HELP: EOS Film Cams & non Canon Manual lenses

[david_smigelskis]

<p>

<p>I use a Canon 5D with many different kinds of non Canon manual focus lens mounts. Metering is not a serious problem since I use an EE-S screen that aids greatly in obtaining correct exposure. I use both manual and aperture priority modes without problems. All of my adapters are AF confirm ones that work well with the 5D.<br>

I have film cameras with the different lens mounts for the lenses I have and use them fairly regularly. My bright idea was to reduce the number of these by using some EOS film cameras with the AF confirm adapters I already have. I read up as much as I could easily find about potential problems with metering with EOS film cameras. I shunned those that seem to cause problems.<br>

I picked up for $10 a perfectly functioning Rebel XS (500). All worked fine in all relevant ways. In particular the metering in all of the modes was spot on and linear.<br>

I next found for $15 a perfectly functioning Elan II (50). Metering was possible and proper in all the modes and was linear. HOWEVER if I tried to take pictures or just clicked the shutter in manual or aperture priority even with just the adapter on the body the mirror would hang up in these two modes. Somehow all the adapters I have cause this hangup. It is not lens related. All worked as it should in Program and Shutter Priority.<br>

Is this a recognized problem with Elan II cams and if so is there a fix that would allow full operation in manual and aperture priority?<br>

Given what I read online I stayed away from A2 (5) and Elan 7 (30) cams because of the claim that metering with non Canon manual lenses on these cams is a serious mess for which there is no real straightforward cure. If I am wrong about this it would be nice to know since I would much rather use an A2. It has a much better build and some nicer features than the two EOS film cameras I have tried.<br>

More generally is there a FAQ or website that has a rather full discussion of the use and possible problems and any work arounds of non Canon manual lenses with the many different EOS film bodies?<br>

Thanks in advance from someone who appreciates both digital and film.</p>

 

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[bjscharp]

Well, I don't know where the bad reputation of the EOS 30/Elan 7 comes from. I have it, and have used it with several adapted MF lenses. Never had any problems, even when doing macro.

 

I've used it with OM, T2 and M42 mount adapters, both with and without AF-confirm chips. All worked fine.

 

(Oh, and it's a great camera.)

[robin_sibson1]

<p>"Metering is not a serious problem since I use an EE-S screen that aids greatly in obtaining correct exposure." Type S screens have distinctive light transmission characteristics and require the appropriate custom fucntion setting for correct exposure readings to be obtained, but I have never previously heard them described positively as an aid to obtaining correct exposure. Correct focus, yes, when used with a fast lens, but correct exposure?</p>

<p>Now, as to your actual question. EOS bodies detect the presence of a lens. If no lens is detected, then you will usually see an aperture reading of 00, the camera will fire normally, and if you have some optical system not recognised as a lens in front of the camera then with certain limitations, metering will work. If a lens is detected, then the camera interacts with it in the usual way <strong>if it can</strong>. The problem arises if the camera thinks an EF or EF-compatible lens is present but it is not (or possibly if it does not detect a lens that is actually there). In that case, when the shutter is released the camera will either lock up (earlier models) or show an error code such as error 99 (leter models). No damage is caused, and at worst removal and reinsertion of the main battery will reset the camera. The effect is easily demonstrated by fitting a Canon Extender, Life Size Converter, or Extension Tube to the camera with no lens attached to it.</p>

<p>Possible inconsistency in behaviour arises because over the years two different mechanisms have been used to detect the presence of a lens. Older bodies have a mechanical switch operated by the movement into place of the bayonet flange of the lens. Newer bodies detect the lens electrically – I am not sure, but I think this is done through the two pins on the camera side that both contact one large pad on the lens side. If you want to mount something, a "lens" with no electrical contacts, on the camera and avoid the lock-up, you have to defeat the detection mechanism. For the older mechanism, this was done by manufacturing the bayonet flange of the "lens" with a small section missing, so that the mechanical switch was not actuated. Older "dumb" (non-AF-confirm) adaptors used that approach, as did mirror lenses, and although the cut-out is redundant for newer bodies, it does no harm, and because there is nothing electrical for the body to connect to on a dumb adaptor, these adaptors work with both types of detection mechanism – provided that you don't then try to put an Extender, etc, between the body and the "lens". If a dumb adapter does not have the missing bayonet section (because that is not required for correct operation on newer bodies) then it will cause lock-up on older bodies.</p>

<p>"Smart" (AF-confirm) adapters should not need to defeat the lens detection mechanism with either older or newer bodies. However, it is well-kown that mainstream third-party lens manufacturers, particularly Sigma, have had problems over reverse-egineering the Canon communication protocols. AF-confirm adapters come from a considerable distance further into bandit country than off-brand EF-compatible lenses. There have even been reports of AF-confirm adapters frying cameras, something I have never heard with off-brand lenses. So it would not surprise me if such an adapter produced inconsistent behaviour depending on which camera body it was attached to. In particular, if an AF-confirm adapter has been produced by fitting contacts and a chip into what was originally designed as a "dumb" adapter with the missing bayonet section, then on a newer body that should work without any problem, but on an older body there could be problems because electrical contact is being made but the body is not detecting the presence of a lens.</p>

<p>I can't claim that this reponse resolves your problem definitively, but I hope it throws a bit of additional light on the rather murky area!</p>

[david_smigelskis]

<p>Robin Sibson:</p>

<p>Thank you very much for your comprehensive answer. It helps greatly to know the possible variables and that ultimately the answer is basically try each adapter with each camera and then PERHAPS fiddle with certain settings on the camera (such as the switch at 10AM inside the lens mount) or on the adapter.</p>