Back Filter

Where would i get one of the filters for the back of the lens? I have heard about them on this site but i can never find them on B&H. I am interested in getting one for my 24-70mm 2.8L if that helps/narrows down the question.

Rear mounted gel or glass filters can only be used on those lenses which are designed to use them. These are usually lenses that, either because they're ultra-wide-angle, they have a large and protruding front element, or they just have an extremely large front element, can't take front filters. The 24-70 L isn't one of those. You could always tape a piece of gel back there, but I can't think why you'd want to.

Thank you. Yeah i didn't know what to think when i read about rear filters and gel i couldnt see how it would fit on the back of the 24-70 anyway. again thank you

yeah that's definitely NOT the case with a 24-70, just use a standard filter for that