EOS 100D / 1200D / 1300D with vintage manual focus lenses via EOS adapter

Started 9 months ago | Discussions thread
2ndact scene1 Forum Member • Posts: 95
Re: EOS 100D / 1200D / 1300D with vintage manual focus lenses via EOS adapter

brightcolours wrote:

2ndact scene1 wrote:

Interesting question. I would be interested in doing the same thing. There is a thread in the 7D forum on DP Review in November 2011 on this subject. It discusses changing the focusing screen on the camera to get proper metering.

That is nonsense then. You either misunderstood, or there is nonsense info in that thread.

It may be nonsense but it raised an interesting question. Here is the relevant quote from CarVac in 2011.

CarVac • Senior Member • Posts: 1,246Re: Contax / Yashica lens adapter for CanonIn reply to Jane S • Nov 14, 2011

The standard focusing screen only gives accurate metering if the camera knows what aperture the lens is set to at the moment. As you can probably tell, the brightness of the viewfinder is not proportional to the set aperture of the lens: it's equal in brightness for all lenses f/2.8 and faster. The metering cell in the finder doesn't see exactly what you see, but it's a good analogy. For manual lenses, which don't communicate with the camera body, the body assumes the lens is somewhere around f/3.5, and exposes accordingly. Thus, it overexposes heavily.

If you have a chipped adapter, though, you can ask the seller to program the chip so that it will report to the camera the max aperture of the lens you expect to use. Then, you use Av mode and tell the camera what aperture you will be closing down to by setting that with the control wheel. At that point, you have to lock the exposure, stop down the lens, and take the photo. That sounds time-consuming (I don't have a chipped adapter, so I don't know), and it would only be useful for lenses with matching max apertures.

However, if you use the Ef-S focusing screen (you can order it online for 35 bucks from Amazon), the meter sees light proportional to the amount of light that comes in, all the way out to f/1.8. With an unchipped adapter, the camera will show an aperture of f/0.0, which is a meaningless value, but it exposes correctly for any aperture smaller than f/1.8, and overexposes a third of a stop for f/1.4. Just stop down and take the picture: it'll expose correctly.

The related issue being raised here is that on fast lenses (the Contax 50/1.4 was mentioned in the thread) the use of a different focusing screen (ee-s for a 5D and Ef-s for the 40D/50D/60D) can make manual focusing much easier. As I understand it, this is because the viewfinder shows the shallow depth of field on these fast lenses more accurately than the standard f2.8 view. The downside is that the viewfinder gets pretty dark around f5.6.

I plan to try the ee-s screen on my 5D because I have difficulty judging DOF wide open and DOF preview doesn't help beyond f2.8 (at least that I can see - but I have less than perfect eyesight).

I thought what CarVac said in 2011 made sense - however I have not tried any adapted lenses to date - so I have no personal experience - yet.

This is also a bit off topic because the OP was asking about the 100D.  Wonderful camera that it is,  I am pretty sure it  is not set up to allow changing focusing screens.

Any Canon DSLR will meter properly with adapted lenses. If you change the focus screen for a different one with a split prism, from the film DSLR era, the metering will not be accurate anymore since the focus screen, which sits in front of the metering system, has changed its brightness.

No mention of intrusion of the back of the lens too far into the mirror box.

That only is an issue with some lenses/lens mounts (like Canon FD) on FF bodies, and most problematic with the old cameras (5D, probably 1DS and DS mk II)

I am sorry, I am on my phone and cannot link directly to it. It came up when I did a Google search on adapting Zeiss lenses.

The adaptors are apparantly not expensive.

Hope this helps.

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