I have a question about a telecentric lens Ive been studying (for physics research!) and was wondering if you guys could help clear some cobwebs in my head. For starters, I am simplifying the TC lens as a compound lens. Also, this lens has 2 degrees of freedom: (1) it can be extended and retracted (2) it can rotate (I believe rotating the lens changes its f# e.g. aperature).
So when I fully extend the telecentric lens (specifically http://computarganz.com/file.cfm?id=167) it is focused at infinity. I interpret this as it being being able to image an object at a distance of infinity and produce an image focused at the CCD behind the lens.
- Is this a correct assumption? Will the TC lens focsued at infinity produce a focused image at the CCD? What does this mean for an object not at infinity? For objects close to the TC lens? Are their images still produced at the CCD?
Continuing, if I placed an object at some distance in front of the lens (not equal to infinity), I could create a focused image of the object at the CCD by retracting the lens until I see a focused image at the CCD.
- How did the focus/image of the object change as the TC lens was retracted, going from focused at infinity to focused at the image location? Is it that the object is focused but the resultant image is not at the CCD until you adjust the lens (by retracting it) until the image is placed on the CCD?
Thanks so much for your help in advanced. This stuff is really bending my brain lol!