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The Corner Cube and the Telecentric Lens
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PostPosted: Sun Oct 10, 2010 12:04 am    Post subject: The Corner Cube and the Telecentric Lens Reply with quote

Equipment self-portrait:

Focus on center of cube:

100% crop:

Telecentric attachment lens (Melles Griot Invaritar 59 LGA 435):

Cube center with telecentric attachment:

100% crop looks like I missed focus oops:

Without telecentric:

100% crop:

With telecentric:

100% crop:


Corner Cube
Telecentric Lens

PostPosted: Sun Oct 10, 2010 1:33 pm    Post subject: Reply with quote

I think the specialty of this Melles-Griot lens is that it's telecentric on the object side. That means it has basically no perspective effect! Smile The magnification of objects is independent of distance (objects that are further away do not appear smaller, even though they may be out of focus).
This is particularly useful for what is called "machine vision", which is often used in production lines where the tolerances of mass produced items have to be precisely checked.

This is just a little summary from the wiki article and my own experience with these lenses.

PostPosted: Mon Oct 11, 2010 1:12 pm    Post subject: Reply with quote

Telecentric lenses are very interesting!
But they have to be bigger than the object - that results in very big telecentric lenses with a diameter up to 400 mm! But as far as I know, these very big lenses use fresnel lenses for the big diameter lenses.

PostPosted: Thu Oct 14, 2010 11:00 pm    Post subject: Reply with quote

More photos of the Telecentric lens, a Melles Griot Invaritar 59 LGA 435. The mount is M52x0.75mm filter thread.

PostPosted: Sun Aug 28, 2011 9:05 pm    Post subject: Reply with quote

Oh no! The dreaded threads. Laughing :

Now I get to see inside! Twisted Evil :

Easy to take apart. Spanner gets used to remove notched rig holding in front element group. (note to self, next time use the correct tool, not cheap calipers!):

The element group is BIG, about 3.25" diameter, and THICK:

The rear element looks like a filter now. It is a filter! Mounted from the inside(!):

Hmmm, I was mistaken about the part number. the true part number was hidden under a mounting bracket:

All together and clean now:

Now for some snaps:

PostPosted: Mon Aug 29, 2011 8:34 am    Post subject: Reply with quote

Very interesting!