a considerably thinner DOF. This becomes clear when you compare she shots looking in the lower right corner. To make it better visible, the last two shots are taken after I shifted the tripod, sot that the folder in focus finds itself in the upper right corner.

#1 Toprcor Re 1.8/58 at f1.8


#2 Topcor Re GN 1.8/50 at f1.8


#3 Toprcor Re 1.8/58 at f4


#4 Topcor Re GN 1.8/50 at f4


#5 Toprcor Re 1.8/58 at f1.8, a 100% unprocessed crop of the upper right corner


#6 Topcor Re GN 1.8/50 at f1.8, a 100% unprocessed crop of the upper right corner

[kiddo]

Thanks, as expected, the GN is wider (as it should be) and the 58mm oof areas is thinner also (again as it should be) , in the forest pics, the things looked quite different, I thought that you might have mixed the pics between 58 and 50mm . [/i]

[alex ph]

That must be an effect of the enchanted forest!

[John Shriver]

It would be interesting to compare curvature of field. The classic RE. Auto-Topcors do have curvature of field, it's what they let "slip" to make the other aspects of the lens good.

I've never tried my RE GN Topcor 50/1.8, but did like the results with the RE GN Topcor 50/1.4.

[alex ph]

That's an interesting question, John. I'll make some more test shots in mid-January.

Sorry for the delay with my reply and for the announced waiting. I am having a bit messy period.