HDR Postprocessing

by Allen Rockwell

Today I'm going to stray away from Aperture a bit and discuss a post processing technique that, while it can involve Aperture for part of the processing, it uses other software for the majority of the post processing.

HDR_Thumb.jpg
The process/technique is known as High Dynamic Range processing or simply HDR. HDR and Tone Mapping is a process which two or more differently exposed images (normally one properly exposed, one underexposed by one stop, and one overexposed by one stop) to produce a single image with much higher dynamic color range. Why would we do this? Well, a digital camera sensor is capable of capturing about 3-5 stops of color dynamic range where the human eye is capable of seeing about 11 stops of color dynamic range. What this means is that you see a beautiful scene and then photograph it and then get home and review your images and you are disappointed that your images are just not the way you remember seeing the scene. There is nothing technically wrong with your images, they just are not what you remember seeing when you were there.

There is a lot of information on the web about HDR, tutorials, etc so I will not get too deep into the mechanics of how it all works. What I'm aiming to do here is to make you aware of this process and you can go out and do some research yourself if it interests you. One thing I would like to mention is that in my opinion HDR processing should be used to enhance good pictures and it should be used sparingly ... sort of like the same analogy I've heard used to describe post-processing with Photoshop "use it like an emery board, not a sledge hammer". In my opinion a lot of people use HDR to push images way too far and they end up with something that looks like a cartoon .... but that's just my opinion, all that really matters is if the finished product looks good to you.

Here are some good HDR resources:

Photomatix software by HDRSoft (my choice for HDR processing)
Some of my HDR Images on Flickr
Trey Ratcliff's HDR Tutorial
HDR on Wikipedia
HDR Tutorial at PopPhoto

Until next time,

Keep shooting.

Allen Rockwell
Allen Rockwell Photography

8 Comments

Bill Griffin
2006-12-22 18:13:58
Thanks for this recommendation Allen. I'm shooting a landscape calendar for a company over the next twelve months. I hope to develop skills quickly here to dramatically improve my images.


Bill

Edward
2006-12-23 18:56:14
Allen: do you believe that HDR processing will become a feature in a future version of Aperture? I have tried Photomatix and it's not exactly the most user friendly solution. I would like to see an Apple twist on this.
Allen Rockwell
2006-12-23 19:23:41
Edward,
I think that would be a very interesting feature to add to Aperture ... after all you, you are already in Aperture looking at your RAW files, why not select 3 of them and Ctl-Click and select "Make HDR". That would be very cool.
The Aperture developers watch this blog ... maybe they'll see this post and make a note of it for a future release.
You can also use the Aperture feedback form at:
http://www.apple.com/feedback/aperture.html
Mark
2006-12-29 03:12:35
I am curious to know - the movement shots in your Flickr HDR gallery - are some not 3 shot HDR but just adjusted with Photomatix? How do you take three different exposures of a surfer or pedestrians?


Nice photos and thanks for the tips.

Allen Rockwell
2006-12-29 14:31:21
Mark,
Some of my HDR images are tone mapped from a single RAW file. It's a sort of undocumented feature of PhotoMatix ... you go to the Automate menu and select "Batch Processing" and then just select one RAW file and click Run.
Tom
2007-01-17 11:19:39
Personally i prefer Artizen HDR as it is a full true HDR application with 11 tone mapping operators compared to Photomatix 2. My only wish is that i would work on the Mac OSX.
Peter
2007-01-26 12:03:41
Your flickr photos need some of your own advice: "HDR processing should be used to enhance good pictures and it should be used sparingly".
Allen Rockwell
2007-01-26 12:16:59
Thanks for the comment Peter. I would like to visit your website and see your awesome photos ... but alas you did not have the courage to link to it :(


I have 713 images on my flickr page, 82 of them have some level of HDR processing done to them... that's 11.5%. I'm not sure what your definition of sparingly is, perhaps you'll enlighten me on that point.


If you are attacking the general quality of my images or my photography in general please keep in mind that flickr is a photo community, not a fine art gallery. I post pictures on flickr that I want to share with family and friends ... not images that I necessarily think should be hanging in galleries.


I look forward to you posting a link to your superior images on flickr so that I may enjoy them.


Thanks.