----- Original Message ----- From: "Andre Langevin" Subject: Re: Wideangle lens choice
> >graywolf wrote: > > > >>AFAIK the filter glass is computed into the lens formula. That > >>would mean replacing the filters with gels would not be a good idea. > > But to add it behind the lens would not cause any problem. It has > been tried by some PDMLers I think. Gel filters are apparently optically neutral. The polyester ones certainly are, and are a whole bunch tougher. For those who are interested, the SMC Pentax 6x7 45mm f/4 has a gel holder on the back, so it must be doable. William Robb
