Telephoto lenses are expensive and if you have one intended for an older SLR camera, you may consider using it with with your DSLR. My experience is that this is doable but there are a few critical issues that you have to deal with.
Contemporary DSLR cameras are rather unfriendly to older lenses for different reasons such as the lens-sensor distance , the mounting mechanism or even the camera software.
It is important to mount the old lens on the camera at the precise distance without damaging the internal parts..
In this instructable I'll show you how this can be done by a specific example using common tools and materials.
I picked this used and damaged telephoto from a street market. It was a zoom 80-200mm F/4.5, ~400gr weight, with the JCPenney (an American multistore) brand on it and the sign "made in Japan" . Even at its own time it would be inferior compared to those made by Yashica, Nikon or Vivitar with similar specifications.
It was practically separated in two and full of dust, but the external lenses did not seem to have any scratches. Initially I intended to remove the lenses for other uses but looking at it more carefully I realized that the mechanical problems could be fixed.
The challenge was to repair it and mount it on my Olympus E-420.
Step 1: Preliminary steps
Find out the camera-lens distance
- Attach the camera on a tripod and remove its own lens. Holding the telephoto with both hands in front of your camera with the setting of the telephoto at infinity, try to focus a very distant object. If you have a problem to keep the lens to the correct position use a paper inner tube but do not touch the internal parts of your camera.
- Rotate the focusing ring a few degrees and focus again. In the final construction it is better to set the infinite point a few degrees before the rotation limit. This will allow sharp focusing by leaving some space around the correct point.
- Focus on close objects. Try to find the minimum focusing distance available. In my case the distance measured was 1.7 meters at 200mm and 1.5 at 80mm.
A T-ring is the best type of adaptor for this work. It offers two possibilities for mounting a lens, either by using the 42M threading of the internal ring or by removing the ring and fitting the tube on the main connector directly. The one shown here is the Olympus Four-Thirds T-ring for DSLRs which has a bayonette type mounting.