Reducing the focal length

[stynx]

Im going to try to add 'glasses' to an Argus 3 to get closer to objects. ZnSe, GaAr and Germanium lenses should be acceptable for the 7-14um wavelength.

The other method would be to use a metal or metalized concave mirror. This would distort the image with a classical concave shape if used in a 90° reflective arrangement. There are special concave mirrors to retain the geometry in this arrangement but these are mostly of the normal glass-type (absorbs the MIR wavelengths). Bigger specialized (laser) mirrors are extremely pricy... (>$1000)

Does anyone have experience with these kind of mods?

-Jonas

[stynx]

I have modded my argus 3 to allow me to change the focus from the original 1-30m to 20cm-30cm. I had to remove the serial port in the front and moved it next to the position, where the Video-port is located. I changed the serial to a standard db9 connector. In the now accessible hole in the front i glued a smooth metal tube to allow me to put a screw through. There screw was countered with a nut until I could still move the screw and glued it in place. On top of the nut I installed a short wooden stick with 2 holes in both ends that is fixed to the screw in the serial port hole. One part of the arm is now complete. The 'elbow' is now connected to the 'upper arm' of the construction. On the end of the 'elbow' I glued on a wooden peg that is fit though a loop I glued to the focus fixing screw on the optical assembly. I have provided a picture of the construction...

I will add a dial on the front on top of the screw for focus that I don't need a screwdriver to reset the focus.

-Jonas

[stynx]

Here is an image I transferred via serial
The focus is a bit above minimal focus.
... the battery gets eaten like no tomorrow. I have ordered 2 new batteries (30€ each).

A2e_02.jpg (34.99KiB)Viewed 6864 times

EDIT: The thing in the Picture is an Apple //e platinum (open case).