Strong ND filters.

[rayonline_nz]

Hi all,

Has anyone compared a strong ND filter to without the filter to see if there is color casts? I get a magenta cast. Not sure if I am the only one here.


Thanks.

 

[brucemuir]

Who made the filter?
Some of the cheaper ND filters most certainly can introduce color casts and can be uneven in density.

 

[rayonline_nz]

B+W 6 stop solid ND.

 

[brucemuir]

hmm B+W makes good filters usually...
how are you arriving at the magenta cast conclusion?
what films are you shooting and how are you evaluating this result (printing, scanning)?
is the cast evident across the entire dynamic range (ie: in both shadows AND highlights)

 

[Monito]

10 stop B+W ND is very nice, but it does alter the colours slightly with a bit of a brown cast. Probably less than almost any other similar ND. Remember, a flat spectrum out of 10 stop filtration (practically black) is hard.

 

[rayonline_nz]

I was seeking if you guys had similar effects.

I have not yet shot the B+W on film yet, I am at the moment and where I am film and processing are very expensive, I need to export my film to the USA for development.

In the past I have shot Hitech, might of been a 4 stop Cokin P square filter and that had a even stronger cast than the 6 stop B+W. For the moment, I have evaluated the B+W on a digital camera and it is a magenta, brown cast. The 2 stop is pretty neutal with a slight warming effect, the 6 stop my black camera bag gets like a red tinge.

 

[rayonline_nz]

Here is a 4 stop Hitech filter, taken with my dSLR.
Film used is Kodak E100G. Exact 4 stop was added to the shot before (without filter).
http://farm7.static.flickr.com/6145/5939140700_e771b8b717_z_d.jpg

 

[jbbooks]

Saw this earlier today on the Large Format Forum.

"Be aware that most NDs pass IR and can affect the shadows and shift them red. A hot cut filter, or the Panchro Mirror NDs will work quite well. The more ND, the more color shift. You can read the shift (for the most part) with a color temperature meter and adjust your other CC filters to compensate. That said, the order doesn't really matter except for Leigh's comment."

Good luck!
__________________
Mark Woods

 

[Green Goddess]

Also remember that if you are using the ND filter in order to give long shutter speeds (>1 sec) the colours of your film will alter due to reciprocity failure. This is more likely the cause of the problem rather than the filter itself. To test my theory, shoot two exposures on a DSLR (one with the ND filter and one without) If the colours are the same then it's not the filter (remember to turn off AWB). If you don't have a DSLR, try and do the same test on your film camera but make sure the shutter speed stays below 1 second with the filter in place i.e. do it in bright light with a wide aperture and on fast film if necessary.

 

[David Henderson]

My 10 stop B+W is certainly warm. It is not reciprocity failure.

 

[ann]

Lee"s Big stopper won't give you a color shift, but they are hard to come by as it is a small company.

what you are seeing is very common with ND filters.

 

[E76]

Also remember that if you are using the ND filter in order to give long shutter speeds (>1 sec) the colours of your film will alter due to reciprocity failure. This is more likely the cause of the problem rather than the filter itself. To test my theory, shoot two exposures on a DSLR (one with the ND filter and one without) If the colours are the same then it's not the filter (remember to turn off AWB). If you don't have a DSLR, try and do the same test on your film camera but make sure the shutter speed stays below 1 second with the filter in place i.e. do it in bright light with a wide aperture and on fast film if necessary.

E100G has a cyan color cast with very long exposures (over 120 seconds) and not a magenta one. I'd place the blame solely on the filter.

 

[rayonline_nz]

Since I am so uncertain may get it when I am overseas and can test before paying...

I have a dSLR - the B+W 6 stop does have a warm cast, so does the 2 stop but slight. Yep, shot in daylight WB, not auto.

The one above linked in the picture is film shot well under reprocity limit and it was a 4 stop Hitech. Got a refund but they allowed me to keep the filter.