filmguy123
Veteran
After some reading and research, I've realized The GH4 had an OLPF. I was aware the GH5 removed this, *BUT* I was under the impression it only affected moire/sharpness. This also removes the IR filter which the GH4 had, thus basically making the GH5 a "full spectrum" camera. The GH4 was not, which explains why I have suddenly started having these issues that I have never previously had (dramatic color shifts/tints with Fader NDs in bright sunlight). Minor before, major now.
So my questions are as follows:
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(QUESTION 1)
Wherever you land on the infamous UV Filter / No UV Filter debate, I have equipped all of my lenses with UV Filters. Can I simply replace all my UV filters with these UV + IR Filters, and then simply continue to use my Standard VND filters as I always have?
https://www.bhphotovideo.com/c/product/857393-REG/Hoya_A77UVIR_77_mm_UV_and.html
Would this *hurt* anything to pop the same lens with this UV+IR filter attached onto any camera (including GH4, EVA-1, etc.)? Any problems doubling a UV-IR cut filter on a camera that already has an IR-cut inbuilt?
How about stacking these with another filter that has IR-Cut (ie, a UV+IR Cut Filter affixed to each lens, and then at the end of the pipeline via XUME adapter adding on a Variable IRND?
How about all three? (Camera with an OLPF/IR-Cut... then a UV/IR filter on the lens... then a Variable IRND fader or static IRND filter?)
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(QUESTION 2)
Does adding an IR filter onto the GH5 or any other full spectrum camera improve IQ at all on merit of it blocking invisible light, even if not being used in conjunction with ND exposure control? Could it ever hurt it?
Does it make sense to place a permanent IR filter on the camera for any use use case, even if an ND is not needed (indoor shots, outdoor lower light shots, etc.), to make up for the loss of the OLPF that the GH4/EVA-1 has?
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(QUESTION 3)
My understanding is that it's fine to stack IR/UV/ND filters, in any order, UNLESS using a hot mirror IR filter, in which case that *must* be the outermost layer otherwise you can have trouble with ghosting. Is the Hoya UV-IR Filter that so many recommend as the best a Hot Mirror, or can it go anywhere in the pipeline?
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NERDY "SCIENCE-Y" QUESTIONS
4.) Why does the infrared light spectrum operate in REVERSE of the Kelvin temperature scale? Red is the hottest, blue is the coolest in Infrared. Yet in Kelvin, we see that Orange/red light is the coolest (indoor tungsten) and blue light (outdoor sunlight) is the strongest/hottest/warmest. When Herschel did his experiment measuring temperature, blue light from the sun measured cooler than red light.
5.) I am trying to figure out why my standard, no IR block, VND did not cause issues overseas in Papau New Guinea (where it was bright and sunny). One thought: most of the reflected/absorbed IR spectrum was cooler (blue in IR) due to the dirt and jungle and foliage VS here in the States, I am shooting against concrete, etc. which may absorbing much more heat energy and reflecting back as orange/red in the IR spectrum? Thus, making the problem far more noticeable and causing observable color shifts and tints? Or perhaps the high humidity?
6.) Also trying to figure out why my standard ND filter has not caused problems in overcast weather, such as here in PNW or in Alaska. Will the affect that a non-IR blocking VND gives off be stronger on hot sunny days VS overcast or cool days? I imagine so, because based on my previous theory, if true, it seems that the cooler blue IR light pollution is not nearly as problematic as the stronger/hot “red” IR light pollution? Or perhaps this is merely a factor of how intensely the VND is blocking light; ie when a VND is used past 1.2 for example, the infrared pollution may increase more and more and this doesn't happen in more shaded or overcast settings?
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Thank you for the help in understanding this new rabbit hole of a topic!
So my questions are as follows:
------------------------------------------------------------------------------
(QUESTION 1)
Wherever you land on the infamous UV Filter / No UV Filter debate, I have equipped all of my lenses with UV Filters. Can I simply replace all my UV filters with these UV + IR Filters, and then simply continue to use my Standard VND filters as I always have?
https://www.bhphotovideo.com/c/product/857393-REG/Hoya_A77UVIR_77_mm_UV_and.html
Would this *hurt* anything to pop the same lens with this UV+IR filter attached onto any camera (including GH4, EVA-1, etc.)? Any problems doubling a UV-IR cut filter on a camera that already has an IR-cut inbuilt?
How about stacking these with another filter that has IR-Cut (ie, a UV+IR Cut Filter affixed to each lens, and then at the end of the pipeline via XUME adapter adding on a Variable IRND?
How about all three? (Camera with an OLPF/IR-Cut... then a UV/IR filter on the lens... then a Variable IRND fader or static IRND filter?)
------------------------------------------------------------------------------
(QUESTION 2)
Does adding an IR filter onto the GH5 or any other full spectrum camera improve IQ at all on merit of it blocking invisible light, even if not being used in conjunction with ND exposure control? Could it ever hurt it?
Does it make sense to place a permanent IR filter on the camera for any use use case, even if an ND is not needed (indoor shots, outdoor lower light shots, etc.), to make up for the loss of the OLPF that the GH4/EVA-1 has?
------------------------------------------------------------------------------
(QUESTION 3)
My understanding is that it's fine to stack IR/UV/ND filters, in any order, UNLESS using a hot mirror IR filter, in which case that *must* be the outermost layer otherwise you can have trouble with ghosting. Is the Hoya UV-IR Filter that so many recommend as the best a Hot Mirror, or can it go anywhere in the pipeline?
------------------------------------------------------------------------------
NERDY "SCIENCE-Y" QUESTIONS
4.) Why does the infrared light spectrum operate in REVERSE of the Kelvin temperature scale? Red is the hottest, blue is the coolest in Infrared. Yet in Kelvin, we see that Orange/red light is the coolest (indoor tungsten) and blue light (outdoor sunlight) is the strongest/hottest/warmest. When Herschel did his experiment measuring temperature, blue light from the sun measured cooler than red light.
5.) I am trying to figure out why my standard, no IR block, VND did not cause issues overseas in Papau New Guinea (where it was bright and sunny). One thought: most of the reflected/absorbed IR spectrum was cooler (blue in IR) due to the dirt and jungle and foliage VS here in the States, I am shooting against concrete, etc. which may absorbing much more heat energy and reflecting back as orange/red in the IR spectrum? Thus, making the problem far more noticeable and causing observable color shifts and tints? Or perhaps the high humidity?
6.) Also trying to figure out why my standard ND filter has not caused problems in overcast weather, such as here in PNW or in Alaska. Will the affect that a non-IR blocking VND gives off be stronger on hot sunny days VS overcast or cool days? I imagine so, because based on my previous theory, if true, it seems that the cooler blue IR light pollution is not nearly as problematic as the stronger/hot “red” IR light pollution? Or perhaps this is merely a factor of how intensely the VND is blocking light; ie when a VND is used past 1.2 for example, the infrared pollution may increase more and more and this doesn't happen in more shaded or overcast settings?
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Thank you for the help in understanding this new rabbit hole of a topic!
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