Hi,

I have seen a number of Canon 35mm and 20mm macrophoto lenses on e-bay and most of the sellers state that the lenses require a separate adapter to mount on the bellows. My understanding is that these lenses should come with the adapter. However, if one is missing, which adapter should I get to mount one of these lenses to the autobellows? I have heard that these lenses have a 39mm Leica screw mount, a royal something or other screw mount and everything in between. Does anyone know for a fact what type of a thread these lenses have and whether a third party adapter is available for them?

One a slightly different subject:

I heard that using enlarger lenses will produce good results with bellows since enlarger lenses are flat field lenses. Has anyone tried this and what kinds of results did you get?

Thanks for your help

Alexander

-- Alexander (alexo@interport.net), October 05, 2001

Answers

Hi Alexander,

I would advise you to buy one of these lenses only if it has the adapter. I've seen perhaps one--maybe two--of the adapters for sale in the past 18 months. Almost every lens I've seen for sale has had the adapter, though.

The adapter is called "Macro Photo Lens Adapter," made especially for these lenses. It is a breechlock device about 63mm in overall diameter, about 7mm thick, with a threaded hole for the lens. The threads are about 20mm in diameter, not anywhere near the 39mm Leica. Both the 20mm/3.5 and 35mm/2.8 lenses use the same adapter.

The lenses are pictured, resting on their adapters, at http://www.mir.com.my/rb/photography/companies/canon/fdresources/fdlen ses/fdmacro/2035macro.htm#20mmf3.5

As for the enlarging lens, I have no experience, but I'd suspect it to work well. I've done the opposite, using my 50mm/3.5 Canon macro lens as an enlarging lens with great results. I've tried to mount the macrophoto lenses on my new enlarger, but can't get them close enough to the negative.

-- Alan Swartz (swartz@tyler.net), October 05, 2001.

I'm fairly sure it's RMS--"Royal Microscope Screw"--which is 0.800" x 36tpi thread. I have the 35/2.8. Indeed, only buy the lens if it comes with the adapter. Once you have it, you should be able to use other great microscope lenses like the Leitz Photar and Zeiss Luminar lenses.

You might hunt around to see if there is an RMS-M42 adapter or RMS-T-mount adaper, since it's easy to find M42 (Pentax Screw Mount) and T-Mount adapters for FD. Maybe www.scientificsonline.com has such a thing. You could also have one made by a machinist for around $50.

-- David Goldfarb (dgoldfarb@barnard.edu), October 06, 2001.

The macrophoto lenses are indeed threaded with the RMS. I verified this by screwing the macrophoto lens into a microscope turret.

Cheers

Duane

-- Duane k (dkucheran@creo.com), October 06, 2001.