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108KiB, 800x800, IR LED.jpg

Anonymous Mon 12 Dec 2016 16:47:38 No.2981884 View View Reply Original Report

Quoted By: >>2981892 >>2981895 >>2981912 >>2981914 >>2983131

Anyone had any experience photographing in the IR spectrum or using IR for illumination?
I'm guessing that when you're using a regular digital camera it is best for the IR illuminator wavelengths to be as close to 700nm as possible, but I'm having a hard time finding any below 850nm.

Anonymous

Anonymous Mon 12 Dec 2016 17:10:33 No.2981892 Report

Quoted By:

>>2981884
Normal digital cameras have a filter specifically designed to block IR.
So if you're serious you'll have to remove this filter or buy a specialist camera that doesn't have one.

With an unmodified camera you can capture IR from sunlight by using a lens filter that blocks all light except IR.
But it required long exposures since the camera is so insensitive to IR, and I don't think it's even possible with a weak IR LED.

Anonymous

Anonymous Mon 12 Dec 2016 17:16:04 No.2981895 Report

Quoted By: >>2981914

>>2981884
That is because with a normal non-modified camera the long end of the spectrum it can see is not really IR, it is NIR or near IR. Somewhere between IR and visual. Actual IR wavelength is measured mostly in micrometers. As in over 100nm to 9000nm and more.
It's like your camera can only see in blue but all you have is red.

Anonymous

View Same Google ImgOps iqdb SauceNAO Infra 15 15.jpg, 1003KiB, 1440x959

Anonymous Mon 12 Dec 2016 17:53:04 No.2981912 Report

Quoted By:

>>2981884
Shot several rolls of IR film, it's one of my favorite things to do early summer. All in daylight though. Regular flashguns can be used to provide illumination, but god only knows what the correct exposure settings are. I've noticed that tungsten-halogen car headlights send out a lot of energy in near IR wavelength, so a powerful halogen lamp could work, like the ones used at construction sites. They produce a fuckton of heat though. That is unless you require a "black" light source, in which case I guess you'll have to find an IR illuminator that works in the spectrum your camera is sensitive to. Some old military IR illuminator might be close enough, I assume modern ones work further down the spectrum.

!kurwaRB7YU

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!kurwaRB7YU Mon 12 Dec 2016 17:58:50 No.2981914 Report

Quoted By: >>2981916 >>2982040 >>2982043

>>2981884
The standard procedure is to use a lightource that contains a large ir portion (big incandescent lightbulb) and just filter it down to whatever you need - i.e. with a 850nm ir-cut filter. A 150W lightbulb gives off more IR than a specialised array of several LEDs will - unless you want to take photos in absolute darkness for some reason (wild animals? creepo kys voyeur sexstuff? nighttime concert ir flash candids?) - usually one doesnt mind seeing the shot subject with their own eyes while composing the shot.
>>2981895
near IR is still a type of IR. that's like saying your camera isnt shooting in the VIS spectrum when it can only capture green. semantics and/or nitpicking for some pointless reason.

Anonymous

Anonymous Mon 12 Dec 2016 18:01:16 No.2981916 Report

Quoted By: >>2983230

>>2981914
no one wants the opinion of a retarded slav with bromide drags in all his photographes

Anonymous

Anonymous Mon 12 Dec 2016 21:24:48 No.2982040 Report

Quoted By:

>>2981914
>ultraviolet
>cool as fuck glasses

Anonymous

Anonymous Mon 12 Dec 2016 21:28:33 No.2982043 Report

Quoted By: >>2982050 >>2982070 >>2982290

>>2981914
Huh, glass is transparent to IR.
My dad told me regular lenses would be opaque to IR, but it looks like that's wrong. I guess it can depend on the glass and the wavelengths.

Anonymous

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Anonymous Mon 12 Dec 2016 21:50:27 No.2982050 Report

Quoted By: >>2982069

>>2982043
Yeah, opaque glass is a myth, near IR goes through, although at certain angles it seems to reflect off the glass more than visible light does. With water it can give off amazing reflections at an angle, or just make the water appear almost jet black.

Anonymous

Anonymous Mon 12 Dec 2016 22:32:13 No.2982065 Report

Quoted By:

Many Nikkor lenses even indicate an IR center of focus.

Hot damn, I gotta get me some of that IR film and a 780 (or what's it called anyway) for summer 2017. Guess it'll be manual guestimated long exposures on the F5 though, unless it meters IR. Not like IR is worth anything outside of sunlit stuff anyway, so easymodo from a practical standpoint.

Any experiences with near-IR film, like Rollei's Superpan? Flickr indicates that it'll make trees look quite intense. What about with filters; yellow, green, orange?

Anonymous

Anonymous Mon 12 Dec 2016 22:39:51 No.2982069 Report

Quoted By: >>2982072

>>2982050
sorry if the question is stupid, but I'm guessing that IR film requires a special process to develop right? Or is it regular black and white/C41?

!kurwaRB7YU

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!kurwaRB7YU Mon 12 Dec 2016 22:42:58 No.2982070 Report

Quoted By: >>2983102

>>2982043
maybe he misremembered and thought of UV - optical glass starts heavily cutting off ultraviolet around 350nm and for anything shorter you need quartz or fluorite optics. Long far infrared also transmits poorly or at all, but those ranges are far beyond any CCD's wavelength range.

There is a plethora of very comprehensive and interesting ir digital/film photography websites out there, I urge you to do some research beyond /p/.

[uv+~800nm ir on an old digicam with a poor uv/ir filter through wood's glass from a tanning bed heater]

!kurwaRB7YU

!kurwaRB7YU Mon 12 Dec 2016 22:45:33 No.2982072 Report

Quoted By: >>2983108

>>2982069
regular development. it's still the same type of film, just sensitized for a wider spectrum. I read about ORWO glass plates sensitized for 1050nm, even.

Anonymous

Anonymous Tue 13 Dec 2016 08:45:42 No.2982290 Report

Quoted By: >>2982314 >>2982327 >>2983195

>>2982043
potentially misremembering from glass being opaque to UV light (which is the reason a screw-on UV filter is essentially 100% pointless unless it's used to stop the front lens from being scratched so you can resell it as like-new condition)

Infrared light is blocked in the camera itself for almost all bodies, which is why a screw-on IR filter would be completely pointless and why they're almost never sold.
A few bodies left the IR-blocker out, but this let people take it to the beach and take illegal voyeur photography that sees through women's no-tan-line bikinis, so they were forced to stop selling unblocked bodies.

Anonymous

Anonymous Tue 13 Dec 2016 10:05:10 No.2982314 Report

Quoted By: >>2982327

>>2982290
The IR cut filter doesn't cut the IR right away, there is some light let through in NIR range, this is why on most DSLRs you can do some IR with an IR filter and loooooooooong exposure

!kurwaRB7YU

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!kurwaRB7YU Tue 13 Dec 2016 10:57:44 No.2982327 Report

Quoted By: >>2983188

>>2982290
>Infrared light is blocked in the camera itself for almost all bodies, which is why a screw-on IR filter would be completely pointless and why they're almost never sold.

This is why you don't exclusively rely on /p/ for your information, kids.

>>2982314
unmodified Canon Powershot 570A required 4-6s exposures in full sunlight at iso100 f2.8, minolta dimage Z1 - 7s.

Anonymous

Anonymous Wed 14 Dec 2016 19:33:16 No.2983102 Report

Quoted By:

>>2982070
>maybe he misremembered and thought of UV
Actually he thought of organic glass, which I guess some lenses are made of.

Anonymous

Anonymous Wed 14 Dec 2016 19:51:29 No.2983108 Report

Quoted By: >>2983116

>>2982072
thanks very much, will definitely try, seems quite an interesting way to shoot black and white really

!kurwaRB7YU

!kurwaRB7YU Wed 14 Dec 2016 20:17:30 No.2983116 Report

Quoted By:

>>2983108
remember that without an ir-pass filter ir film behaves like regular bw film with weird red tone rendering - the nominal iso (i.e. rollei ir 400) is for daylight filterless - you have to subtract a few stops for actual ir photography. as far as I understand it. It's unintuitive like that, thankfully there's a fuckton of online resources and guides for it. Film is definitely a good way to get a taste for IR without going all in with a modified digicam.

Anonymous

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Anonymous Wed 14 Dec 2016 20:47:00 No.2983131 Report

Quoted By:

>>2981884
This guy posted some photos using IR flash a while back. Worth a look.
https://danielteolijr.wordpress.com/category/world-leader-in-infrared-flash-street-photography/

Anonymous

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Anonymous Wed 14 Dec 2016 22:37:21 No.2983188 Report

Quoted By: >>2983192 >>2983195

>>2982327
Those are IR-pass filters. He's talking about filters that block IR (hot mirrors) which are almost never sold because they're only needed for really early digital sensors or weird stuff like the Leica M8 sensor.

Notice how the filter you posted is black because it blocks visible light, but pic related is transparent because it blocks IR but not visible.

!kurwaRB7YU

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!kurwaRB7YU Wed 14 Dec 2016 22:48:33 No.2983192 Report

Quoted By:

>>2983188
I completely misread your post and deeply apologise for the tone of my reply.

These are indeed uncommon and expensive.

!kurwaRB7YU

View Same Google ImgOps iqdb SauceNAO 20130206_162735_613099.jpg, 131KiB, 600x704

!kurwaRB7YU Wed 14 Dec 2016 22:51:44 No.2983195 Report

Quoted By:

>>2983188
I completely misread his post and deeply apologise >>2982290 for my reply.

These are indeed uncommon and expensive.

Anonymous

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Anonymous Wed 14 Dec 2016 23:00:28 No.2983198 Report

Quoted By:

Has anyone here heard of any success using RGB lens filters to convert an infrared image to color using the three-color method?

Anonymous

Anonymous Wed 14 Dec 2016 23:46:32 No.2983230 Report

Quoted By:

>>2981916
Isi kill urself

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