Focusing a 40mm or 75mm on an R4A?

[brooy]

If I mount a 75mm lens on a Bessa R4A, I don't see the right framing since this model finder and frame lines stop at 50mm. But is it possible to actually focus a 75mm using the finder?
Same question for using a 40mm on any R4. It fits nicely, and you could use the 35mm frame lines as a workaround - but does it focus properly?

thx Hans

 

[oscroft]

The focus mechanism will work even if there is no appropriate frame, but I wouldn't expect to be able to focus a 75mm accurately on an R4A due to its very short effective rangefinder baselength.

A 40mm should be fine though (with the possible exception of fast apertures at close distances).

 

[brooy]

I would guess that focusing accuracy is the same for any Bessa, e.g. R2x, R3x, R4x since they all have the same rangefinder. So, focusing a 75mm on an R4x is just as easy (or difficult) as on an R3x.

thx Hans

 

[monster]

R4a didn't have frameline longer than 50 mm?

if you wish to use longer lens i think you may try external viewfinder


but 40 mm is fine

you can use 35 mm frameline for tighter composition or use 50 mm for looser composition.


for me, i choose 35 mm for R4a because 50 mm frameline is too small to me.

 

[oscroft]

I would guess that focusing accuracy is the same for any Bessa, e.g. R2x, R3x, R4x since they all have the same rangefinder. So, focusing a 75mm on an R4x is just as easy (or difficult) as on an R3x.

They all have different effective baselengths due to the different viewfinder magnifications, and the one with the greatest magnification (the R3x with its 1x magnification) will be the most accurate to focus. (Though the necessity for accuracy depends on the focal length of the lens, so an R4x with its shorter effective baselength is as good for focusing wideangle lenses as an R3x is for longer lenses).