Mounting FD primes on 5D - a different approach

[anthony_lewis1]

<p>I bought the 5D essential for its movie capability. I have a excellent set of FD 'L' primes, which being manual focus, are the prefect lens for movie mode. I know the FD to EOS adaptors are not very good, particularly at wide apertures.<br>

But why can't I modify the 5D to take FD lenses? Looking at this problem, it appears it could be done by a specialist machinist.<br>

Firstly I buy the 5D lens mounting plate as a spare part. Then I wreck an old FD camera for its lens mounting plate. The machinist will machine the FD mounting plate so it fits inside the EOS plate. Then the FD plate is welded to the EOS plate with the flange on the FD plate offset by 2mm. (EOS flange dist: 46mm & FD flange dist: 44mm). There appears to be just enough room inside the 5D body to take the FD plate 2mm further inside the body - the electro contacts would be the closest!<br>

I then have this fitted to the 5D body - there appears to be 4 screws to change the lens plate over. The mirror should not be a problem as it is locked up in movie mode. In theory the 5D body and the lenses have not been modified at all - which is a good thing as the 5D can easily be reverted to the original EOS lens plate.<br>

I sense there has to a a good, and perhaps very obvious reason why this cannot be done - otherwise it would have been done before.<br>

Any comments?</p>

 

[scott_ferris]

<p>Anthony,</p>

<p>Nice thought and I hope you get some good leads through this thread but the lens is too big to fit inside the EOS mount by 2mm, surely.</p>

[bobatkins]

<p>You mean a 5D MkII I assume. Assuming there's enough room inside the body to actually fit an FD mount (I don't have one to hand so I can't say) and that the lens barrel at the rear is also small enough to fit into the EF mount opening (which may be more of a serious question) then...</p>

<p>The problem is that the mirror may hit the new lens mount and will almost certainly hit the lens. I know it's up when you are in movie mode, but you'd have to enter movie mode before mounting the lens and remove the lens before exiting move mode. You'd also be limited to slow contrast based focusing since the mirror drops down for fast phase based focusing. This assume the mirror can clear the modified lens mount of course.</p>

<p>The flange to focal plane distances are 44mm for EOS and 42mm for FD (see http://www.bobatkins.com/photography/eosfaq/manual_focus_EOS.html).</p>

<p>I suppose you could make a dedicated 5D MkII by removing the mirror or shaving a few mm off the bottom.</p>

<p>If I was going to do this, I think I'd try it on a Rebel T2i rather than a 5D MkII, cheaper if anything goes wrong and the mirror is smaller anyway! It's designed to take EF-S lenses which can stick further into the body. Again I don't know if there's room for an FD lens mount.</p>

<p>I suspect the major problem might be the diameter of the lens barrel near the rear flange.</p>

[alan_bryant1]

<p>Since FD was designed to clear a full-frame 35mm mirror, would the 5D mirror hit it? Does EOS have a larger mirror than the FD cameras did? I suppose it might, to accommodate the behind-the-mirror AF mechanisms.</p>

<p>Another option would be altering the FD lenses themselves. It might be possible to remove the old mount, shave 2mm off the barrel and install an EOS mount. A lot of work though.</p>

[jeffrey_c1]

<p>Sounds like it's a lot of work to get an FD lens mounted on a EOS body. Probably cheaper to buy a used lens when you factor in the time and money to get the work done.</p>

[kelly_flanigan1]

<p>Re "But why can't I modify the 5D to take FD lenses? <br>

<br /><br>

The way some places like old Pro Camera Repair in NYC or Century Precision Optics in Hollywood or my buddy in Simi Valley approach problems/studies like this is you buy some junkers grab some lenses and get out the micrometers; sketch pads and see it one can make a go of it. Similar type Camera mods have been done in the past; buy a junker water ruined camera for parts off of Ebay and study the issue with an Engineering layout is how folks study these type of problems; instead of talk. </p>

<p><br /><br>

One has the issue too of vast zoo of FD lenses with different rear element stuff that can foul too. </p>

[John Crowe]

<p>I thought about all these possibilities five years ago, but then sold all my FD stuff and switched to Nikon manual lenses that are easily adapted to EOS cameras. Have since switched again to Nikon bodies too. </p>

<p>However now that old digital bodies are pretty cheap I may once again consider this project. I'd have to do a lot of testing before mucking about with a $2000-4000 camera though.</p>

<p>Going about changing the FD lens mount and maintaining aperture control is certainly a pain. I still have a half assembled FD mount lens and EOS mount kicking around the house somewhere.</p>

[anthony_lewis1]

<p>Thanks for your responses so far. Sorry, Bob I was going from memory on flange focal distances from your website - I should have looked it up. And thanks very much for your expert advice.<br>

The issue you raised of the barrel diameter of the FD lenses is correct. One would also have to shave 2mm of the EOS lens mounting plate, making it flush with the FD mounting plate. This would make it quite thin, but in principle - still a possibility.<br>

Also the distance the FD lenses projects into the EOS body is problematic. The stop down lever projects quite away and I see as the biggest issue. This is hard to put into words, but if you revolve the FD lens mount by a few degrees from its normal position and put this lever right into the corner of the mirror box - it may just clear.<br>

But in the end if it still does not clear and/or other rear lens elements do not clear the mirror, then you would have to depend on mirror lock-up. This is also problematic as the mirror automatically closes after about 1 minute if you do not Record. I don't think this can be overridden. In this case I would need to find someone who could alter this in the firmware - but still a possiblity.<br>

The point of this post is for me to find out from you, the experts, whether this concept is feasible, and if there is a fatal flaw in my thinking. (My wife and kids find lots of fatal flaws in my ideas). So I appreciate all critical responses. If this does appear to be possible, then I will grab the parts and the micrometer and start work.</p>

<p> </p>

[anthony_lewis1]

<p>John,<br>

I have considered going to Nikon lenses - but hate the idea of counter rotating focus. If this was a project for still photography then I would not do it - as we need the mirror for still photography - but not for movie making! But now people in my position, buy the 5D ii for movie making only - where auto focus is basically a useless feature, and lenses where the focus ring constantly rotates are also not very practical.<br>

If I can get my beautiful FD lenses on this camera - without machining the camera or my FD lenses then I will be a very happy guy.</p>

[christianrafael]

<p>i dont know if this could help, but i happen to stumble to this site days ago</p>

<p>maybe Bob A's comment about the mirror will be solve<br /> <a href="http://www.dchome.net/viewthread.php?tid=854905&extra=&page=1">http://www.dchome.net/viewthread.php?tid=854905&extra=&page=1</a></p>

<p>Christian<br>

edit: forgot to mentions the site is in Chinese, but i figured photographers understand pictures better than words </p>

[William Michael]

<p><strong ><em >“</em></strong><strong ><em >I bought the 5D [MkII ?] essential for its movie capability. I have a excellent set of FD 'L' primes, which being manual focus, are the prefect lens for movie mode. [Detailed retro-fit and specialty machining etc] <br />Any comments?”</em></strong><br>

<br>

Buy a movie camera.<br>

<br>

WW</p>

[anthony_lewis1]

<p>Christian,<br>

Thanks for the link. Yeh, I know people are doing these sort of things to the cameras - removing mirrors and installing PL mounts. However I wish to achieve the same thing by simple changing over the lens mounting plate which is held on by 4 screws - and being able to revert back to EF at any time. I feel this can be done, and I now know the mirror can be held permanently in the up position while ever the camera is in movie mode. However I now feel the biggest issue is the mounting plate will have to be 2mm thinner that it is now, which appears to be 3-4mm thick. Whether there is enough strength in what is left is the problem.<br>

William, I already own very high end, HD & Digital Betacam cameras.</p>

[William Michael]

<p><strong><em>"I already own very high end, HD & Digital Betacam cameras."</em></strong><br>

<strong><em> </em></strong><br>

OK, I misunderstood the wording of the question and thus the general meaning and the reason for your desire to use the FD lenses.<br>

<br />I thought the first sentance meant you bought the 5DMkII, "essentially for" the movie function.</p>

<p>WW</p>

[anthony_lewis1]

<p>William,<br>

That's exactly what I meant! </p>

[William Michael]

<p>Andrew, . . <br>

<br>

:)<br>

<br>

Struth Ruth! - just difference in nuance and meaning of the word . . . I understand what you mean and what you want . . . and why you want to do the modification . . . I would have just used different words to describe the aim: hence my confusion. I just clarified my comment so you would not think I was a Dick Wit. <br>

<br>

Good luck with it. I like your lateral thinking approach to the task<br>

<br>

WW<br>

</p>

<p > </p>

 

[leo s.]

<p>"But in the end if it still does not clear and/or other rear lens elements do not clear the mirror, then you would have to depend on mirror lock-up."</p>

<p>If you "shave" the mirror, this problem can be avoided. That is the standard way to get around protruding rear elements on more exotic (generally fast/wide) optics when mounting lenses of different lens mounts on EOS bodies using an adapter. EOS mount lenses won't be affected, except that with long teles you will be missing part of the scene through the viewfinder. Personally I've not to be a much problem even when using a 600mm with 1.4x TC.<br>

The alternative gear and lens forum on fredmiranda has lots of good information on shaving a 5D mirror:<br>

http://www.fredmiranda.com/forum/board/55</p>