Hi, was not sure if this would be the best topic to reply in, as I'm both going "off the topic title" while I only own an E4, and it's quite old.
But after a thorough search I found it has lots of great info already.
I wish to make a "tele" lens or tele converter for my flir E4, for now preferably without removing the original lens, as I fear damaging the sensor. The goal is using the E4 for spotting nocturnal animals (owl).
The E4 has very wide FOV, around 45, and I wish to narrow this 3x, to FOV 12.5, this would require a focal length of approximately 28mm. Such a lens design could obviously fit different camera's and doesn't have to be E4 specific (preferably not)
A zoom lens like LogoXXL makes would obviously be very awesome, any info and explanation would be greatly appreciated!
Now I have been thinking about what would be the way to achieve said 3x magnification (or more)? I see some options:
1, Keplerian Telescope with plano convex lenses
biggest pro,
- I think this could be possible with the cheap (+/- 50,- for a 22-25mm (up to 1") widely available lenses from the co2 laser cutters (ebay / alie znse or gaas plano convex)
cons,
- Not sure about the image quality and loss of light in tele configuration.
- Image will be mirrored, might be fixable by two solutions which I can't solve (yet)
Possible solutions to the mirror image
1. Use an Flir E4 lens (or identical f6,5 converging) reversed as per Bill W suggestion.
2. Get the Flir E4 to mirror the display, which would be a cool feature but might not be possible at all or have serious caveats.
@Bud might know?
2, Galilean Telescope
pros,
This is the preferred telescope type as image will not get mirrored
cons,
Finding a suitable converging lens for LWIR spectrum.
And the price of those lenses in relation to the price of the E4 (or a dedicated thermal spotting camera, flir scout/hikmicro lynx etc.)
@LogoXXL might be a source of information and optics.
3, Swapping out the lens completely, for which I searched this forum for profusely but couldn't find a topic or example.
It does seems @JoeC walked this path, not necessary changing the lens but rebuilding the E4 and motorising the focus. There is some documentation on his site
http://joe-c.de/pages/posts/waermebildkamera_flir_ex_umbauten_177.php.Well, I have been thinking and searching ebay/thorlabs/etc, but would really love input, I lack knowledge and experience.
kind regards,
Robert