Check my flats please ?

[kirkster501]

Hello guys,

Please view my one of my flats and the associated RGB histogram. Should the histogram be like that or should it be "altogether" in the middle of the histogram?

I am finding my flats are not fully working for some reason - even though I now have the alignment correct. I am shooting flats with White T shirt and iPad with white screen on behind the T shirt at ISO 800 (same as lights and darks) at 1/3 sec exposure in AV mode.

And here is the HorseHead with same flats. Note the blotches that flats is not removing....

Thanks, Steve

[rfdesigner]

Fair enough as far as one can tell, but when I was doing OSC flats, I did them in RAW.. i.e. before CFA correction., so I always looked at the flat in mono.

Derek

[SJJ]

Are you removing the camera in-between taking the lights and flats? It looks as though the blemishes appear in the top left hand corner of the flats and nearer to the centre in the horsehead picture? Just a thought?

[kirkster501]

Hi guys, thanks for the replies. Flats are RAW and no movement whatsoever of camera or anything in imaging train between images and flats. It's bizarre and spoiling my pictures.

Stacking is done in DSS. I use totally automated method and let it choose what to do. Inputting lights, darks, flats and BIAS. 15 or so flats.

Horsehead above was 8 x 3 mins only.

Thanks, Steve