Nikon's 400mm F2 or Tamron's 200mm F2?

I currently shoot with Nikon D7000 upgraded from Nikon D60. I have been shooting a lot of sports games, and a few have been at night. When shooting at night my pictures "suck." I shoot with a 300mm F5.6 & my question is for shooting sports at night should I invest in Tamron's 200mm F2 lens I say Tamron because I can't afford Nikon's F2 lens. I have also been thinking of buying the Nikon 400mm F2 for my day shots. I guess I'm really stuck on whether or not the Tamron 200mm is any good in very low light shooting.

How to make my camera on manual focus nikon D3100?

I don't know how to change my cam from auto focus to manual?

What are cool photography tricks to do with nikon D3100?

I just wanted to know if there are any sites for photography tricks and tips and if you know any good photography tricks or effects to do with nikon D3100.

Light photography on a Nikon D3100?

How do you take light photography on a nikon D3100, Help?!

Added (1). LIGHT GRAFFITI**

Is it okay to bring my SLR in?

Hi, this question is for Singaporeans only! SISTIC Users! Is it okay to bring my DSLR in? It's Nikon D3100, my camera lens is the general one 105mm. Because tomorrow is the SHINee World 2011 Concert! I'm super excited and i want to make good use of my Camera! Any one has tips on how to sneak it in? Or probably just bring it in? Can anyone tell me what will happen also if it can't go in?
Please answer!

What kind of camera brands are there?

At the moment, I'm taking Digital Photography for school and I'm currently using a Nikon. (I love my D3100!) I know that there's Cannon, FujiFilm, and Sony, but out of curiosity, what other camera brands are there? Are there brands that are not specifically sold in the US? It peaks my interest.

Oh and btw, I'm not talking about the Point and Shoot ones. Definitely just DSLR cameras.

Oh and if you do have a DSLR, What Brand and model do you have?

Nikon D40 flash doesn't pop up?

Our nikon d40 flash won't pop up. The battery is full. I switch to any modes but the flash doesn't work. Could somebody help me to fix this problem.

Autofocuisng of AF NIKKOR 50mm f/1.8D not working in D90?

Yesterday I bought a brand new AF NIKKOR 50mm f/1.8D. After inserting the lens into the camera body and when rotated in anti-clockwise direction to lock the lens, I can't hear the "click" sound. While I'm inserting my 18-105mm kit lens and rotating in anti-clockwise direction, I can hear a "click" sound saying lens is locked. But While I'm doing the same procedure with 50mm lens, I can't hear this sound. I'm able to shoot in camera manual mode [M] with manual focus. But I'm unable to do auto-focusing. I set the camera body to AF [The knob in the side].
And When I'm setting the camera to any mode like Aperture Priority /Shutter Priority mode, "F--" symbol is showing up in LCD. This lens will work in manual mode only.

Please help.

Regards,
MLg

Added (1). I'm able to find the lock tab. Can you please explain why we need to lock at f/22. I'm keeping the lens mounting point with the same as camera mounting point while inserting the lens.

For a football game, what kind of camera lens would be best?

I'm taking pictures at my Homecoming here pretty soon, and a friend told me about a website that you can rent lenses from. I need a lens for the game, really badly. I have an 18-55mm/f3.5-6G VR already. The pictures are for yearbook, so I need them to be really good. Any help?
I have a Nikon D3000.

Great DSLR Camera recommendations?

I'm thinking of stepping up with my photography (Currently have a Canon PowerShot SX30 IS. I'm not TOO satisfied with the picture quality, haha). I honestly think I'm up for a more advanced camera. I've been taking photography for almost a year and a half. I'm thinking of getting a Nikon D3100 or a Canon EOS Rebel T3? I'm not very sure on which one to get. I promised myself not to spend more than 700 bucks as well!

What camera would you recommend? Any less expensive, yet great quality picture cameras you'd recommend as well? Any suggestions or things I should know?

Please and thanks!