Jump to content
UltravioletPhotography

[Filter Test] Schott BG40 for Colour Correction in Converted Camera


Andrea B.

Recommended Posts

EDITOR'S NOTE:  2021 Dec 10.

Schott BG38 usually works best for IR-blocking when using a converted camera for Visible photography: Five IR-Blockers Tested for Visible Color Use on Full-Spectrum Camera


 

The Schott BG40 filter works well enough for correction of Visible colour in a converted camera using an in-camera white balance made under the filter.

I think that adding a colour profile improves the results.

Check this out and let me know what you think, OK?

 

 

Equipment: Nikon D600-broadband + Coastal Optics 60/2.8 + Sunlight + Schott BG40

The Nikon Neutral picture control was used with a bit of sharpening only.

f/4 @ ISO-200 for 1/640", 1/400"

 

 

Experiment 1:

Make an in-camera white balance setting under the BG40, then shoot.

I measured the white standard in the raw NEF in NX2 - white is white, as expected.

An observation: the Nikon Neutral setting is somewhat more neutral than neutral settings in non-Nikon converters.

Jpg extraction, as shot.

testFilter_BG40withInCamWBunderBG40_20160131wf_42055.jpg

 

 

Experiment 2:

Set in-camera white balance to Daylight, then shoot with the BG40.

As expected, there is a cyan cast to the photo.

Jpg extraction, as shot.

testFilter_BG40withIncamDaylightWB_20160131wf_42059.jpg

 

 

Experiment 3:

Now I wanted to see whether results could be improved with application of a colour profile made in the converter Photo Ninja using the CC Passport. There is indeed a change in the appearance of the photo when the profile is applied. White & greys do not change, but some of the colours are slightly altered. For comparison I added a two conventional conversions. The first was made in PN, the in ACR.

 

This is the photo from Experiment 1, now converted in PN with Light_Source/Mode set to the colour profile.

testFilter_BG40withInCamWBunderBG40_20160131wf_42055pnProfileWbFromProfile.jpg

 

 

This is the photo from Experiment 1, now converted in PN but with Light_Source/Mode set to use the default Daylight/From Camera settings. This conversion is an improvement over the As-shot Jpg extraction above due to a different application of Gamma curve and W/B points by Photo Ninja. There are subtle differences between this photo and the preceding colour-profiled conversion.

testFilter_BG40withInCamWBunderBG40_20160131wf_42055pnDaylightWbFromCamera.jpg

 

 

This is the photo from Experiment 1, now converted in ACR with the White Balance dropper applied to the white standard and profile set to Camera Standard. Again it is an improvement over the initial Jpg extraction. Again there are differences between this conversion and the preceding colour-profiled conversion. I probably did not need to re-measure WB in ACR, as it seemed to read the Nikon WB setting well because there was only a minor change after in the temperature after the white-click.

testFilter_BG40withInCamWBunderBG40_20160131wf_42055acrWhiteClickCamStd.jpg

Link to comment

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
×
×
  • Create New...