In digital photography, what does it mean to expose for?

I'm a noob when it comes to digital photography and I have been hearing this a lot, eg. "we'll expose for the shadows first and then for the bright portions… " etc.how's this accomplished? What is the purpose? I have a Nikon D90 (fyi)… Any examples or explaination you guys can share?

Best macro lens for a Nikon D60?

I'm looking to purchase a macro lens for a Nikon D60. I would mainly be using it to take close up shot for an inventory business. Items would be jewelry, stamps, coins, etc. For pleasure I would use it to take pictures for flowers and bugs, etc. Your suggestions would be helpful.

Buying camera from USA?

I'm looking to buy Nikon D5000 camera, but can't find good deals in UK, so i wondered is the any good web pages in USA which can label my product as GIFT, so i don't have to pay tax.
I found only one web page which sells cameras BHphotovideo.com
maybe there's more: )

Will the Sigma 30mm 1.4 autofocus on my Nikon d3000?

And If you happen to have it or know about it… Would you consider it a good lens choice for my camera?

Upgrade! What Nikon to get

I want to upgrade from my Nikon D40! I have had it for about 2 years now and I'm looking for something newer and something more challenging! What Nikon camera should I upgrade to?

What is a shoe cover used for on a camera?

I have a Nikon d3000 and i was looking through the manual and some reviews online abd i saw where it said a "shoe cover" and i was wondering what is that used for and also if its needed for my camera/flash to work. I also saw something about rusting. Will you help me understand what its used for?

What is the difference between a Nikon D3000 and a Nikon D3100?

I'd like to know the difference please and which is better for photography.

Problem with Nikon D5000?

I've had this camera for less than a year. It's been working fine, but now I can't get it to autofocus. Anyone know what to do?

How to adjust shutter speed for Nikon D90 while shooting in P mode?

I've borrowed a Nikon D90 and am having a little trouble figuring out how to change the exposure and shutter speed while shooting in P mode. I don't want to shoot in Aperture Priority or Shutter Priority.

How to get this photography effect?

can someone tell me how this effect is achieved?
i'm not sure if it is an editing effect or is it can be captured raw from photography.
i own a Nikon D3100 DSLR but i do not know of such advanced techniques as i'm only just self taught right now.