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"Capturing Infrared"

Don Libby

Well-known member
Earlier this week Bob, Jack & Guy were kind enough to post an article (part of a blog series) I'd written regarding infrared photography. Ranger Rick and I have been discussing the merits of different IR filters and color vs. black & white processing since then.

I hadn't thought of it when I posted the last reply that I wouldn't be able to also add a sample or two; thus this new thread.

One of the major reasons I enjoy shooting digital is the fact I can choose which way the finished image will appear; either color or black & white. Or a combination. While I sometimes miss the smells from the old wet darkroom, I find the newer digital darkroom is faster and much more convenient.

My original thought when I began the response to Rick was to add just two samples however now that I find that I couldn't I'll expand. The first consideration is that all of the following images were captured with the same Sony NEX-7 (the one I bought used from Guy) which I had converted to capture in the 665nm IR range; the range that Life Pixel calls their "Enhanced Color IR Filter"

"String Lake" is from The Grand Teton National Park, Jackson WY and was captured during an early morning hike last June. f/8 1/200 ISO 100 and a 12mm lens. It was processed using a combination of C1-Pro, Photoshop CC and NIK software. Much like everything I do, I let the image guide me to where it wanted to go. The finished result is the color in the sky.



"Taos 1a" is from the area around Taos, NM and was captured early/mid morning last June. f/10 1/200 ISO 100 and a 20mm Sony lens.



"Taos 1" is my favorite of the two and shows a combination of black and white as well as a hint of color. I think if I were using the 720nm or stronger filter I would have lost out on the ability to introduce the color that shows here.



"Taos Tree" is located on the High Road to Taos that we passed several times and each time we shot this tree off a busy road. Seeing the tree for the first time I knew I wanted it in black and white and had I actually had a 720 filter with me I would have used it. Shot at f/11 1/160 ISO 100 with a Sony 20mm lens.



In the end at least for me I enjoy the ability to process files either in color or black & white. I just recently sent a Sony A7r to Life Pixel for conversion and after several days of consideration decided to have it converted with a 665nm filter feeling that I can on occasion put either a 720 or 830 filter on my lens, thus giving me 3-IR converted cameras in one.

I want to thank Rick for starting the conversation on IR and hope this continues it. I also hope this gives others some ideas who might be on the fence on IR.

Don
 
I'm sorry not to see more responses here as I would look forward to more information on experiences with IR digital capture. Thanks, Don, for your front-page piece, and I hope there will be more. I know there is a focus difference between visible light and IR. What I don't know, and would like to inquire, is whether the focus differs for different IR cut-offs -- 650, 720, 830 nm? Or might any differences from one cut-off to another within the infrared spectrum be so small as to be ignored, compared with the adjustment from where we focus for visible light? I have shot some infrared with a Sigma SD1 from which I have removed the IR-cut filter and used a visible-light-blocking filter with the lens, and really guessed about focus. I will also have to check what cut-off point my visible-light-blocking filter is at. Results were good enough to encourage me about further experimentation. --Barbara Armstrong
 

f6cvalkyrie

Active member
Hi, Don,

great idea for a topic !
I'm shooting a Full Spectrum modified Panasonic G1 with different filters ranging from 600nm to 850nm.
The G1 being a mirrorless camera, no problems with focus shift for IR. And, as the AA filter was removed during the conversion, the IR images come out very very crisp. Of course, they ask for adequate PP, but Lightroom in combination with NIK plugin Silver Efex Pro do a great job at that.

Here's just one example (if you don't want other posters to show pictures, just let me know, I'll gladly take it down !)



C U,
Rafael
 

Don Libby

Well-known member
I'm sorry not to see more responses here as I would look forward to more information on experiences with IR digital capture. Thanks, Don, for your front-page piece, and I hope there will be more. I know there is a focus difference between visible light and IR. What I don't know, and would like to inquire, is whether the focus differs for different IR cut-offs -- 650, 720, 830 nm? Or might any differences from one cut-off to another within the infrared spectrum be so small as to be ignored, compared with the adjustment from where we focus for visible light? I have shot some infrared with a Sigma SD1 from which I have removed the IR-cut filter and used a visible-light-blocking filter with the lens, and really guessed about focus. I will also have to check what cut-off point my visible-light-blocking filter is at. Results were good enough to encourage me about further experimentation. --Barbara Armstrong
Barbara, you are correct that IR does shift the focal point however I'm uncertain if it is filter dependant.

Years ago way before digital was even a dream I experimented shooting IR with film and each (or almost all) of the lens then had a separate focal mark for IR. Fast-forward to a couple years ago, I decided to get a 35mm DSLR camera converted that I was no longer using. The company that I sent it to made certain that I also supplied the lens I was going to use in order to perform a focal calibration. After getting it back I found no difference with the focus as it acted as it should; I remember trying a non-calibrated lens and could see the difference.

I contacted Life Pixel last year and spoke with them at length regarding converting the NEX-7 and found that since it was mirror less there would be no need for a calibration. No mention was made of different filter affecting the focus. Since then I've used quite a few different lens on the NEX and with each autofocus being spot on. I did experience a focus shift in using manual lens and was caught off guard when I did as I had gotten so used to the AF being good.

The camera is converted to 665nm and I can also use a 720nm filter on the lens without any adverse effects. As a matter of fact I'm having the A7r converted to 665 as well so I can continue to have choices.

Thanks for the comment and I should have something up either here or on our blog addressing the need for a custom white balance when shooting IR.

Don
 

Don Libby

Well-known member
Hi, Don,

great idea for a topic !
I'm shooting a Full Spectrum modified Panasonic G1 with different filters ranging from 600nm to 850nm.
The G1 being a mirrorless camera, no problems with focus shift for IR. And, as the AA filter was removed during the conversion, the IR images come out very very crisp. Of course, they ask for adequate PP, but Lightroom in combination with NIK plugin Silver Efex Pro do a great job at that.

Here's just one example (if you don't want other posters to show pictures, just let me know, I'll gladly take it down !)



C U,
Rafael
C.U. great image, I hope you continue to share!

We had at least one thread from a couple years ago concerning IR however it appears to have fallen out of favor so I hope this with resurrect the dicussion.

Don
 

Don Libby

Well-known member
Life Pixel is currently holding a photo contest of IR work. The winner will receive a conversion valued up to $775.

I am only a customer of theirs and in no way connected to them in any way other than spending my money. Go check them out along with the rules by clicking here.

Good luck to all who enter.


Don
 

f6cvalkyrie

Active member
Hi,

if you use a DSLR camera, you need to have the camera/lens combination calibrated for IR focus. The calibration will be (theoretically) wave-length dependant. So, if focus is OK for 650nm filter, it will be off for 850nm.

With mirrorless cameras, no such problem, since focusing is done on the sensor.

When asked, I always give the advice to go for a full spectrum modification of the camera, and use external filters. Filters off Ebay are very cheap, and come in all kinds of wavelengths and diameters ...

Here's another shot with the full-spectrum G1



(650 nm external filter used)

C U
Rafael
 
Thank you, Don and Rafael, for your additional posts. This is certainly making me think about how I might proceed with further IR shooting. I love the conversions to b&w where I have nice contrast to start with. Summertime shooting has always been somewhat dismaying as broad swaths of green hold little interest in a final print. But capture the same image in infrared, and it could be mistaken for a beautiful winter scene, with the greens appearing to be snow and tree trunks and structural objects interjecting a dynamic framework. Lots of fun. Also, IR renders beautifully at mid-day, just when we may be most likely to give up on "normal" photographic pursuits. --Barbara
 

Don Libby

Well-known member
Just a brief (because I can never be short...) update.

The Sony A7r was returned yesterday after being converted to shoot 665nm. In the short time I had available last night I tried out the 55 and 24-70 both of which look good.

And on another note the NEX-7 IR has found a good new home and will be residing in WI soon.

I'll have more to share shortly as :worthless:
 

fotografz

Active member
Don, very interested in B&W IR conversion of my A7R. I will do so when Sony introduces the next A series camera replacement for the A7R (probably ay Photokina this year). So, rather than sell the A7R, I'll convert it to IR.

Do you need to use a filter with an B&W IR conversion? If so, does it cut the viewing light a lot? Or does the EVF gain, and show "what you see is what you get" when it comes to exposure?

I'm very interested in B&W IR work in the Tropics … where the trees won't be mistake for a winter landscape :). I want to add IR to some of my Wedding gigs because it's so "Dream Scape" looking.:thumbs:

- Marc
 

Don Libby

Well-known member
Marc, I got the A7r back late Thursday and took it out for a test spin yesterday. I've done some very limited testing with the FE 55mm which look good as well as Sandys 24-70 which look equally good.

I've included two sample from the 24-70, one in color the other in B&W; both were processed using a combination of C1-Pro, Photoshop CC and NIK. I had the camera converted to shoot 665nm which is "enhanced" color; some call it "false color". I can add a 720nm filter to the lens to get less color as well as a 830nm filter to shoot B&W IR; all depending on the subject matter and the look I'm after. This is the 3rd camera I've had converted and the third using the 665nm filter. I've always felt B&W conversion from either the 665 or 720nm filter just looks better than from shooting non-IR color then converting. The thing with shooting IR is that the WB is very tricky yet once you have it no problem.

The real beauty of shooting with either a NEX7 or the A7r is that since both are mirrorless what you see is what the sensor sees so that's what you get. The tricky part is that you need to use Sony Image Data Converter to convert the RAW file to a Tiff before opening in either C1 or Adobe. I have however found that I can open a 720nm file directly in C1Pro and obtain a white balance with a color picker. Not sure on the 830 as I'm still waiting for that filter to arrive.

The thing I like about shooting in IR is that with very little post you get an image that can have a rather "dreamy" effect either in color or B&W.

I'm working on another blog article addressing using a 7r in IR which will also include information on lenses and how they play.



"Fixer Up" Sony A7r FE24-70 (24mm) f/11 1/160 ISO 160 (handheld)


"The Oaks" Sony A7r FE24-70 (24mm) f/11 1/160 ISO 160 (handheld)

You might want to speak with Ken Doo regarding wedding shots in IR as I know he does some of that.

Don
 

Don Libby

Well-known member
Ben,

Since IR is capture in the red spectrum once you open the files in C1Pro or Adobe you'll see the programs struggle. The file will show for an instant as shot before the program takes over and since it sees the file as red convert it to red. C1 Pro has a little more room to work the white balance and in some instances you can get close to what you captured using a 665nm filter but not close enough. There's much more room when shooting 720 and I've been able to get a very near accurate WB using the color picker in C1 Pro. However not so in Adobe (I use Bridge to sort and open) as soon as the files load in Bridge you can watch as they switch from what was shot to what Adobe "sees" which is red. This is true in the case of shooting RAW and might be in the case of shooting Jpeg however I don't know as I never shoot in Jpeg. Opening a RAW file in (in the case of Sony it's a .ARW) the file looks red with the temperature pegged on the left at 2000 and tint at -74; there simply isn't any room to change. Convert the ARW file using Sony's program to a TIF and open the file and the tempperture is 0 as is the tint.

I've converted 3-cameras now to capture IR and in each case I needed to "wash" the files in the manufacture software before working on them. All 3-cameras were converted to shoot 665nm. I've been playing with 720nm (and shortly with 830nm) by placing a filter on the lens. I've found the same thing going on with the 720nm as I did with 665nm. However, I also found that I can get near perfect color balance using the color picker in C1-Pro and expect to do the same with the 830nm. I've tried doing the same with Adobe and failed.

Shooting IR you must shoot with a custom white balance otherwise you get crap. Opening IR files in any of the usual suspects won't work as the programs were all written to specifications that did not include looking at IR files; thus the little extra work needed.

I'm in the process of working on a couple new articles for here and our blog which will address the need for custom white balance as well as shooting IR with the new Sony A7r and various lenses.

Hope this helps clear it up a little.

Don
 
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GrahamWelland

Subscriber & Workshop Member
Don,

Interesting to hear of your white balance approach and use of native software vs C1Pro for example. Do you use an in-camera white balance calibration and use that as the 'as shot' or are you shooting the scene and setting WB from the RAW in post? In my own case with my IR converted Aptus 65M and Fuji X-E1 I always use a preset that I shot from grass on a sunny day as my reference point.

With the false colour rendering are you getting a better and more intense rendering in the Sony RAW converter vs C1Pro? (This is the one thing I did notice when I used SilkyPix vs C1Pro with my 650nm converted Fuji XE-1).
 

Don Libby

Well-known member
Graham, The camera came with a custom white balance however you know me, I just had to see if I could get it better. I also figured since the 7r has a place for 3-custom white balances I couldn't screw it up (too much).

To me this is a little screwy - IR capture in a red spectrum yet a custom white balance for 665 and 720 should be shot using green foliage. I took a reference shot totally out of focus then went into the menu and followed the clues for shooting a custom white balance. And got an error reading. Just for kicks and gags I went and finished saving the setting to CWB #2 and compared with what Life Pixel gave me. The only difference was the temperature; 2500 from Life Pixel 2600 as shot. I also shot two-identical tests using both settings and much preferred #2.

The really great thing about shooting a mirrorless camera is that you get/capture exactly what the sensor sees. I remember using the 1DSII and seeing what the lens saw and having to peek at the lcd - not so with the 7r; I hardly ever look at the lcd and in fact have it set at the faster rate possible which also aids in battery life.

While using Sony Image Data Converter is a huge PIA (I'm on a 64 bit machine and it doesn't always want to play well and crashes a lot) the extra tie and effort in converting the files from ARW to Tif are well worth it. I've also found that I don't have to wash the files if I use the 720nm filter as there's less false color and what there is can easily be fixed back to what the camera actually captured using the picker in C1-Pro.

Just re-read what you wrote about shooting grass and that's exactly the correct method. If I remember correctly I'll need to shoot a white card when I get the 830 filter. The way I see it is I'll have 2-custom settings; one for the 665 and 720, the other for 830 and keep the 3rd open for location specific.

Don

Note: As I was responding to Graham I also noticed I used the term white balance instead of temperature setting in the response to Ben. I've going in and edited it to read correctly.
 

f6cvalkyrie

Active member
Here's one from the Full Spectrum modified G1 with a 650nm IR Filter
PP included the 'midnight' preset from NIK Color EFEX Pro



C U,
Rafael
 
I'm not surprised that it is a clean green (e.g., grass) that should be used for white balance as, at least at the higher cut-off levels (those not yielding the false color effects), it is green subjects that render as white in black & white conversions. I imagine that this has something to do with green being exactly opposite the color wheel from red, but I would be happy to hear others chime in on this. --Barbara
 

f6cvalkyrie

Active member
Hi, Barbara,

I think it is the chlorophyll in the leaves that absorbs a lot in the blue and red parts of the visible spectrum, but reflects most of the green and IR. That's why our eyes see the leaves green, and the IR camera, equipped with the right filter sees them mostly white or light grey ...

Chlorophyll - Wikipedia, the free encyclopedia

But I could be wrong :)

C U,
Rafael
 
Rafael, thanks for your response; it got me thinking, and I would like to understand this. I began to experiment with IR two years ago, with a Sigma SD-14 with the IR-cut filter removed (easy to do yourself on this camera). With the visible-light-blocking filter attached outside the lens, virtually all my data from the sensor was in the red and blue channels -- nothing or a miniscule amount in green. I got very nice conversions to b&w.
Doing the same with the SD-1, I got much more information in the green channel, and felt the b&w conversions weren't as good. Obviously, the sensors in the two cameras, while both Foveon, are different -- more MP in the SD-1, just for starters -- and the readout from them must be different, too, I imagine, to result in this much difference in the files. I'm sure I need to do more experimenting, but anything anyone can add that would help me understand what is going on would be much appreciated. I have been using Channel Mixer in Photoshop for my b&w conversions. --Barbara
 
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