Thanks for your input. I have a display tank that's proven extremely difficult to accurately capture. Doesn't help to have a lousy hack on the other end of the camera. Can you give me some advice as to which settings you might be inclined to start with?
Display tank - Open top ADA 120P w/ 2 150w pendants. Bulbs are ADA "green" bulbs which do indeed have a slight green hue to them.
DSLR - Rebel XTi w/ Tamron 18-55mm (errr, I think) lens
What do you think?
Although mostly a matter of personal taste I find that pictures look the best when you have your focal length as long as possible, especially for detail shots but probably for full tank shots as well.
Sometimes a wide angle is nice if your lens is right up against the glass, but it doesn't have that same "look" as a long focal length...
soooo... set your focal length to atleast 35. But 55 would probably be better for most of your shots.
I don't know exactly how bright those two pendants will make your tank, but I'd start off with an ISO of 400 and try a wide open aperture (lowest ƒ-stop) on a shutter speed of 1/60.
If your too dark or light tweak your shutter speed - if you have to go below a 1/30 shutter speed you probably wan't to raise your ISO to 800.
If you are photographing fish 1/60th will still probably be too slow and they will be blurry so you'll want something around 1/100 depending on how fast your fish are.
You'll have to try out different speeds to see what works.
Also set your white balance to auto, take a picture and if the color looks off then you could try tweaking it warmer or cooler till it looks the most like what you see with your eyes - or you could just go for whatever you think looks cool even if it isn't realistic.
I kind of like setting my white balance a little warmer than what I see in real life for full tank shots.
In our case where we typically have no need to use a smaller aperture you really only need to tweak ISO and shutter speed.