Nikon- AF-S DX Nikkor 35mm f/1.8g Lens?

Would the nikon af-s DX 35mm f 1.8g be a 50mm on my d5100?

Added (1). So when i look into my view finder, i will see what you normally see on a 50mm right? I'm trying to pick between the 35mm and the 50mm and i don't want a lens thats too telephoto.

It would perform like a 52mm does on a full-frame or film camera. However, the focal length is still 35mm and thus will have a greater depth of field for an equivalent aperture.

No. The 1.5x "crop factor" only affects the angle of view so on your D5100 a 35mm lens will have the equivalent angle of view of a 52.5mm on a full-frame DSLR. Since a 50mm lens is considered a "normal" lens on a full-frame DSLR because it approximates the angle of view of the human eye, a 35mm lens on your D5100 is a "normal" lens. Use it when you want your picture to look close to how you saw it through your own eyes. Its still a 35mm lens it just behaves differently on your D5100.

"equivalent" focal lengths have caused much confusion in the camera world.

A 35mm lens is a 35mm lens whether or not it is used on a Dx (cropped) or Fx (full frame) camera. If you were standing beside someone that had a FX camera, they would have to have a 52mm lens to match the exact image you would be seeing through your camera.

Or, if you both had 35mm lenses, the Fx camera owner would have to step forward, or with your Dx camera, you would have to step backwards to obtain an identical image.

And since stepping back increases DoF and stepping forward decreases DoF on any lens, the Dx camera would have a deeper DoF than the Fx camera would have if both cameras were using the same lens, and you stepped forward/backwards until both photos were identical.

In reality, the only time the crop factor is an issue is when you are selecting lenses - especially in the shorter focal lengths, and when you are comparing Dx to Fx cameras.

In my view, too much emphasis is put on crop factors.

On a full-frame camera, a 35mm lens will be a 35mm lens. On your D5100, that same 35mm lens will still be 35mm. Focal length does not change with change of sensor size. Only angle of view changes. On your D5100, a 35mm lens will have the same coverage as a 52.5mm lens (approximately 50mm) on a full-frame camera.

If you're not working with both full-frame and crop sensor bodies at the same time, forget about the conversion and just shoot with what you see. Just remember that 35mm on your camera is the normal/standard angle of view meaning it's the same as your eyes. Lower than that then would be wide angle and longer than that would be telephoto. You only have to remember 35 to keep it simple.