forgive me if this is a stupid question...

[ScruffyOne]

I have become interested in imaging recently and I had a thought. Instead if using a colour ccd and filters, could you use a mono ccd and filters and then convert the separate r, g and b files as channels in photoshop to make a colour image (if that makes sense). Would it even work? Forgive me if i have missed some fundamental imaging rule, it just ocurred to me that in photoshop the actual channel layers are mono, so maybe you could generate colour that way.

[brianb]

Yes ... that's exactly how most high quality "colour" images are made.

[Martyn_Bannister]

I have become interested in imaging recently and I had a thought. Instead if using a colour ccd and filters, could you use a mono ccd and filters and then convert the separate r, g and b files as channels in photoshop to make a colour image (if that makes sense). Would it even work? Forgive me if i have missed some fundamental imaging rule, it just ocurred to me that in photoshop the actual channel layers are mono, so maybe you could generate colour that way.

No such thing as a stupid question, unless it's unasked. What you propose is exactly how early colour film (plate!) photographs were taken and I have no doubt it would work. See HERE for some wonderful examples of early stuff.

When you get some samples, please post for us.

[davew]

You need go no further than look at Brian's post - http://stargazerslounge.com/imaging-planetary/112605-jupiter-31-aug.html

That shows how a photo is built.

Dave.

[ScruffyOne]

So why would you use a colour ccd? Do you still need separate colour files or do you just take colour images? I would think using the separate mono channels would give a better finished image. Stunning images of jupiter though. I have a long way to go before I'm ready for imaging! (complete kit overhaul for a start. its on my letter to santa though!)

[Martyn_Bannister]

So why would you use a colour ccd? Do you still need separate colour files or do you just take colour images? I would think using the separate mono channels would give a better finished image. Stunning images of jupiter though. I have a long way to go before I'm ready for imaging! (complete kit overhaul for a start. its on my letter to santa though!)

Dunno really . I suppose it's convenient to not have to change filters and also, who makes mono cameras any more?

[steppenwolf]

So why would you use a colour ccd? Do you still need separate colour files or do you just take colour images? I would think using the separate mono channels would give a better finished image.

Now you've opened a real can of worms! Welcome to the ongoing discussion of mono and filters versus one shot colour cameras. As usual, there are two sides to very argument but an interesting conclusion was reached by Ollypenrice recently in an Astronomy Now review of two such different cameras - this made very interesting reading indeed (much as it irks me to say so publicly ).

Calling Ollypenrice to the forum ... Ollypenrice to the forum please.

[Earl]

Mono has always given a better quality image.

I think there is much merit to the theory not that i have any experience at it.

But i will do at some point, besides ill be sticking with DSLR for a while as CCD Imagers are not in my price range atm for such a dedicated piece of gear.

[brianb]

As usual, there are two sides to very argument

The essential point about the mono camera is that it is more flexible ... you're wasting photons using a one-shot camera with narrowband filters, and losing badly in resolution if imaging in infra-red (even if the Bayer filter matrix lets you capture the photons). You pay for the extra flexibility in terms of more complex post processing.

For plain RGB imaging, a one shot colour camera is more convenient and will deliver results which are very nearly as good, at the same price level.

[ScruffyOne]

My main reason for asking about the colour ccd is that mono seems to be much cheaper. so if you can get as good or better results for cheaper kit then why use it? is convenience worth that much? (not that I have any experience, just curious:))

[mark7331]

A one shot color(OSC) CCD has a bayer matrix which is a set of filters built into the camera laid on top of the pixels. One 'colour' pixel is made up of four actual pixels (one red, one blue and two green). So the OSC produces images of lower resolution than an equivalent mono. Also the OSC is less suited to capturing specific wavelengths like Hydrogen alpha (as only one pixel out of four is reading 'red').

That said, as Steve has pointed out Olly did an excellent article in Astronomy Now where he compared a mono and an OCS CCD of the same make/model. He seemed to like both and the results were fantastic (as you would expect from Olly ).

As Brian pointed out for general RGB an OSC is ok. For me it's mono as it is, IMHO, far more flexible but perhaps a little more expensive as you need a filter wheel & filters.

[steppenwolf]

My main reason for asking about the colour ccd is that mono seems to be much cheaper. so if you can get as good or better results for cheaper kit then why use it? is convenience worth that much? (not that I have any experience, just curious:))

I really don't think that mono cameras cost less than one shot colour (OSC) cameras - they seem to me to be exactly the same price. If you go down the mono route but want to take colour images then you need to factor in the cost of Red, Green and Blue filters and almost certainly a filter wheel too.