[Voe]

Since I bought the Voigtlander Nokton 58mm f/1.4 (made by Cosina) which is based on Re.Auto-Topcor 58mm f/1.4 made by Topcon, I always wondered how the original compared to its new copy.

My curiosity and lust for lenses made my pull the ebay trigger on a used Re.Auto-Topcor 58mm f/1.4. The lens came with oily and stuck aperture blades, some dust and unfortunately cracked rubber focusing grip.

It took me more than 10 hours to disassemble the lens to it's bits and pieces, clean, lubricate and reassemble it. What a relieve completing this, tonight I will have a good sleep
Tomorrow (Sunday) I will do some comparisons between the Voigtlander and the Topcor.

[augustmoon]

Also interested in in your lens taking apart (and more importantly) putting back together techniques and advice!!!

[rover]

After all that work, how can we not be interested?

And also a simple yes, and also thank you for saving me the $$$ to buy a Topcon and Topcor 58 to answer the question myself.

[walter]

Also interested in in your lens taking apart (and more importantly) putting back together techniques and advice!!!

Same here. I'd like to see pictures of the disassembly if you have any. The lens comparisons would be cool too.

[k100d]

sweet, how much is the Voigt based on the Topcor? is it the exact same optical design?

[Big Dave]

Voe,
Are you going to adapt the Topcor to fit a K-mount or shoot with a Topcon film slr? I know that it has a fairly small lens mount. This may help in adapting it for infinity focus. At 44.7mm you will have to remove some material from the mount area to get infinity on a Pentax. The Pentax regristration distance of 45.5mm is 0.8mm greater then Exacta/Topcon. It should make a great 57mm equivilent portrait lens.

Dave

Since I bought the Voigtlander Nokton 58mm f/1.4 (made by Cosina) which is based on Re.Auto-Topcor 58mm f/1.4 made by Topcon, I always wondered how the original compared to its new copy.

My curiosity and lust for lenses made my pull the ebay trigger on a used Re.Auto-Topcor 58mm f/1.4. The lens came with oily and stuck aperture blades, some dust and unfortunately cracked rubber focusing grip.

It took me more than 10 hours to disassemble the lens to it's bits and pieces, clean, lubricate and reassemble it. What a relieve completing this, tonight I will have a good sleep
Tomorrow (Sunday) I will do some comparisons between the Voigtlander and the Topcor.

[Voe]

Same here. I'd like to see pictures of the disassembly if you have any. The lens comparisons would be cool too.

Sorry guys, I did not take any pictures except the ones taken with the lens while adjusting the focus mechanism.

The hardest part was to put the aperture blades back, it was very frustrating and I was very close to give up. The thing is that the aperture blade mechanism sits between 2 metal plates in the shape of a ring, and one of them has a tiny spring which I did not want to take off as it seemed too hard to put back(it was not the usual spring attachment). This whole package (easily falling apart) I had to put back in the body part(kind of an aperture container about 3-4cm deep and making sure the small spring goes through a tiny whole at the bottom of the container. So with the help of a thread I pulled the spring through the whole while in the same time using a plastic bottle top that holds the 2 ring shape plates (the one holding the blades) to slightly insert it in into the aperture blades container. Basically what I call blades container is the body part joining the back element group and the front element group and also contains the aperture related mechanism and springs.

sweet, how much is the Voigt based on the Topcor? is it the exact same optical design?

Not sure how much, but all I know is that the design was modified by Cosina so it's not exactly the same.

Voe,
Are you going to adapt the Topcor to fit a K-mount or shoot with a Topcon film slr? I know that it has a fairly small lens mount. This may help in adapting it for infinity focus. At 44.7mm you will have to remove some material from the mount area to get infinity on a Pentax. The Pentax regristration distance of 45.5mm is 0.8mm greater then Exacta/Topcon. It should make a great 57mm equivilent portrait lens.

Dave

Hi Dave,

I bought this lens for my Pentax K10D, and I don't have a Topcon SLR. I already modified a Re.Auto-Topcor 135mm f/3.5 and Re.Auto-Topcor 35mm f/2.8 for Pentax. No issues with focus to infinity.

Someone might suggest a better way but I adjusted the focusing by trial and error method. As with my other two Topcon lenses I had to modify (cut about 2-3 cm) the focus limiter spacer on one of helicoids to allow for bigger range of focusing. This way I did not have to shave part of the body holding the lens mount to allow focus to infinity.

BTW I find white lithium grease great for lens focusing mechanism. I have used it on about 4-5 lenses already. This thing makes my old soviet lenses focus like Takumars, really smooth and dampened. The best part is that it does not leak when/if the lens is exposed to hot weather environment.

[Big Dave]

Voe,
Good job on the 135. I guess there is more ways then one to skin a cat. Trimming the helical is another way. Thanks for the tip about grease.

Dave

Sorry guys, I did not take any pictures except the ones taken with the lens while adjusting the focus mechanism.

The hardest part was to put the aperture blades back, it was very frustrating and I was very close to give up. The thing is that the aperture blade mechanism sits between 2 metal plates in the shape of a ring, and one of them has a tiny spring which I did not want to take off as it seemed too hard to put back(it was not the usual spring attachment). This whole package (easily falling apart) I had to put back in the body part(kind of an aperture container about 3-4cm deep and making sure the small spring goes through a tiny whole at the bottom of the container. So with the help of a thread I pulled the spring through the whole while in the same time using a plastic bottle top that holds the 2 ring shape plates (the one holding the blades) to slightly insert it in into the aperture blades container. Basically what I call blades container is the body part joining the back element group and the front element group and also contains the aperture related mechanism and springs.





Not sure how much, but all I know is that the design was modified by Cosina so it's not exactly the same.



Hi Dave,

I bought this lens for my Pentax K10D, and I don't have a Topcon SLR. I already modified a Re.Auto-Topcor 135mm f/3.5 and Re.Auto-Topcor 35mm f/2.8 for Pentax. No issues with focus to infinity.

Someone might suggest a better way but I adjusted the focusing by trial and error method. As with my other two Topcon lenses I had to modify (cut about 2-3 cm) the focus limiter spacer on one of helicoids to allow for bigger range of focusing. This way I did not have to shave part of the body holding the lens mount to allow focus to infinity.

BTW I find white lithium grease great for lens focusing mechanism. I have used it on about 4-5 lenses already. This thing makes my old soviet lenses focus like Takumars, really smooth and dampened. The best part is that it does not leak when/if the lens is exposed to hot weather environment.

[Voe]

Someone can prove me wrong but, I believe comparing these two lenses is something that no one have ever done (at least not published on the Internet).
The Voigtlander Nokton is one of the most respected if not the best of 50-58s bokeh wise. I tried to question that before with my Volna-9 50mm f/2.8 and in a way I succeeded.
Since I got my Nokton I was always happpy with it, but I kept asking myself how will the original Topcor 58mm f/1.4 do in comparison with the Cosina made copy.

Here is the test scene. With all the metallic objects the scene is really tough for these lenses:




The contenders:





Bokeh comparison at f/1.4:

Voigtlander Nokton


Topcor:



Center crop comparison:


The full size crops are here:
http://farm4.static.flickr.com/3112/3105423457_d8c37cf30f_o.jpg

The rest of the images you can get them in full size here:
Flickr: VoeBoe's Photostream

The conclusions are yours to make.

Thanks for watching

[Matt Miller]

The Nokton appears to have more contrast, which is an appealing feature, at least to me. Bokeh looks identical to my untrained eye though.

[Voe]

The Nokton appears to have more contrast, which is an appealing feature, at least to me. Bokeh looks identical to my untrained eye though.

Agree about the contrast, but I see the bokeh of the Topcor slightly softer. Also the Nokton appears slightly sharper (or is it just better contrast) than the Topcor at f/1.4.

Also if you look at the OOF highlight rings, the Topcor has complete circles while the Nokton shows coma aberration (see the viking with the arrows and the red flower).
Leaving this aside the bokeh of the Topcor appears a tiny bit more pleasant.

BTW, I posted some photos made with the Topcor today at:
https://www.pentaxforums.com/forums/post-your-photos/

[rover]

Great work Voe, thank you. The Nok seems like a pretty authentic reproduction of the Topcor imagewise. A little difference here and there, but it does a good job of recreating what the Topcor produces.

[Wombat]

I've really enjoyed this thread, having owned an RE2 for about thirty years. (Wish I'd never sold it). The 58 was a helluva lens, as was the 135. Had no idea of the Voigtlander connection. It does seem a little sharper in your pics, but as you say it may be the contrast. Thanks for sharing.

[k100d]

really appreciate the work here. i too see that the voigt seems to be a bit sharper and higher contrast, but the difference is rather small. but that topcon lens is hawt in silver!

voigtlander made special replica lenses, link to photo here http://cameraquest.com/jpg4/BesFlexSilv5.jpg

[lbam]

Wow, a juicy thread :-P

I knew the Nokton was based on the Topcor, and agree with all the comments about the image comparisons except maybe the bokeh part which is pretty subjective.

Most of all I have to say thanks for putting in the work and doing the comparison... In all my internet trawling I haven't seen a direct comparison either...

I also feel the silver finish of the Topcor is slightly more to my taste.. what a beauty!