What is the dial for on my Tamron 28-300mm lens?

I have a Tamron 28-300mm zoom lens and i noticed the numbers (22 16 11 8 5.6 3.5) on a small dial below where it tells you what zoom you are at. I tried turning the dial when the lens is on my camera but my camera (Nikon D50) gives me an error message? So I'm wondering what the dial is for. The image in the following link shows the dial, it is where the numbers are at the very bottom.

What kind of nikon cameras do you prefer?

I really want a Nikon camera. This is my first one actually handling one though. What kinds of Nikons do you prefer? Do you think the Nikon D5100 Digital will be okay?
I like to record videos and take lots of pictures.

Would it be cheaper to buy a DSLR in Hong Kong?

HI, i've been wanting to buy a DSLR camera for a long time now. I had my picks of Canon Eos Rebel XS, Canon D1100 ( aka T3) or the Nikon D3100. I'm just wondering if it would be cheaper in Hong Kong since there's no tax. The price of hong kong is slightly more expensive than the raw price of ones on Future Shop ( aka, with no tax included yet). Please help

Added (1). I will not be ordering from hong kong, i will be going to hong kong for vacation and wondering if i should pick up the camera there.

How many pictures can you put on a 4GB memory card?

I'm getting a nikon d3100 and I'm going to get a 4GB memory card. How many pics can I fit on that

Is it worth upgrading from the Nikon D5000 to D5100?

Basically I have the chance to sell my D5000 without any hassle for a decent price which would mean adding just £150 to be able to get the D5100 but am wondering if the upgrade is worth it? The D7000 does not look to be a HUGE leap on from the D5100 for the additional cost… Any thoughts welcome.

Where can i find a job at in Indianapolis Indiana?

I'm 14 years old. I'm on summer vacation and looking for a job because i want to buy a Nikon - D3100 and as you know they are not very cheap. I have been babysitting every week for $20 but at my rate i can't get enough to get it. Is there any websites or anything i can do to get more people to let me babysit? Or any jobs like a dishwasher or even sweeping a floor? At this point i don't care what it is i just need money anything will do.

Tips to Photograph a DJ Outdoor

My friend is paying me 20$ to photography him at school lunch.
It will be at 12:06 so around peak daylight. How can you help me on ideas of focuses. Or something.
I have a Nikon D3100. How will the pictures look nice?

Nikon D3100 for first time camera?

I can get it in a bundle with an extra lens, 8 GB mem.card, and a case.

Can Nikon D3100 shoot good portraits?

I'm planning to buy a Nikon D3100 kit (Nikon AF-S VR DX 18-55mm lens). Along with outdoor nature photography, I'm also interested in taking portraits of my family and my kid. Will Nikon D3100 good results in portrait photography too?

Anyone who has/knows about a Nikon D3100?

I have decided to buy this camera… But I would like to be 100% sure.
What is good about it? Bad? Any tips or tricks? Anything else?