Nikon designed their new AF-S 35mm f/1.8G DX lens so photographers using DX-sensor Nikon digital SLRs like the D90, D5000 and D300 could have the image quality and performance of a classic 50mm prime lens. With a fast f/1.8 maximum aperture and an effective focal length of 52.5mm, the 35mm f/1.8G Nikkor is very similar to a 50mm lens on a full frame camera – a focal length historically favored for street photography and photojournalism.
In the Eighties and earlier, most of us learned photography with a 50mm lens. For a lot of beginning photographers, that’s all you had for a while. It’s a reasonably flexible lens – not too wide, not too long, and with a nice fast aperture so you can shoot in all kinds of light conditions. However, as the optical quality of zoom lenses improved, the 50mm lost favor with photographers. Recently, photographers have started to realize (remember) that the 50mm focal length has a lot to offer. A standard 50mm lens has excellent image quality, costs $100 or less and will teach you to compose carefully and “zoom with your feet.” Committing to a 50mm lens will help you become a better photographer.
If you own a Nikon DX body like the D5000, D300 or D90, the smaller sensor’s 1.5x crop factor converts the 50mm focal length to an effective 75mm. That has its benefits – 75mm is a great focal length for portraits. But it’s not the same as a 50mm lens on a 35mm SLR. Sigma was the first to identify the 50mm focal length void for DSLR owners. About 4 years ago they introduced a 30mm f/1.4 prime lens (30mm F1.4 EX DC HSM) designed specifically for digital SLRs. And now Nikon has their own AF-S lens for crop-sensor 50mm aficionados. It’s a compact, well-built lens with a metal mount and AF-S motor so it can be used with the D60, D5000 and other Nikon bodies that don’t have a built-in auto focus motor.