View Full Version : Filters on front and rear

26-Oct-2007, 18:50

I've got a 90mm 6.8 Grandagon and I have a 77mm filter suite. I am thinking of a centre filter. I believe the centre filter will screw on to the 67mm front and steps up to 86mm. I will then not be able to screw on any of my 77mm filters on the front because of this - let alone the issue of filter stacking.

Has anyone got experience with putting a screw-on filter at the rear as well as having the centre filter at the front? Can one use 2 step up rings at the rear say, a 58-67 and a 67-77 ... ??

Is the image significantly compromised by using filters at the rear?

Thanks in advance,


27-Oct-2007, 03:45
i can't see why quality should be any less with filters front and rear than 2 filters on the front. it should actually be better with regards to flare. a lot of short and long lenses for 35mm use filters on the rear.
you may need to check if the stepping rings will damage the bellows with tilts.

Bruce Watson
27-Oct-2007, 05:45
Is the image significantly compromised by using filters at the rear?

Using filters on the rear will shift your focus by 1/3 the thickness of the filter IIRC. So if you use filters on the rear element, you have to make sure you do a touch-up refocus after you install the filter.

Other than that, image quality should be fine. At least is was for me when I was doing the rear filter dance. ;)

27-Oct-2007, 11:09
Just wondering why you want a center filter on the 90 f/6.8? Have you had a problem with falloff? In my experience with the same lens it seems I run out of image circle before I have much trouble with vignetting, but I might be willfully ignoring the signs on my slides :)

27-Oct-2007, 17:04
Thanks guys,

Walter I have shot 6x17 on 90mm at f16 through 32. There is a fall off for certain. BUT! I also wonder whether having such a wide view contributes to it. The shots were taken with the sun and 90 degrees to the sun (all early morning dawn shooting)

I remember getting an almost black sky when I used a polariser in the north of Australia yet I didn't see it in the 35mm viewfinder! Some of these light fall off issues are a bit black magic for me as yet.

Hi Bruce, thanks for the insight. I plan on focussing with the filter in place.

Since I wrote the initial question I have found some prefer to use gelatin filters. I noticed this morning (in the freezing rain at dawn) that my 90mm may not actually have any thread on the camera side of the lens! This would necessitate a slip on arrangement of some sort. Life wasn't meant to be easy! (A quote from an Australian Prime Minister I believe ...)

Cheers guys.