Minolta produced many fine lenses during the film era. It would be a shame if they could not be mounted to an excellent Four Thirds digital camera, which is highly adaptable to use legacy glass. Until recently the only adapter available was fairly expensive and difficult to find. Some problems were reported with adapters going from Minolta to 4/3 in the past. Such as the aperture pin extending into the mirror box, potentially damaging the mirror. In 2007, RJ Camera Accessory Store introduced an affordable, well constructed, adapter. To find adapters by other makers or other lens mounts, just search in the adapters category for a seller of your choice.

Some points to consider when shopping for a Minolta to Four Thirds adapter:

Field of View The field of view produced by a legacy 35mm lens mounted to a Four Thirds camera is close to that of a lens of twice the focal length mounted to a 35mm camera. A 45mm lens mounted to 4/3 camera gives a field of view about the same as a 90mm lens on a 35mm camera. The field of view of a 200mm lens on Four Thirds will be about the same as a 400mm lens on a 35mm camera. The field of view is determined by the size of the image area and the focal length. The aperture is unchanged by mounting on a Four Thirds camera. Depth of field on a Four Thirds camera will be greater than for a 35mm camera.

Zoom Lenses I've heard of mixed results with Minolta zoom lenses. Typically, zoom lenses from the film era are not as good as their modern counterparts. The fixed focal length film era lenses ("primes") can be as good as the best digital lenses and are often better than zooms. It depends on the lens.

Auto Focus Lenses Do not purchase a lens designed for an auto focus camera, such as the Minolta Maxxum, to adapt for your Four Thirds camera. These are entirely different lenses and will not work on your 4/3 camera. You want the MD or MC, MD Rokkor, MC Rokkor, etc. mount lenses or similar from the film era. If the lens fits a X-series camera (X-370, X-700, XG-1, XG-7, XD-7, XD-11, XD-5, XE-series, SRT-101, SRT-102 etc.) it will probably work with the adapter unless it is very unusual.

Checking the Aperture Pin When mounting a Minolta adapted lens the first time, it is important to be careful the aperture pin clears the mirror and other parts of the camera. If you feel anything unusual, stop and check it. Minolta used different lengths of aperture pins on their lenses. Some are longer. Be cautious. Some E-System cameras cannot accept Minolta lenses without modification to allow the aperture pin to clear (at least on lenses with the long aperture pin). I believe this includes the E-300 and E-330. I am unsure about the Panasonic or other Four Thirds cameras.

Lens Mount Lock Minolta to 4/3 adapters are too thin to implement a lens mount lock. Normally, the lens mount lock is on the camera for Minolta cameras. The adapter must be thick enough to support a mount lock or some other means must be provided. Most adapters provide a "set screw," which you tighten to hold the lens in place. Without the pressure from the set screw, the lens can dismount while turning the focus or aperture ring. This can happen without much warning. An Allen wrench is provided with most adapters to tighten the set screw. The process of tightening and loosening the set screw when changing lenses can be a pain. The alternative is to purchase an adapter for each lens and lock it down tight. My personal use for Minolta lenses is very specific, and typically alternating with Four Thirds lenses or other adapted lenses, so I only change the lens attached to the mount occasionally.

After the Purchase When you receive your adapter, check it carefully before mounting to a lens or to the camera. Some adapters consist of two pieces fasted together by screws. Either due to a manufacturing problem or shipping, the screws can sometimes work loose and stick up above the face, thus scratching a lens or camera mount.

My Experience When I purchased my first Four Thirds camera, an Olympus E-510, I wished a compact, lightweight "pancake" lens was available. The kit zoom lenses were light, compact and of excellent optical quality, but they were slow. I was attracted to the Minolta MD 45mm f/2.0 due to its small size, light weight and relatively fast speed compared to the zoom lenses. I purchased it in anticipation of the first MD to 4/3 adapters produced by RJ Photo. Being an early adopter, I was eager to try my Minolta MD 45mm f/2.0 "pancake" lens. I found it worked well on the E-510, but the aperture pin on my version of the 45mm just barely scraped the "throat" of just inside the lens mount. The aperture was sticking, and I could feel the pin scrape when mounting or dismounting the lens. After filing a few thousandths of an inch of enamel off the end of the pin, the pin cleared. I did not have to do any major work on the lens and the mirror appears to be safely beyond the reach of the pin. The E-410 should work as well as the E-510, since they are similar models. The camera felt much lighter and more compact using the lens and the image quality was excellent. In fact, I shot a test against the 14-42mm kit zoom and the edge sharpness of the 45mm was better at f/4 than the zoom. I liked the color and the effective 90mm focal length the lens provided. All the manual focus lenses are image stabilized on the E-510 and other Olympus Four Thirds cameras with in-body image stabilization (with updated firmware). Eventually, my Minolta lens collection expanded to include: 58mm f/1.4, 50mm f/1.8, 50mm f/1.4, 200mm f/4.5 telephoto.

What is Four Thirds? Four Thirds is a standard for digital single lens reflex cameras (DSLR) led by the Olympus corporation defining a lens mount and image format. Any company belonging to the consortium can make a 4/3 format camera, and Panasonic, Olympus and Leica are members. More by accident than by design, it turns out a 4/3 camera with a suitable adapter can mount lenses produced during the heyday of the 35mm film camera, from the 1960s to the 1980s, which are called "legacy optics." Although Olympus produced an adapter to mount OM series lenses on E-System cameras (their digital SLR line), at various times offering for free to previous users or selling it for a fairly steep price, most photographers adapting legacy glass to an E-System camera choose to purchase an adapter from ebay. A number of companies, mostly in China, produce 4/3 adapters. Lenses from Pentax, Nikon, Olympus, Leica, Contax can be mounted to a 4/3 camera and adapters are available for those brands. Except for Canon (with rare exception, there are some Canon to 4/3 adapters).

I have experience with the following lenses:

MD 45mm f/2.0 Rokkor-X Very sharp. Light, compact "pancake" lens. Well worth it for the fast f/2.0 lens @ 45mm compared to the slow kit lens, which is near to f/4 at this focal length. The 90mm EFL is favored for portraits.

50mm f/1.4 A competent performer, similar to other fast normal lenses of the period.

50mm f/1.8 Competent also, more forgiving of manual focus on cameras with small viewfinders than the faster lens. Good for portraits, unless you really go for extremely shallow depth of field. For a 4/3 user, I would recommend getting an OM to 4/3 adapter and a 50mm f/1.8 unless you either already have a Minolta lens collection or want other Minolta lenses, if this is the only lens you're interested in.

58mm f/1.4 Wide open is somewhat blurry and blooming, can be used to good effect, but needs to be stopped down a bit to sharpen up and exposure to even up for use on digital. Very well constructed, beautiful glass. (The 58mm f/1.2 is the holy grail of Minolta normal lenses, with outstanding rendering of out of focus areas).

MD 200mm f/4.5 A robust, metal lens. Mounted to an E-510 (or other 4/3 camera with in-body image stablization) you get an effective 400mm f/4.5 image stabilized lens for a fraction of the cost of a new digital one. 400mm EFL gets close to the start of the range useful for birding.

I'm not allowed to link to it, but the best resource on Mintolta lenses is called "Rokkor Files" hint, hint, get your google out.