
Will my Nikon D3100 autofocus if I buy a Sigma lens?
So, I have a Nikon D3100 and I want to buy a Sigma - 70-300mm Macro DL DG Lens for Nikon AF-D. I know that my Nikon does not have an autofocus motor built in, but the Sigma lens does. My question is, will this lens autofocus on my cam?

Why is the Nikon 70-200mm zoom lens more expensive than the 55-300mm?
I've been looking at zoom lenses for my nikon d5100 and i was curious why the 70-200 is far more expensive than the 55-300 lens. What is the difference between the lenses? It seems to me that the 55-300 would have much better range than the other. Please clear this up for me.

Can you use extension tubes with a macro lens?
I have a Nikon D3100 with a Sigma 50mm f/2.8 macro lens. I love taking pictures of insects, but to get close enough, my lens almost always scares them off. Is it a good idea to use extension tubes? If so, can anyone recommend some?

I have a sony a200 with the 18 - 70 lens, it was my dads and he gave it to me when he no longer wanted it.
As my birthdays coming up I thought I should ask for a newer one, like the nikon d3100 or a canon camera. As they'll record (the a200 doesn't) and have higher megapixles/do different effects and such?
But I heard a lot of people say its not about the body, its about the lens?
I'm not sure whether to ask for a new dslr, or just get another lens?
As i would rather spend £150 on a lens that will be the same as buying a £400 new DSLR?
What should I do?

How to turn a compact digital camera into a SLR?
I own a Canon PowerShot SD870 IS Digital ELPH Camera. How should I play around with the settings (ISO, etc.) to make it take incredible, crisp photos with low noise in low-light settings, much like a digital SLR (Nikon D3100 for example)?
Added (1). What I'm asking is: How do i make my compact digital camera take high quality pictures in low-light settings much like an SLR? Serious responses ONLY, please…

Does it have just as good image quality as the nikon d7000
is it a good starter camera?

I'm gonna buy my first dslr camera, i don't know much about photography and i'm 18.so i've decided to buy the nikon d5100 should i get the kit lens or anything else? What are 18-55 lens for? I just want the dslr for family and friends moments.

Glass on a 35mm lens for Nikon D5100?
My camera (Nikon D5100) was dropped and my 2 month old (35mm) lens had its glass break. I had a lens protector and it broke through both the protector and the lens glass itself. What should I do? I really don't have the money to buy a whole new lens.

Tavel lens' to fit my Nikon D90?
I'm traveling for 6-24 months and am trying to buy some new lens' for my Nikon D90. I currently have the kit 18-55 and 55-200
Looks like the Nikon 18-200 is a definite
I'm still tossing up between the 35 & 50mm. Leaning towards the 50mm.
My only problem is now is ensuring that it fits on my Nikon D90.Am i right in thinking that any AF or AF-S will fit my D90?
Looking at purchasing this today 18-200 http://www.citiwideonline.com/au/index.php?page=shop.product_details&flypage=shop.flypage&product_id=4992&category_id=97&manufacturer_id=0&option=com_virtuemart&Itemid=79
And then between the;
50 1.8 - http://www.citiwideonline.com/au/index.php?page=shop.product_details&flypage=shop.flypage&product_id=4911&category_id=97&manufacturer_id=0&option=com_virtuemart&Itemid=79
OR
35 1.8 - http://www.citiwideonline.com/au/index.php?page=shop.product_details&flypage=shop.flypage&product_id=3173&category_id=97&manufacturer_id=0&option=com_virtuemart&Itemid=54
What's the different between the AF & AF-S?
Is there much difference in the 1.4 to 1.8 to justify the price?
Why is this one so cheap? Http://www.citiwideonline.com/au/index.php?page=shop.product_details&flypage=shop.flypage&product_id=628&category_id=97&manufacturer_id=0&option=com_virtuemart&Itemid=79
Added (1). Thanks Taylor! So realistically there's no difference between the AF and AF-s for my Nikon D90? Also, do you think that the version 2 of the 18-200 is worth the extra money? As far as i can see, the only improvement is the focus creep.

I'm kind of new to cameras and I just bought a Nikon D5100. How much SD memory would be sufficient enough for photos?