Use of old (Olympus OM) lenses on Canon XT camera

Discussion in 'Canon EOS' started by brent_bennett, Feb 14, 2012.

  1. I have just started to learn how to use this camera, and have not had previous experience with any digital camera. I have an adapter for some OM lenses I have, and I would like to know what others recommend for settings on the XT. Should I set it to M mode, or some other? I only want the camera to calculate the shutter speed after I have set the lens diaphram to my choice (f/5.6 for example) for the light that is available. Are there other settings that are recommended for this type of situation?
    Also, if I use the on-camera flash (or an auxillary flash) will the camera calculate the correct exposure by setting the shutter speed?
    Thank You
  2. With Canon, if you are in Av or Tv mode, the camera will make your flash use ambient light as your primary source, and the flash as fill. If you want the flash to be your primary source of light, you have to use M. I *think* the XT has a flash sync speed of 1/200, so your shutter can't be any faster than that when using a flash.
    Since you'll be in M mode, you'll largely be in control of the exposure, although the camera should meter for your aperture (but if it's too wide for your settings, you'll still get an overexposure).
    For an educational point, the shutter speed has little control over the amount of light hitting the sensor when using a flash. Think of it this way...when using flash, shutter speed regulates the influence of ambient light, and aperture regulates the influence of the flash. The flash pulse is generally much shorter than the fastest shutter speed you can use with it, so it's up to the aperture to limit the light.
    If you aren't using a flash, your point is exactly the way you will need to use your lens. Focus with your lens at it's widest aperture, then stop down to your desired aperture when you're ready to meter and shoot.
  3. Using aperture priority seems to work for some people, but I've not had good experiences. I use some OM lenses on my 5D -- it's supposed to work in aperture priority, if you set the aperture on the lens the camera sets the correct shutter speed, but that hasn't worked for me. When I change the aperture one stop at a time, the shutter does not shift one stop the other direction, so by the time I'm stopped down I'm really underexposing. I find that if I meter with the OM lens wide-open, that's a good exposure value, then I set it on manual and figure in my head the appropriate aperture/shutter combination. And I use the histogram a lot.
    With alt lenses, YMMV a lot.
  4. I'm going to add now, and I should have said earlier, that I'm not speaking from experience, just my understanding. Matt has a good point. Might be worth selling all the old lenses to pick up some kind of Canon EOS lens, like the 18-55 IS.
  5. Exposure problems are inevitable with full-manual lenses because the camera needs to know the lens aperture when doing exposure calculations, because the meter sensitivity varies by the aperture of the lens.
    Bracket, shoot test shots, etc. It's generally not a huge problem because, if you've decided to use full-manual gear, you're probably not in a hurry. I used an old MF Tamron Adaptall macro lens for a year and got very good results with it. I would say macro work is ideal for full manual shooting, since it's usually slow work anyway.
  6. In my experience with OM-lenses on Canon EOS bodies, using Aperture Priority (Av) works fine, at least with an adapter that has a focus-confirm chip.
    Just make sure to open the lens fully while focusing, and closing it to the taking aperture before pressing the shutter.
    The image below was taken with an OM 50mm f1.8 on a macro converter, adapted to an EOS 30 with Velvia 100:
  7. I use many adapted lenses including OM, M42, Pentax K, Nikon, and Pentaxon. I use the adapters with the AF confirmation chip and I do find that I have to use E-1 (-1 stop compensation). i do get very good results.
  8. +1 Alan. I use several manual and manual/preset lenses on my XTi. Using E-1 is a good starting point. It works with some manuals, not so much with others. For instance, E-1 compensation DOES work with my FD 50mm f1.8, but underexposes with my Vivitar/Cosina 50mm f1.8. Maybe that has something to do with the infinity focus glass adapter on the FD, but I don't know. I do know what worked for me. Get to know your lens. Shoot, shoot and then shoot some more :) Believe in the histogram! You will learn over many trials how your camera reacts to your lens and thus, almost naturally, you will make proper adjustments more quickly and with great precision. Happy shooting with your manual gem!
  9. If you posted this in Olympus forum you probabaly would have received about 10 pages of responses by now! A lot of folks in the Olympus forum adapt their OM Zuikos on Canon. has a ton of photographers in the alternative camera lens forums using alternative lenses on digital as well. I have shot with OM Zuikos on Canon full frame digital for years. I was the one of first photographers in the world to my knowledge to shoot with the Canon 5DMKI full frame digital and Olympus OM Zuiko ED 100mm f2.0 lens... a very RARE OM Zuiko lens.
    Olympus OM zuikos on Canon digital cameras work excellent. In fact I would recommend you upgrade to a full frame Canon 5D MKI asap so you see the focal length as the same on a 35mm SLR film camera.
    Your only choices for camera modes when adapting alternative manual lenses on Canon digital are AV or M (manual). Tv doesnt work as there is no way to control the aperture. Get used to "stop down" metering and manual focus too obviously with these manual lenses. After using the manual lenses you will start to miss autofocus and a bright VF at small apertures. Its worth it though if you have a rare OM Zuiko lens or any rare lens: Kinoptik, Zeiss...ect. Here is example with the Canon 5DMKI and Olympus OM Zuiko 100/2 ED lens.

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