June 2012: added information on CPU chips on legacy lenses to increase compatibility
Mirrorless cameras tend to have smaller-than-film sensors and shorter than DSLR/SLR distances from lens mount to film plane. This combination makes them strong candidates for adapting existing interchangeable lenses from almost any 35mm mount. Virtually every system has the manufacturer providing at least one lens adapter for their mirrorless cameras (usually for their legacy DSLR/SLR lenses).
While that's good news, beware, as there's potential bad news lurking, too. As I noted in a FAQ response, we've got a number of things to watch for:
- Automatic features (focus, VR, etc.) aren't likely to work. Exceptions: the Sony Alpha mount adapter for the NEX, the Nikon FT1 F-mount adapter for the Nikon 1.
- You may be restricted to certain exposure modes (typically manual exposure mode) and features on the camera.
- You may have to set something on the camera (e.g. "Shoot without lens" setting on some models).
- Manual focus lenses are still manual focus. Different cameras have varying focus aids to help, while some have none.
- You have to be aware of the crop factor: a 50mm lens on most mirrorless cameras is a telephoto, not a normal lens.
- The lenses may be a lot bigger than the camera, especially since they were designed to be used on a deeper camera with a larger "sensor" area in the first place; the adapter sticks out from the front of the camera's lens mount, too.
- Not all older lenses perform great on newer digital cameras.
- Some lenses may need special correction. The Fujifilm X-Pro1 with Leica M-mount lenses is a good example. Fortunately, Fujifilm built correction features into the camera and a way to trigger them quickly from the adapter itself.
That said, quite a few users are enjoying their older lenses on their new mirrorless cameras. Here's a quick set of advice for each of the primary mounts (I'll continue updating it as I get more experience):
- m4/3 -- The m4/3 mount is amongst the most flexible, as we have not only Panasonic and Olympus providing sets of adapters for various lenses, but we also have Novoflex, Voigtlander, and others providing adapters for virtually any lens mount out there. Even C mount lenses have been successfully adapted to m4/3 (though primarily those designed for 16mm movie cameras and 1"+ sensors). All of the Panasonic and Olympus models will work with an adapter out front, though you may have to select something in the menu system to allow the camera to operate without an automated lens out front. Light falloff can be pronounced (especially C mount and Leica S/M mount lenses, and especially wide angle), but some people like that vignetting effect. Both Panasonic and Olympus cameras have some basic manual focus aids that are helpful, though none that are as helpful as what Sony has provided (customizable peaking), in my experience. The 2x crop of the m4/3 bodies means that wide angle options aren't especially abundant or useful. Even a 15mm Leica lens becomes the equivalent of 30mm on the m4/3 bodies. (That's one reason why some have explored the C mount lenses, where we can find 6, 7, 8mm focal lengths that would be wide on m4/3.) Frankly, I'm less inclined to use adapted lenses on my m4/3 cameras these days because we have over two dozen very good m4/3 lens options these days. The hassle of adapted lenses (typically manual focus, more trial and error exposure setting, crop factor, size of the lenses) just doesn't appeal to me when we now have two full sets of zooms and a fairly full set of small primes available. I tend to dip into adapted lenses on m4/3 only when something isn't available in the m4/3 mount. That currently means mostly fast telephotos. There, it makes some sense to look at some of the wickedly sharp, fast, Olympus Four Thirds telephotos using an adapter. Make sure that the lens you're interested in autofocuses with the m4/3 adapter, though.
- Nikon 1 -- The CX mount is derived from the Nikon F mount. Thus, it's no surprise that Nikon will be bringing an F mount adapter to the market shortly. Unfortunately, the 2.7x crop factor of the Nikon 1 sensor means that the FT1 adapter (and any other adapters that appear) are going to be most interesting to people seeking telephoto options. For example, the Nikkor 70-200mm f/2.8, a highly regarded and very capable DSLR lens, becomes the angle of view equivalent of a 190-540mm on a Nikon 1 body. With the FT1 adapter, the lens still autofocuses and supports VR, thus the combination becomes a poor man's safari rig (if a US$2000 lens can be termed "poor man's"). Things become less interesting if the lens you want to adapt is not AF-S: autofocusing won't work. And if the lens isn't chipped (D, P, or G types in the Nikon F-mount world), automatic exposure control is lost and you have to shoot by trial and error in manual exposure mode. I'll have more to say when the FT1 is readily available. Finally, C mount lenses designed for 16mm or 1" video should work fine via adapter on the Nikon 1 (though you'll be manually focusing with very little help from the camera, and setting exposure manually). Note that Nikon has almost no focus aids for manual focusing, just a zoomed view of the central area.
- Samsung NX -- I'll have to admit I haven't really experimented with adapted lenses on my Samsung cameras yet. I'll hold my comments until I have.
- Sony NEX -- Like Nikon, Sony has supplied an adapter that supports its legacy lenses. Actually, two adapters. The first (LA-EA1) is just a basic automatic adapter. In my experience, the Alpha mount autofocus primes I've tried with it perform decently in terms of focus speed for acquisition, poorly for tracking. The second (LA-EA2) includes a phase detect autofocus system and gives near Alpha DSLR performance at the expense of high battery consumption. If you've got Sony Alpha lenses, you'll probably want one of those adapters. The downside is that these lenses, with adapter, will definitely drawf the camera body. You'll be holding "all lens." The Sony also adapts reasonably well for Leica S/M-mount lenses (at least the NEX-3/5 models; haven't tried the NEX-7 yet). The 1.5x crop isn't a killer, meaning my Voigtlander 12mm has an angle of view like an 18mm on film. Still very wide, just not killer wide. Sony's "peaking" method of verifying manual focus also works very well, better than all the other aids I've seen on the other cameras to date. Coupled with the tilting LCD (NEX-5 models) or EVF (optional on the NEX-5n), you can frame, focus, and expose with manual focus lenses pretty darned fast, even for street photography.
- Fujifilm X-Pro1 — Fujifilm's M-mount adapter allows you to mount a number of M-mount lenses on the camera. Not all lenses are compatible (see Fujifilm's Compatibility List). But those that are can be corrected for distortion, vignetting, and side-to-side color shift. You'll be focusing these lenses manually, so pay attention to and learn the X-Pro1's manual focus capabilities.
The underlying question is this: is it worth it to go the adapter route?
Technically, not usually. Funwise, yes. With perhaps the exception of the manufacturer legacy telephotos (4/3 to m4/3, FX/DX to CX, Alpha to E-mount), the primary compelling issue for most people is that they already have some lenses sitting around and they want to see how they perform on their new camera. Great. That can provide endless fun, but it's not technically worth it, in my opinion.
Some think that some used legacy manual focus lenses are inexpensive enough to warrant trying out. I don't dispute that, but the lack of automation makes these much more useful for slow or structured shooting, and I'm not 100% convinced that the image quality gains (if any) are worth the hassle. The one exception to this is the Fujifilm X-Pro1 with Leica M-mount lenses. The Fujifilm is a slow, deliberate camera and manual focus fits with its typical user profile.
Another usually stated reason is "to provide an option that doesn't exist in the current system" (sometimes in conjunction with the "inexpensive" point). Typically, this means fast aperture, as all the systems have the basics covered reasonably well. In m4/3, we now have a reasonable set of fast primes, with fast zooms just about to appear, so I don't judge that m4/3 users really will be able to use this justification for long, if at all. On a Samsung NX or Sony NEX, that justification still applies, though. On a Nikon 1, the severe crop factor makes it only interesting for telephoto work.
If you already have some lenses in another mount, the cost of playing with them on your new mirrorless camera isn't terribly high. I've seen adapters anywhere from US$20 (basic C mount for m4/3) to US$350 (sophisticated manufacturer provided legacy adapter). So, for the price of a low-cost lens, you can use your existing lens, which is why so many people are doing it.
Finally, one other issue often comes up with legacy lenses: automation. If you far enough back into your lens closet, you're probably got manual focus lenses that pre-date all the exposure and focus communication that is in modern lenses. When you use such lenses on an adapter, you often end up very restricted in what you can do (manual exposure mode, need to set "shoot without lens" option, no focus confirmation, etc.). There is a solution.
Back in the old days of Nikondom, Nikon used to sell parts. One aspiring person figured out that you could take one of the so called "CPUs" from a modern lens and retrofit it to a legacy lens. In other words, you could order an appropriate part from Nikon and install it into your older lens. Eventually that spawned a small, almost invisible third-party solution or two: the Letus and Dandelion chips. You can get those for Nikon and Canon lenses, and you can now get the Dandelion chip for m4/3 and Olympus lenses. These chips, properly installed, can be used to fool the camera into thinking that they're dealing with a modern lens, and thus leave all exposure and focus controls intact. That doesn't mean you can suddenly autofocus with a manual focus lens, but it does mean that the focus confirmation (if present) will work.