WHY IS THE CANON 5D / CANON 5D MARK II LISTED IN ITS OWN COLUMN?

Canon 5D owners have reported various adapter & lens combinations catching on the mirror.  If a lens mounts and performs correctly on the Canon 1Ds, unfortunately it does not guarantee it will fit correctly on the 5D or the Canon 5D Mark II.

WHAT ABOUT THE NEW CANON EF-S ON THE 20D, 30D, 40D, 60D, 7D AND DIGITAL REBELS?

Cameras with the EF-S mount such as the Digital Rebels, 20D, 30D, 40D, 50D, 60D and 7D work just fine.  For our purposes here, the EF-S mount is the same as the EF mount.

WHAT ABOUT THE CANON 1D MARK III (ie - 1.3x)?

According to marketing literature the new Canon 1D Mark III sports a new, larger viewfinder.  Initial reports indicate it is best to consider the 1D Mark III as having the same clearance as a 1Ds and 1Ds Mark II. As of December 2010 the Canon 1D Mark III has proven to be pretty much trouble free. If a lens is marked as “YES” in the 1.25x and FF columns, then it will probably work on the Canon 1D Mark III.

THE DATABASE SHOWS “YES”, BUT I KNOW THE LENS DOESN’T FIT PROPERLY...

Initially if a reader reported “Yes”, then the lens would be marked “Yes” in the appropriate column(s). In effect one “Yes” response equaled a categorical yes. The logic being - it is possible for a lens to work with the right adapter. If a lens is not clearing the mirror, most likely the problem is not the lens or the camera body, but the adapter. When it comes to the Canon 5D and 5D Mark II, for every person who says a lens works, another person says they had trouble. So a new category was added - “I”. “I” stands for iffy which means a lens will work, but some people have encountered issues in finding the right adapter.

Since a simple “Yes” and “No” could be misleading, the “IFFY” classification was added. Of course, now just about every lens for the Canon 5D is marked “IFFY”!!! That really didn’t help much, so some specific comments have been in the ‘LENSES’ section.

CONTAX AE MOUNT VS MM MOUNT

The original Contax mounts were called “AE” mounts, later Contax updated the mount to “MM”. The new MM mount offered more exposure / metering options than the original AE. The mechanical differences between AE and MM are moot since the Canon dSLRs do not activate the aperture mechanism. In terms of resale value, whether a lens is AE or MM may make a difference in its price. In some cases the German made AE versions are worth more than the later made MM Japan versions. And there are some German made MM’s which are quite rare, so those lenses tend to fetch a healthy premium on Ebay. Generally the original AE’s were made in West Germany and the later MM’s were made in Japan. This is not true 100% of the time, but it is a relatively safe generalization.

Distinguishing AE vs MM version is fairly easy. On MM lenses the smallest aperture number on the aperture ring is printed green instead of white. Supposedly there are some exceptions, but I have not seen any such lenses. A common internet myth is MM lenses have silver mount, the original AE’s had a black mount. The image above clearly shows that is NOT true. The 18mm Distagon MM has a black and the 100mm Planar MM has a silver mount. Myth busted!

Some MM’s have a tab on the outer diameter - imagine the mount as the letter “O”; this added tab intersects the mount and looks like a “Q” instead. This tab is not a constant from lens to lens, so it is not the best distinguishing characteristic. A picture of the tab is shown in the image at the bottom of the page. Also, some (again - not all) MM lenses have a small pin along the outer edge of the mount; see the highlighted section in the image to the left.

Some AE lenses were updated (minor redesigns) when Contax changed from the AE to the MM mount. As an example, the rear mount on the 18mm Distagon changed. Almost all the PDF guides on the Zeiss site are MM, not the AE’s. Finding the AE’s documentation is probably impossible since PDF’s did not exist in the 1970s and 1980s. Alot of web sites mix the AE and MM data, so there tend to be discrepancies in weight. Fortunately the Zeiss pdf’s set the record straight for the MM versions, but the AE versions still hold some mysteries - which are subject to internet folklore.

In some cases the MM and AE variants were split out in the database. This is intentional because there were some significant deltas in the lens weight of the AE version compared to the MM version. We have no way of knowing what else changed because the number of elements and groups remained constant. However, Zeiss (Contax) could have changed the design of an element, the composition of an element, lens coatings, sub-assemblies, etc.