Lens adapter basics

How to use a lens adapter

Attach the adapter to your lens the same way you would mount the lens on a camera. Align the red dot on the lens with the red dot on the adapter and turn the lens clockwise (counterclockwise for Nikkors) until it locks in place. Look for the red dot on the back of the adapter and line it up with the red dot on your digital camera.

Always mount the lens adapter on the lens and not on the camera. Exceptions are:

  • Exakta to MFT and Exakta to Four Thirds adapters which have lens release levers on the front of the adapters.
  • Medium format lens adapters with releases on the side of the adapters.

M42 Universal mount lens adapter

The M42 lens mount, also known as Pentax screw mount or universal mount, was invented in 1949 for the Zeiss Ikon Contax S. It was a very popular lens mount during the 1960s and can be easily adapted to a variety of digital cameras.

50mm f/1.4 Asahi Pen­tax SMC M42 Taku­mar on a Canon 30D. 1/125 sec at 3200 ISO.

50mm f/1.4 Asahi Pen­tax SMC M42 Taku­mar on a Canon 30D. 1/125 sec at 3200 ISO.

 Notice the silver adapter on the M42 lens doesn't cover the diaphragm pin. The black M42 adapter completely covers the pin and keeps it out of the way.

Notice the silver lens adapter on the M42 lens doesn’t cover the diaphragm pin. The black M42 lens adapter completely covers the pin and keeps it out of the way.

I use the black one on my 10D, 30D and 40D. The silver adapter gives me just enough clearance to use an 85mm f/2 Jupiter 9 on my 5D Mk II. The Jupiter 9 does not have a diaphragm pin.

I use the black lens adapter one on my 10D, 30D and 40D. The silver lens adapter gives me just enough clearance to use an 85mm f/2 Jupiter 9 on my 5D Mk II. The Jupiter 9 does not have a diaphragm pin.

The silver adapter on the right doesn't extend as far into the camera as the black adapter.

The silver lens adapter on the right doesn’t extend
as far into the camera as the black lens adapter.

Stop screws

A lens adapter should have a stop screw ( see arrow) that limits rotation when attaching and removing lenses. Without the stop screw, you won’t know when the bayonet flanges line up with the openings in the lens mount.

 Stop screw on a Nikon lens adapter. Yes, I use non-AI Nikkors on my Canon DSLRs. Don't try using a non-AI Nikkor on a Nikon DSLR.

Stop screw on a Nikon lens adapter. Yes, I use non-AI Nikkors on my Canon DSLRs.
Don’t try using a non-AI Nikkor on a Nikon DSLR.

Chipped adapters

Some lens adapters have chips that enable focus confirmation through the camera’s viewfinder. If you don’t trust an unknown manufacturer’s electronics interacting with your camera, don’t use them.

Debris inside new lens adapters

It’s rare that a brand new lens adapter could have debris on the inside from the manufacturing process. Workers can get in a hurry and package the adapter without cleaning it.

Before using any new lens adapter, blow out any debris that could be inside with compressed air. Then take a lint free cloth moistened with rubbing alcohol and wipe down the surfaces. Dry with compressed air.

Debris from the man­u­fac­tur­ing process will have to be removed before using the adapter.

Debris from the man­u­fac­tur­ing process will have to be removed before using this lens adapter.

EF to MFT lens adapter?

A 50mm Bronica ETRS Zenzanon-PE lens mounted to an Olympus E-600 Four Thirds camera body using ETRS-EF and EF-Four Thirds lens adapters

A 50mm Bronica ETRS Zenzanon-PE lens mounted to an Olympus E-600 Four Thirds camera body using ETRS-EF and EF-Four Thirds lens adapters.

You’re probably thinking why would there be a EF to MFT lens adapter if there was no way to control the aperture inside of an EF lens.

Once you get a manual focus lens adapted to EF, you can always take it down to MFT with the EF to MFT lens adapter. The Icarex BM mount is easily adapted to EF but Icarex to MFT lens adapters are scarcer and they cost more. Kodak DKL to EF is another example.

Never force anything

Never force a lens adapter on to a lens and never force a lens on to a camera! If something doesn’t fit, take a few measurements and find out why it doesn’t.