# Which camera to use on my K40 200X300 bed

I have searched the user groups and I can’t seem to find this topic… I am sure that it is here, I just can’t find it. I have a K40 with a 200 X 300 work area. Which camera would you suggest?

At C3D we carry the 140 degree specifically because you can mount it fairly low on the K40. Some examples are provided on the product page of the C3D website.

Ultimately you need to do the math, figure out where you’re going to mount it, and verify if that’s high enough.

I would be mounting it about 19 inches above the bed. So how do I do the math?

By the way…I just ordered your board…

This is from the Lightburn camera page:

In order to determine the minimum height for the camera to see your whole laser area, use the wider of the two lengths of your system and divide by:

2.7 for the 160 degree lens
1.8 for the 140 degree lens
1.5 for the 120 degree lens
1.4 for the 90 or 80 degree lens
0.825 for the 60 degree lens

So, for example, for my 700 x 500 mm laser, using the 140 degree lens I would divide 700 by 1.8, giving me 389 mm above the bed, minimum, to see the whole thing. For most users, this will mean mounting the camera to the open lid of the laser. The 160 degree lens gets you much closer, only 259mm high with a 700mm wide bed, but likely not quite close enough to see the full width of the bed.

Note that there will always be a bit of image loss from undistorting the image, so you should always err slightly toward having a little extra room.

I saw that on the order page… I am just a little confused as how to do the math… Most time things come to me somewhat easy… My camera will be about 19" off the work area and the work area is 200X300.

So, if I am thinking right…

300 / 1.4 = is 214.29 so does that mean at 214 MM high I would see the entire work space?

Yes, that is how it works. 214mm is about 8 inches.

Yes, and that would be to the lens, so you should assume you need about another 1/2" of space, but you’re still well within your 19".