Has it any effect on image quality if a filter is placed on the rear side of the lens? I'm imaging this to be a better place, causing less flare and to be more protected in field camera work. Searched the archives but couldn't find any answer. Sure everebody else knows. Many thanks.

-- Jan Eerala (jan.eerala@itameri.net), October 20, 1999

Answers

Yes. It can cause a focus shift = to 1/3rd the thickness of the filter. Magnify and defects in the filter, increase the effect of dust, dirt, fingerprints on the filter and be impossible to properly control rotating filters like polarizers, grads, star, prisms, etc.

Flare is easily controlled by using properly coated quality filters that are plane parallel in the front of the lens and using a good compendium.

-- bob salomon (bobsalomon@mindspring.com), October 20, 1999.

bob's comments are quite correct, but i would add the following - while i now use b+w front-mount glass filters, for several years i used gel filters on the rear of my lenses in a wide variety of professional situations with no problems, and i know other long-time field pros who still use this method. precautions for this process include the use of flawless or new filters, and regular inspection and "blow-offs." as bob cautioned, while even obvious defects on the front element are often unnoticeable at the negative, virtually any defect at the rear element can be all too evident on a negative.

-- jnorman (jnorman@teleport.com), October 20, 1999.

Is that why most large format lenses longer than 300 mm or wider than 100mm use filters between the front and rear elements? Intersting. And you aren't supposed to put your fingers on the filter anyway. And I'm sure that any filter manufacturer would have a few choice words for you when you "dis" them like all the great photographers do around here. I've got all sorts of filters by nearly all the different major manufacturers and all my negs and prints come out just as sharp as if I wasn't using a filter. And I enlarge 35 to 11x14 and 4x5 to 20x24. Interesting. James

-- james (james_mickelson@hotmail.com), October 21, 1999.

"Is that why most large format lenses longer than 300 mm or wider than 100mm use filters between the front and rear elements"

NO LARGE FORMAT LENS USES BETWEEN THE LENS FILTERS!!!!

Are you perhaps confusing photographic large format lenses with graphic arts process lenses that are not in shutters?

ALL PROCESS LENSES ARE SOLD IN NF MOUNTS THAT HAVE A FILTER SLOT>

THESE ARE NOT LENSES THAT WERE RELEASED BY THE MANUFACTURER AS A VIEW CAMERA LENS>

No large format lens in a shutter has any way of inserting a filter inside the lens.

-- Bob Salomon (bobsalomon@mindspring.com), October 21, 1999.

My 480 apo artar has a filter slot right between the front element and the diaphram. Along with my friends 47mm SA. James

-- james (james_mickelson@hotmail.com), October 22, 1999.

Your 480 is a process lens.

And where is the shutter in your friend's 47mm?

-- Bob Salomon (bobsalomon@mindspring.com), October 22, 1999.

Bob is probably right, but could use some lithium, possibly.

-- Greg Nelson (gnelson@dodgecity.net), November 02, 1999.