For those of us interested in getting the most out of our digital photography, I pass along the following links:

What ARE HDR or High Dynamic Range images? Perhaps the dawn of a new era.

In computer graphics and cinematography, high dynamic range imaging (HDRI for short) is a set of techniques that allow a far greater dynamic range of exposures than normal digital imaging techniques. The intention is to accurately represent the wide range of intensity levels found in real scenes, ranging from direct sunlight to the deepest shadows. - Wikipedia page on HDRI

HDR in Photoshop CS2 and another explanation (and a third). Note that most of these seem to be based on combining multiple shots of the same scene at different exposures. This is not optimal for stormchasers, where the storm is evolving/moving. The same thing should be possible with various "shots" extracted from a RAW file. This last link promises a tutorial on "building an HDR image from a single RAW file, soon!". I look forward to seeing that.

Soo Photography tutorial

PhotoMatix: HDR photo software & plugin - Tone Mapping, Exposure Blending & HDR Imaging for photography and a Flickr tutorial on using Photomatix (along with tutorial Part 2. Examples of the guy who produced this tutorial's work. The Flickr HDR pool.

This is bound to be somewhat controversial. What say you?

Darren Addy
Kearney, NE

That's one of the benefits of bracketing exposure... Most dSLRs will let you bracket -- meaning that it'll take one shot that is well exposured (per the auto-exposure sensor on the camera), one shot that is underexposed (the amount is usually user-settable), and a third that is overexposed. You can set these as layers, and use masks and transparency to 'overlay' the three images on top of each other, letting you "make" an image that is probably more accurate relative to how our eyes saw it. I've never really done this, but I suppose it'd be most practical during structure shots (not when the adrenaline starts going during a tornado, when I'm too swamped trying to videotape, take pictures, look at road options, etc).

I feel so ignorant for not knowing about this, considering what a freakin' nerd I am and the fact that using Photoshop is part of my job. Guess I'll be filling up the CF card even faster now with all of those bracketed shots! :)

Jeff,

I think what you're talking about here is "Blending" the different exposures rather than the HDRI process. From a cursury glance at the articles, this is a software process that starts with the "Blending" process and somewhere adds something within the programming.

I've used blending several times in photography. Not bracketing though. I use it frequently when shooting waterfalls, or areas with great differences in contrast. I espose the first shot as I would normally expose just about any shot that I take. I use all the standard techniques, light meters, etc. and try to pule a really nice shot. This is my baseline I use for comparison.

My second shot is exposed for the highlights. Basically, I want a good exposure where the highlights aren't blown out. It's deliberate and a new set of settings within the camera. Shutter, Aperture have changed to meet the needs to properly expose the bright area. I'm not worried about under exposure here. The shadows come in the next step.

The third shot is done the opposite of the second. I am now setting the camera to properly expose the shadow areas. I do worry about underexposure here as I want to see what's in the shadows rather than hiding it. I am not worried about over exposure as I have that properly exposed with the previous shot.

About the only thing that stays the same is the White Balance. I will also leave the C-PL Filter in it's position if I'm using one at the time.

I take the two photos and "blend" them in photoshop. I use the various masking techniques that have been around a while to do this. The HDRI goes way deeper into the tones and other areas of the image I don't deal with. Obvioulsy, the HDR! produces a very nice image.

Just to follow up on what John said: What are the differences between Exposure Blending and HDR merge/Tonemapping?

Darren Addy
Kearney, NE

FWLIW, I've got no problem with this sort of image combining, IF the images are taken concurrently, or in quick serial succession. In the end, you can wind up with an image that is actually more "accurate," in that it's closer to your eye's perception. Outdoor Photography(?) published an article a month or two back, arguing that a merged image is much truer to 'reality' than a similar scene that had been dynamically compressed using a fill flash, split-ND, or other artificial means.

(When people start combining subjects that are temporally or spatially seperate, the whole concept of a 'photograph' goes out the window. Cut-and-paste lightning and photoshopnadoes are just plain lame.) :angry:

I'm planning on trying a dual-camera setup come monsoon season. Nighttime lightning scenes contain monstrous dynamic range and it can be very tricky to meter/guess a good compromise exposure. I'm going to tery two (film) cameras, identical lenses, and equal, simultaneous, exposure lengths. Will vary the aperture on each camera, attempting to retain more overall tonal detail.

-Greg

That's kinda cool I'll have to try that. I personally like combining pictures you can see from first page on the website. I just don't like it when people pass doctored photos off as undoctered. However, photography doesn't go out the window. Some of the most well know photographers play with there photographs. The question is when does playing with photographs not make it photography? Personally I think that's a personal choice, because to some degree all pictures are "played" with. I mean you choose an exposure or frame that can contrast or emphasize something may not seem real. I took a picture once with a gumball and a contrail with a high flying plane. The camera store thought it was space scene.

When someone has the time could someone on ST maybe write up a short tutorial on blending photos? I have tried this on photoshop but cant ever seem to find the blending thumbnail that is supposed to be there.

Jason, try this site. It's about the best explaination and way better than I can explain.

Luminous Landscape Blending

I've been searching for more info on creating HDR images from a single RAW shot. This should be possible since a single RAW image contains all of the dynamic data found in a series of bracketed JPEGs. (Note that I have not done this myself, as I don't even own a "real" digital camera that shoots RAW yet... but it is definitely on my list). :P

The big advantage to doing this from a single RAW shot is that: you just need one image, so no need to use a tripod, no need to remember to auto bracket and it will also work if the subject is moving. Much more what "fits the bill" for a stormchaser's requirements. :D

Step 1 is to a take your RAW shot and export (Save As...) some 16-bit TIFFs from it at various EVs. It sounds like most RAW processing software should do this, but if your's doesn't you can use the FREE RAW Shooter Essentials. (If you don't yet have RAW Shooter Essentials, I highly recommend downloading it NOW).

If you are using RAW Shooter Essentials, I can break down Step 1 into the following:
a. open your RAW file in Raw Shooter Essentials (the free version suffices)
b. choose "none" from the "metadata" drop-down box
c. change the exposure as you like (remember the EV - write it down for each image)
d. save as tif 16 bit
e. repeat for other EVs as you like

Now you have a series of TIFFs that are different EVs (example set: 1.5 under, 1.0 under, Normal, 1.0 over, 1.5 over).

Step 2: You are going to combine these images with HDR software to achieve the results you want. While PhotoShop CS2 has a plug-in for this, from everything I've seen you get better results (simpler too) from Photomatix Pro (a free trial version is available which will watermark your images, but would be a good way to test this whole process out without spending ANY moola). The Flikr tutorial (Part 1 and 2) in my original post show how to do this. EDIT: and here's another nice tutorial in PDF.

Since you have multiple EVs, you can use BOTH Photomatix's exposure blending AND tone mapping capabilities to create your HDR image. If you want to do tone-mapping ONLY you can skip Step 1 above and do that from the Single RAW image without making multiple EV copies. See the Photomatix FAQ for more details/tips. Also, if you are interested in doing tone mapping only, Photomatix is available as a Photoshop plug-in instead of buying the full-fledged standalone program (which is available for Mac or WIN).

Some of these HDR images look too "plastic-y" to me. The Flickr tutorial says that if this is the case you can just dial down the "Strength" applied to the HDR conversion (in Photomatix).

If your camera does not have RAW capabilities, you can still create HDR by either manually bracketing multiple shots or using the autobracket setting (if your camera has one). This will require the tripod and will work best on a non-moving subject (.etc).

There are other HDR software tools out there, but it certainly appears to me that Photomatix is the product to beat. See: Artizan and HDR Shot (which I believe is free for academic use)

Hope you find this useful and post some of your results!

Darren Addy
Kearney, NE

Darren,

As much as I would like to believe so, I just can't see a single image having all the information required to do a true blending in either the more traditional manner or HDR.

Once hightlight detail is lost on an over exposure, it's lost. It works the same way with film. You over expose it, that's it, the detail is lost.

Underexposure works much the same way, but you can generally recover more detail on the underexposed shot. The detail washes out as you increase the brightness to get the detail, but it's way better than the alternative.

A single image, be it RAW, TIF, or JPG, simply doesn't have the dynamic range available to do this. Hence, the blending procedure of 2 or more different exposures. It also depends almost entirely on the range of the CCD or CMOS sensor and how much information it actually captures. Though it's agreed that capturing in RAW will capture more dynamic range information, I don't know of a consumer image sensor yet, that will capture what the human eye captures and it able to discern. That's the theory behind the blending and HDR processes we see here. They are attempting to take several exposures and create an image as close to what our eyes perceive when we look at the scene.

Example: When you walk into a room, you are generally able to "see" just about anything you look at whether it's in bright light, or a shadowed area. Our eyes and brain automatically adjust everything to enable us to "see" everything we can.

A camera isn't able to do this. is isn't able to adjust everything to capture as our eyes do. It's a single image. That's why we take the multiple images and "blend" them to get as true to what we actually see.

John,
According to the Photomatix FAQ I linked to in my last post, you are identifying the correct issues and depending upon the dynamic range of the scene (and the exposure used to capture the single RAW file) you may not be able to match what you can do with multiple exposures. But with some scenes you can. Also if you are only interested in using the tone mapping functions you can work from a single RAW (granted the exposure blending would probably be necessary for storm shots).

I have no RAW files to try it with, so this all Book Learnin' at the moment. I'd love to see some of you with RAW storm files to try the trial version of Photomatix and post some results here. (And I'm probably not the only one) hint hint. ;) Share those 'oliday shots (wink wink, nudge nudge)!

Darren Addy
Kearney, NE

Great discussion on HDR and digital photography. A lot of landscape scenes, especially the sunsets/sunrises or any subject (i.e. a supercell updraft) facing the sun will have a fairly huge dynamic range equivilent to a huge number stops of light (maybe 9 or more stops!). I am finding more and more with my RAW conversions, that as long as you do not blow out any highlights (or very few pixels at 255,255,255) in a contrasty scene, I can get a pretty good "blended" exposure from one RAW image up to about about 6 or 7 stops of light in one scene. RAW is pretty darn powerful and it's amazing what you can recover deep in shadow if you are exposing more towards the highlights. Beyond about 6 stops of luminosity contrast, it's almost impossible to recover deep shadows if you expose for the highlights (e.g. a bright sky) even with RAW exposure compensation. There is a limit, but RAW exposure compensation is an amazing thing as long as you have at least *some* shadow information and you expose the highlights almost to the clipping point. I have turned a number of my storm photos into great pictures from one exposure using a very simplified HDR method of blending a +1.7 EV (for the ground) a +0 (for the main subject, like the storm updraft) and a -1.0 EV for example to recover some washed out blue sky. Here's a result from one such manual HDR:

http://photos.photosig.com/photos/63...8170bc0404.jpg

Here is another from last week's chase in OK where I had a hard time with light contrast of a supercell updraft facing the sun. This one I used two blended RAW exposure compensations (I think a +0.3 and a -1.0)

http://www.underthemeso.com/gallery2...2/_DSC1777.jpg

I use RawShooter Premium 2006 which is an *excellent* RAW converter. The premium version allows for detailed white/black point setting of the RAW data using curves/levels (which the free version doesn't allow). It has really enhanced my workflow, and I'm in progress now of re-processing much of my 2005 storm photos since I have only used RawShooter Premium since about December. I use Paint Shop Pro X to blend my exposures and do all the final contrast/saturation tweaking as well as noise reduction and resize/unsharp mask.

Mike U

OK, here's an old one done with 6 images that were bracketed rather than properly exposed. It's also a vertical stitch.

The first three images were of the upper portion of the storm and the next three were of the lower. The entire sequence of images was taken in about 4 seconds, so the storm motion wouldn't show up.

This is about the only one I have online. The others are all printed and archived over to DVD. Too bad, I 've got a great one of a canoe trip in Arkansas a couple of years ago.

http://www.pbase.com/okie34/image/29435280.large.jpg

Wow, great stuff guys. I'm guessing that these are examples of the exposure blending only? Or did either of you try the tone mapping also?

I'm also really curious to see some examples using the Photomatix way (including the tone-mapping).

Keep it coming guys!

Darren Addy
Kearney, NE

After looking at that photomatix site and reading their descriptions of exposure blending and tone mapping... I like to think that what I am doing in my work is applying both methodologies manually, I guess. I am a stickler for trying to make my photos appear as close to how I remember seeing the scene with my own eyes. Unfortunately, it is my experience that algorithms that do HDR automatically are not flawless, and can make the photo look rather strange in some cases. I do everything manually when it comes to blending. This basically means using a layer mask and paintbrush tool of various opacities to create my manual HDR photo. I love the post-processing stage in digital photography; I am allowed the ultimate flexibility in how to make my photos represent the scene how I saw it. The same is true for complex stitching for panos. I do that manually with layers/masks too... all in PSP X. My opinion is, learn and master layering/masking techniques and use the paintbrush on a mask to your advantage. It can do wonders :)

Mike U

Darren,

I'm only blending. No tone mapping or real extra or Uber deep processing. I don't think PS7 allows for the tone mapping anyway. Or it's simply deeper than I care to delve.

Mike,

Oh man.... Simply awesome. That first one, I would almost accuse of being faked, but I know better :D

You know, as far as Storm Photographers go, I tend to believe that this board has some of the best in the world. You folks that pull it off consistantly are my inspiration. I get one or two really good shots each year, where some get 3 or 4 really good shots each storm.

I may have totry some of the stuff I'm readnig about and work more in RAW/TIF formats a bit more.

The fields in SD are really, really green, it's pretty amazing... but the photo may be a bit over processed for my liking... that's one I processed quite some time ago like last summer... before I got Pixmantec RawShooter... That's in the large batch of storm shots from last season I'll be processing more carefully again with RSP and PSPX. The digital noise reduction is much improved now in version X vs. version 9 of paint shop pro. The beauty of RAW, you can always go back to your photos and improve the processing as newer techniques/software emerge :)

Just a heads up that I did some HDR tests today and have posted the results at the blog linked below. I have more to learn about this, but I'm very impressed with what HDR can do. One of the strange things about HDR is that, unless I want to do histo compression, I end up having to selectively put contrast back into images, as the HDR opens the shadows up so much that it almost looks unreal.

Very, very interesting.

An example (there are more on my page):

http://img221.imageshack.us/img221/2...example0gd.jpg

becomes:

http://img62.imageshack.us/img62/874/joshhdr4li.jpg

NIce experiments on every day subject Ryan. Colors are a little more "punchy" that I like, but that's more a personal preference than a detriment. I'm wishing I had PS CS2 at this pint and some nice waterfalls to experiment with. I may try with a fountain this weekend though. Just to see how it come out on blending alone.

Thx John. I liked that program so much I jsut went ahead and got it. This blending is great. It doesnt distort the photo to where it appears fake or tampered. It actually jsut makes the photo appear as if you were there to see it. IMO.

I always use a similar technique of combining exposures for landscape shots. It can be really effective, and is quite easy to accomplish once you learn how.

http://www.deviantart.com/view/29616672/
http://www.deviantart.com/view/28741889/
http://www.deviantart.com/view/25116327/
http://www.deviantart.com/view/23776031/

I have just ordered CS2, so I can't wait to revisit some of these shots using the HDR method and see if they come out better.

Just thought I'd mention that I tried my first HDR storm photo on the 23rd. After some tweaking, here's how it came out:

http://img101.imageshack.us/img101/281/stormhdr9ew.jpg

Hmm, although it looks attractive at first sight, it does appear unnatural to me for the reason that it is impossible to have the land look brighter than the part of sky where the sun shines toward you. The foreground also has no color cast at all, whereas from this position it should have a mostly blue cast because of the sky over/behind it (unless clouds reflect warmer light back from behind you)
Probably you can still use this technique but only if the result seems physically still realistic. This must be possible if the sky is on average 4 stops brighter than the foreground you can crank up the foreground like 1.5 stops, and bring the sky back 1.5 stops. Then watch it if dark sky parts become darker than the land if this was not like that in reality. If not, you are making a nice picture (or horrible, depending on the effect) without realistic meaning - like many postcards I've seen.

Usually utilizing the Shadow/Highlight tool in Photoshop CS with not too large amounts of compensation is perfectly acceptable, even though/because it can't do the same effect.

Oscar

Yeah, I'd definately agree -- it's been very hard so far for me to figure out how to make HDR look 'natural'. The original HDR downsampled file before correction looked even less realistic -- there's just something weird about everything in a backlit scene having nearly equal exposure. Even the human brain doesn't see things this way -- while the above photo is punchy in color and pleasing to the eye, it doesn't look anything like what I saw as I was standing there watching the storm. The bottom of the cloud deck was much muddier and brown-tinted, for one thing.

Still, I think there is a lot of potential here -- I just need to figure out how to make HDR work well!

Post processing using HDR is an art. You can do whatever you wish... there is a fine line, however, between something that looks pleasing to the eye yet still natural looking, and something that has that "wow!" factor, but is surreal and probably unrealistic physically. I'm finding more and more that the only time I use any sort of HDR technique is if the ground is some 4 or more stops darker than the sky... pretty much what Oscar mentioned. In my processing, I try to bring the most out of the photo, trying to recreate what I remember seeing with my own two eyes, but at the same time making the photograph pleasing to look at. Higher contrast and higher saturation is certainly more pleasing to look at versus something flat that comes straight out of the camera in RAW format.

Mike U

So much of this type of "photo manipulation" has been debated in recent years as better cameras come into the price range that Joe Average can afford. It's been debated that doing simple sharpening and selective brightening, contrast adjusting, etc. is "not legal" (for lack of better words). H0wever, much of this falls into the same category as the Darkroom burning and dodging, masking, etc.

There are "purists" out there that really do believe that manipulation of the photo in any way is bad and invalidates the photo. There are those that believe that this same manipulation is simply a way to convey the feelings and present the photo as "more real". Then there are those that wildy manipulate the original photo, add to it, take away from it and come up with something so totally out of whack and still try to pass it off as something they "saw".

It's an interesting debate, but even with the manipulation I've seen on the photographs presented in this particular forum, I certainly wouldn't call them "unrealistic". But then that's really in the eye of the beholder isn't it?

Sorry to get off on the side tangent here. For me, does the final image represent what I want to convey to the veiwer? If it does and the feelings I felt when I took the photo get across, then I've done my work well.

I enjoy all the photos that come across here, but the ones I really enjoy are Mike U's, Mike H's, Ryan's and Aaron's(there's a couple more too, but these are the one's I can name in 5 seconds without looking :D ). These guys have mastered the art of conveying the majesty, power, and beauty of a Thunderstorm. Many of us strive to get there and a few of us get a good photo more by accident than design, but these guys really are the ones to learn from.

I'm a "good" photographer in that I have the technical aspects of it down pretty well. I can do some really nice portraits in the studio and I can even go out and get a few really nice landscapes, but to be able to do it like these guys? Well, I've got a long way to go.

Just a couple quick things -

First, this thread rocks. Like, a lot. Ryan - thanks for going through the effort of Beta testing this method and posting your results. You can bet your buns that there's more than one photog interested in trying this out.

One question for you, though - how many exposures did you take to achieve that shot above? - and if I'm understanding this process right, and a person brackets 3 or 4 exposures that the software can then "merge" to draw the best levels from each, how do you avoid blur or camera shake? - In your images, your subjects are crisp. How did this work if you are dealing with a number of exposures? I've been trying to read up on this, but still haven't figured that point out.

Color saturation is what appears to be the biggest source of contention here (remember when chasers were arguing against Velvia for the EXACT same reason?). Personally, if it pleases your eye and does a decent job replicating the original feel of the scene in your mind, then process within the limits you are comfortable with. I think for me I might try desaturating some of the over-done images prior to merging ... the foreground is probably the truest color here, but just appears washed against that amazing orange behind it. Also - since we are used to seeing photo after photo after photo, we have become accustomed to photos appearing a certain way (usually according to pre-set processing by digital camera manufacturers in jpeg mode, which fall way short from what most folks are actually trying to achieve). Anyway, I think that we may have prejudiced ourselves a bit against imagery like this, simply because we're not used to it yet.

I'm not as concerned with the same ethical arguments against photo improvements again in this thread, as I am in achieving these levels of exposure - which I believe will become an enormous tool for photographers. I doubt we are even capable of seeing where this is eventually headed, to be honest.

------------------

Edit - has anyone thought of trying this with good old b&w yet? - This may really work well for black & white. You won't have the questions about unnatural color, but you'll still enjoy the wide latitudes. I've already ordered PS-CS2 and think I'll give it a whirl just to see what the results are like.

I've been enjoying this thread from the sidelines as well. I'm not very good at digital processing, I only switched over to a digital body this last winter. This technique looks quite interesting - and I'm eager to try it out on a few images I can think of off the top of my head. Anyhow - my question is for Ryan regarding the image above: what lens are you using? The perspective distortion is pretty bad on the vehicles - so I'm guessing it's some sort of fisheye lens, which you are then processing to convert back to rectilinear. I would agree the foreground is too bright - but I think that mainly is disturbing because of the shadowed treeline on the horizon - that gives the illusion that the foreground has some artificial lighting supplement. There also seems to be some color halos in the cloud edge near the upper left - which makes me wonder if this was a slow bracketed shot.

Does anyone have to use the Adobe DNG raw converter for CS? I've found a fairly low tolerance for exposure compensation without introducing a lot of noise. Maybe I should be using some other type of raw processing that others could recommend.

Glen

I've used CS's converter and Canon's and notice if you have to open something up very much it'll always do that. Part of me doesn't think you gain a whole lot extra by using the raw converter to open something up rather than just using photo shop curves or levels. I kind of think it is more or less dealing with the same info. I think you might gain something when you want to lower the exposure with something blown out(since it is supposed to be capturing the raw data as it exposes and somehow keeps that info...so you could take it back down....but it really then wouldn't be getting any extra info to open up since the exposure obviously stopped....if any of that makes sense or is even correct). But anyway, I've seen that noise thing too.

I had some shots one night at I think ISO 400 and ISO 800. The two I had with it set on 400 were under exposed and I had to open them up. The one at 800 was not under exposed. Both the two at 400 when opened up to the same level as the 800 one had more noise. It makes sense and I'm sure is common knowledge, but I figured I'd mention that while it went through my mind just now.

I just thought of something else too ... lol ... I'm thinking that the more exposures a person could take, the better. Like a range of 7-10 is better than a range of 3. If you have a set of three, with an exposure at a stop above and a stop below, then the software may tend to want to pull from the extremes of the two, which would cause the image to whack out a bit more.

If you are running 5-7 different exposures, though - the software will tend to blend from a wider range and the photo should come out looking more balanced in the end. Just an idea - - will be tough to do in a storm environment, and a person will have to be quick. But I would think with a typical landscape (with as little movement as possible), a person should be able to get at least 5 exposures within a split second of each other. Add people, cars, or lots of motion in the cloud base (i.e., a TORNADO), and this probably wouldn't work without losing focus.

Thanks, Mike! I thank Darren for pointing this whole HDR thing out to me to begin with. I really do feel ignorant for not knowing about it, given as much as I use Photoshop.

In this particular shot, I took seven images, each seperated by one stop. My camera's aperature dial moves in 1/3rd stop increments, so I just tripoded the camera, attached a cable release, took a shot, clicked the dial three clicks, took another, lather, rinse, repeat. Altogether it took about seven seconds to do, according to the EXIF info. I've found that one can actually get very useable HDR images just by doing the standard 2 stop bracketing, which takes no time at all, since most Canon digital bodies have a setting that will do this for you simply by holding down the shutter release until three shots have fired.

The reason that nothing looks blurred here is basically because nothing much moved. :) If you look close at the foot of the guy hanging out of the SUV, you'll see that it is a bit blurred in the HDR shot, as he did slightly change position over the seven seconds it took to do the shots. Also, the clouds above look a little blurred. But using the 10mm side of the lens (effectively 16mm) means that something has to move quite a bit to move much in the frame. The storm was also really slow moving, which helped.

Here's some thumbnails of the seven shot RAW sequence that I fed into Photoshop. All should have EXIF info still in them. The timestamp is probably a bit off as I need to set my camera's time again, but everything else should be right.

http://img77.imageshack.us/img77/7568/img87721ta.jpg
http://img189.imageshack.us/img189/9267/img87736eo.jpg
http://img191.imageshack.us/img191/833/img87743ax.jpg
http://img191.imageshack.us/img191/2385/img87755fk.jpg
http://img77.imageshack.us/img77/4497/img87769tl.jpg
http://img165.imageshack.us/img165/7453/img87778eu.jpg
http://img77.imageshack.us/img77/6408/img87784es.jpg





For that shot I used the Canon 10-22 at f/8. The distortion is pretty bad, but it's actually not a fisheye, it's a rectilinear lens. It's just that at an effective 16mm, distortion is always going to come into play. :) From what I understand, the 10-22 controls distortion pretty well for a superwide.


I actually burned down the treeline because I thought it looked fake when it was properly exposed! I was trying to create a deliniation between the sky and the ground. I think that Mike U. is right -- HDR toning really is an art, and I've got a lotta learnin' to do.

http://www.extremeinstability.com/st.../2006/ex10.jpg

Just as an example of how far you can go with one single exposure in just photoshop. If you want to be able to take one shot and be able to open it to where it should be I think your 4th exposure down is the best one. The sky is just barely starting to blow out but it is still very much intact. Right there you are able to open the foreground past where you would even need to. You can also get contrast in the storm and the foreground while keeping the brighter sky in check.

I just think you can get a ton of tone and info from one exposure but it would have to be just right.

Here is the same 4th one down with the foreground darkened back down a bit from where I took it in the example...

http://www.extremeinstability.com/st.../2006/ex11.jpg

That's true, one does have a large amount of latitude to do manipulation, especially if you shoot RAW. For the most part it works, but after a certain point you run into combing histos and banding. This becomes a much bigger deal when you make enlargements. If you're not going to tone map, then just straight doing a bracketed exposure and then composting the layers in Photoshop would be the way to go, as this would avoid running the risk of banding. Of course, this only works if you have time to set something like that up or can hold the camera rock steady -- which isn't always the case when you're near storms.

Below are a couple of examples. One is a 100% crop of the image that you picked, exported to a 16 bit TIFF and opened up with levels and curves to about the point you were indicating with the preview JPEG. Noise and artifacts are starting to show up, but I would say that this is pretty acceptable for a 100% crop. I doubt this would look bad in a print. The other is a 100% crop of the same area of the HDR image. You can see the shortcomings of HDR here: as the person moved, it messed up the HDR process. (There is also some bizarre color banding the comes in to play if whatever you shot moved in between bracketed shots.) It also emphasizes to a high degree any chromatic abberation that your lens is experiencing (I didn't do any CA correction in the RAW import, though I probably should have.) However, you can see that the artifacts are gone and the shadows fade smoothly away. For a completely static scene, HDR offers a lot, though you can definately create an excellent image without the HDR. Ultimately, with that many exposures, if I wasn't going to tone map the best thing to have done would have been to have taken the third shot down, opened it up a bit, and used it for the ground, then composted the sky from the fourth image down on top of that. Between the two, I'd have had all the dynamic range I'd really have needed.

http://img90.imageshack.us/img90/337...100crop3ir.jpg

http://img90.imageshack.us/img90/283...100crop4gt.jpg

Mike,
I said this to Ryan on our way down to Hays on Sunday. Tone mapping is essentially Ansel Adams "Zone System" for color. If that looks "unrealistic" to you, try making it into a black and white. Become the Ansel Adams of storm chasing!

The other thing that I will say about this is that HDR seems much more "honest" to me than some of the "over-processing" (as some might call it) being done with Photoshop alone. Instead of basing your improvements on some algorithm, with HDR you are using real details from the scene (albeit at bracketed exposures) and pulling the details out of each of them.

Kudos to Ryan for showing us where this might go — and he's been doing it now for [what?] a week? I fear that I have created a monster. :blink:

Darren Addy
Kearney, NE

This is what I mean how the image is processed to look better and still looking realistic to my eyes/brain. Very good job on that, Mike! If one can get this out of a web jpeg, imagine what's possible with RAW. Good enough range to not have to go through the inconvenience of having to take multiple shots, while you can use the space on the card for something else :-)

Oscar

Hi Oscar -- no need to imagine, look up! :) I used RAW to create the first 100% crop image above. That's what's possible with RAW with that shot.

Those of us not yet Photoshop Gurus (or maybe just interested in extending your abilities with it) may find Photoshop for Photographers useful. It's a pretty complete introduction to Everything You Ever Wanted to Know and includes a section on HDR (under Basics).

Darren Addy
Kearney, NE

This may be a dumb question, but if you shoot in RAW, couldn't you just shoot one picture, and then use Adobe Camera Raw, or some other app and save 3 or 4 pix with different settings and then combine? Or do you have to actually shoot multiple picutres.

Great topic by the way!

I had this question at first too - and I think from the sounds of the things I've read in the other forums on the subject that this will become a reality - and working from a single RAW image (which would be the best choice) might be able to work with this method - it doesn't sound like it's quite there yet. The only things I'm wondering about involve the fact that when you use a camera's manual settings to actually take separate photos, you are picking up detail in each exposure (especially when it comes to things like toning and color) that would become lost in a computer's attempt to render the same effect (by simply adjusting brightness/contrast or whatever). It still looks like separate exposures are the way to go, for the time being anyway, to get the full benefit. You could REALLY get a shot to look whacked out if you started photoshopping a RAW image and use a blend of different exposures PLUS altering the color of each shot. I wonder if the computer would even know what to do with it. I bet a person could end up with some pretty weird effects.