Sylwester wrote: > you are almost right, as is Bruce R. in his posts. But imagine such a > situation: Canon, Nikon or Pentax decide to produce special version of their > DSLR called "Sports and Nature". They pack it with 4/3 CCD sensor so it got > 2x multiplication factor. Now your FA* or EF L 300/2.8 becomes 600/2.8. And > you know what? It is still similar size to Olympus 300/2.8, although these > lenses (for 35 mm) can do circle of light suitable for 35 mm! That's why I > say, that these lenses presented by Olympus aren't as small as they could > be, taking in consideration, that they produce smaller circle of light.
The problem is that this is equal to adding a perfect teleconverter to your lens with the associated reduction in quality. A lens has a certain resolution in line pr. mm. If you reduce the number of lines and then magnify the image to the same size as befor the reduction, you're basically degrading the lens quality. This is probably the main reason why the manufacturers will make dedicated lenses with a image circle matching the sensor size. P�l
