JSimpson

Hello,

Do any of you who make black and white infrared images use a polarizing filter? If you do, which type (or brand) do you suggest to use? If you do not use a polarizing filter, why not?

Thank you in advance for your comments.

MW

I very rarely use polorizers because I can get most of the desired benefits from post processing without degrading the image with an addition piece of glass. That for non-IR photos.

I’m not sure what a polarizer would do with an IR image if anything. It never even occurred to me to try one when doing IR. The effect would likely be different depending on the kind of IR conversion or filtering you select.

BassmanBruce Loc: Middle of the Mitten

I haven’t done B&W ir but I did try a cp shooting color ir.
Shooting those big dynamic cumulus clouds the cp didn’t change anything or add anything to the shots. I tried this a couple times then quit using the filter for ir.

E.L.. Shapiro Loc: Ottawa, Ontario Canada

All the information you require is here:

https://www.dimagemaker.com/using-circular-polarizing-filters-for-digital-infrared-photography/

Very interesting results and a comprehensive explanation.

petrochemist Loc: UK

Nearly all polarizers transmit IR substantially more than they do visual light. Those I've measured transmit ~50% in visual going up to ~75% in the infra red (900nm +). Based on that I've never tried them - I can't justify IR polarizing filters yet.
I have used crossed polarizers to get an effective IR filter when I'd left my proper IR filters behind.
Looking at the link @E.L.. Shapiro supplied above it seems the effect is noticeable with shorter wavelength IR (I'm guessing a 720nm filter was used for those shots) If you're using a 830nm conversion the polarisers effect will be significantly reduced. I often use a 590nm which should have more effect - I'll have to check it out.

dpullum Loc: Tampa Florida

JSimpson, Thank you for bringing up the subject.... "Whoda Thunk," not me, but in the future, I will add a little magic.

ISO100 Loc: Richland City Indiana

From lifepixel.com/infrared-photography-primer/ch...

A polarizing filter has two main uses; to reduce surface reflections and to darken the sky. This happens because the polarized components of the sky are filtered out, causing it to look much darker and more dramatic. This effect can be advantageous in landscape photography. Unfortunately, most polarizing filters don’t work in IR light and only affect the visible light spectrum.

petrochemist Loc: UK

Lifepixel have obviously just repeated the standard response (even down to ignoring the use of a polariser to BOOST reflections). While the link to dimagemaker.com shared above shows an apparently standard polariser can help. This might be highly dependant on the wavelength range being photographed

lev29 Loc: Born and living in MA.

EXCELLENT article! Thank you for presenting it; however, I disagree with your using the qualifier "All ..." as its discussion and examples employed all pertain to color IR, i.e. portions of the visible light spectrum are acquired with the near-IR spectrum.

"All" is not just a trivial distinction, since it does not, in my opinion, even indirectly, address the subject of this Topic: Polarizing Filters For Black & White Infrared Photography

If one can tolerate viewing about two-and-a-half hours of two webinars given by George Wilson, perhaps one can glean some information that leads to a difference. No, I cannot assert that his claim that Singh-Ray's Gold'N'Blue polarizer for B&W IR photography DOES NOT make a difference, since despite my inability to discern any whatsoever (in the two examples he provided in part 2,) this could be secondary to hardware limitations in his Webinar broadcasts. His quasi-physics explanation did not satisfy me either, as his terminology was clearly "dumbed-down" for what he presumed to be an entirely lay audience.

Here are the URLs and Subjects discussed for each of these webinars:

PART 1:
https://zoom.us/rec/play/uJJ8cbr-qz43T9fBsASDBqAvW9XrKf-s1iceqfEEzEbmASQENlv1b7pGa7F4910kAdFNUU-A_oMXtvfq
A review of what is infrared and its origins
The 3 types of infrared capture
Comparison of color vs B&W Infrared photography
Infrared characteristics and how to expose for them
Focusing adjustments, direction of light, digital noise and exposure starting points
Important accessories


PART 2:
https://us02web.zoom.us/rec/play/tMV5ce-vrG43SYWSuQSDC_R8W9XoLvms2igY-PZZxUmwB3VVZgCkYrpHMetkRmP_oRBb1abLXE5dr62R?continueMode=true&_x_zm_rtaid=gUe6uz7iSj2FJ-A6wgqm6Q.1588122123951.15cbfa0e32e67124c788a20d6244f040&_x_zm_rhtaid=520
Camera conversions – pros/cons
Resin vs glass filters
How IR "reacts" with filters
Step-Up rings
Mor-Slo, Vari ND, Vari NDuo
Using an 830mm I-Ray as a 2-stop ND
Contrast w/ Gold Blue Polarizer
Softening the image w/ Soft Ray
Other useful filters

Despite my skepticism as to portions of these two webinars, I hope they can help someone, albeit belatedly.

lev29

E.L.. Shapiro Loc: Ottawa, Ontario Canada

I apologize for the "all" error. You must understand that like many contributors on this forum , I am not a professional technical writer and someof my grammatical and word usage leaves much to be desired. I have long experience as a professional photographer but much of the advice I offer is a "nuts and bolts" approach to applied photography and not ALL the underlying science of all the equipment and methodologies.

As for inferred and other kinds of photography that includes materials and equipment that records light wavelengths beyond the visible spectrum, I do have some rather unique experience, but again more as an "appliance operator" but not as a scientist. For 2-years, "compliments" of the U.S. Army, I did aerial reconnaissance during my tour in Vietnam. The job was to detect subterranean bunkers and tunnels used by the unfriendly folks. We were supplied with specialized film, filters and cameras and given a relatively short course on how to use and operate them and a very brief explanation of how the heat radiating from undisturbed as opposed to undermined ground differs in the film's colour rendition, and how the film's colour rendition reacts to unstable compounds, in storage, such as explosives and ammunition. The equipment and materials were provided by manufacturers who employed scientists, physicists and engineers- way above my pay grade. My tour ended in late 1967. Nowadays that work can be done via satiate and viewed in an air-conditioned office in the Pentagon with nobody hanging out of a low flying aircraft being shot at... progress! I also did some medical imaging using, inferred materials, to detect abnormalities in blood vessels very close to the surface of the skin. This was was also a set procedure where the prescribed light sources, their positions, and filters were pre-determined by the folks at Kodak.

Another thing you should understand is that most of the good folks on this forum when asking about filters and other practical equipment and technical issues, do not expect a detailed dissertation or Ph.D. calibre thesis on the physics and chemistry related to the materials and gear. There are, however, some members with high levels of scientific education and practice that may better be equipped to answer your questions in greater detail.

If you disagree with the content of the link I posted, why not take it up with the authors. I had no way of knowing that or if the information therein is inadequate for your purposes or applications, plagiarized, dumped or whatever- it seemed a decent enough resource for the average user and a good primer to encourage further research.

These days, I occasionally use inferred photography for aesthetic and artistic purposes in my commercial photography. It makes for lovely skyscapes and interesting renditions of foliage in architectural and landscape work. I use Sing-Ray, and B+W filters because that they are optically sound and sufficient for my purposes and have well-crafted rims that don't strip and cross-thread.

This forum, as I see it, is not a personalized paid consulting service. So many folks here, treat it as if it is and complain if posts are too long, too short, not to their liking, up to THEIR standards, or level of patience or reading comprehension or lack thereof. Oftentimes it's maddening and discouraging!