the missing rainbowby
havenComment by FrankRobinson: Hi Jack, Welcome to the Critique Zone!
My initial take on this is that it is a very interesting and unusual idea, but I struggle to see how it it relevant to the challenge. Given that I have the advantage of your comments, that does not bode well for your score since the voters are mostly pretty unforgiving. I think that this would have done much better in a Free Study.
Technically: I'm not sure what you did, or how you did it but I would suggest that a sharp CD image would have been useful. That would probably be easier to achieve with a shutter speed of 1/250 or better. Your 50D will push ISO 800 or more before noise becomes a real problem. Perhaps you could also have used your 50mm 1.8 for this shot, and selected an aperture of around f4. That would give you a much crisper image.
Artistically: It's a very interesting shot. Well structured and composed with nice light and balance. The cross over of the disc and rainbow is very appealing to me. If being picky, I would probably have cropped off the top inch or so and put a very basic black border around it to give it a 'finished' look.
In summary, I think this really tanked because of the challenge theme. In a more suitable challenge, or a Free Study this could easily have scored five or more. I would therefore give some serious thought to how well your images fit the theme before sticking them up. After all, you got a 'favourite' so that is pretty special! Happy hunting.
Frank.