Mounting Viewfinders On Double Shoe Adaptor

[johnharris]

I've just bought my first rangefinder - Bessa R with 28mm and 90mm lenses and viewfinders. It also came with the type A double shoe adaptor. It would obviously be very useful to use it to mount both viewfinders together, thus not having to switch back and forth with lens changes. However, as viewfinders are normally centre-mounted on the hot shoe, does the fact that they would be to the left and right of centre mean that what you see through them is not what will be photographed?

 

[fuwen]

I think the double hot shoe is better for an external view finder and a sprit bubble level.

 

[Leigh Youdale]

John,
The main (intended) use for the double shoe was, as Fuwen describes, to accommodate the viewfinder and bubble spirit level when using the 12mm and 15mm VC lenses.
However, there's no reason why you couldn't use both for viewfinders. It's a toss-up which one should go in the centre. Theoretically as the shift in perspective is going to be greater at closer quarters, you'd put the 28mm finder as close to centre as you can - the 90mm finder offset would have minimal effect - but on the other hand, the perspective on the 28mm is such that a little offset would hardly be noticed. best put the camera on a tripod, check out what you see in the viewfinders in the alternate positions, note it down, take a couple of reference frames and see if there's any detectable shift between what you framed and what you recorded.
I'm actually using one for portraits at the moment on a Perkeo II 120 folder to hold a Kontur viewfinder and a Voigtlander rangefinder. The rangefinder is too wide to fit alongside the Kontur so it's attached to one of those short flash swivel fittings which raises it just enough to clear.

 

[nf3996]

Doesn't the Bessa R have built-in frame lines for the 90mm lens anyway? If so, I'd suggest not using the double shoe at all. Set the camera frame lines to 90mm and put the 28mm viewfinder in the camera's own hot shoe. You don't need to switch back and forth changing lenses to see what each lens will frame (unlike an SLR), just move your eye between the camera's eyepiece (for the 90) and the hot shoe-mounted viewfinder (for the 28).

Alan