Author Topic: ZnSe lenses on Ebay  (Read 8927 times)

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Offline _Wim_

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Re: ZnSe lenses on Ebay
« Reply #50 on: November 03, 2019, 09:11:13 pm »
This seems like a nice lens for only 40$ including shipping:

https://www.ebay.com/itm/CO2-LASER-LENS-OPHIR-61982-FinnPower-PrimaPower-055491-USED/174070321640?hash=item28876651e8:g:p5wAAOSwCX5dqzDA

Specs:
ZnSe Meniscus Lens Ophir (Newport)
Diameter: 1.5"
Focus: 5"

Probably replaced due to thermal lensing becoming too high, but I would think this is still useful as a macro lens for a thermal cam, especially at such a low price. I bought one to give it a try.
 

Offline _Wim_

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Re: ZnSe lenses on Ebay
« Reply #51 on: November 14, 2019, 09:02:16 pm »
Lens arrived. It does show some discolouration that is not due to reflection in the coating but probably due to heat from being exposed to high power CO2 laser beam. This does not seem to affect the working at a first preliminary test. Zoom effect can be seen from the 2 pictures at minimum zoom distance of the flir E30 (with upgrade to E60).
 

Offline Uho

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Re: ZnSe lenses on Ebay
« Reply #52 on: March 28, 2020, 01:41:26 pm »
Making a macro lens holder for Seek thermal from metal. In the video I showed the main stages of manufacturing. It turns out a reliable and beautiful holder.
https://youtu.be/bVIwKN6C8Xg
 

Offline Fraser

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Re: ZnSe lenses on Ebay
« Reply #53 on: March 28, 2020, 02:20:02 pm »
Uho,

You have always been a master of metal turning  :-+ Beautiful work  :-+ :-+ :-+ :-+

Fraser
Cogito, ergo sum
 

Offline Fraser

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Re: ZnSe lenses on Ebay
« Reply #54 on: March 28, 2020, 02:33:19 pm »
A couple of comments that I hope will be helpful......

When mounting the fragile lens element it is important to not apply point source pressure to it as this can promote a fracture, especially if the holder changes temperature. To avoid this it is important to have a small clearance gap around the lens element outer edge and to mount it between two soft ‘washers’ if it is not being fixed in place with a mastic compound. The ‘washers’ may be nitrile ‘O’ rings or common fibre plumbing washers. The expansion gap and mounting rings/washers ensure that no point pressure is applied to the lens element. It is possible to use very thin soft washers or ‘O’ rings so they are often not visible when installed. The cross sectional profile of a Plano Convex or Meniscus lens element is not well suited to being clamped ‘bareback’ between metal surfaces.

When making a clamping screw that will impact upon a soft or easily scratched surface, like a lens barrel, it can be a nice idea to use a slightly larger finger screw diameter, centre drill it’s tip and make a nylon insert tip (top hat shaped) that provides the required pressure but not the potential scratching to the clamped surface.

Fraser
« Last Edit: March 28, 2020, 02:55:05 pm by Fraser »
Cogito, ergo sum
 

Offline Fraser

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Re: ZnSe lenses on Ebay
« Reply #55 on: March 28, 2020, 03:07:17 pm »
Examples of pre made nylon tipped finger screws :)

Fraser
Cogito, ergo sum
 

Offline Uho

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Re: ZnSe lenses on Ebay
« Reply #56 on: July 01, 2020, 04:40:43 pm »
I made a macro lens holder for the Flir I series thermal imager. Although these thermal imagers are no longer manufactured, many have them. My solution to the lens holder can be seen in this video.
https://youtu.be/59f501u4_CU
« Last Edit: July 01, 2020, 04:42:57 pm by Uho »
 

Offline talrove

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Re: ZnSe lenses on Ebay
« Reply #57 on: September 15, 2020, 05:22:47 pm »
Uho adapted his design to fit my FLIR i7 thermal camera, with fantastic results.

It fits the camera securely and by using two focal length lenses either by themselves or stacked, I am able to achieve several magnifications. At the highest magnification, the field of view is approximately 7 mm across, allowing for sub-millimeter resolution.
 
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