Optical Stimulator 2.0
SV ordered parts to assemble a mockup of the optical stimulator, including 2 CCD cameras, a Nikon 4X objective lens, 2 200mm tube lenses (2" and 1" diameter), and a cheap projector. We can use rails and 12"x12" plates to assemble a mockup that lies on the table. Also included in the parts is a microscope slide holder that we can use to hold a scale bar for test images.
The questions that we want to answer with the mockup are the following:
Can we figure out how to make any objective parfocal? What do we need to move? Ideally, can we move the intrinsic camera only to achieve parfocal under any circumstances? Also, let's try keeping the tube lens requirements the same by using a Nikon 4x (made to be used with a 200ml tube lens)
Why does intrinsic work with the 4x but not the 10x? Is there some relationship to tube size and depth-of-field?
(Not directly related to optical stimulator 2.0): What is the best light source for intrinsic imaging?
Info from Fitzpatrick lab:
The Fitzpatrick lab intrinsic arm is 1" in diameter, with a 1" tube lens. The focal length of the tube lens isn't known, but it is exactly 10cm from the CCD chip, suggesting that the focal length of their tube lens is probably 100mm. Sharon reports that their field of view corresponds to more like 5-6x, which is expected given that this focal length (F=100mm) is smaller than the Nikon objective assumes (F=200mm).
Meredith's measurements of co-dependence of specimen to objective distance and tube lens to camera distance.
These are really interesting. They show that the specimen-objective distance for the 10x is relative insensitive to the tube lens-camera distance. This probably explains why it has been easier to achieve parfocal for the 10x rather than the 4x. The 4x working distance is particularly sensitive to the exact position of the tube lens relative to the camera. This is true whether the tube lens is a 100mm or 200mm lens. The 2" diameter lens seems to produce a prettier image than the 1" version. Is that true Meredith?