Fotoman 45PS 75mm cones

[viablex1]

Just checking , I have a 45PS with a cone for a 75mm Rodenstock f 4.5, I have a nikon 75mm F4.5, I tried to calibrate the nikon to infinity but was just a little off, is there a way to fix this? I am thinking there isn't but just checking.

thanks

Matto

[Oren Grad]

The 75/4.5 Grandagon-N has a specified flange-to-film distance of 82mm, while the specification for the 75/4.5 Nikkor SW is 81.3mm - oh-so-close, but off in the wrong direction for fixing with a shim.

Depending on the structure of the cone, you might be able to have just a little bit milled off the end to accommodate the slightly shorter register.

[viablex1]

hey thanks man that is what I thought, wrong way!!!!!!!! lol

but maybe close enough for scale focusing?

thanks

Matto

[Oren Grad]

but maybe close enough for scale focusing?

Could be. In principle, there are two strikes against you - you can't *quite* reach infinity, and the focal length for which the scale is laid out probably doesn't exactly match that of the Nikkor (which is specified as 76.1mm).

If you're going to stop the lens way down, then calibrate the focus at some middle distance and you should be fine relying on scale focusing and DOF.

If you want to use it at larger apertures, try some tests where you scale focus at various distances and examine the image critically on the GG to see how far off you are.

[George Hart]

Have a look at the front of the cone—sometimes there is a spacer ring at the front, just behind the HFM. If so, this can be removed, and depending on the shim thickness, the lens may be able to be focussed at infinity.

[John Schneider]

Look here:
http://www.fotomancamera.com/downloa...matCameras.pdf

These are instructions for adjusting the helical mount to account for lenses that are slightly longer or shorter in focal length than the design f.l. (as each individual lens has a slightly different f.l.). It may be possible that the helical can account for 0.7mm or so of difference. Try it first, and if it's not enough adjustment, than you'll have to take Oren's advice and mill off 0.7mm (0.027", or about 1/32").

[viablex1]

Have a look at the front of the cone—sometimes there is a spacer ring at the front, just behind the HFM. If so, this can be removed, and depending on the shim thickness, the lens may be able to be focussed at infinity.

hey thanks, found it!!!!!!!! ding ding ding, I am almost certain this will work,

thanks!!!

matto

[George Hart]

Good! PM me if you need some help with removing the HFM.

[viablex1]

Good! PM me if you need some help with removing the HFM.

hey thanks but I just did it not too bad really and worked like a charm!!!!!!!!

thanks again!!

matto