Hi there

Before I start to capture a series of images I capture a preview (format set to fits) and look at the histogram. The maximum appears to be in the first fourth. So theoretical it should be possible to exposure a little bit more.



But when I take an image in native mode (cr2) and the same settings (iso,exposure) and I look at the histogram of the cr2 or the dcraw converted tiff the image seems to be nearly overexposed:

native cr2:


draw -W -6 -T:


so which histogram can I trust to determine a proper exposure/iso setting?

The difference is that KStars FITS viewer displays the histogram of the raw linear data, while the TIFF histogram is for the scaled non-linear data hence the difference.

But what does this mean in the matter of exposure time? Are those images overexposed? Or can I expose a bit more.