I have just received an AF confirm lens adapter for Olympus OM lens onto Four Thirds (Olympus/Panasonic) dSLR bodies from RJ Camera Accessories Ebay store.

I am using this on my Olympus E-510 but it should work the same on other Olympus cameras and he supplies other models for other model cameras.

It seems reasonably well built and certainly seems to fit more solidly than my last Chinese-made OM adapter.

The great thing about this adapter is that when you are manually focusing (as you have to do with legacy lenses on dSLR bodies), you get a AF confirmation light and if in S-AF or C-AF mode, you also get a very useful audible beep when subject is in focus which allows you to concentrate a little less on focus and watch the subject and composition.

When I first put it on, it didn’t seem to work but after removing it and replacing it and half-writing a letter back to the supplier, it suddenly started working.

If it is working properly, when the viewfinder data becomes active by half-pressing the shutter, the aperture defaults to f/2.8 and focal length to 50mm irrespective of which lens or aperture you have on. He states the adapter can be programmed to change these – I’m waiting to find out how (ps.. he emailed me same day with detailed instructions on how to program it) – it will not effect image quality, only EXIF data, although you can adjust back-focus setting.

When in an AF mode on the camera, you half-press the shutter while manually adjusting focus on the lens and when subject comes into focus, the green focus confirmation light in the viewfinder comes on and stays on (not blinking) and the camera will beep.

When in manual focus mode on the camera, you don’t get a beep (unless you set manual mode to m:3 – my favorite setting and use the AFL button to “focus confirm”) but focus confirmation light seems to work without half-pressing shutter (although you do need to half press the shutter to activate viewfinder data which stays active for a few seconds).

The AF confirmation works in apertures down to f/8 inclusive (amazingly, it even worked down to f/16 in low light on contrasty carpet pattern).

This has made using my Olympus OM 200mm f/4 lens that much more usable on the E510 as I can now quite quickly accurately focus even in relatively low light (indoors on a heavy cloudy day) and with the image stabiliser set (to 200mm) use shutter speeds down to 1/50th sec hand held (1/30th sec at a push if you are really steady) which is not bad for a 400mm equivalent focal length magnification. The nice thing about this lens is that it is very light and compact for a 400mm reach and it is very usable leaving the aperture at f/5.6 instead of wide open at f/4.

Here is a previous blog showing how good the Om 200mm lens is on the E510 hand held when a car caught on fire in a main shopping strip.

Now you could use the beautiful ZD 50-200mm lens instead and get sharper images and AF but it is quite a big, heavy intimidating lens when used at 200mm.

Alternatively, you could use the very compact, light ZD 40-150mm kit lens for perhaps better image quality but it only gives 300mm reach not 400mm and widest aperture is f/5.6 which can be limiting.

Another option is the much loved ZD 70-300mm lens which gives even more reach but AF is said to be a bit slow at the long end and images are not quite as sharp – but what other camera allows a compact, light 600mm equivalent focal length hand held at f/5.6 with IS in the camera?

Now if only Olympus would make a compact, light, high quality ZD 200mm f/2.8-4 lens I probably would not bother with the OM lens or any other lens on the Olympus cameras given the optical resolution of the ZD lenses far surpasses any lens made for 35mm film cameras that I am aware of.

Post script:

In actual use, it is still difficult with moving targets, the beep on AF confirm is difficult to hear in noisy environments and you need to turn the focus ring slowly and watch the viewfinder AF confirm light which detracts from composing and timing your shot.

For static subjects where you have time, the AF confirm makes a BIG difference.