Infrared filter placement?

Just wondering if an Infrared "black" 87 filter is equally effective in front of, or behind the camera lens. I purchased a Lee 4x4 filter, and a Lee filter holder, and for a few of my bigger lenses, the only way it will attach is to the smaller rear element of the lens/shutter. I would assume that is OK? Focus the camera, stop down, remove lens put on filter, replace lens, shoot photo. I am referring to a 4x5 view camera, with the lenses on easily removable lens boards.

PHOTOTONE said:

Just wondering if an Infrared "black" 87 filter is equally
effective in front of, or behind the camera lens.

Click to expand...

I'm quite sure rear mounted filters are not so uncommon.
May even be included with the super size or the super
wide angle lenses. Dan

It doesn't matter. Make sure you adjust your focus for Infrared 'cause it's not on the same plane as the visual spectrum.

As Dan says, it isn't uncommon. The Lee polyester filter is so thin that the small focus shift* caused by the filter shouldn't matter. There's a thread on IR focus shift (there was a url link here which no longer exists), by the way.

* About a third of the thickness of the filter - see this thread for much more detail.

Best,
Helen