Yamasaki Congo 500/9.5 feedback

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A few month ago I submitted a question to try have some feedback on the Congo Tele 500/9.5. Since none seemed to have used that lens, I will relate my first impressions after the first film test.

After some unsuccessful stories of trying to put my hand on a Nikkor T500 at a decent price, I finally grabbed a near new Congo at a used price. I was a bit anxious though as someone had suggested this was a piece of crap. Jeff at Badger was more than evasive when I asked him how it performed compared to the tenors from Fuji or Nikon but did not dissuade me.

So the very day it came on the post, it was mounted on my Technika for some test shots. I made some shots at close range (about four meters) and most at 100m to infinity. To have a comparison, I made the same shots with an Apo-Ronar 360. So here I have the Velvia's on my light table and I'm impressed! I dug out some 4x5 I made with a Nikkor T500 borrowed from a friend and, well, it appears to me that the Congo has nothing to want as far as resolving power and contrast are concerned. Under the 10x loupe, the 6x9 are as sharp as the Apo-Ronar's and maybe (but this is not a real lens test) sharper than the Nikkor's! The only flaw is a slight vignetting in the sky on a 4x5 but this should be easily corrected by mounting the lens on the right lensboard, as I used a lensboard that puts the lens off center.

For this is the concession to be made! The lens has only a tight coverage of the 4x5 format! No movements. But this is not too annoying for me for the kind of photography I want to use it for. As for other specs, the lens is a Tele-Xenar design on Copal 1, very light for a tele of this power: only 500g! Filter thread is 67 and length 15 cm. (yes a bit long compared to a Fujinon C 450! But when the bellows are not there...) It focusses infinity at 280 mm. It is multicoated, finish looks good. Perhaps a stain on the coating of an inner lens element, visible only under certain lighting (invisible when looking through the lens). Should not affect the quality at all and if this is the reason the price was so low, it is quite acceptable to me! Will have to work for a while to be sure the lens is really good but looks promising!

-- Paul Schilliger (pschilliger@smile.ch), December 07, 2000


I have seen good results from Congo lenses too. I think a lot of people who bad mouth them really have no experience with them, and just repeat what they have read from various sources (if its not from a 'name brand' mfr., it cant be good). The lens formulas used by Congo are tried and true designs, nothing fancy, and seem to be executed well.

-- Ron Shaw (shaw9@llnl.gov), December 07, 2000.

I am surprised that the 500 would barely cover 4x5! My Congo Commercial 180 gives me plenty of movement with my 5x7. I agree with regard to quality. These are solid, beautiful lenses.Very sharp!

-- Matt O. (mojo@moscow.com), December 08, 2000.

Matt, there was an earlier version of the 500 mounted on Copal 3. It had larger image circle but was big! It is still mentioned on a web site under the brand "Osaka".

-- Paul Schilliger (pschilliger@smile.ch), December 08, 2000.


I have an older 180/6.3 congo lens & sumbled across Congo's website in reaearching it. Congo specializes in Tessar formula lenses. Tessar's are good lenses. It's a sound & well-known formula, but their main disadvantage is a lack of covering power. I have had mine for about 20 years & am quite happy with it. Enjoy it!

-- Ted Brownlee (omfbh@aol.com), December 08, 2000.

I believe that the Congo and the Osaka 500mm f9.5 are the same lenses. Accordingly it comes in a copal #1, is a tessar design and has an image circle of 217mm at F22. As with all tessars the image at the periphery of coverage can be, well, fuzzy until working apertures are reached. What is remarkable about this lens is its small bellows draw considering its long focal length. More information can be had from Bromwell who imports the lens.

-- Pat raymore (patrick.f.raymore@kp.org), December 11, 2000.

Pat, I have been puzzled by the numbers given on Ted Bromwell's web site and sent an e-mail to Mr Yamasaki some month ago. He kindly answered me that he was the maker of the Osaka line. The 500 with 217 image circle was the early version on Copal#3 he told me. It is no longer manufactured and the new one comes on Copal#1 with 160 mm image circle. I guess there is an error on Bromwell's site, unless there is another version I'm unaware of.

The website for Congo Yamasaki (Osaka) lenses is at: http://www.cosmonet.org/~congo/index_e.html

The TeleCongo 500/9.5 is indeed very short on bellows with 287mm (same as my Fujinon C300). The Nikkor T500 needs 350mm to focus infinity.

-- Paul Schilliger (pschilliger@smile.ch), December 11, 2000.


I hope you will report more about your results with this Tele Congo lens. I have been looking for a longer lens to my Toyo 45A. A Fujinon C 450 would be nice but it would need the back extension (which I don't have) and some additional extension on the front. Then I looked at the data of the Tele Congo 400 mm, it is relatively compact, has No 1 shutter, weights 460g and is 13 cm long and covers 5x7". I would have the opportunity to buy it new at a decent price (old stock). But so far I have hasitated because of the conflicting opinions about the optical quality of these lenses. If you, Paul, or someone else can give additional information, I would appreciate.

-- olli Jaakkola (olli.jaakkola@uta.fi), December 14, 2000.

Hmm... OK, I should have sold the lens before writing the following, but don't want to induce somebody in a wrong decision either. Well well well! Interesting. The rollfilm shots are very nice. Perfect 6x12, sharp and contrasty. But the 4x5 slide I have here has dark corners. Despite advertising 160 mm image circle at f22, the lens has only 125 mm of evenly illuminated area at infinite (f22). Beyond, the light fall off is...remarquable (1 stop). Somebody shooting only rollfilm looking for a nice inexpensive tele out there?

I made the shot with a Toyo monorail and with no filter or lens hood attachment to make sure nothing would get in the way. This flaw may not affect other Tele-Congo's with larger image circle though (300-400).

-- Paul Schilliger (pschilliger@smile.ch), December 23, 2000.

I had a mail exchange with Mr Yamasaki. He kindly answered in a very honnest way and I report his answer here. Also contacted Jeff at Badger who was sorry and is taking the lens back.

"Thank you for your inquiry. The lens seems to be behaving normally. The compact overall costruction and shorter flange focal distance are attained at the sacrifice of lowering illumination of outer area of image circle. As you pointed out there is vignetting to some extent. The illumination of outer area is about 40% of the center. A lower contrast film like "provia" would give you better result than a high contrast film like "velvia".

Best Regards,

Keizo Yamazaki

Yamasaki Optical Co.,Ltd

congo@cosmonet.org ------------------------------------------------------------------------------------------

-- Paul Schilliger (pschilliger@smile.ch), December 26, 2000.

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