Hello Everybody, I just found this web site and I am very impressed. I have a question for everybody. I cannot seem to find any info on my pentax 500mm f4.5 lens for the pentax 6x7. Any info about this lens would be appreciated. Its big, heavy, with a front glass width larger than 100mm. It says "Asahi Opt. Co. Lens Made in Japan Takumar 1:4.5 500" on the front. The rear says "Asahi Pentax 6x7 Japan".

Thanks, Jamie Heath

-- Jamie Heath (terrasaurus@hotmail.com), December 03, 2001

Answers

It's an f/4.5 and not the f/5.6? The f/5.6 Pentax is fairly common but I have heard of the 4.5 but never seen one. Also have never seen one for sale. It is not an SMC Takumar or Super Takumar? Its serial number should tell us something about its production date. I would bet it is a 3 series or 4 series number. Please post the number for us.

-- Steve Rasmussen (srasmuss@flash.net), December 04, 2001.

I have this lens and actually carry it with me in my LowePro pack. If you think it's heavy let me introduce you to the 600MM F4.0!

The 500 has a 95mm filter diameter and you can find out more about it at:

http://www.pentax.com/products/lenses/lense_model.cfm? lenseType=67&lenseModel=67+SMC+LENSES

Hope it helps!

-- Rolf Strasheim (rolfs@thelunatech.com), December 03, 2001.

I used to own a 500mm f/4.5 Pentax from their 35mm system that I had adapted to Nikon. Anyone know if this is the same lens being discussed here? A lens this long might possibly cover the 6X7 format, especially if it does not have a lot of internal baffling.

-- Paul Shambroom (pshambroom@mn.rr.com), December 08, 2001.

I have seen email pictures of this lens, (serial number was out of focus, but the first number is 3) and I believe it is a converted 35mm lens for 3 reasons. First, it isn't found in any P67 literature. Secondly, it has the look of a converted lens. The lens tapers to a small size at the back, as if it would match up to a 35mm camera, then the large 6X7 mount appears at the very end, as if it was grafted in. And lastly, all of the 6x7 lenses I have seen say "6X7" on the front. This one does not. It says "6X7" on the mount only. I think I read somewhere this lens has a removable tube at the mount end. Maybe this feature makes it easily adaptable to the 6X7 format, since something would have to be removed to achieve infinity focus on a 6X7 camera.

This lens looks identical to the 35mm version, except for the mount, and all the specs are the same, i.e. aperture range, minimum focusing distance, size and weight, etc.

I found a website (http://digilander.iol.it/aohc.tak05e.htm) that says this lens was made from 1966 to 1971 as a Takumar 500/4.5. From 1971 to 1976 it became multicoated and says "SMC".

-- Bobby Mahaffey (mahajen@prodigy.net), December 08, 2001.

I think you are exactly right about this being a 35mm lens. I had a friend read through all his brochures, Photokina literature, etc., and there is no mention of a P67 4.5 500mm lens. And, when you search this lens you always come back to the 35mm configuration. As you say, they look the same, and the tapering is ununual. This is not to say the lens is necessarily worse than the P67 500mm. Although the edges would probably be soft on this 4.5, the center could well out-perform the p67 500mm; it might all come down to what you would use it on. While it might not make a great landscape lens, it might turn out to be great for astro work. For instance, I have seen photo credits in astronomy magazines read "Pentax 6x7 & Takumar 500mm f4.5" - so people have used it with some success. It might also be a great lens for small wildlife and what not, and it would definitely weigh less than a P67 500.

-- Miles Stoddard (p67shooter@yahoo.co.uk), December 10, 2001.

The SMC Takumar 4,5/500, 1000mm and 135-600mm zoom for the 35mmm S version screw-mount had a removable tube with a bayonet. This was to handle with the disadvantage of the screwmount for the big lenses. With this tube removed the lens is ofcourse shorter. Asahi Pentax sold an adapter to use these lenses on the 6x7. In my 1975 pricelist the price for the adapter was about $50. The adapters for 6x7 lenses on 35mm are more known. Peter.

-- Peter Gooijer (rockrose@freeler.nl), December 28, 2001.

I picked a lens like this..

So it would probably cover 645 format?

thanks

-- Pete (gregarpp@icqmail.com), March 11, 2002.

I was preparing to move and boxing up various photo books/mags etc. I came across two reviews of this lens, and typed in a summary in case anyone was interested. The first review I have is a second- generation photocopy, and the source is unknown (though since “last year” for the author was 1975, one can assume it is 1976); the second review is from Modern Photography, 1975. Neither review mentions MF adaptors, though MP indicates that additional 35mm “rear sections” are available for Minolta and Konica mounts. The lens is listed as $679 by the one mag, and $659 by MP. Both sources imply that the lens has been redesigned, though they aren’t all that specific (MP= “Since this version [SMC] of the 500mm lens probably went through a slight optical redesign to bring it up to date, we have taken a fresh look at it” ; sorry, they do not give the citation for their first review of it). The unknown review offers very high praise of the SMC, as does MP to a lesser extent (“...the multi- coating makes a real difference for medium distance subjects (100-300 ft)). Both reviews compared the new version to the original, uncoated one (and much preferred the newer, no surprise). Both reviewers found filter installation/changes to be a nuisance, and MP claimed the UV filter Pentax supplied with the unit was “...too colorless to be effective”. Again, both reviewers found it odd there is a custom hard case, but nowhere in the case for you to store the filters. The reviewer from my unknown article claimed it was “...for the lack of a better word, stupid…” not to design into the lens, a handle of some sort; MP didn’t go anywhere near as far as “stupid”, but did state that “If this lens had a carry handle to grasp, near its center of gravity, it would be a little easier to work with”. Both reviewers praised the build-quality. The lens was tested by both publications. The unknown magazine claimed the lens to be “...really quite excellent...across a surprisingly broad range...” (f8-32 = excellent; 4.5-8 & f45 being nearly excellent). MP have much the same to say, and also offered these lpm numbers (f/stop = center lpm / edge lpm): f4.5 = 36 / 32 ; f5.6 = 44 / 40 ; f8.0 = 50 / 44 ; f8.0 = 50 / 44 ; f11 = 56 / 44 ; f16 = 56 / 44 ; f22 = 50 / 44 ; f32 = 44 / 44 ; f45 = 36 / 36. I tried, unsuccessfully, to find lpm numbers on another 500mm lens from the mid-1970's; I wanted to make comparisons, but couldn’t find the stats to do it. One last tidbit from the reviews is that the unknown reviewer claims the Pentax lens a “likely contestant in a match against the longest Leica”. As best I can tell, and I am no Leica expert and not necessarily even a Leica fan, is that the author is referring to the Leitz Teleyt 560mm f.6.8 - which cost about double the Takumar. I think it is worth noting that this 500mm Pentax lens can deliver lpm numbers greater than the 35mm Pentax 300mm f4.0 (which is more or less 50 / 40, f-5.6-f22). Of course, none of this gives you all that much to go on for use in 6x7 format; you would have to do your own tests, and edge lpm may or may not be impressive, or even tolerable - which may or may not matter, depending on specific use.

-- Michael Tolan (mjtolan@kbjrmail.com), April 05, 2002.