R3A vs Canon EOS 3 framing?

[tempest68]

I did a quick comparison between my R3A 40mm frame lines and my Canon EOS 3 with the Canon 40mm f2.8 mounted. I find it odd that when I lined up the top of the frame lines and the top of the viewfinder that the bottom of the frame lines are higher than the bottom of the viewfinder, yet the width seems to match. I know rangefinders are not as accurate as an SLR, but the difference in height of the frame seemed significant. Has anyone else done a similar comparison?

It also seems like the meter is a stop under exposed on the R3A when I meter at the same ISO and aperture. That might explain my results not being quite what I expected too. The EOS is accurate enough that slides are properly exposed.

 

[Huss]

It also seems like the meter is a stop under exposed on the R3A when I meter at the same ISO and aperture. That might explain my results not being quite what I expected too. The EOS is accurate enough that slides are properly exposed.

It's not as simple as that. The Canon uses a different metering pattern than the Bessa. Also you need to understand the metering pattern in both cameras. You cannot tell if the meter is off comparing one to the other unless you are positive they are metering off the same exact area.
To put it in a different way, you may be getting 'correct' exposure with the Canon because you are using it in such a way that it is metering the way you want it to. You may then be shooting the Bessa in the same way as the Canon, not realizing that it is not metering the scene with the same emphasis. It may be biasing its readings from the bottom center of the image for example.

But there's more. Unless you use the same lens on both cameras, the light transmission may not be the same even if they are using the same marked apertures. Because they are different lenses.

But there's more. The shutter speeds may time differently from the indicated speeds on both cameras...

I would shoot test scenes with the Bessa, making note of where you are metering from (you can use the exposure hold button and recompose) and compare the results. It will give you an idea as to how the meter pattern works.

 

[Pioneer]

Decide what you prefer about the EOS3 exposures and then do a bit of testing with the Bessa to see if you can recreate what you like. The differences may be the result of different exposure meter patterns, it could also be the result of different lenses. Each lens brings its own rendering to the photo. Contrast, color, flare, and so on. It may not be possible to completely recreate the photo you expect.

 

[ferider]

Regarding frame-line coverage, compare the EOS with the Bessa at different focal settings.

When you change focus from infinity to close focus, two things happen:

- Parallax: The Bessa compensates for this by shifting the frameline, mostly horizontally. You will notice the shift when you compare the location of the focus patch that doesn't move in the Bessa.
- Breathing: when you focus closer, the lens becomes longer, and the FOV decreases. The Bessa compensates for that by having less than 100% coverage at infinity.

Roland.

 

[tempest68]

Thank You everyone that replied so far. My unscientific test was done indoors so the light was consistent. On the Canon I cycled through the four different metering modes, and the shutter speed remained the same regardless.

But thinking about the difference in the lenses, the Nokton 40mm is the single coated version. Wonder if there would be a difference in light transmission between the single and multi coated versions? (i.e. less coating = more light passing through?)

As I usually underexpose anyways, it would explain things if the camera is already underexposing for my subjective view the camera isn't metering the way I expect.

And I didn't thing about the parallax correction. I didn't vary the focus on the lens on the R3A. I may have to retest to see if that accounts for the difference in framing.

 

[Lss]

Thank You everyone that replied so far. My unscientific test was done indoors so the light was consistent. On the Canon I cycled through the four different metering modes, and the shutter speed remained the same regardless.

The metering pattern is anyway different. The lower left-hand corner is weighted most on the Bessa. I bet none of the Canon modes gives this.

 

[BlackXList]

The metering pattern is anyway different. The lower left-hand corner is weighted most on the Bessa. I bet none of the Canon modes gives this.

There has to be a reason for that design, can anyone explain?

 

[Lss]

There has to be a reason for that design, can anyone explain?

I haven't seen any official explanation (actually I even remember seeing some references to these cameras having center-weighted metering!), but it's easy to guess based on the resulting meter behavior.

The metering pattern is very efficient in not being fooled by sky. While you may have sky in any part of the scene, you are likely not to have sky in the bottom corners. Of course, this assumes that you rotate the camera correctly for portrait orientation.

 

[BlackXList]

Very interesting. Thank you