taking flats

[brrttpaul]

Hi guys its probably going to sound a stupid question but if I take some flats I end up with the tartan effect so do i colour convert and do digital developement first? I was watching a maxim tutorial and the guy had a nice grey vignetted photo so I presume you have to colour/DD first but again not sure

[D4N]

You should definitely not be doing digital development on your flats, that will destroy your images.

 

The tartan pattern is because of the bayer matrix, this is fine and can be used to calibrate your light frames as is.

 

If you make flats with a mono camera it will indeed just be grey and vignetted as there is no bayer matrix.

 

You can colour convert then dd to inspect them but don't save the changes overwriting your master flat.

[brrttpaul]

ahh thanks this explains where I have been going so wrong with the flats then, I have been colour converting then doing DD then checking the average using the information window to get them roughly 25000, its strange though that in the maxim tutorial the flat he took and used was like a vignetted white is that just a case of a different camera or something? Im using a starlight xpress  SXVF-H9c OSC and the tartan effect on it is quite large, so no idea if thats right or wrong

[D4N]

Well flats on my DSLR are covered in a crisis cross pattern as they aren't debayered, once they are debayered they look much the same as the mono CCD ones which is a bright area in the middle and the odd dust bunny.

 

What you are describing does sound a little odd, does the tartan go away once the flat is debayered?

 

I don't have any experience of maxim, I use Nebulosity and PI.

[brrttpaul]

been going about it wrong , being a OSC camera I need to tick the boxcar filter in the calibration area

[ollypenrice]

The boxcar filter debayers OSC images, whether flats or lights.

Olly