Reducing the focal length

Discussion of Argus 3 cameras
Get advice and repair hints from fellow owners and share project ideas for salvaged parts.
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stynx
Posts: 9
Joined: Fri Apr 28, 2017 5:01 pm

Reducing the focal length

Post by stynx » Sat Apr 29, 2017 11:25 am

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
Posts: 9
Joined: Fri Apr 28, 2017 5:01 pm

Re: Reducing the focal length

Post by stynx » Sun May 07, 2017 3:04 pm

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...
argus 3 mod.png
argus 3 mod2.png
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
Last edited by stynx on Sun May 07, 2017 7:26 pm, edited 1 time in total.

stynx
Posts: 9
Joined: Fri Apr 28, 2017 5:01 pm

Re: Reducing the focal length

Post by stynx » Sun May 07, 2017 6:56 pm

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
A2e_02.jpg (34.99 KiB) Viewed 1927 times
EDIT: The thing in the Picture is an Apple //e platinum (open case).
Attachments
A2e_01.jpg
A2e_01.jpg (31.86 KiB) Viewed 1927 times

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