![Portrait with a Clumber horse [10/52]
I actually intended to try and do quite a straight portrait and include the horse at the side of me. I stood with my back to the horse with my camera at ...](http://publicenergy.co.uk/Projects/52-Weeks/20100306-1145-0017-Edit/803460292_nQg6M-Th.jpg "Portrait with a Clumber horse [10/52]
I actually intended to try and do quite a straight portrait and include the horse at the side of me. I stood with my back to the horse with my camera at ...")
Infrared FAQ
Most of what I know about infrared photography I found out after trying things. I had read some tips on various web sites and a lot of that was useful, but when it came down to it, it was only the practical experience of taking the photos, playing with camera settings and different methods of editing that eventually led me to a way of doing things.
Everyone has their own way and will no doubt vary slightly or a lot from what I’ll describe below – I don’t consistently follow a set of rules or instructions, I eventually end up editing each photo in it’s own way, but generally speaking, this is what happens.
I’ve been sent so many messages through this web site or via Flickr asking questions about infrared. Every time I end up writing quite long replies and then thinking I really ought to write this down somewhere for when the next person asks – and up until now I never did.
Normally, the advice comes down to two things. If you want that blue sky look, get a filter that cuts of at 720nm like a Hoya R72, and regardless, setting white balance in camera makes the world of difference.
Can I take infrared photos with my digital camera?
The easiest way of testing if your digital camera can see infrared or not, is to pick up a remote control device and take a photo of the transmitter end as you’re pressing one of the buttons down. If you can see the infrared transmitter light up, then you’re in business.
What kind of filter do I need?
Since 2005 I’ve used a Hoya R72 filter. I got that particular filter because it was easy to get hold of and was mentioned as being a good one on various web sites I read at the time. This filter works for me, but there are other filters out there and the results you get will very along with them. The infrared filter actually filters out normal visible light. When you hold one up to look at, it seems to be jet black and you can’t see through it. The R72 allows wavelengths of 720nm and up through it. Infrared has wavelengths between 750nm and 1mm. That means that you’re letting in some red light as well as the infrared light. Is that a bad thing? Well, it depends. If you want to make false colour infrared images with what look like blue skies, then no. If you’re only interested in making black and white images, then a filter that cuts of above the visible range may be better for you. I’m intending to get another filter with different characteristics this year so that I can do proper comparisons. Using infrared you can see a lot more on hazy days and I suspect that a filter that cuts out more visible light will be better at cutting through that haze.
Why do my exposures need to be so long?
Digital cameras normally block some infrared because it tends to make normal light images look a bit crap. When you did your test to see if your camera could see infrared, what you’re actually seeing is the infrared that is left after your camera has tried to filter it out. In practice, with a black filter on the front of your camera, you’re exposure is likely to be around 1 second on a sunny day. This varies from camera to camera though so the best way is to experiment with what you’ve got until you get images you’re happy with. I’ve tried infrared photography on 3 different Canon Ixus cameras, my Nikon D50, a modified Fuji S5600 and a Ricoh GX100 – all of them behave differently.
So, given that exposures will be long, using things like monopods, tripods or Gorillapods is a must. Using the timer so that you’ve not moving the camera is a good move too.
Why do you use that silly looking compact camera when you could use your DSLR?
The short answer: laziness. There are pros and cons for using each. This first image was taken with a compact:
Taken on a different day but more or less in the same place with a DSLR:
Plus points for the DSLR: Image quality
Minus points for the DSLR: Really fussy and hard to use. You can’t see what you’re doing through the viewfinder because it’s blacked out by the filter. So I had to compose the shot without the filter in place, focus, put the filter on and then take the shot. In theory I should have adjusted the focus manually after the filter went on as well. This is time consuming.
Plus points for compacts: You can see what you’re composing with the LCD screen
Minus points: Images not as good as DSLR.
I think if I’m honest, that given the quality increase in the DLSR images, it’s worth the effort if you’ve got the patience. I do wonder if newer DSLR’s with live preview make this easier.
Having compared these two options I use a third option though…
Converted camera?
Above was a section explaining why the exposures need to be so long. That isn’t so much of a problem if you want to take static photos, but try and get photos of people moving and you end up with a blurred mess.
The reason for that long exposure is the built in infrared blocking. A converted camera simply has that blocking screen removed or replaced with something that doesn’t block infrared. The end result of that is exposure times that are almost back to using a normal colour digital camera. This is great for people shots.
I use a converted camera myself but I still use my other cameras sometimes. Those long exposures are great when you actually want that blur – like moving clouds on a windy day.
I’ve taken some pictures and they look red or purple
In all probability, your camera will be set to auto-white balance. Because you’ve got a black filter on the front of it, it’s interpretation of what is white isn’t going to be much good. There are two ways around this: 1. Using RAW files and altering it when you process your image 2. Set a custom white balance in camera before taking your shots.
Whichever way you choose to do it, it came make quite a lot of difference to the image you end up with. The red image below is one of mine from a few years ago. The white balance was set to ‘Tungsten’. That seems stupid on the face of it, but at the time I thought that rather than having auto white balance, if I had a fixed one then at least I’d know it was the same in all of the images I took and make correcting the images easier. Well, that was true, but it’s not as good as just making sure it’s right in the first place.
How do I get that blue sky effect?
You use your editing software to swap the red and blue channels. You usually have a channel mixer somewhere, and in
that you can say make red
blue and make blue red.
You can see in the screen shot that I’m changing the red channel and setting red to 0% and blue to 100%.
I’d then open the blue channel and set that to 100% red and 0% blue.
At that point your image probably won’t look how you’d like, but then you’re down to personal choice and how you tweak it to make it look nice. Typically I might have to use a curves adjustment layer to alter the white point if something that I think should look white isn’t white. This is required less if you set custom white balances when shooting though.
What about Black and White infrared images?
By far the easiest way it to just desaturate the image. I normally have to boost the contrast a little and auto-contrast normally works fine.
This post will be updated and corrected as needed
Esteban, 
Howard and 3 others are discussing. 
Trying To Find The Road Not Ta 1:31 pm on July 9, 2008 Permalink |
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