Exposure Compensation for LB Camera?

Some of the specs from the LB website page for the LB camera:
Sensitivity: 600mV/(lux • s)
Pixel Size: 1.4x1.4um
Dynamic Range: 67 dB
F/No: 2.8
EFL: 3.34 mm
Relative Illumination (Sensor): 70%
AGC/AEC/Whiter balance: Auto

I am guessing the AGC and AEC are auto gain control, auto exposure control, yes? With that said, I find my camera is blowing out highlights with its images. A black line on a white piece of paper is often not visible. I am guessing the black interior of the laser is wreaking havoc on the camera’s auto exposure algorithm and thus causing the camera to over-expose.

Is there any way exposure can be adjusted manually via adding a slider on the camera control window? Or better yet, just putting a dial on the camera control window that functions like the exposure +/- compensation dial on a DSLR camera?

In regard to aperture, this camera is a single aperture that can’t be changed, correct?

The camera is a fixed aperture as far as I’m aware, yes. I’ll look to see if the exposure control can be accessed. I’ve found from my own use that even putting a sheet or two of paper on the dark bed shifts the brightness up enough to prevent the blowout you’re talking about, but that won’t be a great option for large beds.

1 Like

I tried using the extra sheets of paper, and that really didn’t do much for me. So, I grabbed my camera kit and pulled out a couple of ND filters, an ND4 and an ND8, stacked them and just held them in front of the lens before taking a snapshot. That helped tremendously. So, now I’m on the hunt for an ND16 in a smaller version, something I can incorporate into my 3D printed camera mount.

1 Like

So it is not only me whose camera blows everything /overexposure/

it’s not just you.

the camera has no exposure controls yet

but i have such faith in Oz that i’m sure it won’t be long before he adds the real-time brightness and contrast controls we need.

I have looked through the controls that the camera exposes, and tried other software as well - it appears that auto exposure is all that this camera supports.

I’ve done some testing with the camera and found that the auto-exposure control seems to have an upper limit of light that it can handle, beyond which it does blow out. If you can reduce the lighting , or make it more even, it helps, but too much light will cause issues.

That is unfortunate. I hope you will consider switching cameras once your current stock gets low and it is time to reorder. You can’t trace images that get blown out and you sometimes can’t make use of some printed registration marks for aligning via the camera because they are not visible when the camera blows the lighter areas out.

agreed
this is very unfortunate.

my solution is to have a piece of white card with a small hole in it , hold it near the lens and shoot through it.

that way the camera never sees the black bed, which is what is causing it to over expose.

Hi everyone,

For those that have issue with over exposure I found solution. Like TooTallTommyT noted ND filter will do the trick.

I found Gelatin ND Filter Set 29x29mm, ND4, ND8, ND16 5 of each on amazon and they work great for a little less than $10. The can be cut with scissors or just tape it over the camera lens.

You can buy it from here: https://www.amazon.com/Irix-Gelatin-Filter-29x29mm-Lenses/dp/B073M4RY13/ref=sr_1_4?crid=TJTGKJ9393VW&keywords=irix+nd+filter&qid=1555016576&s=gateway&sprefix=irix%2Caps%2C325&sr=8-4

I hope this little dirty trick helps

2 Likes

How many stops of light in total did you end up blocking?

3 stops works best for me /ND8/

Thank You for the link acho … would it be better to install the Filter before alignment of the camera ?

Take Care

 Brian

My understanding is filter has to be installed and camera mounted before calibration

Thank you again acho