Thanks for all the quick reply's!
I actually had made a longer post in the seek supplemental lens topic a little while ago:
https://www.eevblog.com/forum/thermal-imaging/seek-reveal-and-reveal-pro-supplemental-lens-adapters/msg3855689/#msg3855689Sorry for making it a mess, i'll quote it but it uses some insight from the topic:
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
Fraser, thanks for the link, bill w had a similar insight in the seek topic about an inverted original, biggest issue I still see is getting an f6,5 flir E4 original, the laser lenses are all of much higher focal length, and thorlabs doesn't seem to have any either, but it would defenitely be a great way without inverting.
Bud, sorry if I was unclear.
I understand and can operate the brightness menu. But I wish to have a lower low.
The lowest brightness on the E4 is still very bright in a dark environment, I was hoping to find some LCD Brightness value, prerably something simple like (0 - 255), so I could tweak a bit.
I am pretty sure it will mirror left right, as that's the telescope way, but I will research it a bit better.
Bill, it seems you have quite some experience with lenses, thanks for the insight.
I am not sure if I am ready to tear down my E4 yet. I do like the results in the F1G2 lens' thread.
I hopefully soon have my hand on a stack of cloudray lenses (ordered on 11.11) and a autoliv NV2 lens, and as the other path's to tele seem just as expensive as a new E4 I'll probably end up prying it open soon enough
thanks!
Robert