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The prime fixed focal length lens are great. At restaurants we never use flash and there is typically with low lighting, so also bump up your ISO.

We use the a 50mm 1.8 and for most applications. Occasionally, we use sigma 30mm 1.4. Both are also small and not too big to be over ostentious in restaurants.

Check out our reviews of Mo Chica Peruvian, LA and Animal, LA using the 50mm 1.8 lens.

I agree with ravenouscouple and sailordave, although you'll probably also want a macro lens? I used to have a 50mm F1.8 lens but I hated carrying around a prime when I wanted more versatility, so I got a 18-50mm F2.8 macro lens and that works well enough in dim lighting...because I can increase the levels in photoshop. >_

Everything old is new again...In my old photojournalism days, the 28/f2.0, 35/f1.4, 50/f1.2, 85/f1.4, 105/f1.8, 135/f2.0, etc. were my standard tools. Pay close attention to your plane of focus when shooting wide open, because your depth-of-field is minimal, especially close-up.

I have the Nikon 35mm/f1.8 and the 50mm/f1.4. They're both fabulous for low light. You can shoot either in natural, window light without worrying about a flash. You can also shoot fairly wide open for nice depth of field.

Also for the love of real information please stay away from Rockwell and others, half the time doesn't even have the equipment in his hands when he writes a "review"...just speculates on specs...like reviewing a restaurant by proxy via a perusal of the menu :D

I use a fixed 50mm f/2.5 canon lens, and usually stop it up to around 3.5 or so, because I find that the depth of field at 2.5 is really too shallow for all but the tightest of shots. This does mean that you have to compensate by bumping up the ISO (about 800 is the highest I'll ever go to - any more and even at blog quality, it's grainy).

Two tricks I find extremely useful:
1) If you can't use a tripod (and it's kinda rude to do that in a restaurant unless you're on some kind of assignment and the staff knows it), set up a "tripod" on the table. A water glass usually is the best option. Just ask the waiter for an empty water glass, then rest your camera on it to steady it. Depending on how steady your hands and how stable the glass/water contraption is, you'll find you'll be able to get nice, blur-free photos even with the shutter speed bumped up to several seconds

2) Keep a tiny flashlight handy in your bag. I use a small LED bicycle light (the kind that attaches to the front of the bike). It costs about $10, and is bright enough that you can use to to spotlight food bright enough to take a flash-less, tripod-less photo. It's not ideal because it generates some harsh shadows, but for blogging needs, it's much better than nothing. It helps to have a friend with you to hold the light while you take the picture.

This is posted in just in time. We were thinking about getting a new lense for low light photos (restaurants), but I don't understand enough about cameras to even understand some of this seemingly great advice. I'll ask my husband to read it. haha

Old-school photographer here. I still shoot on film with fast prime lenses and calculate f-stops on the fly, including fill-flash-- all, including focus, done manually.

Pictures of food in restaurants with no lighting help? I don't mean to be a downer, but you're not going to get good results regardless of the lens. That said, even an f/1.8 lens might be too slow, at least at 50mm. At 50mm, you're looking at shooting at 1/60 (shutter speed) handheld at the slowest, which isn't going to be enough in the subdued lighting of a restaurant. And 50mm is going to be too long to use an improvised tripod on the table. Then again (I'm thinking as I type), a wide angle lens is going to give odd perspectives.

A 50mm 1.2 will give you an extra stop of light (i.e., use half the light), but be much more expensive. Likewise a 28mm 1.8 will also give you another stop of light (handheld shutter speed of 1/30 vs 1/60 with 50mm), but will also be expensive.

I'm not that familiar with the D70, but I don't think it's a full-frame (i.e., same coverage/sensor size as 35mm film) camera, so my handheld shutter speeds numbers may be too fast for your camera.

Like accidentalepicurian says above, stay away from zooms for low-light performance. For anything macro, though, you'll need a tripod, and still need lots of light (e.g., strobes) if you want anything over an inch of depth-of-field.

Here's the bottom line-- if I were shooting this for money, I'd get permission from the restaurant and shoot 85mm on a tripod with lights, if they let me, or worse-case, sans lights, but still on a tripod. If you have to do it hand-held, go as wide and fast as you can afford (Nikkor 14mm is nice but expensive, 20mm is more affordable). Check keh.com for used lenses-- I've bought a lot of used gear from them and have never been disappointed.