IR HDR?

[zombiemann]

I've been playing around with IR photography lately. It can be a bit.... tricky trying to get the exposure right. As such I've taken to shooting 3 bracketed shots to give myself a better chance of capturing the right exposure. With the IR filter on the camera the built in metering is worthless, so is autofocus. And while I understand the fundamentals of exposure/aperture/ISO/etc even an educated guess is still a guess. I did some IR work today and got the bright idea to try stacking one of my brackets. I went through and made sure I had a consistent white balance, swapped my red and blue channels as usual when processing IR shots (gives it a blue sky and makes it look less like a film negative). I then fed them through photomatix. The first image is the "neutral" exposure of the stack "as shot" with no white balance or anything other than convert to jpg and resize. The second image is stacked and tone mapped to B&W. The third is a color tone map that I think works well for this pic. Keep in mind, this is not shot in visible light, so the fact that it looks "weird" is part of the goal.

 

[Bynx]

There is some strange stuff going on where details are gone replaced by a solid gray -- across the road into the bushes. You cant mean that was your goal?

 

[zombiemann]

no, that wasn't my goal. It's not actually a road but a mowed grass path, my best guess that is a "ghost" like effect of extended exposures with the breeze ruffling the grass. Sort of like when you take a long exposure of the surface of moving water. Other than that part though, what do you think of the over all effect?

 

[unpopular]

Maybe try taking this further, an IR stack with a Visible stack to represent a wideband image?

 

[that1guy]

try focusing before you put your filter on thats what we do before day time long exposures

 

[mjhoward]

These don't look at all like IR to me. You said you put an IR filter on the camera, but did you remove the IR cut-off filter from in front of the sensor? In an IR image, the vegetation should be white and it isn't white in any of your photos, including the one you said was "as shot" with nothing done other than convert to jpg.

 

[zombiemann]

I do focus before putting the filter on, sometimes the act of putting the filter on knocks it out of focus just a hair. Not enough that I notice on my LCD when reviewing but when I get home and start processing I end up scrapping them.

Mj, I have not done the full conversion on my camera. I don't have the spare money for a dedicated IR only body. My camera doesn't have much in the way of IR cut off as it is. It's weak enough I can point a tv remote at it without a filter on and see the light from it. I am not sure why the vegetation is coming out so dark. I have other shots using the exact same method I took these with that it did in fact come out white. Actually there is a thread over in "Landscape and Cityscape" where I posted pics I took that came out as you mentioned. http://www.thephotoforum.com/forum/landscape-cityscape/295054-playing-my-new-ir-filter.html

 

[Bynx]

I guess I just cant appreciate what you have done. IR is just something I dont have any interest in.

 

[zombiemann]

So you have no interest in IR yet you felt compelled to come comment? I am truly confused...

 

[DGMPhotography]

Well he's interested in HDR, not IR, but seeing as this is a combination of both, he would have some sort of interest I would assume.

 

[Bynx]

Exactly as DGM says. Since this is the HDR forum and I am greatly interested in HDR my comments would be towards the HDR aspects of your picture. The area of blankness I mentioned is not a result of a breeze blowing across causing absolute loss of detail and creating a totally single gray tone. I have shot with IR film before and got decent weird results with vegetation turning white and people looking like ghosts, so Im familiar with IR. I quickly lost interest after a couple of rolls. Looking at your efforts, hasnt made me miss doing it again. Keep trying, you might get it some day. Just not today. I just checked out your other posts and I see you have no problems with blank areas that you have here. Whatever you have done different here, doesnt work. The images in Playing with your IR filter look in focus and somewhat ethereal with the weird colors. Again not my cup of tea but if you like that kind of thing, go for it.
On closer examination that blank area is only on the B&W and the Color version and doesnt appear in your red one so its caused by something you are doing and not what someone higher up is doing.

 

[zombiemann]

Bynx, I'm not sure what exactly caused the issue but it was something in photomatix. No matter what I tried the trouble area was there. I merged them in photoshop and got a much better result. A couple of clouds have a weird edge to them but the path looks about a lot better.


Here is another stack I tried from a different scene that I think turned out fairly well

View attachment 17553

 

[unpopular]

Just because it doesn't "look like" an IR doesn't mean it isn't an IR. The question should be if the image is interesting or the technique worthwhile. I think combining HDR with IR is an interesting persuit, though I am not crazy about the false color aspect.

Whether it looks like how an IR "ought to look" is completely irrelevant.

I never much cared for commercial HDR applications, their proprietary tone mapping I think is often unreliable, and as a general rule I think exposure fusion is a better approach.

google "enfuse gui".

 

[zombiemann]

Thanks Unpopular. I'll spend some time over the next couple of days playing around with enfuse gui.. looks like its got a bit of a learning curve but I think it will be worth it.

 

[unpopular]

It's only a learning curve if it doesn't work with the default settings. 99.95% of the time the default work out fine. It's really a no-brainer in most cases, and works very well.

One nice thing about enfuse is that it actually tends to decrease noise, rather than increase it. It doesn't really change so much change the data it's provided, but fuses the existing data into one image on a local level. Tone mapping OTOH makes a high depth image, and then adjusts it to fit. Tone mapping is inherently subtractive while image fusion is additive. (though the combination into a single HDR source is additive, of course)

The uncompressed output files are true 16 bit TIFFs, so provided that you feed it good data, you end up with significantly more data than you started with in any one exposure. Many tone mappers (not all) produce only 8-bit images.