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Posted: Sun Aug 31, 2008 8:17 am
by Andy
Every September (well, at least since 2005, when I found, and joined this great place), I start to think about the "foliage" season, which coupled with views and the great light of fall, creates some of my favorite photo opportunities. Then, I start to check in hear nearly daily, to see who's on, and what they are reporting.

Then, I naturally gravitate to this forum (partly in hopes that we'll someday start a rousing conversation about the photographic side of Vermont Foliage).

Over in the Foliage Forum, there was was an ever-so-brief conversation about "my first digital camera." It got me thinking about where this is all going.

"My" first digital camera was a 3 megapixel, Canon "point & shoot" (P&S). Like old computers, we still have that camera, in a "junk box" somewhere in the basement. It rendered JPEG files that were small, and kind of "noisy" (grainy) and which couldn't generally be printed much larger than 5 x 7 with anything close to quality. But the instant gratification was pretty exciting (I still remember my mom getting a "Polaroid Swinger" for Christmas one year). But for me, a 35mm SLR user since the mid-1970's, it wasn't quite ready for "prime time" yet.

Back "in the day," (we used to use something called "film" :lol:) most "serious" photographers eventually gravitated toward 35mm "SLR", medium format, or for the stout of heart, large format "view" cameras. It was not uncommon to purchase one of those and still have and use it regularly 20 years later.

In contrast, it seems to me that today's digital cameras are more like computers, and have a much more limited "shelf life."

At the same time, what they can do for us technologically is amazing (of course, other than giving us certain technology, they don't make us "better" photographers -- or make "better" photographs from an aesthetics viewpoint).

I have recently begun to experiment with "HDRI" (high dynamic range imaging). In my studies, I was pleased to learn that research is coming ever-closer to being able to create a sensor that can capture the range of light that the human eye can see. At the risk of boring/offending the knowledgeable among us, in the days of film, we spoke in terms of how much "latitude" a particular film had. Photographers generally measured this in terms of "stops" (since the camera/lens system worked in stops). Today, digital "experts" refer to it as "dynamic range."

If you have ever been to a very dramatic scene and seen a beautiful blue sky with puffy white clouds, and beautiful trees, flowers, rock formations, etc., in the foreground and shot a photo to capture it -- only to be very disappointed when the slides or prints came back from the lab because the sky was completely burned out, you have experienced the (current) limitations on film/digital sensors. Its not that the camera cannot capture the same range as our eyes, it just cannot do it in one exposure.

The human eye can see the difference in thousands of these stops. The camera, at best, can capture ("see") a few stops (at a time). So far. But, "we've come a long way, baby." The sensor and hardware on my current SLR (Nikon D200) is capable of capturing a RAW image that has the potential of 7 stops of dynamic range (and it is, at 2 years old, already a bit "dated" technology!). The ability to "manipulate" (I use the word with some trepidation) the digital bits and bytes with programs like photoshop have given us the ability to have an Ansel Adams - like darkroom experience.

HDRI is even more exciting, giving us software which will allow us to capture several images and then mesh them to get that dynamic range which approaches what the eye can see. And within my lifetime (I hope), I believe we will see affordable cameras capable of capturing this in one exposure.

Posted: Sat Sep 06, 2008 8:08 am
by Andy
Carol: There are several software options available. The "most popular" one seems to be a program called "Photomatix." When I attended the John Shaw seminar last winter, he touted that program and used it in his illustrations. Another popular program is "FDR Tools." While the interface looks less sophisticated than Photomatix, it appears to have essentially the same functionality, and from the comparisons I have seen, gives a more "photorealistic" result. I have downloaded the "free" version of FDR tools and will play with it. I will probably upgrade to the "pro" version. If I remember correctly, they are both around $100.

PS CS3 has HDR capability -- but, alas, its just not very good. I have tried it, with pretty disappointing results. I guess they cannot do everything at once. What I expect will eventually happen--like so many other functions which have been added/improved over time in PS--is that ADOBE will acquire one of these third party softwares, or license its use and it will be integrated in a later version. Or, maybe they will just get their own version right.

The details of HDR--not surprisingly--cannot be done justice in a series of exchanges, here. There are several excellent books available on HDR/HDRI. Before trying to respond, I did a quick search for "HDR" on Amazon, and the first two in the list are books I have have. One is a good overview, the other in a little more depth. The first 3 or for results from the search should be a good start. I highly recommend some "study" before attempting serious HDR imagery.

What I have learned from my reading is that there are many technical points you need to be aware of in order to do this right. It is more complicated than just a series of brackets at different exposures. There are issues of depth of field (which means you really want to take your series of exposures at the same f-stop), "ghosting" which will happen if any movement occurs in either your subject or the camera (a tripod will be a requirement here), and knowing the correct "High" and "Low" exposures for your subject. Also, HOW you bracket will become important. If using RAW, for example, anything less than 2 stop brackets really don't give you full advantage of HDR. In fact in many cases, less than 2-stops will ALREADY be captured within the RAW file. So most are suggesting brackets at 2-stop intervals. It is possible that "closer" brackets may give a smoother transition during the "blending" process.

I personally am at the very beginning of the learning curve, here. I have tried it with PS from some shots taken last year with disappointing results. My plan is to take some bracketed shots during my upcoming trip to NM and then work with FDR tools when I return. More later :)

Posted: Sun Sep 07, 2008 11:40 am
by Andy
I am thinking the "HDRish" is really just a "program" that does some things you could already do in Levels and Curves (and now the Shadow/Highlights) tool in Photoshop. You are still limited to the "pixels" captured in your shot.

What HDR does is takes several images which--together--exceed the range a single capture can. The HDR software combines it. Surprisingly, when you open the resulting HDR image, it looks pretty awful. This is because the computer monitor is limited in the range is can display, just like the capture devices. After the "blend" you will eventually choose what CAN be displayed on monitors in and print (by a process they call "tone mapping") and then eventually condense it back to a LDR (L="low") image. Most of us will save the HDR files, just like we save the RAW files now.

Again, as I have preached to Carol privately, if you aren't using RAW you really should give it serious thougth--especially in Landscape Images.

Posted: Mon Sep 08, 2008 10:28 am
by Andy
With all due respect to "HDRish," the clear "best" exposure of the 3 is the original image.

What true HDR would/should do (as well as other PS type adjustments, to the extent possible) is to "save" the highlight areas (mainly the sky in this photo) and any "blocked up" shadows (blacks). I this case you did a pretty good job with the overall exposure of the subject and foreground. Where you might want some additional detail and/or drama, is in the sky. What your program should do is to "darken" the sky a bit, without sacrificing the other parts of the photo.

In RAW capture, I might actually open two "versions" of my RAW file, making adjustments to RAW files so that the sky looks good in one (ignoring everything else) and another, making the rest look good (ignoring the sky). Then I would "layer" one on top of the other and "paint" out the "offending part."

Without the ability to do this, the only other thing you can really do is select the sky and try to work with it in levels or curves.

In an HDR workflow, you would meter the sky and the darkest area you wanted to have nice detail in. More than likely, it would prove to be several stops more than you could capture with one shot. Thus, we traditionally had to make choices about which was the most important area to have detail. With HDR, you would expose for the sky and not worry that the barn and grass would likely be severely underexposed. You would then take a series of photos between that and the proper exposure for the grass/barn (in which the sky would be overexposed). The HDR software would then "merge" all the photos, giving you the full "dynamic range" between your "lowest" and "highest" exposure.

The "tone mapping" process then takes the best of what you have, based on what you can display on your monitor.

Posted: Mon Sep 15, 2008 8:19 pm
by autzig
I use Photomatix for HDR and find it does a nice job of expanding the dynamic range of photos. Here are a couple of examples from my website.

Often HDR is used for the artsy effect, but it can really turn a scene with extreme darks and lights into a good photo. In both of these examples I could not have gotten the shot without HDR.

Posted: Tue Sep 16, 2008 8:37 am
by Andy
Beautiful stuff, Al. I am currently "torn" between Photomatix and FDR Tools. I hope to have a chance to run them both "through the paces" following my upcoming trip to NM this October.

Good to see you back here.