What would be a good lens for taking portraits and weddings?

I'm about to purchase a Nikon D300s and would like to know what would be a good lens to have for portraits and taking wedding shots. Would a 18-105mm zoom be any good or something like a 200mm?

Portraits? AF or AF-S 50 mm f/1.4
Weddings? AF or AF-S 50 mm f/1.4, 24-70 mm f/2.8 and a good external flash, flash diffuser and flash bracket.

The 200 mm is far too long (and expensive - 70-200 mm f/2.8, $2, 400 and 200 mm f/2, $6, 000)

My guess is you have never worked as an assistant to a portrait or wedding photographer. Spend about six months doing that and the equipment you need will become apparent

Portraits usually are best with a high f stop, which leads to a shallow depth of field and a nice softly blurred background (bokeh). Most people suggest a fixed 50 mm (or 35 mm) because of the lower prices (per f stop) and higher quality. However if you are only using one lens for the wedding as well, I think you are on the right track with large zoom range to capture more shots. If you are the hired photographer, then you should be fine with the 18-105 range as you will be able to walk around without disruption. However if you are just sitting in the seats, you may need closer to 18-250mm.

Might I also suggest www.borrowlenses.com. I rent from there on big occasions to get better lenses than I can afford on my own.

My favorite lens for my Nikon D200 is the F2.8 70-200mm lens because it is a telephoto and i can take indoor wedding shots on a monopod without flash and the pictures are crystal clear. I also have a wider zoom lens F2.8 17-55mm i switch to for wider shots and close ups. You need something with a large aperture like 2.8 because of low lighting conditions. You also need to invest in high quality glass because they are the most important part of making your pictures look professional. It is unbelievable how much better my pictures are with quality lenses compared to the ones that came in the Nikon D70s kit. You will have to spend 1, 000+ on each lens if you are serious.

If you have to ask this - you are not ready to shoot a wedding. One lens is NOT enough. You need fast lenses for low light situations where flash is not allowed;

50mm f1.4 (of f1.8), 24-70mm f2.8 and 85mm f1.8 are all good choices. You need a second DSLR body that can use these lenses plus off camera flash (speedlights) and a modifier for the light.

More importantly you need the knowledge & skill to judge exposure, use off camera lighting and shoot in manual and get it right - these are once in a lifetime photos.

Provided you're just planning to take wedding photos as a guest (i.e. They wedding party has hired somebody else) then a D300s and 70-200mm f2.8 VR would be more than enough. Don't forget even if you're asked by a friend to be the tog as a favour and should you screw up that's not a good place to be in. Think very carefully before taking up the position of the wedding photographer (even if you're doing it for free).

I have to say, DeepBlue is spot on, not only is one lens not enough, one camera isn't enough. Remember that absolutely nothing can break, and you can't be wasting time swapping lenses about, you need a 2.8 zoom on one camera, and a fast prime (probably a 50mm f1.4) on the other.

As to portraits, it's all about lighting gear, at the very least a reflector, if you're serious about it some flashes, stands, light mods and triggers would be essential to go along with. The cheap 50mm f1.8 D is a perfectly good enough lens on a 300s.

A 50mm flat prime would be best much better than a small aperture zoom.