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Fisheye Lens for All Sky Camera

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I'm looking into a suitable lens for my all sky camera and would welcome suggestions, please :)

I currently have a Fujinon YV2.2x1.4A-2 zoom lens.  f1.4 1.4mm - 3.1mm FL 1/3" CS mount.  This is reasonable but I feel I could do better for resolution.  The camera I plan to use is a ZWO ASI185MC

2.3 Mega Pixels 1944*1224

Pixel Size       3.75µm
Sensor Size 7.3mm*4.6mm

The camera came with a 2.5mm FL f1.2 prime lens which is nice but the image from a 180° FOV is too big for the camera sensor, being about 7mm diameter and loosing a lot in the vertical axis.  The ideal FL would be something like 1.5 or 1.6mm and I would prefer a prime lens for the better resolution.

Edited by Gina

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The ideal focal length for a prime lens would be about 1.7mm or very slightly less as shown in this diagram of the image size from a 180° FOV on the image sensor.

Images & Sensor Area 01.JPG

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That's not going to be easy, Gina, because you want a lens with at least a decent image quality.

This option, http://aggregate.org/dit/peepfish/, is very inexpensive but won't give you the I.Q. you're after (I guess).

Maybe you can combine the lens of a discarded compact camera combined with a fisheye converter?

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I use a 1.56mm lens from Kamera2000.com and I'm very satisfied with its performance.

My use is to monitor cloud cover, nothing more. I know I'm not going to get astronomy  POTD awards and I'm not trying for good quality, a flat field or a telecentric view. Just to see which bits of sky are clear, which aren't and what the (difficult to see, visually) thin, high, cloud is up to.

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Thank you both :)

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