Digital camera madness
I recently tried to learn a bit more about photography (I can recomend you this book). I've owned several film-based cameras over the years (both compact and reflex) and since 1996 when I bought a Casio QV-10 (not that I can recommend that battery eater) all of them have been digital units (Canon S10 and A520 and lately Panasonic DMC-FZ7, all of which I can recomend).
I was thinking to finally jump to the Digital Reflex bandwagon but I was waiting to get a better idea of that segment. But it seems the waters are not that clear. Although it seems that Nikon has settled with the so-called APS-C sensor size, Canon has mixed feelings and now it has three different sizes from full-size 35 mm sensor (like the one on EOS 5D) to APS-C size (like the one on 20D, 30D or 350D).
Why sensor size is important? Well, one of the reasons professional photographers have kept the reflex market going was compatibility. You cannot be compatible if you change the sensor size. And, it does not matter you can still use your old lenses (in case you have any) from your old film reflex camera. The results you get are just not the same.
Here is when the idea of multiplier come into play. Think on a camera focusing a person's face fully. All that image is projected by the lenses on the film or sensor surface. Now think on reducing the area of the sensor. What happens? Now the image only show the nose and maybe the mouth of that face.
What it looks like? It seems now this new sensor is enlarging the image. So it looks like you are getting a longer lens. It looks like you are multipling the lens focal length by a (larger than one) multiplier. So, reducing the sensor translates into an increase of the focal distance (if you keep the same lens).
But why is this important? Well, reflex camera users have created their lenses collection by carefully selecting the different focal lengths to achieve the different types of shots they (or their paying customers) have come to love (i.e. portraits).
The bottom line: No matter the new digital reflex cameras promise you can use your old (and expensive) lenses, the end result will not be the same unless you are getting an expensive camera body with a full-size 35mm sensor (and I am afraid the cheaper one is Canon 5D at around $2500).
I am not saying that going reflex is a bad idea, but don't do if for the wrong reason. At the moment it seems that either Nikon D80, Sony A100 or Canon 400D are solid performers for under $1000 with access to a good set of lenses (all of it with APS-C sensor size, or a 1.6 multiplier).
An interesting alternative is the so-called Four-thrids spec, backed mostly by Olympus that offers a set of reflex cameras with slightly smaller [squared] sensors and a multiplier of 2. These cameras and their lenses can be smaller and lighter but lenses can still be exchanged easily.
Another amazing discovery has been that the multiplier has an effect not only of the focal distance but on the depth of field too. To make a long story short let's say that the multiplier also increases the depth of field by the same amount, which is mostly a welcome effect. However, it also makes more difficult to achieve the, sometimes desirable, blur of the background. This is even more noticeable with non-reflex cameras equipped with smaller sensors where shots have an amazing wide depth of field at almost all focal distances.
I think for the moment I will keep on reading before buying the wrong camera (though my guts are telling me get the Canon 400D). At any rate, please note I have not mentioned at all the word "megapixel", isn't it curious?