Nikon DX Lens f/stops

[martianfrogz]

Does anybody know why the Nikon DX lenses only go to about f/3.5? Why have they stopped going up to f/2.8? I've heard, and am guessing myself, that the DX lenses aren't of as high quality as the "normal" film lenses. It's all a question of depth of field and aperture. Thanks!

[Brett_Henderson]

I can't answer that question.. but can't you use the better, Nikon AF lenses on a camera that accepts the DX lenses ?

Maybe the "DX" is a digital, budget line ?

[Ivan]

Does anybody know why the Nikon DX lenses only go to about f/3.5? Why have they stopped going up to f/2.8? I've heard, and am guessing myself, that the DX lenses aren't of as high quality as the "normal" film lenses. It's all a question of depth of field and aperture. Thanks!

less f = more weight...
so its a reasonable guess that the frame gets damaged by a heavier lens.

I've seen a 2.8 fisheye somewhere but i dont know if that one is available where you live.

[microlight]

It's nothing really to do with the quality of the lenses, or even the amount of glass in them - it's more to do with their complexity. For example, a macro zoom lens has to do more mechanically than a fixed focal length non-macro lens. Since f-stops are a measure of light transmission, the more a lens has to do, then the less its maximum aperture is likely to be. So in 35mm terms, a 50 mm standard lens may have a maximum aperture of say f1.7 (which means that the amount of light leaving the rear of the lens is 1/1.7 of the light that entered the front of the lens) whereas a zoom which includes 50mm as part of its range (say 35-70mm) may have a maximum aperture of f3.5 or f4 because the mechanical complexity is such that the lens may not be physically capable of transmitting the amount of light that a fixed-focal-length lens could.

Any clearer?