I have just finished converting a zuiko 21mm f3.5 and a 40mm f2 to alpha mount to use with my A900. The process was a lot easier than I anticipated. All took ~2-3 hrs for the conversion. Basically, I just replaced the old mount with a M42 to A mount + a 0.5mm spacer. Infinity adjustment was made thru the side of the zuiko after removing the focusing rubber. The good new is that the process is totally reversible just in case I decide to use them on my canon again.
Here are a few photos:

1) 21mm f3.5:

Wonderful! I was just speculating in another thread here about using a similar approach (attaching an M42-Alpha adapter) but thought I would have to dremel part of the original mount off... were you able to just directly attach the adapter after removing the original lens mount? Did you just drill new screw holes in the adapter and spacer to match the existing ones? Was there any gap or anything afterwards?

More pics (both of the conversion and with the lenses) would be great!

That's very impressive! I too would love to see more pics such as the rear of the converted OM lenses. Of course, a photographically illustrated step-by-step would be awesome for such a conversion. I sold my OM 24 long ago as I did not think it would be such an easy conversion.

interesting. how does that compare to the minolta 20/2.8?

pingflood/Tarig,
I was able to remove the mount and directly put a replacement mount over. It was dead simple. I just needed to pull the internal aperture level using a spring (left over from a rokkor) so the lens can stop down without the need of the original mount (similar to a rokkor 85 f1.7 if you have done one). I used epoxy as I planned to put an M42 mount on them later. Unfortunately I forgot to take photos of the process. The only one I took was of the 40mm f2 with the back mount removed so I would remember how to put them back. That piece in the photo was removed as well before I put the adapter in.
I also have a 28mm f3.5. Let me open it and see if it is similar. If it is, I can make some photos.

Jim,
I've never owned a minolta 20mm f2.8 I have no idea how they compare. I suspect the zuiko has better resolution and color but that's totally speculation.

Thanks for posting the picture and the explanation.

Sorry all I haven't been able to get back to the 28mm f3.5 until now (I have been so occupied with my C/Y to alpha project). I recorded the process this time which is similar to the other two. Without further ado, the the zuiko 28mm f3.5 on Sony:

1) Original Mount removed:

Hope this helps?

Helps me turn green with envy, I would love a low cost but fine res/colour 21 prime on the A mount. The lovely little Zuikos make the A900 look like a Pentax 67!
Looks a lot like Sony is the next frontier in alt lens deployment.

Would be very interested in any comments you might have re the output of the wide Olys on the A900 compared with the same lens(es) on your Canon. Thanks for posting.

philip_pj,
I like the wide olys much better on the sony since the sony provides better dynamic range and also in my opinion better color. Are you looking into converting one?

It's been a while since the last post. During that time I did convert a few more zuikos to Sony, including a 50/1.4 and a 50/3.5 macro. So far, the zuikos seemed to be one of the easiest to convert to alpha mount and importantly the conversion is totally reversible to the original mount. A few days ago, I received a rather special one, the zuiko 50/1.2, and finished the conversion. Again, the 50/1.2 is as simple as the others. It's so compact for a 1.2 and pretty sharp wide open (on par with my rokkor 50/1.2 and 58/1.2).

debuggerus wrote:
philip_pj,
I like the wide olys much better on the sony since the sony provides better dynamic range and also in my opinion better color. Are you looking into converting one?

Well, this is another proof that the Sony color comes from the camera not lenses. Beautiful photos and great color!!!

I'm very new at the whole lens conversion thing, so forgive me if these questions are very basic. I'm also at work, so I can't look at your pictures.

1) I notice this lens is originally for Olympus, correct? Is this lens large enough to cover the entire area of the A900 sensor? The only thing I know of Olympus is 4/3 which is why I ask.

2) When using the lens, I'm going to assume it is manual focus. Do you get any metering with the lens whatsoever, or is everything manual?

Thanks for your help! I may look into experimenting with some very cheap stuff at first, to see how I like it.

Olympus has been making 35mm lenses for ages, so no problem covering the A900 sensor. If you adapt a lens without a ROM chip, you must use M mode, but the meter does work.

Your mission is the 21/2 :P

cputeq wrote:
I'm very new at the whole lens conversion thing, so forgive me if these questions are very basic. I'm also at work, so I can't look at your pictures.

1) I notice this lens is originally for Olympus, correct? Is this lens large enough to cover the entire area of the A900 sensor? The only thing I know of Olympus is 4/3 which is why I ask.

2) When using the lens, I'm going to assume it is manual focus. Do you get any metering with the lens whatsoever, or is everything manual?

Thanks for your help! I may look into experimenting with some very cheap stuff at first, to see how I like it.



cputeq,
As Douglas said, these are lenses for the old OM cameras which are full frame. You can use them on a canon body with an adapter but you can't on a Sony or Nikon unless you do a mount replacement (hence this thread)
You might want to try the OM 50/1.8 or 28/3.5 which are excellent lenses without sweating your wallet. The 50/1.8 is around $30 and 28/3.5 is around $50.

ricardovaste wrote:
Your mission is the 21/2 :P

yeah I almost bought one a few months ago. Now, I only think about the distagon but who knows. Maybe a 21/2 pops up at a price I can't refuse?

any updates on your c/y to alpha conversions?

They're just as easy - if you can only find some place to anchor the spring to load the aperture lever. This is how I did it on the 50/1.7 - a bent & dremeled (dremelled? dremel'd?) pocket clip from a ballpoint pen super-glued to the rear lens barrel.

And to retain the click-stops on the aperture ring you have to do some reconstructive surgery... Unfortunately. The click-stops are indents in a brass shim that rests in between the original mount and the lens barrel. I removed it, cut it to fit the new M-42 adapter, found the correct position - and superglued it.

Yes, I use a lot of super-glue... :-) It saves a lot of trips to the machine shop, and I use a special type of glue that's extremely stable until the temperature hits ~100º celsius - then it just peels off. This is convenient when you redo things (like "re-converting" an already Nikon-converted Contax to fit Alpha in stead...)

theSuede wrote:
and superglued it.

Yes, I use a lot of super-glue... :-) It saves a lot of trips to the machine shop, and I use a special type of glue that's extremely stable until the temperature hits ~100º celsius - then it just peels off. This is convenient when you redo things (like "re-converting" an already Nikon-converted Contax to fit Alpha in stead...)


Would you mind telling me exactly what glue you use?

Here is an easier, yet costlier option.

leitax.com

"Here is an easier, yet costlier option"

Indeed. Not all of us are keen to rip far into lenses, armed with glue (fortunately Superglue is low toxicity) - or equipped to deal with problems that arise.

Just to add that the Leitax mounts are totally reversible and readily accept James Lao chips for EXIF, focus confirm, optimal in-body stabilisation and A mode metering on the Alpha 850/900.

I am also of the opinion that you would have much more success selling a Leitax mount lens than a stuck together lens - but whatever floats your boat(!)

Do the Lao chips work with a 35-70 zoom lens? Don`t they have to be programmed fot a specific focal length? I am thinking of mounting a 35-70 Angenieux to my Sony a850.