Rangefinder Closeup Accuracy

[Iskra 2]

Hi Yashica experts,

After I adjusted my GT rangfinder for infinity focusing, the closeup values seem to be off about one foot when focusing on a subject about ten feet away. Is this typical or should I readjust the rangefinder to focus correctly at approximately the ten foot range?........ or should I get an M3? 🙂

 

[Pherdinand]

It should be possible to make that much more precise, iskra. Both of my GSN's are focusing accurately at short and long distances.

 

[Iskra 2]

Thanks for the info, when I finish the current roll of film I'll re-adjust the rangefinder. I've assumed that the mechanical lens coupling is correct but I think a quick check with ground glass is in order.

Regards.

 

[Rob]

I test rangefinders at closeup range rather than infinity. I set my cameras on a tripod with the film plane exactly 5ft from my test target taped to a white wall. I use floodlights to light the target to focus on. I make a ground glass from scotch tape and an index card and put that into the film plane. I make a mark on it to focus my eye on and I use a eyesocket loupe
to make sure I am really focusing on the film plane. The lens barrel should read 5ft when I am in focus. I also do my horizontal adjustments at this time, then recheck everything. Depth of field is so shallow closeup I want my focus to be correct here. Infinity will take care of itself.

 

[jlw]

I test rangefinders at closeup range rather than infinity. I set my cameras on a tripod with the film plane exactly 5ft from my test target...The lens barrel should read 5ft when I am in focus.

I assume you also check the rangefinder to make sure the images coincide? Otherwise you'd just be checking how accurately the distances are marked on the lens barrel...?

 

[stet]

If available, use a reversed 50mm lens as a loupe. At infinity, the two images should just coincide.

Would this work for checking infinity on a 55mm lens? I'm getting ready to relube my Industar-61, but buying a loupe is what's made me put it off for so long.

-Rick

 

[Pherdinand]

Some kind of support is indeed good. I usually just put the lens on something of the correct height (a box, a pile of cd cases, etc).
A 28mm (slr) lens is even better, by the way. But at some moment the grain of the ground glass/tracking paper/frosted tape will be the limit, not the loupe.

 

[Pherdinand]

"AF type" - is that autofocus?😀

 

[stet]

ha! I didn't even know loupes were that cheap. I kept putting it off because I'd only use it for this relubing, until I get a lightbox. Now I'll probably get one, which means the lightbox will follow, then some Kindermann tanks ... where was that Diafine thread again? 😛

 

[nervousfede]

Vertical

Vertical

I've adjusted my GS infinite. Close shoot looks OK.
Anyoune kno where the vertical adj. screw is?

Tjaks

Federico

 

[Rob]

I assume you also check the rangefinder to make sure the images coincide? Otherwise you'd just be checking how accurately the distances are marked on the lens barrel...?

Yes, the rangefinder I set to focus correctly at 5ft via the method I described sorry for the
confusion about the lens barrel 5ft mark but it is usually very close. I make sure looking thru
the lens at 5ft the focus is good then adjust the rangefinder to match the lens...

 

[Iskra 2]

Rob, I like your method. Better to be focused correctly up close than at infinity. When you adjust this way do you see any major problems with distant focusing?

Regards.

 

[nervousfede]

Vertical focus

Vertical focus

OK, I found the vertical range adj. screw.
How can I set?
I have to adjust the vertical focusing at a certain
distance, at infinite?
If I set it for 2 meters it is not good for infinite.
What I was doing?

Thaks

Federico