A Site for Photographers by Photographers


Hening Stepfield , Jul 28, 2012; 08:44 a.m.

been looking for eos lens alternatives in the used departments, it looks to me that the M42 adaptors to EOS do not require glass to fit between the non-canon lens and my 5dII, do I have this right - if so, then M42 may fast become my passion


Craig Dickson , Jul 28, 2012; 09:55 a.m.

Yes, you can focus to infinity with a properly-made glass-free M42 to EOS adapter. This is also true for mounting Nikon, Olympus, and Pentax K-mount lenses on EOS. It is not true for Minolta lenses.


This article includes a table of lens mounts which has the flange focal distance for each mount. If a given mount has a flange distance at least 1mm greater than Canon's EF mount, then it is probably possible (given an appropriate adapter) to use those lenses on an EOS camera as long as the lens doesn't require any electrical support from the camera and doesn't have parts that stick out the back far enough to strike parts in the camera. Most manual-focus Nikon F-mount lenses, for example, will work fine on an EOS camera with an adapter, but I've found one (the Nikkor 20mm f/4 AI) that won't mount because it bumps into the inside of the 5D Mark II near the lens mount's electrical contacts.

I've only tried a few M42 lenses on the 5D Mark II, but I had no trouble with them.

Louis Meluso , Jul 28, 2012; 10:23 a.m.

To follow Craig's idea, here is a list of the M42 lenses you can, and can't, mount to your 5D2 (lens rear element hits the mirror).
I use a group of M42 Pentax SMC and several old Zeiss lenses to good effect with my 5D2. In case you don't know how to adapt lenses look at this:

Craig Dickson , Jul 28, 2012; 12:06 p.m.

A couple more points that the WikiHow page neglects to mention:

Canon cameras are surprisingly intelligent (more so than, say, Nikons) about dealing with foreign-mount lenses. When an EOS camera can't electronically detect a lens (which it can't with non-EF lenses), it falls back to stop-down metering mode, which means that it assumes that the lens is already stopped down; in other words, it assumes (correctly) that whatever light is coming through the camera right now is the same light you will be shooting with. This basically just means that you can trust the camera's meter; there's no need to calculate an adjusted value or anything like that.

My recommendation is that you focus with the lens set to its widest aperture, then stop down to the aperture you want to shoot with, check the focus again (many lenses suffer from focus shifting when the aperture changes), adjust your shutter speed or ISO until the meter says your exposure is correct, and then shoot. Working this way, I found that I consistently got very sharp images -- often sharper than what autofocus would produce.

You may also find that putting a Canon Eg-S focusing screen in your 5D II improves your manual focusing accuracy, at the cost of the viewfinder image becoming a bit dimmer at small apertures. In bright daylight, I never found the dimmer viewfinder image to be a problem even at f/11, which is the smallest aperture I usually shoot with. (In dim light, you probably won't be using f/11 anyway.)

Sarah Fox , Jul 28, 2012; 01:45 p.m.

Film Music (that's not your real name, is it?), I love M42 lenses. If there were only one mount of lens I could adapt to my EOS cameras, it would be M42. You get all of the glorious old Takumars, plus all sorts of interesting and often excellent Soviet bloc lenses. There was never a more universal mount than the M42. In fact it was often called a "universal screw mount."

The old manual Nikkors adapt equally well to Canon EOS -- even better than they mount up to modern Nikons. If I couldn't have an M42 adapter, a Nikkor adapter would be my second choice. However, don't forget that Canon makes a multitude of truly superb lenses. I've only found it useful to adapt lenses for special projects. The bulk of my shooting is with native Canon EF lenses.

Pete Ferling , Jul 28, 2012; 10:22 p.m.

First. They are both cheap and have excellent builds when compared to modern equivalents.

Second. Many lenses once consider junk by film standards can be excellent with digital workflows that allow for sharpening.

Third. Many of these lenses will render looks we have become familiar with growing up.

Fourth. If you have a crop sensor you will gain the advantage of extra reach, while using the more sharper lens centers.

Finally, they can certainly can be a little more challenging, which adds more fun to your shoots and can raise the level of confidence as you become the real brains behind them.

Jim Service , Jul 29, 2012; 01:09 p.m.

Craig - I've known of focus shift from zooming, but never from aperture adjustment. Was this a typo? If not, I have some painful re-adjustment in my life and outlook! : )

Professor K. , Jul 29, 2012; 02:07 p.m.

This basically just means that you can trust the camera's meter; there's no need to calculate an adjusted value or anything like that.

There are exceptions. I have used a 600mm 5.6 Nikon lens on a Canon body with an adapter. At an aperture of 5.6, the metering was correct; however the camera overexposed by one stop at f/8 and nearly two full stops at f/11. Without electronic information from the lens, the camera is not able to adjust for non-linearity in the metering system at small apertures.

Louis Meluso , Jul 29, 2012; 04:56 p.m.

I've known of focus shift from zooming, but never from aperture adjustment. Was this a typo?

No typo, Jim. Often seen in higher speed lenses but some par speed lenses can also shift focus when stopping down.

Hening Stepfield , Aug 03, 2012; 05:44 a.m.

thanks all!
I enjoy hunting for bargins...the m42 glassless adapter approach soundzzz smashing!
please, toss me a link with you favorite adapter

Back to top

Notify me of Responses