Which lens is better? Nikon

For the nikon d3100, is the 70-300mm lens better than the 35mm 1.8 for photo shoots and party events? Which one do you prefer and why? I need a lens that will give me beautiful bokeh

You won't get your desired shallow DoF with the 35mm, regardless of aperture. It's focal length is too short. Getting limited DoF if 50% equipment and 50% technique.

http://www.althephoto.com/concepts/selectivefocus.php

And Bokeh is a different subject. Bokeh is the quality of the out-of-focus area, not just that the area is out of focus. While the 70-300mm lens (with the proper technique) will produce superior out-of-focus to the 35mm, it's bokeh may or may not be what you want.

http://www.althephoto.com/concepts/bokeh.php

Bokeh, bokeh, bokeh! Are you taking individual portraits at the party with the whole context of it being at a party blurred out? If so buy an 85mm f1.8 portrait lens. If you want to capture the party, get an SB700 flash, and bounce it off the ceiling to get good pictures with your 18-55mm kit lens.

35mm! How big is this event?

First, the word bokeh is a Japanese word that, translated, is used to describe the quality of the out of focus highlights in a photograph. Its largely a product of the design of the diaphragm inside the lens - the rounder the opening the smoother and better the bokeh.

Second, you (and others who answered this) need to remember that your D3100 has a 1, 5x "crop factor" that affects the angle of view of any lens used. On a 35mm film camera or full-frame DSLR a 50mm lens is considered a "normal" lens because its angle of view approximates that of the human eye. A 35mm lens on your D3100 will have the equivalent angle of view of a 52.5mm lens on a 35mm film camera or full-frame DSLR. So for indoor events such as a birthday party in an average sized room the 35mm lens on your D3100 may not be wide enough.

Third, you need to learn about Depth of Field (DOF) - what it is and how to control it. There are three factors that affect your DOF:

1) The focal length of the lens.
2) The aperture used.
3) The subject distance.

This site will explain DOF: http://www.cambridgeincolour.com/...-field.htm

You can use the DOF Calculator at this site to compute your DOF for any combination of the three factors imaginable: http://www.dofmaster.com/dofjs.html

Many people just assume that a wide angle lens will automatically give you a large DOF but that isn't necessarily true. By using the Calculator I'll show you its possible to have a fairly shallow DOF with the 18mm end of your 18-55mm zoom and the 35mm lens you referenced at their widest apertures 3.5 for the 18mm and 1.8 for the 35mm.

18mm @ f3.5 focused on a subject at 5'-0'' DOF is from 3'-9'' to 7'-6''. Anything from 1'-3'' in front of your subject (3'-9'' in front of your camera) to anything 2'-6'' behind your subject (7.-6'' in front of your camera) will be in focuse. Keep your subject 3'-0'' or more in front of the background and the background will be nicely out of focus.

35mm @ f1.8 focused on a subject at 5'-0'' DOF is from 4'-9'' to 5'-3''. Anything from 0'-3'' on front of your subject (4'-9'' in front of your camera) to anything 0'-3'' behind your subject (5'-3'' in front of your camera) will be in focus. A mere 3'' in front of and behind your subject is a fairly shallow DOF.

As you can easily see from the examples all three factors affect DOF and the difference in focal length and aperture becomes apparent when one factor such as subject distance is held as a constant. Obviously, anyone who thinks you can't achieve a nicely out of focus background with a 35mm lens at f1.8 on your D3100 is mistaken.

In my opinion the 35mm lens on your D3100 may not be wide enough for indoor events and the 70-300mm zoom would only be useful outdoors or in very large indoor venues. Set your 18-55mm zoom at 35mm and see how that works indoors for you. You may find that using an external flash that you can bounce off the ceiling and the 18mm end of your 18-55mm zoom will be a better choice.

50 mm f1.8g.

The 70-300 is entirely too long, the 35mm would be much more appropriate, and something like an 18-55 kit lens would be even better for such work. A 17-55 f/2.8 would be even better, or any similar wide to short telephoto with decent aperture. Even the old 18-70 Nikon kit lens would be pretty darn good.

Have you ever actually done event/party work, or are you just pulling guesses out of your but?