However, from a shooting standpoint, I think there is a huge difference. I don't "see" cropped images when I shoot -- I see the whole image area in the viewfinder. Having been trained to fill the frame, I hate shooting loose and cropping later. That's just not how I see. I would much rather put a 1.6x camera on my 300, and get an effective 480mm/2.8 lens, than shoot with a full frame camera and have to crop after the shoot.
I take it you mean lens? Sorry to nit pick. I was on the Nikon Cafe earlier and a poster was talking about differences between FX and DX and the "greater reach" DX has. It is a myth? The effective 480mm/2.8 lens is also a myth? This marketing disinformation that has to be cleared up for the benefit of photographers?
No, I mean camera. A Canon APS-C camera has a so-called 1.6x "lens conversion factor." That's so because the sensor is smaller than full frame -- it is a *different format* than the full frame camera.
This is no different than in the days of film -- different film formats gave very different results with the same focal length lens
. For example, I still own three 90mm lenses -- the 35mm version is a nice portrait short tele lens, while the 6x9cm version is a normal lens, and on my 4x5inch camera it is a wide angle. With film cameras it was much easier to understand this concept because all three of those 90mm lenses were different -- I had three separate lenses with the same focal length
, each giving a wildly different result on its matching camera system. Why? Because the smaller the film size, the more apparent magnification you get from the same focal length.
With digital cameras, we're usually talking about the same lens. Say, for example, a 300mm f/2.8 lens. The cameras look the same, too, which adds to the confusion. So we take the same lens and put it on two different cameras that look the same, and get different results, and then we argue about it.
It's much easier to talk about this when we have cameras that are similar in all other respects than sensor size. The Nikon D300 and D700 fit this bill nicely -- they are 12-megapixel cameras that look very similar in size and shape and user interface, but one is DX and one is FX. Now put your 300mm lens on each camera, and take a photo of a distant object. Notice that the photo from the D300 (with its smaller sensor) shows a more magnified view. Why? Because the smaller the sensor size, the more apparent magnification you get from the same focal length.
If we start comparing Medium Format Digital cameras to the "35mm-style" DSLR cameras, nobody would think twice about the difference in field-of-view between an 80mm lens on the MF camera and an 80mm lens on either FX or DX digital bodies. They are different because of the different formats (i.e., sensor sizes.) But we have endless discussions about this with DSLR bodies.
So getting back to that "480mm lens" discussion. It's not really a 480mm lens -- it's a 300mm lens on a *different format.* If I put a 300mm lens on an 8x10 camera, it would be a normal lens, not a telephoto. If I put a 300mm lens on a 35mm film body or a full frame DSLR, it's a nice telephoto lens. On an APS-C camera with the smaller sensor, it has a narrower field of view, and provides more apparent magnification. So yes, it does have more "reach," but it's not a "480mm lens." We have adopted the shorthand of calling it a "480mm equivalent" because most photographers have the 35mm film camera system as a shared point of reference, and it lets us compare lenses across different formats.
Does this help?