Is the banding in the image itself (and therefore visible on screen) or just in the prints you make?

Does subject matter make any difference? What are the pictures of that show banding?

Are you using a JPEG file and at what quality level?

The XtraFlash can only be used with cameras with either no pre-flash or where the pre-flash can be turned off.

I've decided to only accept PayPal from overseas buyers, and certainly to only use PayPal when buying myself from overseas.

So many people don't read the instructions on the auctions and I've had dollar cheques sent (bank charges £9 plus) that say pay $11 instead of £11 and all sorts of other minor problems. It just causes so much hassle and delay....

The only exception is that Sterling cheques are OK (they usually arrive from Alliance & leicester) and it can be an alternative to send cash by registered mail.

I think you're right to stick to PayPal wherever you can.

I do actually use a number of 256MB SD cards, and the reason is that a card failure would not lose as many images as larger cards would. I would rather have four 256MB cards than one 1GB card for this reason.

77 images percard would be enough to lose anyway, but not as bad as four times as many!

I wonder if the chance of a card failing is greater or less than the chance of a laboratory messing up or losing a film....

The *istDS is set up with factory defaults that include the highest JPEG quality so you will be able to use it effectivelt straight out of the box. Reading the manual and getting to know the camera will reap benefits though.

Personally I shoot in JPEG and for your purposes it may well be that this will will be all you need. You are used to exposing accurately and there shouldn't be any real problems for you.

There are a few threads about RAW capture on this forum, and these may help if you want to explore that.

There are plenty of fast Pentax lenses that you can use. A 50mm makes a very nice 75mm-equivalent optic of superb quality. For best compatibility, use "A" lenses or later.

The camera is great, hope you enjoy it!

I don't have much knowledge to help you on this, but two things might be helpful.

The *istDS has long exposure noise reduction that works pretty much how you describe, basically deducting the noise image from the actual image.

There is a firmware upgrade on the Pentax website that is intended for astro-photography and apparently reduces the noise levels in the green channel. This is probably essential for your requirements.

The K mount bellows lens was the 100mm f4.

Yes it is great!

The Spotmatic is getting quite old now, so maybe it could do with an overhaul? Nothing goes on forever without some attention and quite possibly it needs readjustment and relubing to operate in such low temperatures.

In Photoshop go to Image>Image Size and you can change the pixels/inch resolution, the image output size and the number of pixels as you wish. This is the place to do it, not in the camera even if you could.