If I were selling you my coins, I'd be better off showing 200x300 pixel files rather than 2000x3000!
Aside from that I think that Doug is right. Trying to get maximum resolution is a mistake if you don't have the best equipment.
I think there are two issues.
How you
sell your coins is one matter but for personal purposes, even for a worn coin, I'd always seek to make the highest resolution photo. There may be important details e.g. hidden traces of plating, clarity on defects etc, that an owner would want to know for scientific reasons, and it costs no more to make a hi-res pic. A full-on, warts and all photo, will reveal details like a microscope. Great. One can always reduce the photo for display purposes.
The second is how to make the photo look
good (or, charitably, more like the coin in hand). I've participated in a number of debates over the last year on this, where the debaters fall into two camps, the really
good photographers (led by Doug and
Pat) who advocate establishing the right circumstances (controlled indoor lighting, SLR camera, stand etc) to take coin photos, and the lazy photographers (me) who advocate instead quickly taking multiple shots of the same coin at various angles and in a variety of available natural lighting situations and/or backgrounds, choosing the best outcome - the one that pleases you most - and adjusting lighting, colour contrast, and linearity of lighting (gamma) so that the coin looks terrific (or, charitably, more like the coin in hand). Of course the very best photographs are taken by the really best photographers with great equipment, but the lazy approach is quick and the end results can be quite excellent, comparable to the pre-staged, get-it-right-first-time approach with a lot less
work.
By choosing the best shot from many, followed by post-shot adjustment so the coin looks just-right to you, this brings the human factor (your selection) into the picture and thus entirely resolves the "much better in the hand" dilemma. You get to choose.
Here are some recent pics taking using my voting method. I like the
Octavian. Tha
Lepidus and the gold 20 As with corn-ear could be better - they are shiny coins with surface defects and these were the best compromises I could come up with. The bronze
As is terrific. The
semis, whilst looking lovely, is
still much more powerful in the hand - for example the hair on the
obverse is absolutely
sharp as a knife and the coin is unworn and of a very large size (33mm, 25 grams), but these aspects do not come across . Incidentally I do have many worse photographed examples but I just know I need a different day and different lighting and different luck to re-shoot them.
Pic links:
http://www.flickr.com/photos/ahala_rome/4788136950/http://www.flickr.com/photos/ahala_rome/4788137846http://www.flickr.com/photos/ahala_rome/4772692575/http://www.flickr.com/photos/ahala_rome/4772686395/http://www.flickr.com/photos/ahala_rome/4636136343/