IR Help please :)

[Lyncca]

I went yesterday afternoon and took a test shot at a park with my IR filter. It seems to have come out alright, but I thought in IR the skies are supposed to be dark? Is it maybe because it was late afternoon? Does the time of day change this, or am I doing something wrong?

I can post the raw if needed. I want to figure out if it's my shooting or processing thats screwy. Thanks!

 

[Arch]

Its hard to tell from this image if your procesing needs altering, but i can tell you IR skies don't always come out dark. As you probably know, if you take any normal image in the right kind of light (generally with the sun behind you) you can achieve deep blue skies as apposed to one with any kind of glare or weaker light source.... the same applies to IR.
The deepest skies i have achieved with IR is when its a very bright clear sunny day and the light direction is near perfect on the subject.

 

[Lyncca]

Thank you for the info. I think that solves it. It was after work, and I was losing sun quickly. It also wasn't an overly bright day to start with.

I'm shooting some waterfalls mid-day this weekend, so hopefully I will get some better opportunity there

 

[Garbz]

Well the deepest skys are achieved when no IR light is passed at all. The sky really doesn't react to IR light. What the issue here is that on a digital camera you're literally fighting one filter against the other. One that blocks IR light and the other that blocks visible light. Effectively this cancels itself out and the end result often looks similar to what you would get if you just simply removed the IR block filter from the camera and shot normal. Your image is made up of visible light and IR light, but the digital cameras are very biased to the IR bit which is why you still get some of that white glow effect.

If your camera had it's IR block filter removed, or you shot IR sensitive film you would get the true effect.

Shot with a 720nm filter (Hoya R72) on Kodak HIE film. No post processing. (on my flickr)

 

[Lyncca]

Thanks Garbz. I'm actually considering converting my D70s after my new D300 shows up, but I wanted to get the process down before making that decision.