Infinity testing indoor for digital camera

[hans voralberg]

Guys I want to check infinity focusing but where I live has really bad access to the moon and has nothing in a few miles radius that is easy to focus on.

Any idea on how to create infinity target indoor? I specifically want to calibrate an M9 RF.

 

[Sarcophilus Harrisii]

Guys I want to check infinity focusing but where I live has really bad access to the moon and has nothing in a few miles radius that is easy to focus on.

Any idea on how to create infinity target indoor? I specifically want to calibrate an M9 RF.

I've not carried out this procedure with a rangefinder, personally, but Rick's a pretty handy camera repairman and he says it is effective, so I think it's worth trying. Let us know how you get on.
Cheers,
Brett
http://rick_oleson.tripod.com/index-123.html

 

[pbo]

I've not carried out this procedure with a rangefinder, personally, but Rick's a pretty handy camera repairman and he says it is effective, so I think it's worth trying. Let us know how you get on.
Cheers,
Brett
http://rick_oleson.tripod.com/index-123.html

That's very neat, thanks for the pointer! I'll be trying this with my camera soon.. Since they are published around the Internet, I think we can start with rangefinder base lengths as the "X" distance and maybe check against the actual infinity to confirm.

 

[Rob-F]

There's a problem trying to do that when adjusting an M9: the target camera's lens is bound to be too small to aim both the finder and rangefinder windows through!

 

[pbo]

There's a problem trying to do that when adjusting an M9: the target camera's lens is bound to be too small to aim both the finder and rangefinder windows through!

There's two tutorials on that page - the one for rangefinders is towards the bottom.

 

[Sarcophilus Harrisii]

There's two tutorials on that page - the one for rangefinders is towards the bottom.

Precisely.

I've used an SLR many times as an auto-collimator to good effect, and can vouch for the effectiveness of this, providing the camera used to inspect the one under test is in good adjustment of course, and a suitable focal length is used, (preferably at least double the focal length of the lens fitted to the test camera). Measuring the rangefinder baselength between centres to fabricate a focus target I haven't tried, yet, but in principle it looks reasonable. If I needed to do it myself, I think I would measure the distances with my vernier calipers as precisely as I could, and apply this distance to a suitable material as carefully as possible for maximum accuracy.

On the one hand, with a digital M you cannot visually inspect the image formed at the focus plane with a ground glass, but on the other, pre-focusing the RF at certain distances, and then critically inspecting digital test images made at those distances, should be at least as accurate as the equivalent of a ground glass and loupe with a film RF (if not not much more so, due to the ability to greatly enlarge the test image on a monitor for inspection, I would have thought).
Cheers,
Brett

 

[maddoc]

Thanks for pointing this out, very helpful!

 

[Sarcophilus Harrisii]

No probs guys, credit to Rick for hosting such a great site with so much quality repair information.
Cheers
Brett

 

[hanskerensky]

In the very old days they used collimators like this one in camera factories and service shops :


Collimator Mont 7515 (01) by Hans Kerensky, on Flickr

And still usable with a modern DSLR like the Nikon D40 :

Collimator Mont 7515 (08) by Hans Kerensky, on Flickr