My turn to ask for some help
I have just purchased a Therm-App 19mm lens for experimentation. There seems little technical information on this lens apart from FOV. I checked the Opgal site for similar lenses but that was also unhelpful.
The lens is coming from the USA so will take around 2 weeks to get to me. In the mean time I would love to gather some information on it, if available.
I know only that it is an F1.1 with a HFOV of around 20 Degrees when used on the Therm-App basic camera.
I would appreciate any additional information from owners of such a lens. Useful information includes...
1. Lens barrel diameter
2. Lens thread diameter and pitch
3. Actual lens element visible diameter (I am guessing around 20mm)
4. Rear of lens images as I have not seen this side of the lens.
5. Is it Germanium or Chalcogenide IR glass ? I thought Germanium but may be wrong.
6. What is the approximate back focus distance when set to infinity focus ? This may be hard to judge so even the approximate distance between the rear of the lens element and the microbolometer window would be useful.
7. Has anyone found a threaded adapter compatible with the lens thread ? I know unlikely so I may have to design one for 3D printing.
8. Has anyone seen an Opgal technical drawing of the lens ? Some manufacturers produce useful drawings showing camera and lens dimensional data. Theses can be very useful when adapting a lens to other cameras.
Well there you go. Lots of questions but I am just putting them here in case a Therm-App owner has found more technical detail on the lens.
Many Thanks in advance for any and all comments on this neat little lens. It cost me $43 so I thought it worth a look. I may even operate it in reverse as a thermal microscope lens
Fraser