[ripit]

There is no reason that there could not be a good quality one that didn't cause severe image degradation (there isn't one I'm aware of but there is no reason one could be made). One of my I'll get around to it one of these days projects was to take the mount off a canon fd mount camera and make a minimum thickness glassless adapter. Hand holding a few canon mount lenses to my camera, I'm still thinking that won't give me focus further out than a couple of feet. This thread got me to thinking though. The few lenses I have converted from canon fd to pk were easy (as easy as any lens I have converted anyway, it takes some work). The canon fd mount is so thick, removing it sets the lens back plenty. So what about taking a canon fd teleconverter, and convert the rear mount to k mount? The only adapters available might be cheap Chinese glass but there should be some decent fd mount teleconverters? A 1.4x would be great, but the only one I have found so far is a canon brand one and it is only for lenses longer than 300mm. They are pretty pricey too (too much to pay to go hacking it apart for an experiment). Does anyone know of any decent 1.4x fd mount teleconverters that might be had cheap? Alternatively there are 2x converters. For actual canon ones there seems to be an a (for lenses longer than 300mm) and a b (for lenses less than 300mm). The b also seem a bit pricey to hack apart. I wonder how good the glass on a vivitar one is (I already have one though I can not even recall where I got it). I don't have a lot of free time right now but seeing as I have a vivitar 90mm 2.5 bokina in fd mount sitting on the shelf collecting dust, I might be interested in putting a rush on it...
So any thoughts on how well this would work and or ideas about a cheap 1.4x to use? Any opinion on a 2x one with better glass than the vivitar that doesn't cost a fortune?

[ripit]

It won't happen. Put your FD lenses on a NEX or m4/3 or Q. Modding FD glass to PK is not feasible. I've chopped numerous lenses, but Canon FD isn't even worth trying without a machine shop.

Are you talking about actual canon brand glass or aftermarket? If memory server I have only modded a vivitar and a soligor from fd mount (I modded so many lenses during a short period I can not recall for certain which were fd mount but there were a couple), but there were no issues beyond the stuff you run into with any other lens mount. Removing the thick canon mount set the lens back plenty (I think I had to shim it back out on both). Of course I wouldn't expect better than wide open only or screw mount type operation. That is unless you want to go fabricating parts which would make it quite the task.
I think I already asked you this question at one point but can not recall the answer?

[RioRico]

Are you talking about actual canon brand glass or aftermarket?

Actual Canon glass. The few 3rd-party Canon mounts I've ever had weren't worth even trying; and the actual Canon glass was too good to chop; I sold it for wonderful profit!

[Ratmagiclady]

Actual Canon glass. The few 3rd-party Canon mounts I've ever had weren't worth even trying; and the actual Canon glass was too good to chop; I sold it for wonderful profit!

That'd be a very viable option. If I had the money, I'd propose the solution of, "Here, give me that lens and I will give you several hundred dollars. Apply this money to something that works better for this, and I will apply this lens to my old Canons. "

[ripit]

Looks like using a teleconverter to make an adapter with better glass (at least a vivitar one) is a lost cause (maybe). There is an outer shell that forms the entire body. The canon mount ring that goes to the lens you will attach screws to the front of this. All the glass is a contained unit in the middle. It only attaches to the outer body at one point at the rear (the rest of it is just floating inside). Unfortunately, that one point that holds the 2 parts together, is the exact area that I would have to remove to clear the camera. I thought it was a lost cause, but then got a crazy idea. Assemble it, fill the entire internal cavity with epoxy thus permanently attaching the 2 parts, then cut away the rear part that won't clear.

[excanonfd]

Certain Canon FD lens conversion to K mount is doable. I bought from the marketplace a Canon FD 200/4.0 Macro lens, which according to the seller (who did the conversion) miscalculated the amount of the barrel to be removed and the maximum distance the lens can focus is about 50 feet. In my tests the distance seem more like 60 feet or so. I bought it for macro use but not having infinity focus can be nuisance. I say certain lenses because the FD 200/4.0 macro has rear element group that's set deep inside the lens barrel and there's lots barrel that could be shaved off, I also believe the same seller did the conversion for the FD 300/4.0 to K mount that littledrawe is referring to as well. Looking at my FD 135/3.5 lens, the conversion seem possible but what would be the point of converting such a mundane lens. Oh, the mount that was used was a flanged m42 to K adapter made of brass that's been chrome plated.

[ripit]

I think in general, aftermarket lenses are going to be easier. I have been led to believe that they often design a single lens and then make different mounts for it. I have converted a couple of Canon and a hand full of Minolta aftermarket lenses (also supposed to be hard) where all that was required was removing the old mount and slap on a new mount without cutting the lens itself back. Of course either wide open or m42 type operation is what you typically get that way and the new mount needs to be aprox the right thickness (by thinning and or shimming it). I recently learned that isn't universally true though with the vivitar 2x fd mount teleconverter. The fd mount (all except the lock ring) was a single manufactured piece integral with the entire body of the lens. Further, cutting it back will destroy the only place where the body and the internal lens assembly connect. Of course, having already trashed the teleconverter, I decided to continue on and it is sitting with epoxy hardening that will permanently attach the body to the lens assembly after the rear section is cut back.

So has anyone ever heard of a canon brand lens being converted without having to cutting back the lens itself?

[newarts]

I did a DIY conversion using a flange type m42-PK adapter to replace the FD breach mount. The tedious part is shimming (and maybe cutting) to get the right registration distance - the need to shim or cut will depend on the particular lens' construction - Third party lenses like SIgma, Tamron, etc will likely be easiest to do because they made those lenses for more than one camera, hence the optical part of the lens is more separated from the mounting method and had to accommodate longer registration distances like Nikon.

I wouldn't bother to do it again unless I had a superb FD lens to start with.

[ripit]

I wouldn't bother to do it again unless I had a superb FD lens to start with.

I have had ones that were a breeze and took very little time while I have had others that were a nightmare. One in particular that was a nightmare was my fault though. I must have mis-measured somewhere. I used a donor mount and thought that I might actually be able to rig camera control of the aperture but I had to take substantially more off the mount that expected. The hard part was taking more and more off the mount while still maintaining even thickness. I had to thin a couple of mm more than I expected if I recall right and wiped out the hole for the aperture spring retaining screw.

I have kind of switched to the idea of making adapters to see how that works though. I have miranda?, canon, minolta and nikon cameras (junkers I got really cheap in a lot). I'm thinking something along the lines of silver soldering the mounts off the camera to an m42 adapter or something along those lines to get a minimum thickness glassless adapter. Of course with canon, minolta etc I would only get macro but it will be interesting to see what I get with nikon. I suppose I'll see if there is already one made first of course before starting one. If the canon one with the teleconverter goes good I may try other mounts from teleconverters, which in theory could potentially have good glass and not loose too much image quality. The biggest thing standing in the way, is that a 1.4x would be ideal and they tend to be expensive to go hacking up.

In the end though, if adapting doesn't work out well, I will probably continue to convert the lenses I have. Sure, sometimes its a pain but often its not too bad. It seems what parts you have available can have quite an impact on how hard it is (in particular what you have to make shims with). As far as new purchases though, I defiantly think I will stick to better lenses. Sometimes obsolete mounts can be quite a bit cheaper compared to k mount though.