Hey folks,
To continue the series of blog posts we have our good friend Brian chime in on his thoughts on HDR photography. HDR photography has been generating quite a buzz in the photography circles lately and we wanted to know what Brian (HDR extraordinaire) thought about it. Wether you are interested in HDR or never heard of it, give this post a read, as Brian shares some good tips on how to shoot HDR.
The School of Bracketology
Let's face it. HDR is here to stay. And, really, why shouldn't it be? I believe that it will go down as one of the great factional debates in photographic times akin to Color vs. Black & White and Digital vs. Film. Regardless of the reason, HDR photography offers an allure to its followers and admirers. And perhaps you are starting to dabble in it. Maybe you're looking to expand your horizon or start on a fresh new one. Wherever you find yourself in the HDR universe, as with anything important in life, if you're going to do something, try doing it to the best of your ability. That's where I hope this guest blog post will help.
I recently had the great opportunity to lead the Boston leg of the 3rd Annual Scott Kelby Worldwide Photowalk. I was accompanied by a cadre of great people, a lot of whom expressed their interest in shooting HDR, and brought with them some really great questions. There was a common theme that gave me the idea for this post. The line of questions hovered around the actual process of shooting brackets - mostly "How many brackets should I shoot?" "What stop-interval should I bracket at?" and "Should I use all of the brackets that I take?"
I use the term 'brackets' affectionately. They have come to represent the individual images that your tone-mapped HDR image is comprised of. And if you think about it, the quality of your tone-mapped image really depends on the quality of your brackets. As an analogy, let's say you are painting a picture of your living room on a canvas. The bracketed images will represent your paint. The canvas is your tone-mapped image. In your living room is a nice bay window showing you a beautiful tree-lined street. You have a nice coffee table, sofa, and fireplace as well. You want your painting to display all of the wonderful details of the scenic tree-lined street outside as well as the details in your living room, like the centerpiece on your coffee table and the nice candelabra that you have perched in your fireplace.
Now, with your painting, if you do not have the right color paint or enough of it, you won't be able to truly convey what you had originally envisioned. The same holds true with tone-mapping. If your bracketed images do not contain the details across the full tonal range of your scene, you will simply not be able to accurately express it. Instead of seeing that candelabra in your fireplace, you may only see a blotch of shadow and some unsightly artifacts. However, if you do have that one bracketed image that has all of that glorious detail in the fireplace, you're set. You've got the right paint on your palette and you can apply it accurately onto your canvas.
So, we've established the the importance of the quality of your brackets. Now, onto the quantity of brackets. Will three brackets suffice? Five? Seven? Twenty seven? I wish there was a hard-and-fast answer to this but the reality is there is no good answer. I could say 'three brackets is usually more than sufficient'… until it isn't. I could even say 'five brackets will do the job'… until they won't.
I get a lot of emails from viewers who see the EXIF details that I post below each image on my blog and comment on why I use nine brackets. The truth is that, in my experience, nine brackets gives me all of the tonal information that I need plus some insurance on the highlight and shadow ends of the range. Before I leave a scene that I've just shot, I review my brackets and if it's clear that I have all of the tonal detail from my highlights thru the midtowns and all the way down to the shadows in six brackets, then I'll only use those six. Have there been times when I've had to use all nine? Plenty - and it's usually in scenes with varying degrees of shadow depth and highlight information. Think of the information in each of these images as containing varying degrees of shadow and highlight qualities. Combining them in tone-mapping will give you the most paint to play with.
This does not mean I am advocating that everyone start taking nine brackets. Nine is not the magic number. It's just the value that I have keyed into my Promote Control (the device that I use to capture my brackets) that works best for me. Rather, what I am advocating is the following, returning back to our lovely living room:
1. Study your scene before you shoot it: Spend a minute or two and survey all of the details in the bright areas and the dark areas and everywhere in between (outside the bay window, around the coffee table, and inside the fireplace). Familiarize yourself in advance of what details you want to grab in your brackets (the tree-lined street, the centerpiece, and the candelabra).
2. Expose and review your brackets: Assume you just shot three brackets using your camera's AEB (Automatic Exposure Bracketing) function. Review the images on your camera's LCD. Look for the details that are exposed in your mid-range bracket. Do you see a majority of the detail within the living room and on the coffee table? Cool. Move onto the highlight bracket (the darkest image). Do you see the blue sky and the trees lining your street? Sweet. Now, move onto your shadow bracket (the brightest image). Do you see that candelabra in the fireplace? Not really. Ok, then adjust your shutter speed to a longer value, expose, and review again. Repeat this process until you are satisfied that you have the details that you're looking for.
By spending the extra time and care to ensure you get the best quality brackets when you're behind the camera, you will start seeing a marked improvement in what your tone-mapping software has to play with when you're in front of your computer. What you will be left with, hopefully, is a great HDR image that conveys all of the wonderful details that make up your scene.
On a final note, I'd like to thank the good people at LensProToGo for asking me to contribute to their blog post. These are some of the nicest and most knowledgeable people to work with for all of your camera gear needs. If you're thinking about renting a lens out prior to buying one or you just need that 200mm f/2 for this one upcoming shoot, there is no one better to work with.
Thanks for the opportunity to hang around these parts. It has been a pleasure. Please feel free to reach out with any questions or comments!
Cheers,
Brian
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