BetterPhoto Q&A
Category: New Answers

Hi-Dynamic Range Imaging

Recently I’ve taken some interest in (HDRI) or High Dynamic Range Imaging.
I am far from being an expert and probably don’t even qualify as a novice yet; but thought some might be interested in this relatively little used technology; at least for us photographers. I’ve been reading about this technology for some time and just thought it was time to teach this old dog some new tricks. LOL

The program I used is called “Photomatix.” I am still using the trial version and as yet am not totally sold; but I think with time I might be based on what I‘ve seen. There are many images on the internet demonstrating this technology; some quite impressive.
I won’t go into all the adjustments within the “Photomatix” program, but suffice it to say, there are many possibilities. The learning curve is far less demanding than Adobe Photo Shop. This program is NOT a substitute for post processing software like Adobe or any other. It is designed to do one thing only with some basic manipulations to color and contrast.

Why try it?...Like many; I have experienced that all too often exposure impossibility. You know, bright sunny day with beautiful clouds embedded in a deep dark blue sky..AND a pure white sandy beach with all sorts of cool patterns. The f/stop range may traverse at least 6 stops or more. Really no way to expose this with just one shot..at least not w/o graduated ND filters etc...
Graduated ND filters are great in the right situation, but fall short when the dynamic range of the photo encompasses the horizontal aspect being covered by the Graduated ND, like a white seagull flying in the (deep) blue sky.

Well, like many again, I had to resort to shooting at least TWO photos; layering them in photoshop, and then doing some fancy dodge & burn or layer erasure proceedures. A tad time consuming.

(HDRI) claims to have solved this problem in one fell swoop; well, almost.

“PhotoMatix” will combine several photos; shot at various exposures, (Under, spot on and over exposed. Apparently, one can expose for the darkest area of the image and then all the way to the brightest..with many exposures values in between the two extremes.
Your exposure values might look something like this: (-3,-2,-1,0,+1,+2,+3) or more extreme (-6,-4,-2,0,+2,+4,+6)
No way a digital will cover that dynamic range in one shot.

Through a technique called “Tone Mapping”, the program will (smooth) out the highs and lows and mid ranges to produce a balanced photo. I began reading the math behind this technology and soon went on to trying the program. LOL Yikes!

I played around with this program a little this evening. I am impressed to say the least.

I am uploading two photos..Please; no artistic critique, that is not my intention. LOL
The first image is the tone mapped photo in it‘s completed form. The second is a extreme crop showing the amazing dynamic range.
I tried to shoot this scene with one shot..no matter what exposure I used, I could NOT capture this (Range.) Even using dodge & burn with layering and blending; to get all this dynamic range would be almost impossible and no doubt would take a very long time if you could.

I took 5 exposures in TIFF format and changed only the shutter speed to produce very underexposed images to very over exposed images. The values were: Matrix metered as:
(-4,-2,0,+2,+4)

The photos are untouched. No Adobe post processing. I had no interest in white balance in this test as it has little to do with (HDRI)
Post processing IS often necessary to refine your results.

I hope to gain more experience with this in the near future.
From what I’ve read, (HDRI is not a cure all, but it sure seems like it could come in handy on many a shoot.

All the best,

Pete

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March 20, 2008

I like to have seperate layers for each image so I can tweak each layer as I want before merging but I do not find Photoshop clumsy or limited to use for this process.
Here is a link with more info - http://blogs.adobe.com/jnack/2006/11/creating_profes.html

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March 20, 2008

I've been doing quite a bit of research on the strengths and weaknesses of both systems.

I have CS as well and hope to do some comparisons soon.

It seems HDR is a bit of black magic coupled with some intuition as a guide; unlike doing basic exposure comps. LOL

Photomatix seems a great alternative for those not interested in the expense with CS.

I am curious as to the "tweaks" you perform? Let's take the most underexposed and over exposed image as an example..what "tweaks" do you perform? Contrast? Saturation? Gamma?

all the best,

Pete

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March 20, 2008

everything you need to know

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March 20, 2008

I am going to try this again using a circular polarizer so that I will not only have under & over exposed images, but a variance of color/contrast with the polarizer as well. Aint technology fun ?

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March 20, 2008

I haven't tried it in Photoshop but I do have Photomatix and it's a lot of fun, although I have a lot more to learn. I mostly use tonemapping, although I've done a few proper HDR images (5 or so different exposures).

One problem with it that bothers me is the serious noise issues that result. I'm not sure they can be completely resolved, from the brief bit I read about it.

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March 21, 2008

I'm not really sure I can agree with your opiniion concerning noise.

As I stated in my first post, I am hardly an expert with HDRI, but based solely on what I've seen with my very first test, I can not agree with you on the noise.

If you look at the cropped image I posted, I see very little noise. The crop is extreme too, 400%!

I've also seen online examples that are quite impressive..at least to me.

As far as using HDRI for people photography, I'm not sure why one would? The dynamic range of a person is not to high at all.

The jury is still out in my opinion.
I hope to post updates in the future...so who knows?...Maybe HDR is cool..maybe not.

Perhaps an expert in HDRI might chime in.

Pete

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March 21, 2008

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March 21, 2008

As for HDR portraits, they're all over the web, including here on BP. Carlos Malvos (? or maybe Malvas) is one photographer who does HDR portraits--at least they sure look like HDR. You can see them at Photoworkshop.com, if not here. I'm not saying it's inherently bad; it's an acquired taste, maybe, and not for everybody. And in less-skilled hands, it can look almost grotesque, imho.

Your images posted in this thread look fine to me, as far as noise goes. Maybe it's a matter of how you use the tonemapping and/or HDR functions. We've both indicated we need to learn more about the program, and you may just be better at utilizing it than I am. :)

Having said all that, I do think HDR is cool. :)

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March 21, 2008

First, I am NOT disparaging Carlos Malvas' work, which is fantastic. Some of his portraits look like HDR to me, but I can't be sure if they are. In general, they are done with a much "lighter" touch than many others I've seen; I only mentioned his name because it was the one I remembered offhand. That's not really fair to him, though, since I don't know the facts, I'm just guessing he uses this technique.

Secondly, Pete, I just went to the Photomatix website to verify what they say about noise, and it appears that it's more of an issue with tonemapping than true HDR. Of course it also depends on other factors, as well, which brings me to ...

Third, I noticed you have a D300, and I have a D70s ... I'm guessing my camera shows more noise all around than yours does. Maybe not, but it's a thought... :)

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March 21, 2008

You might be right about the noise due to camera differences.

As I mentioned earler, I'm not ready to buy the program yet. LOL

Art to film to digital and now HDR? ..OH nooooooooooo. LOL

all the best,

Pete

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March 22, 2008