My googling skills cant be up to much as I thought I would find the answer easily. I want to move a 355 G Claron out of a barrel into a spare prontor 3 shutter that came from a 240mm symmar. The prontor has the scales for the 240mm lens.
F8 for the 355mm lens is 44.375mm and F5.6 for the 240mm is 42.85mm. The diameters stay within 5% as you stop down. For non critical work can I just assume that the shutter scale is one stop different or do I have to apply some additional factor to get the true value ?
If I need to adjust the aperture scale is it a simple matter of getting F values from the calculation that match the aperture size and reading it from the scale - so for e.g. F45 for the G Claron would be where F30.5 (silly, I know !! - theory I am testing here please humour....)
Thanks
Dave
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