Canon FD lenses on Sony DSLR with M42 adapter

[rick_strome]

I just bought a Sony Alph 100 dslr camera that takes Minolta lenses. I also

have several Canon FD lenses that I found will work on the Sony with the use

of a M42 adapter. I got the adapter from B and H and it does not work very

well. It is made by Bower. It has a glass element that allows infinity focus

and allows me to take pictures with some restrictions. Can anyone tell me if

they have ever used these adapters on the Minolta/Sony or other cameras. The

problems are:

1. The adapter will not go on some lenses. The 50mm f 1.8 and 28 mm f2.8 will

go on but the 70 - 210 f4 will not.

2. The adapter is very poorly made in that it is difficult to get on the lens,

it will not lock and the only way to get it off is to pry it off - not rotate

it off.

3. None of the lenses will open up to more than F 5.6. I went to a M42 site

and found nothing. Thanks for any advice on the above, Rick

[SCL]

Any FD adapters with glass elements in them to provide infinity focus typically produce lower quality results than the lenses are capable of, and may also require an increase in exposure, as the light has to pass through additional surfaces. That said, I've used M42 Bower adapters (without glass) for other camera types and they work just fine, construction similar to other manufacturers. It sound like you may have gotten a poor sample, and also you may not have done your research on which FD lenses will work with a glass adapter and which won't. Adapter's glass element often obstruct the rear element of certain lenses, so you really need to measure travel distances before trying them on an adapter with glass, so that you don't scratch the surfaces or cause other damage.

[paul_de_ley]

<p>I've tried a different Bower adapter, the 7000/9000+CF for fitting FD lenses directly to Maxxum bodies (also sold by B&H but hard to find through their search function, their catalog nr is GBCAMAFC). </p>

 

<p>It magnifies by about 1.25x, loses light by about two-thirds of a stop, and works well enough on most of my FD mount lenses except the 400mm/f4.5. I was pleased and love my FD lenses enough that I ended up getting two more units of the same adapter. That showed me Bower's machining standards were not very exact: both extras needed minor drilling work to make the maxxum mount locking pin click into place properly.</p>

 

<p>I also modified one of the three more extensively to make it work specifically on my uncooperative 400mm/f4.5 (which is a new FD mount version). Basically the problem was that the diaphragm bayonet stop-down slot in the adapter cannot accommodate the 400mm's unusual bayonet motion, which has more of a swiveling action instead of just sliding sideways as in other FD lenses. So I drilled out the stop-down slot to make it both deeper and longer and now it works fine.</p>

 

<p>If you'd like to see some examples of image quality check out the grebe and heron shots in my photo.net portfolio:</p>

 

<p><a href="http://photo.net/photodb/folder?folder_id=803575">http://photo.net/photodb/folder?folder_id=803575</a></p>

[rick_strome]

Stephen:

Thanks for the answer. I did as much research as possible, but have not been able determine what lenses work and won't work. Is there a link that shows that. I could not find that information even on the M42 site. I called B and H and they gave me the name of the distributor and I will call them tomorrow to see if they have an answer. Thanks, Rick

[SCL]

Rick - I don't know of a single site which merely lists the hundreds of lenses which might or might not work. I do a lot of work with another brand camera which shares similar issues with using other manufacturer's lenses on it, and the issues are sometimes rather complex. The best information I've secured has involved lots of searching of archives from user groups and repair persons specific to individual lenses (rather than a group of lenses). In some cases the results were determined in advance by merely measuring the movement of rear elements in the main lenses with a micrometer and comparing that distance to the flange to internal lens distance of the adapters. In some cases of adapters without internal lenses, the problems have centered about the nature of the lens and the size of the mirror in the DSLR it is being attached to, in that the mirror of certain models in a manufacturer's line actually hits the rear element of the some retrofocus lenses, so the mirror has to be shaved. Good luck in your research on your lenses for your camera.

[rick_strome]

Paul:

I called Bower (the mfg of the unit sold at B and H) and they said I probably have an older unit that may not work properly in all cases. My unit has a green and red dot with 7000/9000 on the side. The newer unit has only a red dot with open/close on the side with no 7000/9000. Do you know what your adapter had written on it?

Thanks, Rick

[paul_de_ley]

Hi Rick, in that case I have the same version as yours: green and red dot with 7000/9000 on one side. B&H probably got a big batch of those a few years ago and didn't sell them as fast as they expected!

 

I have FD 50mm and 28mm lenses that accept the adapter, but no FD 70-210 to try it on. Maybe your FD f4 70-210 has a bayonet that sticks out just a little too far to fit the stop-down slot in the adapter? To avoid any confusion: when you mentioned that the adapter doesn't lock on the 50 and 28, did you mean it doesn't lock on the lens (as opposed to not locking on the body)? In that case perhaps the bayonet of your 50 and 28mm lenses doesn't get shifted quite far enough to fully engage stop-down and that might also explain why those of your lenses that do fit only close to f5.6.

 

If you have a vertical drill stand (or know someone who has one) then a simple way to test and hopefully fix things would be to first drill through the stop-down slot in the adapter so it will take longer bayonets, or bayonets that tilt while they shift. If that doesn't solve all problems, then the stop-down slot might also need to have a few mm extra added towards its trailing edge. For my 400 f4.5 I not only had to drill through but also extend the length of the slot, which took several attempts to get right. If you like I can take a pic of my retooled Bower specimen and upload it to clarify things.

[ralph_flaugher]

My lens mount adapter( the one with 7000-9000 CF and red and green dots) accepts my 50mm and 28mm primes as well as my 75-200mm 4.5 but will not take the 35-70mm 3.5

[paul_de_ley]

Hmm... Ralph's comment reminded me that I have a 35-70mm 3.5 that I rarely use anymore. Indeed it won't take my instances of the 7000-9000 CF adapter either. I tried the one that I modified to fit my 400 4.5 by drilling through & extending the stop-down slot. It looks like the bayonet of the 35-70 needs an extra mm or two of clearance to turn with the slot. Will try extending it further a teensy weensy bit and report back on the outcome.

[pawel_sokolowski1]

I would like to buy new version of this adaptor. Any idee where?

[paul_de_ley]

Google "maxxum canon adapter" and click on the second shopping link from the top ($36.95 for B&H) then scroll down the list in b&h webpage. ebay usually has a few too, though not nearly as cheap as b&h. It's not clear to me whether Adorama sells these, their picture is wrong.