Tuesday, October 23, 2007

Demo (Redux)




Alright. I was asked to go into a little more detail about how I work HDR images, specifically, the contest winner. Let me start by saying that if you really want a good HDR demo you should check out the one by Trey Ratcliff over at Stuck In Customs. Trey's the master at this stuff and he does a great job of explaining it. That being said I think I'll give this a shot. Let me also say that this is going to take some time to put together so expect this to come in several installments (plus this gives me an excuse for blog posts).

So I guess the first step is to shoot your scene with a minimum of three differently exposed frames. I typically set the camera to aperture priority and use auto bracketing in one stop increments. I have become accustomed to setting a seven shot bracket, but I rarely end up using all seven frames. For most scenes three frames is enough, while five frames works for the more contrasty scenes. It all depends, I like having the extra frames just in case. Whats most important is that you have enough exposure variance to cover the full dynamic range so that at least one of your frames has no highlight or shadow clipping. In this example I ended up using four frames. I think a tripod is a must (although I have seen claims of handheld), and a cable release helps. Also, I like to shoot with mirror lock-up to help reduce camera shake. Oh, I also like to focus manually and turn off auto focus to make sure there is no variance between frames.

Now on to the post... Once the images are downloaded I do a quick conversion to DNG (not required, but I really think DNG is the way to go for raw files). This is where I differ from most other tutorials I have seen. Now I can adjust the raw files in Bridge CS3 using ACR 4. The controls in ACR 4 are simply phenomenal, but make sure you apply the same settings to each file. Once done I click okay, then its back to Bridge where I do a select all then go to Tools>Photoshop>Merge to HDR. I think this is enough for now. More in a few days.

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