Topcor LTM Topcor LTM Lens Compendium

[Miles.]

Hi all,

I've spent the last few years collecting and using a few of the lenses Tokyo Kogaku (Topcor) made in LTM. There is very little info about these lenses available online and I thought it best to share what I know, what I don't, and any other resources I've found along the way. Please comment below with what you've learned, too, and I'll try my best to update this first post as we go. This project started out because of a lack of production info about these lenses and grew from there.

Topcor 3.5cm f2.8 LTM
A classic 6/4 double gauss lens with two filter mounts (34mm and 40.5mm). I've found this lens to be particularly exceptional on film and rivals the best 35mm LTM lenses of the era. Originally sold with a very large external viewfinder. No known variants.

Production info
Earliest Known: 28571
Latest Known: 29893

Topcor 5cm f1.5 LTM
A 7/4 Double-Gauss with quite a few variations along the way. Early examples are marked Simlar and have a red C on the name ring. The barrel design changed several times with the design, or lack of, knurling on the front rim. At around 152xx the filter thread changed from 39mm to 40.5mm, and the aperture went from click-less to clicked. It seems the type of glass, coating, and optical formula changed slightly throughout production.

Production Info
Earliest Known: 150030
Latest Known: 153879

Topcor 5cm f1.8 LTM
A 6/4 Planar. No experience yet with this lens. Uncommon.

Production Info (Small sample size)
Earliest Known: 580080
Latest Known 581220

Topcor 5cm f2 LTM

No experience yet with this lens.

Topcor-S 5cm f2 LTM "All Chrome"

One of only a handful 5cm rangefinder lenses with a Biotar optical formula. An exceptional performer on both film and digital. 40.5mm filter thread. Heavy chrome over brass construction.

Production Info
Earliest Known: 210034
Latest Known: 218847

Topcor-S 5cm f2 "Panda"

Same barrel and materials as previous but with a different color scheme. Some have suggested that there is a difference in optical performance but I haven't used enough examples to confirm this. This variant is the rarest of the three and commands a premium. 40.5mm filter thread.

Production Info
Earliest Known: 217984
Latest Known: 220100

Topcor-S 5cm f2 "Black/Silver Aluminum"

A complete design departure from the two previous variants but I haven't used enough examples of each to suggest a difference in optical performance. The barrel is now aluminum and the focus throw is reduced to a short 90 degrees. The most common and affordable of the three. 40.5mm filter size.

Production Info
Earliest Known: 540253
Latest Known: 552843

Topcor 5cm f2.8

An uncommon 5/3 Heliar, perhaps the only classic 5cm ltm lens with such an optical design. Very high resolving. The focus throw is a short 90 degrees. The original hood is ingeniously designed, allowing it to collapse over the lens when not in use. Uncommon and under-appreciated given it's unique optical formula. Due to it's size and weight, it's a perfect pairing for a pre-war Barnack. 34mm filter size.

Production Info
Earliest Known: 270154
Latest Known: 272319

State/Simlar/Topcor 5cm f3.5

A 4/3 Tessar. No experience yet with this lens. Lots of variations along the way.

State/Simlar/Topcor 9cm f4 & f3.5

A 4/3 Tessar. No experience yet with this lens.

Topcor 13.5cm f3.5

A 4/3 Tessar. No experience yet with this lens.

Additional Resources

Topcon Club is a Japanese collector website that has a lot of great information on these lenses, including optical diagrams. The site is often buggy, down, and is not easily found when using an english language web browser.

Link: TOPCON CLUB-Topcor Lenses 6

 

[Sonnar Brian]

Very Interesting- my Simlar 5cm F1.5, 150074- no red C. Stops down to F16. I've read the earliest ones stopped down to F12.5, used the early Leica progression. Internally, my lens has a "10" inscribed. Thought it might mean the 10th with F16, but not sure. Mine came on a Leotax D-IV, early one with 4-digit SN.

Early lens: this one had to soak for 4 days to loosen the helical. The Six flat-head screws- all had to be screwed back into the same holes that they came out of. A real hand-made job. I suspect production got more uniform with later lenses.


Hope you do not mind the Photos- not many teardowns of this lens have been posted. I've done this for two lenses. This one is mine.

 

[Miles.]

Very Interesting- my Simlar 5cm F1.5, 150074- no red C. Stops down to F16. I've read the earliest ones stopped down to F12.5, used the early Leica progression. Internally, my lens has a "10" inscribed. Thought it might mean the 10th with F16, but not sure. Mine came on a Leotax D-IV, early one with 4-digit SN.

Yours is the second earliest I have documented, making 150030 the only I've seen with a red C. Thanks for sharing your info/insights! Somewhere I have a photo of 150030 and I'll post it when I find it again.

 

[Sonnar Brian]

I should also add that the Simlar 5cm F1.5 is a Double Gauss lens, 1-3-2-1 Seven elements in Four Groups. Take a standard 1-2-2-1 double Gauss lens (such as a Biotar) , and split the front doublet into a triplet where each element is of lesser power. This saves two air/glass surfaces compared to other lenses such as the Nikkor 5.8cm F1.4 and Summarit 7/5. The Canon 85mm F1.5 is also a 1-3-2-1 configuration.

 

[Miles.]

I should also add that the Simlar 5cm F1.5 is a Double Gauss lens, 1-3-2-1 Seven elements in Four Groups. Take a standard 1-2-2-1 double Gauss lens (such as a Biotar) , and split the front doublet into a triplet where each element is of lesser power. This saves two air/glass surfaces compared to other lenses such as the Nikkor 5.8cm F1.4 and Summarit 7/5. The Canon 85mm F1.5 is also a 1-3-2-1 configuration.

Thanks for the correction, Brian. I thought that I might be able to continually edit the post but seems that is not the case.

 

[newst]

I don't know whether this indicates a split such as you list in the Topcor/Topcor-S 2/50 lenses, but my copy is a Topcor-S 1.8/50. It is a standard planar design with excellent sharpness. I have never seen a 1.8 for sale on its own and was just lucky enough to notice that an ebay seller had listed a Leotax camera with a Topcor 2/50 lens, where the photographs were clearly of a 1.8/50. When the seller confirmed that the lens for sale was actually a 1.8 I bought the camera immediately. The lens is S/N 580168.

 

[Miles.]

I don't know whether this indicates a split such as you list in the Topcor/Topcor-S 2/50 lenses, but my copy is a Topcor-S 1.8/50. It is a standard planar design with excellent sharpness. I have never seen a 1.8 for sale on its own and was just lucky enough to notice that an ebay seller had listed a Leotax camera with a Topcor 2/50 lens, where the photographs were clearly of a 1.8/50. When the seller confirmed that the lens for sale was actually a 1.8 I bought the camera immediately. The lens is S/N 580168.

Here’s the optical diagram for the Topcor 5cm f2 vs Topcor-S 5cm f2



Thanks for sharing your thoughts on the 1.8!

 

[David Murphy]

My experience with the Topcor 5cm F1.8 (or possibly F2), not sure which model, although it had a bright finish (not black), was that it was exceptionally sharp. On the other hand, I found the Simlar 5cm F1.5 to be lacking optically, which is surprising considering how much people pay for these now. I now own a Tokyo Optical 5cm F3.5 collapsible, a real beauty of a Japanese-made Elmar copy. It is not marked "Simlar", like the Elmar copy that was often sold with Leotax cameras. Were these lenses also Topcon products?

How about the Leonon 5cm F2 also sold with Leotax cameras? Was this a Topcon lens? I own one and it gives very good results IMO. Nicely made as well, and not too expensive.

 

[Coldkennels]

How about the Leonon 5cm F2 also sold with Leotax cameras? Was this a Topcon lens? I own one and it gives very good results IMO. Nicely made as well, and not too expensive.

This website goes into the various Leonon lenses quite well: Leotax Rangefinder Cameras

The key takeaway seems to be that while they're very similar to Topcon lenses provided with earlier Leotaxes, "It seems to me that the two later Leonons at least are different enough to not be typically Tokyo Kogaku made", and "Several Japanese web & blog sites, including the respected Topcon Club [...], claim that “the Leonon lens” (all three, two, one?) was made by Showa Koki (not related to Shōwa Kōgaku)".

The Leonon 50/2 I own (230997) is very weird; not only does it noticeably back-focus compared to other LTM lenses (the focus point for both of these was the broken-off section sticking up vertically in the middle of the frame), but it also acts like a totally different lens at f/2 compared to all other stops. Here's it at f/2:



Soft, glowy, almost pictorialist. Then you stop down to just f/2.8 and everything sharpens up. This is at f/4, but the jump between f/2 and f/2.8 is just as dramatic:



I can't see any sign of it being tampered with - screw heads all look pristine - so I assume it shipped like this out of the factory. I've considered sending it to Skyllaney for them to investigate, but I'm not sure I want to sink £240 into it purely out of curiosity; I'm not a fan of the overly-long barrel or the short 90º focus throw. But it is a beautiful lens once stopped down a bit, so it is tempting...

 

[hilltime]

Paul Sokk's website, listed by COLDKENNELS above, will give you about all there is to know about Leotax, the lenses for them (Topcor and Fujinon), and the many accessories manufactured for them. I started a number of years ago being interested in Leotax and the Topcor's and have collected a good majority of the different bodies and lenses. Starting with a DIV and the very rare Olympus 4cm/2.8 which came with it, I now have a TV, T2, (2) FV's, TV2, T2 Elite, and a Model G. I also have gathered Topcor lenses, 3.5/2.8, 5/1.8, 5/2.0 Panda, 5/2.0 Black, 5/2.8, 9/3.5, and 13.5/3.5. After being in contact with Paul, he graciously gave me credit for a number of images I sent him for his research. He also has definitive research on Canon, Nicca/Yashica, and Minolta rangefinders. I have found his information about as up to date as there is and he has dispelled many of the inaccuracies attributed to many of these models which have carried on for quite some time in a way which is not boastful or mean spirited. I thank him for all the time it must have taken in putting together his chapters of the best of the best of Japanese Leica copies, an area of major interest in my 30 yrs of camera collecting.

 

[dexdog]

I have never seen a 1.8 for sale on its own and was just lucky enough to notice that an ebay seller had listed a Leotax camera with a Topcor 2/50 lens, where the photographs were clearly of a 1.8/50.

One currently on eBay. Not in great shape, has haze

Topcor-S 5cm 50mm F/1.8 Lens Tokyo Kogaku Leica Screw LTM L39 581021 AS-IS | eBay

Chiyoda Kogaku Super Rokkor 5cm F1.8 Lens Leica LTM L39 from Japan 1204204 Exc++. Nippon Kogaku Tokyo 40.5mm Front Lens Cap Nikon Genuine PAT PENDING Exc++. Canon 50mm F/1.4 Objektiv Leica Schraubbefestigung Ltm L39 Aus Japan 85738 EXC.

www.ebay.com

 

[hilltime]

One currently on eBay. Not in great shape, has haze

Topcor-S 5cm 50mm F/1.8 Lens Tokyo Kogaku Leica Screw LTM L39 581021 AS-IS | eBay

Chiyoda Kogaku Super Rokkor 5cm F1.8 Lens Leica LTM L39 from Japan 1204204 Exc++. Nippon Kogaku Tokyo 40.5mm Front Lens Cap Nikon Genuine PAT PENDING Exc++. Canon 50mm F/1.4 Objektiv Leica Schraubbefestigung Ltm L39 Aus Japan 85738 EXC.

www.ebay.com

She also has another in much nicer condition, for all of $649... The example I bought for my G came straight for Japan, quite Mint-, but not quite that $$$.

 

[dexdog]

Topcor-S 5cm 50mm F/1.8 Lens Tokyo Kogaku Leica Screw LTM L39 580843 Exc++ | eBay

Find many great new & used options and get the best deals for Topcor-S 5cm 50mm F/1.8 Lens Tokyo Kogaku Leica Screw LTM L39 580843 Exc++ at the best online prices at eBay! Free shipping for many products!

www.ebay.com

I agree that this one is a beauty

 

[hilltime]

Three of my favorites.... Leotax G w/3.5CM/2.8, Leotax FV w/5CM/2.0 Panda, and Leotax T2 w/5CM/2.8 Topcors. The picture of the G was before
I found the correct lens generally sold with it, the 5CM/1.8 Tpocor. The Panda is very hard to find in good condition...if at all. This lens was purchased from Japan and was quite costly.

 

[newst]

She also has another in much nicer condition, for all of $649... The example I bought for my G came straight for Japan, quite Mint-, but not quite that $$$.

My copy was optically brilliant but has minor paint scuffing on the barrel. It came with the Leotax camera for half of what this lens is selling for. I consider myself very lucky.

 

[CameraQuest]

the book TOPCON STORY concentrates on SLRs, also lists and details the LTM lenses

 

[hilltime]

Wish it was still in print.....

 

[newst]

the book TOPCON STORY concentrates on SLRs, also lists and details the LTM lenses

I have had this book on an ebay search for two years and it has never come up.

 

[Coldkennels]

One of my favourite places to look for odd books is AbeBooks. They normally have everything, but...



Does anyone have the ISBN for it?

 

[CameraQuest]

TOPCON STORY published by Nasa Watch Gallery , Collectors Camera Publishing
by Marco Antonetto - Claudio Russo

PO Box 230-CH 6907 Lugano-Switzerland
http://www.ticino.com/user/marcoant -- check out on time machine
C 1997
ISBN: 88-87161-00-3