Can PhotoLab process infrared images with channel swapping?

mikemyers · November 27, 2021, 3:38pm

7Artisans introduced a 35mm f/5 lens in Leica mount, which sells for only $280 new. My first lens wasn’t sharp, so I had KEH send me another, which is brilliantly sharp - but the edges aren’t until/unless I step down. My goal for the lens was to put it on my Leica M8.2 camera, where thanks to the sensor crop, the weak points of this lens are cropped out by the sensor.

I had some time this morning, and took a series of photos at “normal” exposure, with an infrared dark black filter, with a polarizing filter, and with a dark red filter. For me, Infrared Photography can be in color (with “fake” colors), or in B&W which is an accurate representation of what the sensor saw. However, the infrared photos were all out of focus - so I had to experiment to find where to place the “infinity” mark on the lens to get a sharp image, which ended up being between the f/8 and f/11 marks on the depth of field scale. Then I got what I wanted.

I’m placing this on hold for a while, and going back to things Joanna just showed me about how to use control lines better, but here are two images, one from using a red filter, and converting to black&white, and another for what the infrared filter created, straight from my camera (but converted to TIFF so it can later be edited in PhotoLab 5). You might want to try this too, as if you don’t adjust your focus for infrared light, the images will be out of focus…

For all images - 7Artisans 35mm f/2 $280 lens, on Leica M8.2, all exposure settings taken from the M8.2 exposure meter, adjusting until the focus spot was bright red (so the camera thought the exposure was good).

Straight from camera, no processing:

Same as above, but with polarizing filter:

Normal photo, red filter, converted to B&W in PL5:

Real “infrared”, Leica M8.2, f/8, 1/4 second, ISO 160:

Same infrared image as above, but with saturation and vibrancy set to zero:

That last image is sort of my goal for “real” infrared images, but I can probably use PL5 to improve it - maybe tomorrow. I can also try to process it with channel switching for a false-color image, but not now.

Joanna · November 27, 2021, 3:56pm

Could be interesting but, for me, you’ve just touched IR perfection

mikemyers · November 27, 2021, 4:21pm

Thank you!!!

I think I may quit while I’m ahead - as the false-color images are as much “art” as “photography”, and to me they are “real”, as I don’t do anything “silly” other than for needing to manually set the focus “closer” than whatever my rangefinder indicates. Oh, and I better take my new tripod wherever I go. You scored a “home run” when you suggested this model - it’s better than anything I dreamed of - and a “flaw” in the M8.2 works out to my advantage, as the “mount” for the tripod screws into and locks against the base plate of my M8.2, so I just remove the base-plate to remove the memory card, and don’t need to remove the tripod mount.

This $280 lens gets me a better end result than anything I’ve tried before, mostly Leica lenses. I’ll be visiting my brother again in a week, and with all the trees and bushes and vegetation, I should have a lot of fun.

Not sure how I can ever thank you enough, for everything I’ve learned from you! I couldn’t do this well prior to getting involved in this forum!!!

jknights · November 27, 2021, 4:26pm

I have never tried this with my IR shots. I just tried it on an image from a FS converted camera (but no polarising filter used). It works to a point but it is not as I would get in Photoshop.
One interesting thing I did find also was if you put the Colour Temperature up to 10000K then it looks a little more IR like.

I really do wish I could have a Channel Mixer widget for PL5 like the one in Photoshop.
I have C++ code for that widget that was used in another editing app and it works. Free to DXO Development Team.

mikemyers · November 27, 2021, 11:16pm

Just as a test, forget color for a while. If your camera is converted, that means it’s just like my M8.2 but better. Put on your “blackest” IR filter, and either set exposure by the meter, or do a lot of bracketing.

You will have to deal with the same focus issue I described. When you set your focus to infinity, white light focuses on your sensor. Unfortunately, infrared light does not. Make a series of shots of something at “infinity”, but start focusing (manually) closer. When you review your shots, check which focus setting gave you the best (sharpest) image. For me, the focus ring needed to be moved about 1/4" to achieve this. Once you know this, you will use this trick for both color and B&W, when you’re using an infrared filter to block out the white light.

I too REALLY wanted to do the channel mixer work, but then I decided to master B&W first. It’s a struggle. When you do take a test image, all the “foliage” in your photo should turn white.

jknights · November 28, 2021, 8:32am

I am using an IR full spectrum converted mirrorless camera so the focusing is more accurate as it is checking focus on the sensor itself so that isnt an issue for me. Exposure can be a issue but I am using the Kolari IRChrome filter as I want colour infrared results similar to the old Kodak Aerochrome or Ektachrome IR films.
It seems that modern software developers dont understand that the Channel Mixer has uses in general purpose photography, as well as IR, so just dismiss any requests for it as niche!
I can always use PL5 later in the workflow but it would be good to have a one stop shop.

mikemyers · November 28, 2021, 1:42pm

Just for a test, can you take one of the images you have captured, load it into PL5, and do whatever adjustments you think will help, and finally set the saturation and the vibrance to zero? You should get a B&W image similar to what I posted, with a very dark sky, and white leaves.

Also, I was thinking about this the way you described it several weeks ago, but there was an intermediate step I hadn’t considered. Before doing the channel swapping, it is necessary to remove the “red cast”. I tried this using PL5, but it was overwhelmed by the red - PL5 is mostly correcting white balance, but it didn’t know what to do with my red negative. I started to try other programs, but gave up, and opened my raw image in Photoshop. Following the suggested tools, I eventually removed the red cast completely. Apparently, only after that is done, could I do the channel swapping and get the desired results.

There may be other programs that do this, but I had something that seemed to work - but the trees and leaves were yellowish. Someplace on the KolariVision page they say that to get the leaves white, not yellow, I need to also swap the “green channel”.

I suspect that your converted camera is just like my M8.2 camera. For you, the anti-IR screen has been removed. For me, the anti-IR screen was never installed.

For filters, the image above was taken with a mostly black “B+W 52 093 IR” filter. In my case, I need to buy a step-up ring for my 7Artisans lens so I can mount the filter properly.

My other filter is a very deep red “B+W 39 092 IR 695 20-40x”. I used to mount that on my Leica 50mm Summicron lens, trying for color and B&W IR photos.

Some helpful information follows that I found here: https://www.photo.net/discuss/threads/ir-filter.438732/

B+W makes 3 IR filters, the 092, 093, and 094

092 is erroneously listed in some catalogs as equivalent to a Hoya R72 or Wratten 89B. Its 50% pass point is at 695nm (that’s why the Schott glass used in it is called RG695) while the Hoya R-72 and Wratten 89B are 50% at 720nm. That doesn’t sound like much, and as I said, the difference is hardly noticeable on real (Kodak or Maco) IR film. But it’s a big problem on digital, because the camera’s build in IR blocker is a sharp-cut dichroic filter at about 700nm. With the 092, you get a picture dominated by BVR (barely visible red) light from 680-700nm, with essentially no IR content. With the Hoya or Wratten, you get a “false color” image, with IR in the green channel and BVR in the red channel.
093 is a deeper IR, 50% at 850nm, it will give you an essentially monochrome IR picture on an “old” no-dichroic filter DSLR like a Nikon D100, or on a newer one that’s had the dichroic filter removed. It’s between a Wratten 87 and 87C.
094 is a hard-to-find filter that is 50% at 1050nm. It requires a camera with the dichroic filter removed, and the IR is so deep that it hardly registers on IR film. But it’s very dramatic. It’s “stronger” than the (also hard to find) Hoya RM-90.

I also have a Kolari 49mm 590 filter, so I can create false color IR images like what Kolari shows on their website. I will order step-up rings so my filters fit my new 7Artisans lens (which acts like a normal lens on my M8.2 camera). I don’t know about my 39mm 092 filter - I would need a step-up ring, which probably wouldn’t work - too small.

mikemyers · December 21, 2021, 1:00am

I purchased a 52mm B+W 093 infrared filter, and used it on my Leica M8.2 with my 7Artisans 50mm lens. It took a while to figure out the “focus point” (which is different than when using normal light), and the filter blocks so much light that exposures are very long, so I need a tripod.

I have a choice of doing my developing in DarkTable, which works directly on the Leica raw file, or converting to TIFF and processing in PhotoLab. Since I’m just starting out, I used the DarkTable software. I’ll post the results below. For the next image I process, I will use DarkTable to convert the image to a black&white TIFF file, and do the rest of the work in PL5. I’ve only developed one image so far:

I enjoyed my infrared color photos, which I thought were quite artistic, but it bothers me that they are all “fake”, as the colors are created by switching channels and doing strange things to create colors in the software that were not in the image. I used to think that black&white images were boring by comparison, but now I think they are more “real”, even if we can’t see those images with our eyes, which are not sensitive to infrared light.

platypus · December 21, 2021, 6:21am

Have a look at a few IR images here:

Joanna · December 21, 2021, 10:21am

This is simply lovely.

You definitely need to experiment more with one of your cameras that isn’t “IR-ready”. It might mean longer exposures but, as I found, it is possible and you will get RAW files that you can work on in PL.

You really don’t need to use DarkTable for conversion, simply open the file in Preview and export.

mikemyers · December 21, 2021, 11:39am

I will try converting from dng to tif by using Apple Finder sometime later today. The benefit, is I can then do all the processing in PL5. What I might lack, is if I don’t get the exposure right in the camera, one of the things I’ve learned here is to correct exposure on the raw file before I do anything else.

Surprisingly, with the Leica M8.2, every shot I took during this visit was done using the camera’s built-in metering. Because the camera has no anti-IR filter, it selects exposure based on any light reaching the sensor, visible light or not. I brought along a small Sekonic meter in case the built-in meter wasn’t accurate, but then I’d have to adjust every reading because the Sekonic “sees” all light, including the visible light. The M8.2 measure only the light that reaches the sensor, and when I have the filter in front of the lens, blocking most (or all) visible light, that’s what gets metered.

I used to use a red filter, like the ones on the KolariVision pages, that also allowed me to capture “false” colors from the infrared and near-visible infrared that made it through the filter. I wanted to also try that during this trip, but never got to do so. I figured I should try one thing at a time, and learn it.

Something else I discovered this trip, is that the infrared light only makes leaves “white colored” if/when the light reaches them. Here’s another shot where I deliberately got the plants at my left in the photo, but because they were in the shade, they don’t turn “white”, and in the middle of the photo there is an area that is in the shade, so the same thing happened. I’ll remember this for next time.

If I stick with shooting with only infrared (by using a filter like the 093), there are no false colors to concern myself with, only “real” photography. I thought I liked playing with channel switching and everything else, but I think I’ve given up on that.

One last thing - you wrote:

That’s very true!!! I’m using a tripod anyway, so I just need a longer exposure. I still have my old Nikon lenses with 52mm filter threads, so I can put one of those (non-AI) lenses on my Df, use my tripod, and experiment. Now that I think about it, it’s obvious - thank you. Then it’s a regular image that PL5 will accept, and later on, I can use Film Pack for the best B&W appearance. In fact, anybody reading this can do the same.

Amazon has lots of 093 filters - here’s the one I bought, for a reasonable price:
093 52mm infrared filter

Joanna · December 21, 2021, 11:59am

What do you mean, “if I don’t get the exposure right”? Sir, you surprise me

Which I have to say is equally love, especially with the clouds as well.

Have you thought of deliberately under-exposing a bit to see if it gives any more clarity in the foliage?

I found I needed an exposure of about 4 minutes at ISO 100, f/10 and you will not be able to rely on any meter, internal or external, to measure that, it will have to be a “suck it and see” magic setting that you ascertain and just remember.

mikemyers · December 21, 2021, 12:09pm

No, actually, I was being serious. Yes, I can judge, estimate, and measure daylight, but I can’t measure something I can’t see. The question becomes how much infrared light is reaching what I’m photographing, which varies for lots of reasons. I thought about buying an infrared light meter, but they cost too much.

The 093 filter also blocks the “near infrared” light, but the M8 metering takes that into account.

Oh, and for using a DSLR: “After you have chosen the proper subject and composed the scene, make sure to cover your viewfinder while shooting. IR leakage can occur through the viewfinder”. This doesn’t apply for my rangefinder camera but for most cameras, it’s important.