Lens adapter

Hi,

I've found a lens which looks very nice. The only problem is its mount, which has a protruding lens element and bayonet (is this the proper term?) which would interfere with the mirror.

So, does anyone know...

1.) The name of that mount

2.) Whether an adapter between that mount and EF lenses exists

3.) Any information which would help me find out more about that lens or retrofitting it to an EF mount.

To my (untrained) eye, it appears as though I could take the bayonet off and add a shim under the shiny silver piece so the mirror wouldn't smash into the rear lens element. This would cause me to lose infinity focus, though, wouldn't it?

Thanks for your help!

Looks like a video lens to me = will not be useable.

I don't believe it's a video lens, but an old slr lens with a mechanically operated aperture. That pin sticking up is the lever that closes down the aperture blades when the shutter is fired. There would be a corresponding lever in the mirror box of the camera it goes on. There is no way you could adapt this lens to EF mount as the aperture in EF lenses are closed down electronically.

JWright wrote in post #4531120
I don't believe it's a video lens, but an old slr lens with a mechanically operated aperture. That pin sticking up is the lever that closes down the aperture blades when the shutter is fired. There would be a corresponding lever in the mirror box of the camera it goes on. There is no way you could adapt this lens to EF mount as the aperture in EF lenses are closed down electronically.

Yeah there is. Still will/might need optics to keep the lens in original condition. What could be done is keep the lens stopped down to the selected aperture and use the ring to control your aperture. You'll have to use stop-down metering and change the ring between focus and metering assuming you're not shooting wide-open.

SolidxSnake wrote in post #4531150
Yeah there is. Still will/might need optics to keep the lens in original condition. What could be done is keep the lens stopped down to the selected aperture and use the ring to control your aperture. You'll have to use stop-down metering and change the ring between focus and metering assuming you're not shooting wide-open.

Yeah, but is it really worth the effort? That lens is probably 1960's vintage and the optics are not up to par with today's lenses. For what would be spent trying to convert it to EF mount the OP could probably go out and buy a 50mm f1.8. And there's no guarantee the bayonet would fit. Do you know how many different bayonet mounts are out there? Hundreds... Canon even abandoned their own FD mount when they developed the EOS cameras.

John is right - the pin/lever is what stops the aperture down to the preselected value.

One consideration in mounting another brand of lens is the register distance. This is the distance from the face of the camera's mount to the sensor/film surface. We in Canonland are reasonably fortunate in that the register distance for EOS camera is 44.0 mm. Many lenses have a register distance greater than this which means that we can put some type of mechanical coupling between the lens and our EOSs. Only the Olympus 4/3 cameras have a smaller register distance (38.67 mm) and thus more lenses can be fit to them.

Nikon owners (with a register distance of 46.50 mm, have fewer lenses that will work with their cameras.

As you may know, if the register distance of the lens is not maintained, infinity focus will be lost.

The following link has a table of register distances for various cameras and lenses (sixth post):

http://forum.mflenses.​com …light,register+​table.html

JWright wrote in post #4531233
...For what would be spent trying to convert it to EF mount the OP could probably go out and buy a 50mm f1.8...

I have one, actually. It's a great lens.

This lens is a 9-27mm zoom which, combined with a price of $35 and aperture of f/2, made it quite intriguing. I would like to try converting it to EF mount, but it probably won't happen immediately. When I do, I'll be sure to document the procedure.

It isn't worth it, I agree, but it most likely is possible. Canon did make an FD->EF adapter in a limited quantity to sell to professionals who had a huge amount of FD lenses when they made the switch to EF.

And, FWIW, the FD mount was a "Breechlock" mount, not a bayonet mount

Don Quioxte wrote in post #4531535
I have one, actually. It's a great lens.

This lens is a 9-27mm zoom which, combined with a price of $35 and aperture of f/2, made it quite intriguing. I would like to try converting it to EF mount, but it probably won't happen immediately. When I do, I'll be sure to document the procedure.

One wonders what camera format that lens is for...9-27mm would hardly be a lens for 135 format and probably covers a much smaller image circle than even APS-C...maybe it was from a movie film camera?

Do you see a two-letter designation on the barrel somewhere? That often is the mount type, and that would also give a clue as to format it was intended for originally.

Don Quioxte wrote in post #4531535
I have one, actually. It's a great lens.

This lens is a 9-27mm zoom which, combined with a price of $35 and aperture of f/2, made it quite intriguing. I would like to try converting it to EF mount, but it probably won't happen immediately. When I do, I'll be sure to document the procedure.

You're tilting at windmills .

runninmann wrote in post #4533137
You're tilting at windmills .

These guys aren't going to agree:

http://forum.mflenses.​com/

http://forum.manualfoc​us.org/

It's a big world out there when you look around.

Don Quioxte wrote in post #4530958
To my (untrained) eye, it appears as though I could take the bayonet off and add a shim under the shiny silver piece so the mirror wouldn't smash into the rear lens element. This would cause me to lose infinity focus, though, wouldn't it?

Thanks for your help!

Ignore the stated focal length, the MOST important issue for mounting any lens is the mount-to-focal plane distance!!!

You can have a 75mm lens with 50mm distance or 75mm distance, or 60mm distance from mount to focal plane distance...one would be 'retrofocus', one would be 'normal' and the last would be 'telephoto' in its optical design. You cannot alter the mount distance, that is part of the optical design. And that is why the FD-to-EF adapters are forced to incorporate an optical element to alter that distance!

The second most important issue is the IMAGE CIRCLE SIZE...if it makes only a 10mm diameter image it wouldn't be very good even on the (relatively) dinky APS-C, though it might be useful on an 8mm film move camera! If it has a 40+mm image circle, it would cover APS-C but be too small for FF/135 format.

KODAK EKTON 9-27MM F/2.0 SVS ZOOM LENS
These were made in Japan for Kodak and were originally used on video cameras that were even used by NASA! Front clear lens diameter of 40mm, barrel is threaded inside at 52mm and has an OD of 60mm. Rear clear lens diameter of 14mm, has a bayonet mount with a diameter of 38mm. The entire lens assembly is 65mm long. Has focus adjustments from 3.5 feet to infinity and zoom adjustments from 9-27mm. Also has macro focusing capabilities. Multi-element and multi-coated. In excellent original condition!

probably useful to a Kodak collector, but not going to be too useful on an EOS...