drop in filter question

[twistedphrame]

hey all,


so I'm just curious since I don't have any sort of money to spend on a lens that would need one but could anyone explain to me how drop in filters work and do you just buy normal filters and put them in the holder or do you need special filters for the holders. Like I said I'm just a little curious.


~Jordan

[WAFKT]

Super telephoto lenses have very large diameter front lens elements -
which would require an equally large (and very expensive) filter if it
were a traditional screw-in type. Just take a look at the cost
difference between a 58mm vs. 77mm of the exact same filter. As a
result most super telephoto lenses use drop in filters. In the case of
the 400mm f/2.8 L IS USM it has
a52mm drop in filter located further in the lens assembly - since filters are not really optical (at least in the sense that they don't typical curve light like lenses do) it doesn't really matter where in the sequence of lens elements you place the filter. The drop in filter holder can accept any standard screw-in filter of the same size as the holder.

[twistedphrame]

Thanks WAFT that cleared up quite a bit