If you have seen my flickr photostream, you should know that I go to a lot of car shows, and shoot almost all my shots in HDR. I am fortunate enough to live about 5 minutes from a weekly car show called Cars and Coffee here on the border of Las Vegas and Henderson. Just this past weekend, it was perfect weather with overcast skies but no sun – giving us a nice even light with no annoying bright sun ruining many angles. So here is one of my favorite shots from that day.

The Shoot
I carried my tripod that day, ensuring many stable auto-bracketed HDR sets. The lighting worked for almost any angle works because there is no sun to worry about. I set the tripod up behind this Mini Cooper S and fired off 3 shots with the Canon 5D and 17-40mm f/4 lens (essential for car shows and landscapes). Cars usually look good from the corner angles and given a bit of tilt to add perceived motion and aggressiveness. A shot from the ground (mouse-eye view) usually works good too, but this time I opted for eye-level looking down so you can see the top of the Mini. The deep metallic grey and double yellow lines really makes this particular Mini stand out, and I thought it would turn out well in HDR. You decide:

By pongky ©

The Processing
Since the AEB set of exposures were shot on a tripod, I didn’t have to check the “align images” box in Photomatix – thus reducing the merging time. I dragged it into Photomatix and made sure I adjusted the colors and exposure levels. Usually what I do in Photomatix is increase the gamma so that it looks slightly overexposed (maybe by half a stop) so that I can do more with it in Lightroom in terms of blacks and contrasts. I find this technique works very well. In Lightroom I cropped out all the useless background elements (which is why the roof is partially cut) and adjusted the tones and color saturation to get it to this point. I hope you like it – and if you are really interested, you can also have the AEB RAW files by downloading from here. Let me know if you use it and come up with another result!

Have you ever wondered how much that extra exposure value (EV) range would help improve your next HDR image? Would, an image taken at 3 exposures at -2,0,and+2 EV be better than an image taken at -4,0 and +4 EV? This article will help you determine this issue. Does using more exposures really improve image quality?

Depending on the camera you use, you might run into some technical limitations. Some cameras (such as the Canon EOS 5D) is only able to take an auto-exposure bracketing (AEB) set of 3 exposures with the maximum range of 4 EV. If you want to do 5 or 7 exposures you need a tripod and have to do some creative exposure adjustments to get the extended range. Nikon’s D200 and above offers up to 7 auto-bracketed exposures going up to +4 and -4 EV I believe, totaling a range of 8 EV in total! I know someone on flickr who does a whopping 17 exposure HDR!

Well, when we get down to it, it’s really the image quality result is what we aim for. I have an auto bracketed set of a scene here in Las Vegas of the west valley wall. I believe I captured 5 auto bracketed exposures, at -4, -2, 0, +2 and +4 EV. We will try to mix the exposures up so you can see what works well and what does not. Note that these are images exported as tiff via Photomatix using the same exact Details Enhancer settings, and has not been further processed in another software.

A) EV -4,-2,0,+2,+4 (all 5 exposures merged)

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B) EV -2,0,+2 (3 exposures)

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C) EV -4,0,+4 (3 exposures)

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D) EV -4 +4 (2 exposures)

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So you can see very little difference between A and B. C seems to be a little faded and washed out due to the higher range differential than A and B. D is obviously very noisy and not a satisfactory result. If you compare B and C,I think the smaller EV range results in a better image quality. The local contrast using 5 exposures seem to be higher (A), but otherwise the tones and color definitions are extremely similar. After further edits in Lightroom I figure you could not tell the difference between the A and B.

So, in conclusion, I would say that it is not worth the extra effort if you did a 5-exposure HDR versus a 3-exposure HDR – where you save time is in the HDR merging and also file storage savings. I am now happy with the -2, 0, +2 EV maximum range on my Canon EOS 5D.

If anyone has any input about 7 or 9 exposures and higher, please let me know.