CF necessary on the 47XL ?

[Myco Megasoid]

I'm considering this 47XL on a Cambo Wide DS. Is it possible to somehow use the CF behind the lens in this body, or a standard bag bellows view camera body? I suppose that if the rear lens element diameter were much smaller than the front, that the filter might not work, but I don't have them to examine. As long as the center spot gradient accomplished its job, as determined by real world testing, that's all that should count.

I use many other filters behind the lens to avoid flare problems.

Myco http://www.megasoidstudios.com

[Bob Salomon]

"Is it possible to somehow use the CF behind the lens in this body, or a standard bag bellows view camera body?"

No. Placing a filter in back of a lens makes it become part of the optical system of the lens. It will cause a focus shift = to 1/3rd the thickness of the filter, it will degrade th image if there are any marks, scuffs, cleaning marks, finger prints, dust, dirt, etc. Filters belong in front of the lens unless the lens was designed for specific filters to be placed inside or behind the lens.

flare is easily controlled by compendiums, gobos, coatings, etc and CF especially bre for the front.

[Myco Megasoid]

Wow, thanks Bob! As Johnny Carson used to say in metered verse, "I did not know that." I suppose that since I've only used gel filters behind lenses, I haven't seen such optical effects. I'm now curious and will experiment with some thicker glass filters behind lenses, just to learn.

In my use of 65mm lenses on 4x5, I've exploited the luminance falloff to the corners and sides. And then, there's Photoshop, since everything is scanned and improved there anyway. So I may just end up doing that with the even more extreme falloff inherent in a 47mmXL, as long as there is sufficient shadow detail in the falloff areas--or, could shoot a 1 and 2 stop series of overexposed chromes and merge them with gradient masks in Photoshop--but only if I had a flare situation with a CF in front of the lens.

I've found that for lenses as wide as a 65mm on 4x5 and wider, that compendium shades and the like won't work without vignetting--I usually try to make a flag to gobo the flare source if possible.

Myco http://www.megasoidstudios.com