Adaptors for the Canon EF-mount
The Canon EF mount has a shorter register distance than many other popular SLR/DSLR brands. As a result, it is possible to make adaptors that will let you use glass from other cameras on a Canon body.
There also exists adaptors that let you use lenses created for Canon's older mount system FD (discontinued in 1987). But because the FD-mount has a register distance that is even shorter than the EF-mount, retaining infinity focus requires an FD→EF-adaptor to contain glass elements.
In this article discusses the most requested adaptors for the Canon EOS-system.
1. Nikon F-mount to Canon EF-mount adaptors
The Nikon F-mount has a register distance of 46.5 mm while the Canon EF-mount has a register distance of 44 mm. As a result, it is possible to make a 2.5 mm thick adaptor that will let you use Nikon glass on a Canon body.
Two types of adaptors exist. One that also works with Nikon's modern, electronically coupled lenes (known as “Nikon G”), and one type that only works with Nikon's older mechanical lenes(known as “Nikon AI or AI-S”).
Nikon G to Canon EOS adaptors
16-9.net / Novoflex
The good people of 16-9.net, best known for their tests and reviews of lenses by a variety of manufacturers, prefers to test Nikon glass on the latest Canon EOS bodies. In order to do this, they have developed an adaptor that allows Nikon G-type lenses (that is lenses without an mechanical aperture ring) to fit on a Canon EOS digital camera with full control of the lens' aperture.
In the initial version of the adaptor, aperture could be controlled by twisting the lens slightly. There is a good description of how this works in this field test by David Clapp. In the most recent version (version 3) there is a blue control lever on the adaptor to set aperture.
As of March 1, 2010, version 3 of the adaptor is available. It can be fitted with an autofocus confirmation chip EUR 39 extra cost. The adaptor is manufactured by Novoflex. Its model name is “Novoflex EOS/NIK-NT Lens Adaptor for Nikon G Type Lenses to Canon EOS DSLR Cameras” (EOS/NIK NT). It is available through most Novoflex distributors, including B&H.
The adaptor contains no glass and maintains infinity focus. However, VR (Vibration Reduction), autofocus, and auto-aperture functions are not retained. A scene is typically composed and manually focused with the aperture wide open. The optional autofocus confirmation chip will add through-the-lens focus confirmation (red or black square and beep), just like a Canon lens. For the exposure, the lens must be manually stopped down. Canon cameras meter through the lens and fully automatic stop-down metering works as one would expect.
However, with few Nikkor-G lens models the removal of the weather sealing rubber ring (mount side) may be necessary to attach the adaptor. This does not affect the function of the lens, but may affect its warranty and resale value.
For more information, visit 16-9.net/nikon_g.
Recently I also spotted the home page of the Japanse company RayQual Works that manufactures and sells various adaptors, including a G-EOS adaptor for around YEN 14700 (USD 180). The company's web pages are in Japanse only. If you don't read Japanse, there is of course Google translate.
Nikon AI/AI-S to Canon EF adaptors
If, on the other hand, you want to use older pre-AI, AI, and AI-S Nikkors on a Canon EOS body, take a look at this useful article on Bob Atkin's website.
Atkins points out that with a suitable adaptor, a lot of older lenses, including vintage Nikkors, will work on a Canon EOS body with manual focus and stop-down metering.
You may, however, be able to pick up cheaper alternatives elsewhere, like eBay.
2. Canon FL/FD to Canon EOS adaptor
Before Canon introduced the EOS system and the EF mount there was the FL (1964-1971) and FD (1971-1987) mounts. The two are very similar, with the same breech lock and register distance. Unfortunately, the FL/FD mount has a shorter register distance that the EF mount (42 mm vs. 44 mm), this means that it is impossible to make a glassless adaptor to use FL or FD-mount lenses on EF-mount bodies and retain infinity focus on most lenses.
Adaptors still exists. They come in two flavours: Glassless adaptors that retains the optical quality of the FL/FD lens, but where you usually lose infinity focus. And adaptors with glass (a short 1.3x teleconverter) that let you retain infinity focus, but where there is noticable loss in quality. (Search eBay for FL/FD→EF adaptor.)
FL/FD lenses have a mechanical aperture ring, but you need to use stop-down metering to meter the light. Some of the better adaptors have a chip fitted to give autofocus confirmation and correct EXIF data.
The norm with glassless FL/FD→EF-adaptors is that you lose the ability to focus at infinity. A glassless adaptor works like an extension tube with a thickness equal to the length of the adaptor plus 2 mm. This means that with most glassless adaptors, the lens will be 4-10 mm (depending on adaptor) further away from the focus plane than it is “supposed” to be. This shifts the focus range of the lens. How much the focus range is shifted depends on the thickness of the adaptor. Thick glassless adaptors shifts focus more than a slim one. As with other extension tubes, the focus shift is inversely proportional to the focal length of the lens: Shorter lenses are shifted much more than longer lenses.
A Candian named Jakub Edward Mika (aka. EdMika) has worked extensively on making glassless ultra low-profile FL/FD→EF-adaptors. In this this article he writes about the process behind his adaptors, and how they work. The idea behind the EdMika adaptors is that by having them precision machined to a thickness of only 0.75 mm, he is able to reduce the thickness of the “extension tube” to only 2.75 mm. Because certain FD telephoto lenses has been designed to let you focus “past infinity”, he has found that a glassless adaptor this thin can retain infinty focus with the FD 600 mm f/4.5 and FD 800 mm f/5.6 L. Testing a 0.75 mm thick adaptor with some shorter lenses has produced the following data on maximum focus distances: FD 400 mm f/4.5 100 m, FD 200 mm f/2.8 RF 10 m, FD 50 mm f/1.2 L and FD 50 mm f/1.8 1 m. EdMika also makes a conversion kit for the excellent Canon FL 55 mm f/1.2 lens.
Search eBay for:
Note that not all adaptors advertised on eBay as ultra low-profile are 0.75 mm thick, so if you plan to buy one of these, read the description carefully. An adaptor with a 1 mm profile will make the FD 800 mm f/5.6 L focus on 200 m, but not infinity.
A company called Elefoto manufactures a FL/FD→EF-adaptor with glass elements that retains infinity focus that are reported to be of superior quality. (Search eBay for Elefoto adaptor.)
At one point, Canon manufactured an excellent FD→EF-adaptor with glass (Canon part number C54-2131). It sold for around USD 240, and it was only available through Canon Professional Services. It is very rare these days – expect to pay USD 1000 or more for a used sample in mint condition. This adaptor allowed the following FD lenses to be used on an EOS body with infinty focus:
- FD 200mm f/1.8 L
- FD 200mm f/2.8 RF
- FD 300mm f/2.8 L
- FD 300mm f/4
- FD 300mm f/4 L
- FD 400mm f/2.8 L
- FD 400mm f/4.5
- FD 500mm f/4.5 L
- FD 600mm f/4.5
- FD 800mm f/5.6 L
- FD 50-300mm f/4.5 L
- FD 85-300mm f/4.5
- FD 150-600mm f/5.6 L
The Canon adaptor can not be used on other lenses than those listed because it had a large protruding front element which will physically collide with the rear lens element on other FD lenses.
The loss of infinty or quality when you use an FL/FD→EF-adaptor is unfortunate. A better way to keep using any old FL/FD-glass you may have is for macro photography. You do this by fitting them with a reverse adaptor ring. Read more about this option here.