DIY flats source

[Ivor]

One of my little projects during the absence of decent nights has been building a flats solution, I'm nearly complete but I'm not sure if the light source is both flat or bright enough.

This is the output through my 400D with zoom lens at 50mm, it appear pretty flat in PS but I'm not if this is good enough, please can someone advise?

[Carole]

What does the histogram look like Ivor?

I don't normally find single flats tell me very much, so I normally check my flats by examining the master flat and stretching it to see if it reveals vignetting and dust particles.

Carole

[Ivor]

The original histogram looks like this:



I've stretched this image in PS and it looks like this



Is this what I shoulds expect?

[MarkS]

Hi Ivor,

That is pretty much exactly what I would expect to see.  It shows vignetting and it shows specks of dust.

It looks pretty noisy - I am guessing it is a single flat at a high ISO.  Take lots of flats at a low ISO then stack them together and everything should be good.

Mark

[Ivor]

Thanks, you are right it was just one sub I wanted to check the design was OK before fixing all the bits down. I will write my design up shortly but at the moment the unit price is under a £5 and it would work with any scope up to 20cm.

I was a little creative with the materials or I wasn't sure how well it would work e.g. the diffuser was one of these:
http://www.tesco.com/groceries/Product/Details/?id=256185906

[Carole]

Love the chopping board.

My diffuser for the DSLR costs even less, it's a bit of typing paper made into a lens cap, but the CCD camera's diffuser is opal perspex off fleabay at £6.  But now I have the newt I have to start all over again with a new bigger light box, so I'll watch out for the your cheap design before I do anything as my scope is 20cm. 

Carole