[beholder3]

[deleted]

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Last edited by beholder3; 08-12-2013 at 01:52 AM.

[RioRico]

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.

[twilhelm]

The only adapters I found were cheaply made, and required glass in the adapter. Didn't seem like a good idea, so I sold my FD glass and bought K glass.
Good luck.

[beholder3]

[deleted]

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Last edited by beholder3; 08-12-2013 at 01:52 AM.

[Docrwm]

RioRico probably is too nice a guy to say this but he's got "real experience". He's modded and used more types of lenses on his K-Mount cameras than most of us have even heard of. IF all you want is someone to say "Sure, go ahead - you can do it!" then here:

Sure, go ahead - you can do it! I believe in you!

[hoanpham]

Depends.
If you have a macro in canon fd mount, it may work, no infinity.
I have 7 canon fd lenses, try as hell to adapt the 85/1.2 with no luck.
Nikkors and zuikos are ok.

If your lens is worth the modification, then it's also worth a nex or a m4/3.
But if your lens is worth an irreversible modification, then maybe getting a canon fd film body is better.
Chopping up a lens will reduce it's value to zero regarding resale.

The 85/1.2 is unique, but if you prefer mod lenses, there are lots of nikkors, zuikos for cheap outthere.
Old zuiko OMs cannot use with dslr olympus, and only few model of nikon dslr can use old lenses, therefore great prices.

FD can be mod to EOS then.

Me too:
Sure, go ahead - you can do it! I believe in you!
Please tell me how.

[stanislav]

I did it, it took me a lot of time and to frankly say if it was worth it well, both yes and no.

What I did was that I removed the mount from the lens. then I cut the apperture lever (so that there was nothing sticking out of the mount). Then I took a cheap K extension tube, removed the mount and drilled holes in the mount (where holes on the lens were) so that I could use screws that held the FD mount to hold the Pentax K mount.

The lens in question was Soligor 400mm f6.3 in Canon FD mount.

Well now some observations:

Canon FD has shorter mount to sensor (or film plane) distance than pentax K. Meaning that If you want to retain infinity focus you have to get rid of some material at the mount side. Usually it is should not be a problem if you can live with completly manual aperture control.

Since my lens was a telephoto it is not as important to get the exactly correct distance from the rear element to the sensor (or film plane). I think that my lens is something about 0.5 mm too close to the sensor resulting that I can focus "past" infinity. On the other hand I have lost something on the closest distance (i.e) the lens can not focus as close as it could originaly. furthermore since the lens is for full frame and I was using it on APS size senzor there was no visible vigneting either.

Now to the question if it was forth it:

Yes - I got nice piece of glas making photos comparable to Bigma (Sigma 50-500) @ 400mm. I learned a lot of lens construction and something about the repair.
No - It took just too much time, that should I take that into account it would have been more cost efficient to by similar lens in K or M42 mount.

Now would I do it again?

The answer is yes, but only if I can get hold on a fast Canon telelenses (300mm f2.8, 400mm f4 or similar). For shorter lengths it is too critical to get the exact spacing on the mount (FFL) that it should be worth it.

Here is link to a russian forum with some photos and some more info about it (I used is as a guidance to my work)

????????? ????????? Canon FDn ?? Pentax - ?????? ?????-?????

if you need any more specific information about what I did, feel free to contact me.

[boriscleto]

https://www.pentaxforums.com/forums/pentax-camera-field-accessories/96884-ada...addiction.html

Some samples with a common optically corrected FD adapter (works as a short teleconverter) and a Canon FD 50/1.4

Wide open


@F8


Wide open


@F8

[Lowell Goudge]

There was a thread in the accessories forum about all sorts of adapters about a year ago. I have 2 "optically corrected" adapters, one for Nikon to PK and one for canon FD to PK. They are effectively cheap teleconverters. To correct for the change in regestry distance the Nikon adaptor ends up with a multiplation factor of 1.25 and the canon adaptor 1.45.

They do offer infinity focus and manual aperture control and will meter in Av mode like any M42 lens.

Are they worth it, I'm not really sure. I thought I would try them as I had both a canon and Nikon 50mmF1.8 lens. they are somewhat soft wide open and there is real color bleed at the edges but when stopped down work acceptably.

[Lowell Goudge]

Check this thread

https://www.pentaxforums.com/forums/pentax-camera-field-accessories/96884-ada...addiction.html

[beholder3]

Great infos guys! I also checked the other thread.
To me it seems that for Tele and macro applications it might be worth looking at it. Wide open IQ seems to degrade though the picture with 85/1.2 in the other thread looks good.

[Lowell Goudge]

I think if I tripped over a really good canon or nikon lens I would use my adaptors more, but I got them just for the fun of it so to speak. The test on focal length multiplier, I did by using a Tamron 28/2.5 with PK Nikon and canon mounts, so I had a direct comparison of enlargement taking three photos form the same spot, one using PK mount only, one using thecanon mount and the adaptor and the last using the Nikon mount and adaptor
Dut to magnification I concluded the same thin, this is a normal to tele use only

[stanislav]

Here is list of register distance (mount to film-plane / sensor). There is however no information about the diameter of the mount opening.

Camera Mounts Sorted by Register

Now a general observations are:

1. It is easier to adapt lens which has bigger register distance to the mount with smaller (a simple "extension" tube or plate would do the job.
2. It is easier to adapt lens with smaller mount diameter to the body with bigger mount opening (as it is easier to fill the gap).

Now Canon FD and Pentax K are similar in diameter, but Canon FD has 42mm vs Pentac 45.46mm that means that the lens has to be shortened by at least 3.46mm at the mount side. If you add a Pentax K mount, you'll end up with about 5mm of material that just has to go off. Now that is some fairly advanced mechanical engineering.

The other option is to modify the camera body and to try to get rid of the mount replacing it with canon FD mount.

And of course there are some optically corrected converters as well...

[Lowell Goudge]

Here is list of register distance (mount to film-plane / sensor). There is however no information about the diameter of the mount opening.

Camera Mounts Sorted by Register

Now a general observations are:

1. It is easier to adapt lens which has bigger register distance to the mount with smaller (a simple "extension" tube or plate would do the job.

actually you need circular shims and a longer set of screws for th emount. I have managed to swap mounts on a nikon mount kiron 24/2 and spent a ton of time stacking out with shims only to find later that it is quite easy on the kirons to shift infinity focus.

2. It is easier to adapt lens with smaller mount diameter to the body with bigger mount opening (as it is easier to fill the gap).

which is what the M42 to K does, and to a lesser extent any mount to a new canon mount, because it is very large in diameter

Now Canon FD and Pentax K are similar in diameter, but Canon FD has 42mm vs Pentac 45.46mm that means that the lens has to be shortened by at least 3.46mm at the mount side. If you add a Pentax K mount, you'll end up with about 5mm of material that just has to go off. Now that is some fairly advanced mechanical engineering.

actually if you consider the wasted space of thebreach mount mechanism, there is not a lot else that needs to be done, remove that and you will actually find the lens needs shims to mount correctly

The other option is to modify the camera body and to try to get rid of the mount replacing it with canon FD mount.

although this is not possible for a canon mount because it requires being recessed into the body, that is a non starter for canon, although i have been thinking about doing this with a pentax body and implanting a nikon mount on the body, although at that point why not just get a nikon body, because we are, after all discussing modification to lenses, if you are going to commit a body to nikon mount lenses just buy a nikon. The FD lenses are a different issue because nothing mounts them directly, except a micro 4/3.

And of course there are some optically corrected converters as well...

i have one, and if a company were to properly do the optics, with good coatings and a retrofocus element as well they could get back to a 1:1 adaptor, but the cost would then go through the roof. the optically corrected adaptors are not actually that bad, if you stop down. I consider them a use if you don't have anything else handy, and at present, since I don't have a 70mm lens, using the FD adaptor on a 50/1.8 gives me a really cheap 70mm lens.

[littledrawe]

There was a lens for sale that was an FD 300mm f4 for sale I believe a couple months ago, that had been modded for pentax. The forum member used the m42 to PK adapter with a flange that on a Takumar prevents infinity focus. Have you tried the impossible lens club??