How do these filters work ?

Philistine

Hi Folks,

I was reading an article earlier on a new lens by sigma. It stated that the lens was "compatable with rear-fitting gelatine filters". Can someone please explain where exactly the filter goes or how this works ? Cheers

Valentia

When you take the lens off the camera there is a grooved holder for filters at the bach of the lens. The filter will be IN the camera when you replace the lens.

It is about 2cm high and 1.5cm wide. You buy the gels and cut them to size. A metal plate comes with the lens and this acts as a template for cutting the gel. Tou cannot use polarising filters, well you can but you wont be able to rotate it. They are a pain really and I have never used one with my Sigma 12-24. That said I think Sigma have compensated in some way with the soating on the lens because there is great saturation from it.

Fajitas!

What Valentia said!

It's usually fisheye lenses, where the glass of the lens is too round to get filters onto it.

Philistine

Thanks for that. Sounds a tad complicated though !

Fajitas!

Well, it means you have to take off your lens if you want to use a filter, so yeah!

Plus it gives those people that worry too much about sensor dust a chance to rant