Jump to content


Histogram exposure for narrowband flats


Recommended Posts

Usually when i take flats, i just setthe camera to aperture-priority and let it set the exposure - but with narrowband this didn't seem to work so well?
With the Ha filter for example, i noticed the red channel reaching almost the top of the histogram, and with OIII the green. Although the "total" histogram showed OK at 1/3-1/4 or so.

So just to confirm, should i expose acording to channel the filter is for, or the total?

Link to comment
Share on other sites

I guess you are using NB filters on a colour camera then?

I would say that the total histogram is meaningless in this case and that you need to pay attention to the channel you are actually exposing.  Aperture priority is probably not well designed for exposing a single channel, I would guess that it is averaging the channels which is why it is over exposing.

  • Like 1
Link to comment
Share on other sites

Thanks for the replies! :)

Indeed i am using NB filters on a color camera, and after some testing i came to the same conclusion. I had best results exposing acording to the histogram for the spesific channel instead of letting the camera run in aperture-priority as it was overexposing to compensate for the lack of light in the blocked channels.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.