Filter Questions?

IrishDame · Nov 27, 2006

Hey all! This is my first post. So I have the Rebel XT with a Canon 18-55mm lens and a Quantaray 70-300mm lens. I want to buy filters but I don't know what sizes I need to get.. can anyone help?

250Gimp · Nov 27, 2006

If you look at the end of the lense you will see the specs for the lense. Among those specs you will see a diameter given in millimetres, which is the filter size you require. I believe the 18-55 is a 58mm diameter filter.

Hope this helps.

IrishDame · Nov 27, 2006

Ok thanks. Yeah my 18-55 requires 58mm.. but my 70-300 doesn't have it on there.. is there anyway i can just buy a bigger filter and adapt it to the 58mm one?

JamesD · Nov 27, 2006

Yes. Here are some examples: http://www.bhphotovideo.com/bnh/controller/home?O=NavBar&A=search&Q=&ci=420

Some expensive ones are at the top of the list. Select Sort by: "Price: low to high" and browse for the one you need.

IrishDame · Nov 27, 2006

Thanks for the link

Garbz · Nov 28, 2006

The diametre is written on every lense. If not the inside ring then somewhere else. The Nikkor AF-S DX G lenses have them at the bottom right next to the serial number. If you have threads on the inside of the rim it will be mentioned somewhere.

There is a limit to how far you can step up with filters. It does prevent the need for buying multiple filters. The filters also get more expensive for larger ones.

However one thing you should ALWAYS have no exception is a UV filter. Slap it on every lense in the native size and never take it off. They can be bought at most camera stores or for about 1/3rd the price off ebay. Use them just to protect your lens. It's much better to have salt damage or scratches on something replacable, and I'm surprised they don't come standard on lenses!

Digital Matt · Nov 28, 2006

Look on the inside of the lens cap. You should buy a filter for the biggest diameter lens, and then use step up rings for your other lens.

JamesD · Dec 6, 2006

Garbz said:
However one thing you should ALWAYS have no exception is a UV filter. Slap it on every lense in the native size and never take it off. They can be bought at most camera stores or for about 1/3rd the price off ebay. Use them just to protect your lens. It's much better to have salt damage or scratches on something replacable, and I'm surprised they don't come standard on lenses!

I agree with this conditionally. If you're in a particularly hostile environment, then it's a good idea. However, for 90% or more of shooting situations, a lens cap is a better solution. It doesn't degrade optical quality, and much more importantly, it's substantially better at protecting than a thin glass filter.

The one time a UV filter may have protected my lens is when I dropped the camera from a vehicle--my fault, becuase I should have had the strap around my neck. The broken glass of the filter scratched the coating on the front element of the lens, and I had to spend another $10-$15 to replace the filter. If I'd had the lens cap on, like I should have, or the strap around my neck, like I should have, all this would have been prevented.

However, if you shoot in dusty conditions, sandstorms, aboard a salt water vessel in rough seas, or need to remove UV from a scene, then a UV filter fits the bill pretty well. Also sometimes recommended is a Skylight filter (1A, I think), particularly if you're shooting landscapes.