Schierer Space

The second question one should consider in a digital camera acquisition is the typical subject of your pictures. I’ll loosely group subjects into the following categories: Macro/Still life/Portraits, Wildlife, Landscape and Action. There is also a broader topic: light level, but since lighting will affect all of the categories, I’ll cover it in this prequel to the real Q2, Subject.
As any student of photography, or the most casual taker of snapshots has come to realize: if there isn’t enough light on the subject, you probably won’t get the picture you’re after. Briefly, the amount of light that forms the picture is driven by the ambient lighting conditions, the light produced by a flash (if used), the light collecting ability of the lens*, and the sensitivity of the imaging device (i.e. film in traditional cameras or the sensor in a digital camera). The ambient conditions are generally not controlled by the photographer, but the last three can be used to compensate in a digital camera. Here’s a summary table:

Pretty much all digital cameras come with a flash of some kind. Most are pretty pathetic on range (i.e brightness/power), but can be handy in close quarters. GG types may come with a flash shoe where an external flash can be mounted; SLR always do. N and RM classes are generally stuck with what they’ve got… and usually that’s not much. Using the flash also eats batteries. If the camera uses a standard type (e.g. AA), consider rechargeable batteries and a charger as your first accessory.
The primary contributor to light collecting ability in a camera is the diameter of the lens. In an RM camera this can be quite tiny. You can guess how much light manages to squeeze through that hole. The bigger the lens, the lower light you’ll be able to shoot effectively in. Looking at the camera literature, you would think that a 10mm lens collects as much light as a 35mm lens because you don’t see this reflected in the specifications. I’m not sure how this works out mathematically. SLR and GG tend to have the largest glass available to them.
Finally, sensitivity can be controlled in most digital cameras (although lower models may be automatic). Typical cameras will allow adjustment from ISO100 to ISO400 (400 is 4x more sensitive than 100). Some will extend further on either end. The trade-off is that depending on the quality of the imaging sensor, noise can be a significant disruption in high ISO images. The more you spend, the better useful range you can expect in the imaging sensor. Individual cameras will vary, of course. My G2 is virtually noiseless at 200, but is really grainy at 800. The D20 is clean at 400, some noise at 800 and even 1600 is usable (at low image sizes). It goes all the way to 3200 (which is pretty nasty grainy).

This entry was posted on Tuesday, October 2nd, 2007 at 9:39 pm and is filed under Advice, Photography. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.