RF645 rangefinder trouble?

[Maarteun]

I'm having a little bit of trouble with the range finder, and I'm not sure if it's off, or if I'm doing something completely wrong.

The main part seems to be that when I shift my eye a little bit to the left or right the patch moves. Is this normal? I have used a M7II for quite a while and never seemed to have any problems getting things in focus. Either way, this happening makes it that when I look into the VF it's sharp, but when I recheck and I move my eye a little to be able to read the exposure metering it's slightly off again.

Since it's the only RF I have at the moment, I was wondering if anyone could confirm that it's normal with rangefinder camera's that it depens if you look straight into the VF or from a slight angle, if the patch aligns correctly. It seems wrong, it doesn't make the rangefinder reliable at all =[

I hope I'm explaining this in an understandable way!

 

[Keith]

It's funny how you often never think about something until someone mentions it ... I've just taken my RF645 from the cupboard to check and it's the same.

All rangefinders do it though ... some worse than others and it's something you just accept about the system or not! My Zeiss Ikon is worse I might mention! 🙂

 

[sevo]

The main part seems to be that when I shift my eye a little bit to the left or right the patch moves. Is this normal?

It is - if you move your eye, you indeed do move it in relation to the patch vernier or aperture, and the patch cropping shifts around in proportion to the displacement, base width, pupil size and enlargement of the finder.

Only the cropping changes - the focusing is not affected negatively. Many people instinctively use it to focus on something slightly off-centre without repositioning the camera.

 

[Maarteun]

So if I understand correctly, if I align an edge, and I move the camera to the left a little bit it should still be aligned. This is not the case however, it slightly becomes misaligned. It's not just the cropping that changes. The direction I move the camera to determines the direction the alignment changes.

It's so confusing, I'm still debating wether I'm doing something wrong or the rangefinder is actually off. It seems that most of the pictures I have taken so far are slightly off, the focus is actually in front of the subject.

 

[sevo]

So if I understand correctly, if I align an edge, and I move the camera to the left a little bit it should still be aligned. This is not the case however, it slightly becomes misaligned. It's not just the cropping that changes.

Something like that will inevitably happen on out-of focus targets, as the finder optics are not perfectly flat field, and you look through either side at a different angle. A in-focus edge should always stay perfectly overlapped if you shift the eye around, though, or your finder is misaligned or operating beyond its limits (wasn't there a lens for the RF645 later cancelled because it was too long for the base width?).

 

[jtm]

This is just about the only thing that bothered me about the RF645. The RF baseline is pretty short to begin with, combined with a low magnification finder, so already you would want to be pretty careful about focus. Then, on top of that, the overlap shifts a little when you move your eye, so you start worrying about whether you have your eye in the right place for proper focus.

Not all RF cameras do this, so it must depend on the way the rangefinder is combined with the viewfinder. The Bessa R I had did this, maybe a little more than the RF645 (and its framelines were tilted a little, too). The Hexar RF does it just slightly. The Leica M2, M3, and M4 don't have the problem at all (the few I've used, at least), which makes focus a happy thing on these cameras.

On the other hand, I never did get a picture from the RF645 for which I thought the finder had made it out of focus. In practice, it works well enough (unless you're using the 100mm lens wide open, maybe). I usually just ended up moving my eye to be in the middle of the position range where the rangefinder patch was visible.

 

[Maarteun]

I tried to see if a M7II has the same problem, but it doesn't. With an M7II it stays perfectly in focus even if I move my eye from corner to corner. I dit some testing with actually measuring the distance from the focal plane, and taking a reading of the lens, it seems o.k. Yet the misfocus I have been getting with the 65mm at f/4 is annoying. Especially since I actually took the time to perfectly align the rangefinder from every angle.

Here's an example, not the best scan, but it illustrates the problem. I focussed on the 'white' frame sticking out of the middle of the pile.

I guess one more test roll. Maybe I just have to get 'used' to the camera..