I think I've been having some issues with my 4x6 size Singh-Ray 5 stop ND filter. I seem to get a pink/purple or red color cast whenever I use this filter (the severity depends on the original skyl.

Here are some examples of just using a Singh-Ray ND grad, ND Grad plus 5 stop ND two shots and then right after with just the ND grad again. NOTE: I didn't bother cloning out the marks from the dirty sensor.

Anyone experienced this In this particular case the differences in exposure were about 2 sec expoures without the 5 stop Grad filter and 30 seconds with the filter. I thought it may be bcoz of moving clouds, but there is no way that there was that much movement that there would be a color cast over the entire sky and part of the peaks. Moreover, I also experienced this with much shorter exposures in the past. I also found that if i switched to my ND Vari-ND filter, i wouldn't have an issue. The problem is the Vari-ND is to too thick (i have slim version), to use with ultra-wide angle lenses.

Does this look like a quality control issue - should I be calling Singh-Ray

Last shot, after removing the 5 Stop ND filter

For an explanation of the problem, read the following thread on NaturesScape.net: Magenta Color Cast with Heavy ND Filtering on 5D MkII.

Make sure to read all the way through.

The effect is a combination of your camera's sensitivity to certain wavelengths, along with stacking same-brand/same-design filters.

It is not a problem with any individual Singh-Ray filter as such.

Hope this helps.

Rob

RServranckx wrote:
For an explanation of the problem, read the following thread on NaturesScape.net: Magenta Color Cast with Heavy ND Filtering on 5D MkII.

Make sure to read all the way through.

The effect is a combination of your camera's sensitivity to certain wavelengths, along with stacking same-brand/same-design filters.

It is not a problem with any individual Singh-Ray filter as such.

Hope this helps.

Rob
Thanks for the link. It sound like the same issue. However, I'd also be interested in hearing people's feedback regarding the effect of stacking filters with the 1DIII, since I also experienced the issue when I had the 1DIII. Although, I don't think it was a strong of a Magenta cast at that time.

I've never had this issue to this extent, but I have the same 5 stop Singh Ray and use it with a 5D. I found that I don't have this issue if I set the camera as follows, WB - sunlight or custom, Color Temp - 5000, Color space - Adobe RGB picture mode - faithful, and I only use the camera in Manual or Bulb setting. My original RAW file is relatively the same as the environment I shot it in, no magenta cast, then in PS I can then adjust my RAW file as I like. Hope this helps

KFG1 wrote:
I've never had this issue to this extent, but I have the same 5 stop Singh Ray and use it with a 5D. I found that I don't have this issue if I set the camera as follows, WB - sunlight or custom, Color Temp - 5000, Color space - Adobe RGB picture mode - faithful, and I only use the camera in Manual or Bulb setting. My original RAW file is relatively the same as the environment I shot it in, no magenta cast, then in PS I can then adjust my RAW file as I like. Hope this helps
Thaks for the advice. I'm doing all of my processing in DPP. So I have tried to adjust the WB in DPP, and while it does reduce the Magenta cast somewhat, the foreground is way to cold. I guess I need to look at doing further adjustments in PS - currently, I really don't use PS for anything other then resizing or stichting panos.

Most ND filters do not do as well with IR as they do with visible light. Depending on the camera's cut filter you may or may not see the increased magenta cast (from the IR).

If you do, B+W has an IR cut filter #486 http://www.schneideroptics.com/Ecommerce/CatalogItemDetail.aspx?CID=677&IID=4397

Available at a (more) reasonable price at http://maxsaver.net/B-W-77mm-Digital-486-UV-/IR-Blocking-Filter.aspx

John

i stopped using Formatt polyester ND filters because they are transparent to IR. this is not good when deliberately shooting IR with ND filters to get long shutter speeds. the B+W ND 0.9 is about 3 stops as in visible light, but the ND 1.8 is 6 stops in visible light while only 5 stops in IR. the ND 3.0 is 2 stops less, being only 8 stops instead of 10 as in visible light. i haven't tested my Singh-Ray 5 stop filter but because it is an acrylic filter, i expect it to be nearly transparent to IR.

Herb...

jrsforums wrote:
Most ND filters do not do as well with IR as they do with visible light. Depending on the camera's cut filter you may or may not see the increased magenta cast (from the IR).

jrsforums wrote:
Most ND filters do not do as well with IR as they do with visible light. Depending on the camera's cut filter you may or may not see the increased magenta cast (from the IR).

If you do, B+W has an IR cut filter #486 http://www.schneideroptics.com/Ecommerce/CatalogItemDetail.aspx?CID=677&IID=4397

Available at a (more) reasonable price at http://maxsaver.net/B-W-77mm-Digital-486-UV-/IR-Blocking-Filter.aspx

John
Thanks for your reponse John.

The filter you are referrng to appears to be a clear UV filter thatblocks IR light.
Can you clarify whether using this filter in combination of a Singh-Ray ND Grad and the 5 stop ND Grad will negate the effect of getting a magent cast when the ND Grad and the 5 stop grad are used together?

Is there any other potential undesirable effect of using this filter, such as endingup withan overall colder tempertures or look to the image

HerbChong wrote:
i stopped using Formatt polyester ND filters because they are transparent to IR. this is not good when deliberately shooting IR with ND filters to get long shutter speeds. the B+W ND 0.9 is about 3 stops as in visible light, but the ND 1.8 is 6 stops in visible light while only 5 stops in IR. the ND 3.0 is 2 stops less, being only 8 stops instead of 10 as in visible light. i haven't tested my Singh-Ray 5 stop filter but because it is an acrylic filter, i expect it to be nearly transparent to IR.

Herb...

jrsforums wrote:
Most ND filters do not do as well with IR as they do with visible light. Depending on the camera's cut filter you may or may not see the increased magenta cast (from the IR).


How much of an effect is there (I.e. Magenta cast) if ther is a 1 or 2 stop difference between visible and IR light

On the 5D2, I notice some colorization with the B+W 106 (6 stops) and very noticeable with the 110 (10 stops). On other cameras with different IR cut filters, you may not see this. It is fixable in PS, but requires a bit of masking to make the changes just to the effected(noticeable) area.

I cannot talk to Singh-Ray, but would epect similar results.

The 486 cuts the colorization out...so is much easier to get proper colors. Please note the limitation at bottom of http://www.schneiderkreuznach.com/tipps/uv-ir_cut_filter.htm the ^0 deg. FOV eguates out to be ~30mm horizontal on FF...so any wider and the IR cut effect is diminished.

khurram1 wrote:

How much of an effect is there (I.e. Magenta cast) if ther is a 1 or 2 stop difference between visible and IR light

Totally depends on your camera's IR-cut filter. If the filter is weak, the result could be significant...approaching 2x to 4x the amount of light.

John

it isn't. it is a very carefully coated filter so that it reflects or cancels everything except the visible light spectrum. one catch with using it is that the FOV of the lens has to be less than about 60 degrees. more than that and the filter doesn't block in the corners and leads to funny color shifts that sort of look like odd vignetting because of the IR/UV leakage. what you actually see depends on what your camera's spectral response looks like from the long wave IR to short UV.

Herb...

khurram1 wrote:
The filter you are referrng to appears to be a clear UV filter thatblocks IR light.

it really depends on the camera and its IR sensitivity. none of my Nikons show any effect because they effectively have no practical IR response.

Herb...

khurram1 wrote:
How much of an effect is there (I.e. Magenta cast) if ther is a 1 or 2 stop difference between visible and IR light