Originally launched in 1972 as the M-1, the name was changed to OM-1 after Leica objected to the M-1 name. The OM series was designed by the Olympus Pen line team led by Yoshihisa Maitani.
Who ever the genius was at Olympus who decided to let the Pen team lose on the SLR world was, Thank You. They took what had been a large chunky segment (think Nikon F) and proved that you can reduce it down to the size of a rangefinder. The OM-1 is about the same demotions as a Leica M.
The lens mount also includes the shutter speed selection ring. This is built into the body but is flush with a mounted lens. The focus ring is next and then the aperture ring on the end of the lens. That is great to have all of them right where you need them. Except if your use to shooting traditional SLRs or even most rangefinders that have the shutter speed on top by the film advance. (The Yeshica Electro 35, had this but the dial was lower profile and not as easy to confuse.) On the OM-1 that is where you find the ASA/ISO. Fortunately it is locked with a small button release, other wise I would have been changing it thinking I was adjusting the speed. Once you get reoriented the OM-1 is simple to use.
The OM-1 is a mechanical SLR there is a battery only to drive the light meter. The one I shot had an issue with the light meter. It was giving a reading that was not even close. I figured it may be due to the use of the wrong battery. The correct battery is the discontinued PX623 1.3v mercury battery. So I changed it our for a modern adapted battery that fits and gives the correct voltage. Still not giving anything close to correct, so sunny 16.
The OM-1 was a nice surprise for me. I had seen them but to be honest dismissed them due to the size. I figured they were not "real" SLRs and never gave them a much thought. I knew they had their fans but did not know why. Now I do. This was a well built camera that was nice in the hand and fun to use. I shot a 28mm lens on this one. Overall a very nice set up. I would have like to have had the meter but the fact that it is a mechanical camera meant I could still shoot. Lesser cameras would have left me stranded.
I can see this as great travel SLR. I don't mind a full sized SLR for shooting, but I do mind the size and weight after a few hour. Especially for travel. I have a strict no checked bags rule so space and weight are alway in play. The OM-1 would be a great travel camera even for the lightest of packers.
Lens: Olympus OM-System G. Zuiko Auto-w 28mm f3.5
Film: Kodak BW400CN