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Tips on doing IR

PostPosted: Thu Feb 17, 2005 1:31 pm
by gooseberry
Hi All,

This is just a summary of how I do IR with my D70, along with some simple post processing I picked up from reading on the web.


1. Firstly, you'll need an opaque filter capable of blocking visible light and letting through IR. Typical filters for IR work are Hoya R72, Wratten 89B and Wratten 87. You can also experiment with sheets of unexposed, but processed E6 film, but results I've seen aren't as good. Some are darker than others (remove more visible light)

2. On a nice sunny day, head out somewhere - parks or places with lots of trees and vegetation is a good start - along with your camera and tripod. Tripods are a must becuase of the longer exposure required.

3. Do a custom white balance with the filter attached to the front of your lens and pointing your camera to a bright patch of grass or leaves. Use this preset white balance for your images, otherwise your images will come out with a red tint which you'll need to remove in post processing.

4. Compose and pre-focus your image without the filter on (you won't be able to see anything through the viewfinder with most of the darker filters). Attach your filter and take a shot. Check the historgram to make sure you've got a good exposure - be careful not to overexpose as most of the response is in the red channel, and the histogram display is actually the green channel on most cameras.

5. At the end of the day, bring your photos back home and load them up in Photoshop. A simple technique is to do a B&W conversion. Another technique to create a coloured IR picture is to do this. Open up your image. Do a levels adjustment to your liking. Select the Channel Mixer. Select the Red Channel, and slide the Red percentage to 0% and Blue to 100%. Then select the Blue Channel, and slide the Blue to 0% and the Red to 100%.

6. That's the basic process - of course you can tweak the colours etc to your personal preference.

If you have any questions, just ask.

Hope that helps those that are looking at doing some IR. Look forward to seeing a lot of creative IR shots on this site.

PostPosted: Thu Feb 17, 2005 5:32 pm
by Killakoala
Thanks for that Gooseberry. I never even thought about doing the white-balance thingy beforehand with the filter on. ;)

Would you be able to supply some of your favorite links to what you consider to be the best websites you have used for learning good IR please?

PostPosted: Thu Feb 17, 2005 6:47 pm
by gooseberry
Killakoala wrote:Thanks for that Gooseberry. I never even thought about doing the white-balance thingy beforehand with the filter on. ;)

Would you be able to supply some of your favorite links to what you consider to be the best websites you have used for learning good IR please?


No worries... I'll post the list when I get back home tonight.

PostPosted: Thu Feb 17, 2005 10:11 pm
by Killakoala
Thanks mate ;)

PostPosted: Fri Feb 18, 2005 2:45 am
by gooseberry
Steve,

Here are a few sites that I've read that I've gotten information and grabbed techniques from.

http://www.naturfotograf.com/UV_IR_rev00.html#top_page
http://www.a1.nl/phomepag/markerink/mainpage.htm
http://www.outdooreyes.com/photo94.php3

That last one has the channel swapping technique which I use.

PostPosted: Fri Feb 18, 2005 2:49 am
by gooseberry
Another note about IR. Sometimes you will see "hotspots" in your IR images - these are spots in the centre where the image has a brighter white or yellowish colour to it. These hotspots seem to be lens specific - certain models of lenses will exhibit these hotspots whereas other lenses will be fine.

PostPosted: Fri Feb 18, 2005 6:54 am
by Killakoala
Thanks for the links

As for the hotspots, i think they are caused by the sun on the filter. I noticed the spots and then used my hat to prevent the sun shining in the filter and it seemed to get rid of the flares. I will do a test in complete shade to see if it is correct.