Originally posted by: 996GT2
Originally posted by: thegisguy
One more question... The Olympus uses 3/4 lens. Is that going to be a problem? It seems most cameras use a 2/3? Am I over thinking things?
This weekend I plan to head to a camera shop to get my hands on a couple of the ones I've mentioned to I have play with them. I'm just the type that likes to know everything I possibly can before I set foot in a store.
Olympus uses the
4/3 (not 3/4) system, because their DSLRs have smaller sensors than Nikon or Canon's crop sensor cameras.
A full frame camera like the Nikon D3 or Canon 1Ds Mark III has a 1x field of view crop because the sensor is the same size as 35mm film.
This means that a 24-70mm lens mounted on one of these cameras will still work as a 24-70mm lens, with an effective focal length of 24mm (moderate wide angle) to 70mm (normal range).
However, Nikon's APS-C DSLRs (D40, D50, D60, D70, D80, D90, D100, D200, D300, D1, D2, D2x, etc) have a 1.5x field of view crop because their sensors are smaller than the size of 35mm film; as such, only the center portion of a 35mm "field of view" is captured.
Because of this, when you mount a 24-70mm lens on one of these cameras, it actually turns into a 36-105mm lens due to the FOV crop. This means that the lens is no longer a moderate wide to normal...it's more like a normal to slight telephoto now.
Canon's APS-C DSLRs (Rebel series, 10D-40D), are similar, but have a 1.6x FOV crop instead of Nikon's 1.5x due to having a slightly smaller sensor. When you mount a 24-70mm lens on one of these cameras, the effective focal range is about 38.5-112mm.
Olympus's DSLRs use a 4/3 sensor, which is smaller than both the Canon and Nikon APS-C sensors. Because of this, Olympus DSLRs have a 2x FOV crop. This is why you often see Olympus kit lenses starting at 14mm instead of Nikon or Canon's 18mm. The view is not really wider; when mounted on the camera, a 14-45mm Olympus lens works like a 28-90mm lens.
If you were to mount a 24-70mm lens on an Olympus DSLR, the equivalent range would be 48-140mm...VERY different from the focal length written on the lens body.
Also, the smaller sensor is why Olympus's DSLRs don't perform as well at higher ISOs as competing models with larger sensors.