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Home >> Photography >> Accessories Pentax
42mm Lens Screw Mount to Canon FD adapter
A coworker handed me a perfectly fine Tokina 80-200mm f4 zoom lens and 55mm diameter close-up lens. She had them sitting in a drawer at home and did not even know how she came to have them around and since she had nothing that could utilize them, she handed them to me, gratis, as they say in French. Only one minor problem though, the Tokina lens was not in a Nikon, Canon, or Yashica mount that would have allowed me to use it immediately. The lens has the old Pentax 42mm screw mount and as much as I appreciated my coworker’s generosity, I was not so sure that this lens wouldn’t go from my hands to the used bin at a local shop. However, a bit of research and surfing on the ‘net and I discovered that the lens could still have a second life with me. A trip to Stephen Gandy’s Camerquest website got me details on a Pentax 42mm screw mount to Canon FD mount adapter and after a bit of musing, I ordered one from Mr. Gandy. A Paypal transaction and about a one-week wait later and I had the new and very well made adapter in my hand. Cost was $50 US plus $5 S&H, which translated to a little over $70 CAN after conversion. The adapter works like a charm to adapt the Tokina lens to the Canon FTb body I have, with both mounts smooth and secure. I even like the FD mount of the adapter better than the real thing on the Canon 50mm f1.4 lens I have for the FTb. One little catch though, there is no auto-diaphragm metering with the lens. Cameras have used auto-diaphragm metering since at least the 1960s. All this means is that the lens, camera and film ISO are indexed so that you can look through the viewfinder as if the lens’ aperture is wide-open while the camera “knows” what aperture you actually want to use and will present you with the correct meter reading. The wide-open view is to allow you the ability to manually focus with the brightest view of the scene.
Cameraquest did indicate that there would be a lost of metering with certain adapter and camera mount combinations, so it wasn’t a complete surprise. As one stops down the aperture, one notices the viewfinder getting progressively dimmer and dimmer. How does one work with this? Since I had never used stop-down metering before, I had to research if this to see if it could work for me in this situation. Stop down metering is apparently taking a meter reading with the lens stopped down to the working aperture you wish to use and then adjusting the shutter speed dial accordingly to achieve a correct exposure. If this is really how stop-down metering works then it does not work for me, someone more experience, please enlighten me. As it turns out there is one reading that the Tokina lens with adapter could relate to the camera’s meter and that is wide-open. By adjusting the shutter speed dial to correspond to the f4 maximum aperture, I have a working exposure setting to guide me. After this, it isn’t so hard to adjust the aperture and shutter speed dial for a reciprocal exposure setting desired. I also have the Sekonic L188 handheld meter to use too. So, when something appears less than useful, don’t discard or disregard it straight away. Do a bit of research and you never know, it just might find new life for you. And I’m just thankful that there are fellows like Stephen Gandy around who love the old classic cameras of my father’s time and inform the public with his knowledge, as well as making available some useful accessories for them. Now, maybe I should look for decent wide-angle lens to use to fill out the range for that old, but still going Canon FTb. |
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Correspondence & About this website Copyright © 1998-2008 Edwin Leong |
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Being
known as a photography enthusiast sometimes opens up new opportunities,
such as photographing weddings, family portraits, and maybe even the
odd commercial venture. Some regard such forays as nerve-racking ordeals
to be endured whereas I like them for the new opportunities they present
to expand the photographic horizon. And occasionally, one also benefits
by receiving certain cast offs.
Nikon
users of old may recall with amusement the manual indexing in the pre-AI
days (AI = Auto Indexing), which required a little ritual of indexing
the maximum diameter of the lens to the film’s ISO speed before one
could use the lens and camera properly (set the lens to f5.6 before
mounting on the camera, then turn the aperture to its minimum setting
and then back to maximum for indexing the meter to the aperture). Or
actually, perhaps a lot of Nikon users of old are still doing this little
ritual with their F’s and