Very wide angle lens for TAU?

[hap2001]

Hi, is it possible to get a very wide angle (such as 90 degrees) lens for TAU 320, 25um pixel?
There was a 5mm lens in brochure, but that's for 160 only, means the image circle is too small.
I'm not afraid to modify / duct tape a lens in place, but I just cannot find one with both short focal length and big image circle.

[Fraser]

With only 3 complete pixels in every degree of horizontal view on a 320 x 240 pixel TAU, FLIR thinks such a lens HFOV better suited to a 640 x 480 pixel TAU and so only offers the 90 Degree HFOV on that version of the TAU. 90 degrees HFOV really is a wide field of view for anything less than a VGA sensor array. I have no doubt that a company like Ophir can provide such a wide angle lens for you to adapt to your TAU core, but it will not be cheap and the results may disappoint. FLIR do produce supplementary lenses for some QVGA cameras that provide a 90 Degree HFOV but these are often specialist models intended for viewing inside electrical cabinets via a view port.

The security cameras that I have worked with sometimes use a 90 Degree HFOV for wide coverage but they invariably use a 640 x 480 pixel core. The image detail that they produce is little different to a 320 x 240 pixel core that is fitted with a 45 degree HFOV lens when operated at the same distance. It is the need for a continuous view of a large scene that justifies the additional cost of the VGA thermal core.

Fraser

[hap2001]

Thank you very much Fraser.
I think Flir should be more open-minded, I remember saw a 47x47 imager with 120 FOV...

[Bill W]

The security cameras that I have worked with sometimes use a 90 Degree HFOV for wide coverage but they invariably use a 640 x 480 pixel core. The image detail that they produce is little different to a 320 x 240 pixel core that is fitted with a 45 degree HFOV lens when operated at the same distance. It is the need for a continuous view of a large scene that justifies the additional cost of the VGA thermal core.

Fraser

Indeed, it is too easy to think of higher resolution cores giving you greater resolution, when it can often be more useful to think of them giving you extra pixels around the edges.

An Argus P-type 640 being an extreme example, it only ever processed & displayed a 320x240 image.  The benefit was that at 2x zoom it used the middle of the sensor sensor 1:1 pixel, and out of zoom ran 2x2 binned (so at lower noise, wider field)

Bill

[hap2001]

I can answer my own question now.
The 5mm Flir lens is indeed too small of image circle.
A good choice is the 6.3mm f1.2 lens from Photon 160, the only thing is you have to think about how to mount it.

[DaJMasta]

I think Flir should be more open-minded, I remember saw a 47x47 imager with 120 FOV...

Sounds like a glorified PIR sensor more than anything you can get an image out of.

How wide a field are you looking for?  It sounds like fish-eye-lens territory.  Maybe a visual demonstration of approximately what your image would look like would be to take an analog TV camera and slap a fish eye lens on it - that will look roughly like the 640 core, and I suspect it won't look great.

[hap2001]

I think Flir should be more open-minded, I remember saw a 47x47 imager with 120 FOV...

Sounds like a glorified PIR sensor more than anything you can get an image out of.

How wide a field are you looking for?  It sounds like fish-eye-lens territory.  Maybe a visual demonstration of approximately what your image would look like would be to take an analog TV camera and slap a fish eye lens on it - that will look roughly like the 640 core, and I suspect it won't look great.

I do have a few EIA camera, and when use with wide lens, they still provide good pictures.
I don't want fish-eye lens, just something like 80-120 HFOV would be great.

[hap2001]

BTW, are TAU and Boson lens compatible? Their 640 lens would be good fit for the TAU 320.

[hap2001]

BTW, are TAU and Boson lens compatible? Their 640 lens would be good fit for the TAU 320.

I just tried putting Boson 640 4.9mm lens on TAU 2.
The mount is different, but that's not the main problem.
It seems Boson's sensor is closer to the package surface, even I put the Boson lens directly on the TAU's sensor surface, it won't focus 

However the Indigo 6.3mm f1.2 lens from Photon is a good choice.
It completely covers the 25um TAU 324's image area, but you need to use the "clamp mount" version of front cover(which is thinner), and hard-modify it to get a bigger hole.

[Logan]

Another successful overclockarea of lens: Seek 4.0mm f1.0 lens is good for 17um 320x240 sensors.
However similar to your Boson lens, Seek lens is also not good for thick sensor packages.

[Logan]

Here are 4 more lens possible good for 17um-640 or 38um-320 sensors, not tested yet:
9.8mm f1.0 - from BAE500
10mm f0.8? -from Fluke
11mm f1.05 - from Raytheon 4500AS
?mm f? -from Cairns Viper
The last one is capable to work on 50um-320 or 25um-640 sensor, while still having a big aperture, and wider than most BST lens.

[Bill W]

?mm f? -from Cairns Viper
The last one is capable to work on 50um-320 or 25um-640 sensor, while still having a big aperture, and wider than most BST lens.

The Viper was a 60° HFov on a 50um 320x240 (BAe Lockheed VOx), so that is 14mm  FL.
You can work out the aperture from the front element diameter, 14mm would mean f/1, while 20mm or so means f/0.7

Bill

[Abbott242]

The lens from the BAE Check-6 Seems to be roughly 9.8mm FL and will illuminate 320 25um no problem as it is designed for the MIM-500H core. If my memory serves correctly it can even illuminate the 640 MIM-500X. So that would be a great wide angle lens for tau, the only issue being that it does not have focus threads (focus adjustment is actually on the sensor side and the lens is bonded to the housing)

[Logan]

The lens from the BAE Check-6

Your lens/sensor looks almost the same as my BAE 500L, in my case the lens is fixed to the housing only by screws, so it's easy to take off.

[hap2001]

Another successful overclockarea of lens: Seek 4.0mm f1.0 lens is good for 17um 320x240 sensors.
However similar to your Boson lens, Seek lens is also not good for thick sensor packages.

Here are several other lens that looks like (*) having enough image circle to cover 17um-TAU336, while wider than stock lens:
1. Flir 5mm f1.25 for TAU 160.
2. Thermalexpert 5.7mm f1.1.
3. Flir 6.3mm f? for i3/i5/i7.
* I tested them with my Boson 640 which have a bigger sensor, based on covered/uncovered area I guessed that.
However, #2 may have the same issue as your Seek lens, the back focal length maybe too short for TAU sensors.