Manual lens on analog EOS camera, metering problem. (Samyang 85mm f/1.4 on Canon EOS 650)

Question

I have a Samyang 85mm 1.4 lens that I have used on a Canon 550D (Rebel T2i) and I have loved it. But now I want to use it on an analog camera, the Canon EOS 650.

The problem I am having is with the metering. The Samyang has a manual aperture ring and it has no electronic communication with the camera. On the 550D the metering wasn't a problem because of the exposure meter in the viewfinder. But the 650 doesn't have a meter, instead it only shows the recommended exposure (for example in shutter priority mode it shows the recommended aperture). This works well with Canon lenses because they are wide open up until you actually take the picture and they can communicate with the body, so it knows it is metering with the lens at the aperture wide open.

With the Samyang however, when you change the aperture the body doesn't know that; it thinks the scene just got brighter or darker. So if you are at f/2 the metering recommends f/8 and vice versa. Now of course at some point in between, the set aperture on the lens and the recommended aperture on the meter match, but I think that's not the correct value because I tried different lenses on both bodies and every combination yields the same exposure, except this one, the Samyang on the 650.

My question is, does anyone have some experience with shooting with the analog EOS cameras with manual lenses? What I thought to do is to compare the recommended exposure on the 550D and the matched lens/recommended exposure on the 650 and just set the appropriate exposure compensation for use on the 650. I am not sure, though, if it is a constant value or not. Any thoughts or recommendations are appreciated! Thanks for any info. ;)

Answer 1

I will recommend three possible solutions to your problem:

1) Shoot in Manual mode using an external light meter to obtain the correct settings.

2) Use the camera's internal light meter with the lens wide open to obtain the correct settings. When when you stop down the lens, do the mental math, or use a chart, to set the correct shutter speed in Manual mode.

3) Add an advanced Programmable AF Confirm Chip to the lens mount so that the camera will communicate with the lens. You can stop down the lens and then the camera in Av mode or manual mode will be able to properly communicate with the lens.

I use these chips with my manual focus lenses mainly because I can program the focal length and aperture into the chip so that it shows up in the EXIF data. With a DSLR I always shoot in manual mode and review the image to get the right exposure. Theoretically any of these programmable chips should allow more accurate metering. I have experimented in Av mode with these 3 Programmable chips but I have only found one that seems to give consistently accurate results.

The Adplo AF chip can be programmed to report any focal length and aperture. it also allows you to adjust the camera aperture using the aperture wheel on the camera. In Av mode I set the camera aperture to match the lens's wide open aperture. As I stop the the lens, the camera seems to know what shutter speed to select for accurate exposure.

In my experience the Big_Is AF chip (factory default programmed to 50mm f/1.4) allows you to change the camera aperture but does not seem to communicate with the lens for accurate exposure in Av mode.

The Tagotech "Dandelion" or "Euro" AF Confirm chip can be programmed to any focal length or aperture but does not allow you to set the aperture in the camera. This chip also does not seem to give consistently accurate exposure in Av mode.