dslr - My viewfinder is too small — what can I do about it?

I own a 450D, and I am very satisfied with the image quality, features, and so on. The only thing that disturbs me is the viewfinder. I can barely see the whole image when looking through it (black blends in near the edges as my eyes focus the image) and as soon as I look through it slightly from the side, e.g. when I'm shooting near the floor, the whole thing gets to be controlled by luck. Manual focus is almost impossible to get right — especially with the crappy focus ring on the kit lens (it's slightly better with the 60mm/2.8). Later, when I view the photos on my PC, I can see details that I haven't noticed at all while using the viewfinder and therefore did not have control of.

Am I the only one having these problems? Is there any possibility to improve my viewfinder's image without buying a new camera? And last but not least, which cameras do have good, big viewfinders? Does it have something to do with the size of the sensor?

Answer

There are a few things conspiring against you. First is the fact that your camera uses a pentamirror rather than a pentaprism to orient the viewfinder image so up is up and left is left. Mirrors are nowhere near as efficient as total internal reflection within a prism, but they are a whole lot cheaper. And unlike a prism, they get worse rather than better the further away from the normal angle you get. (The 60D, 7D, 5D, 1D and 1Ds all use a pentaprism.)

The focusing screen makes a difference as well. I don't know enough about the actual construction of the screens in the various Canon models to say for sure whether that's a contributing factor in your case, but I do know that back in the day the Minolta Acute Matte screen was brighter than other designs by a significant enough margin (nearly a full stop of apparent brightness compared to the screens Nikon and Canon were using) that Hasselblad licensed the technology for their medium format cameras.

The reflex mirror is only partially silvered these days as well (it used to be just an ordinary front-silvered mirror in the Dark Ages). Again, I don't know if there is a significant difference in transmissivity between the various models of camera, but it wouldn't surprise me if there were.

The image erector, the screen and the reflex mirror (not to mention the optics used at the eyepiece) are all places where a camera maker can save a buck or two when making an entry-level camera.