43 Rumors

Do we know what mount use these lenses?

These are lenses from x-ray machines, either used for copying or for video. They have extremely low f-stops so the radiologists could use low amounts of x-ray radiation on the patient. They have no aperture so you’re stuck wide open, and they have no focus mechanism. The large threads are made specifically for the machines they once occupied and their rear element would sit very close to the sensor (in the single digits of millimeters). And because they were only made to x-ray people near the lens their preset focal distance is at most a few feet, and even then the rear element has to be able to at least sit on or fit through the mount throat of your m4/3 camera or else you’re shooting macro.

Don’t spend more than $200 on one of these. That Varo Industries lens is way overpriced and I see that a lot, the sellers can’t find other copies of the lens and assume that because it has a low f-stop it’s rare and valuable. Probably the same with the Canon. This De Oude Delft Rayxar lens went for under $200 and is both faster and just about as rare: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200474673857

So far I’ve bought a Kowa 90mm f/1.0, a Kowa 95mm f/1.4, a Rodenstock TV-Heligon 42mm f/0.75, and two right-angle Rodenstock 50mm lenses all from that eBay user lisa_ctrsurplus for anywhere between $10 and $15 each. The 90mm weighs about a kilogram and has a huge ring around it like that Varo Industries lens and I can’t seem to unscrew it. If I’m able to get it off the rear element still won’t fit through my E-P1′s throat, so the focal plane is only about 3 feet away, and I’d still have to account for the extreme weight. The 95mm seems to be a common lens from that seller (they usually have a gold-colored gear going around the barrel) but the one I got had some weird chemical lubricant on the threads that made my hands tingle so I decided it was probably unsafe and threw it out. The right-angle 50mm lenses are interesting, I just got them and am still not sure if I’m going to try to make mounts for them.

The TV-Heligon is the most interesting and usable, it weighs only about a pound. Just holding the lens up to the mount I could focus about two feet away and the focal plane is only a few millimeters wide. Since I couldn’t figure out how to get a helicoid or some sort of aperture on it (it only has a 60mm threaded mount) I bought a 52mm reversing macro ring for m4/3, ground down the 52mm thread and used some JB Weld metal epoxy to glue it to the back of the lens. Since it’s wide-open only the flare and ghosting can be crazy, but because I can take a pretty fast shot at ISO 200 in low light it’s fun even with its limited use.

I’ll be posting some pictures to the DPReview forum and Flickr some time soon…

The Noktor sadly seem to be crap reading from the reviews.

I’d much rather get the Voigtländer Nokton 50/1.1 + adapter in that case.

Very nicely done Milna!!! 1,8m is much better then most x-ray lens adaptations to SLR camera’s. Can you give some more information on how you adapted the lens and fixed a mount to it? Sample images? Good source to buy?

Milna, 1.8m is a great distance of an x-ray, congratz, pity the crop factor of m4/3 that make the 75 too long for that distance, but hell is very good what you have achieved, can you tell me where I can see a picture made with the lens ?