It would be tough to capture on film. If you stick to Wedgewood, Royal Doulghton, etc., you can be pretty sure you're getting good stuff. You need to be careful though, I know that RD has a diffusion line that's not as good as their expensive stuff. Wedgewood might as well. Maybe my memory is colored but based on when I was comparing, I think the better stuff wasn't just more translucent, but it seemed a more brilliant white as well. It was not only more translucent btw, but finer. The better plates have a more reflective quality. The plates were also thinner and lighter than the cheaper ones. Despite that, I've read that the better fine bone china is actually more resistant to breakage, but I don't know if that's true or not.
Anyway, you really have to compare side by side in the store to decide whether it's worth it for you. When you do that you may decide it's not worth spending double to get one of the expensive lines, but like I said before, for me, it came down to shape as well as well as the quality of the china. I really love the shape of the set that I chose. There's a slight curvature of the outer rim (not the actual rim but the ~1" inset from the rim, whatever it's called, but it's punctuated by a well-defined edge. You can barely make out the curvature in the pic of the bowl above.
