^^ both of these guys. I would probably go with the 35 over the 50 on a DX body. Do exactly as Syborg said, set your lens at 35mm and at 50mm and walk around and see what kinds of shots you can take at both settings.
FWIW, the f/1.4 should be better built overall. There is more of a quality difference on the Canon side of things, but I'm pretty sure that it applies to these Nikon lenses as well.
Also FWIW, I generally get fine results from my 50mm f/1.4 at f/1.4. That sens, all lenses will be better/sharper stopped down (not just because of depth of field). You can always go up in aperture numbers, using the same lens. You can set the 50mm f/1.4 aperture to be f/1.8, f/2.8, f/5.6, f/11, f/16, whatever. (Usually max is f/16 or f/32) This is called "stopping down" and it will generally result in better quality, but of course less light coming in. The f/1.4 designation on the lens simply means that f/1.4 is the largest aperture (lowest number) possible with that lens.
If you're mathematically minded: the f-value is the ratio of the focal length to the diameter of the aperture. So if you have a 50mm lens at f/2, the aperture is 25mm in diameter. If you have a 50mm lens at f/4, the aperture is 12.5mm in diameter (half of f/2). However, since the aperture is (roughly) a circle, and the amount of light coming in through the lens is related to the area of that circle, the amount of light coming in varies proportionally with the square of the diameter. So at f/4, the aperture is half the diameter of f/2, but it lets in only (1/2)^2=1/4 of the light.
In photography terms, a doubling of the amount of light is called a "stop". This can be referred to in terms of shutter speed (1/50 of a second is twice the light of 1/100 of a second, therefore 1/50s is 1 stop slower than 1/100s). So shutter speed is easy, just halve or double the number, it halves or doubles the amount of light coming into the camera. In terms of aperture, you have to multiply by the square root of 2: 1.0, 1.4, 2.0, 2.8, 4.0, 5.6, 8.0, 11, 16.
(On most cameras, the adjustment wheels give 1/3 of a stop per click: 3 clicks to go from f/2.8 to f/4.0, or 3 clicks to go from 1/50s to 1/100s, for example.)
So an f/2.0 lens lets in 2x as much light as an f/2.8 lens, and 4x as much as an f/4.0 lens, and 8x as much light as an f/5.6 lens, and 16x as much light as an f/8.0 lens. So if you shoot at f/8.0 and get a good exposure at a 1/100s shutter speed, you could have shot at f/2.0 and 1/1600s shutter speed and gotten the same exposure. Sometimes this might be necessary for, say, sports or racecars or hummingbirds; where your subject is moving so fast that you have to have a very fast shutter speed in order to keep from having motion blur in your photo.
The difference between f/1.4 and f/1.8 is roughly 2/3rds of a stop. So, take a low-light situation: an f/1.8 lens will let you shoot at 1/20 second exposure, while the f/1.4 will let you shoot at 1/30 second exposure. This could make the difference between a blurry shot and a good shot; or it might not.
In all, I would say probably go with the cheaper lens (although AFAIK the 35mm f/1.8 is priced equally with the 50mm f/1.8G, in which case I recommend the 35mm over the 50mm). You can always upgrade later, and you can always sell your f/1.8 to somebody for $150.
Facebook
Twitter