Problem with Isolette II

[FM2N]

Hello All,
Purchased Speedex special R but the shutter was messed up. Had it CLA'd but when all was done the blades would not stay closed. Person who was helping me with the repair then got a Isolette II from a friend with a perfect working shutter but bad glass so he took the glass from the Speedex and placed it on the isolette shutter giving me a franken Isolette with speedex glass.

He adjusted the focus and it takes tack sharp pics. When testing with rodinal(stand developed) to get EI for this camera it seems that Fuji Acros 100 will have to be exposed at 800. The negatives were way to dense at asa 100. He seems to believe that the f/stops may be off causing this problem.

The speedex usually is 85mm at f/4.5 and the Isoltte is 75mm at f/4.5
Could this be the cause and if YES then how do I figure what the correct f/stops are?
Shutter speeds were tested and were within specs.
Thanks
Arthur

 

[Ole]

The difference between an 85mm and a 75mm - or rather, the size of the physical opening of the aperture of the two at the same setting, is far less than the 3 stops your exposures were out. Not even the most exotic lens constructions could come even close.

There has to be some other problem.

 

[FM2N]

Thanks Ole,
Any ideas?

 

[Steve Smith]

More likely that the shutter is running slow. Do you have a way of testing it?



Steve.