Thread: Matt's HDRs.

Originally Posted by Numpty's Missus

My first attempt at an HDR using 3 images

Nice. It looks like a picture from an old brochure.

Handheld HDR taken in Beechworth, Vic at the weekend.



Matt.

One that I took in Cambodia last year, and wasn't happy with the way i processed it originally, think it is a lot better now.

Angkor Wat at Sunrise, 3x exposure HDR. Used Photomatix and Lightroom.

(click to enlarge)

Matt.

nice!! shame you lost the middle ground

To get the best out of Tone mapping, it helps if you know your monitors response (min and max luminance) and work with an algorithm that uses it. Which is not easy because it can vary by +/- 30% over the surface of the monitor and is also time dependent. The weak link in the 'dynamic range chain' if you like, is generally not the camera. Most consumer monitors these days are 6bit panels, and whilst you can represent any dynamic range you like with 6bits, the quantisation steps become very large and introduce nasty color shifts and worse. Most tone mapping algorithms try to boost local contrast based on how human vision works. That is the eye does not 'measure' absolute luminance, instead it responds to relative changes. Which is lucky for us because an outdoor scene on a bright day can easily have an average luminance of 20,000 cd/sqm , whilst our monitors are lucky to do 300 cd/sqm (LED backlit LCD's are higher). The problem with local contrast tone mapping is the reverse halo effect that appears to be evident in most images on this thread - that is a dark halo around bright areas in the image. To get the best results, you need to experiment with different algorithms until you find one that works for your image. There is no one tone mapping algorithm that works for all images.

Originally Posted by Taz

To get the best out of Tone mapping, it helps if you know your monitors response (min and max luminance) and work with an algorithm that uses it. Which is not easy because it can vary by +/- 30% over the surface of the monitor and is also time dependent. The weak link in the 'dynamic range chain' if you like, is generally not the camera. Most consumer monitors these days are 6bit panels, and whilst you can represent any dynamic range you like with 6bits, the quantisation steps become very large and introduce nasty color shifts and worse. Most tone mapping algorithms try to boost local contrast based on how human vision works. That is the eye does not 'measure' absolute luminance, instead it responds to relative changes. Which is lucky for us because an outdoor scene on a bright day can easily have an average luminance of 20,000 cd/sqm , whilst our monitors are lucky to do 300 cd/sqm (LED backlit LCD's are higher). The problem with local contrast tone mapping is the reverse halo effect that appears to be evident in most images on this thread - that is a dark halo around bright areas in the image. To get the best results, you need to experiment with different algorithms until you find one that works for your image. There is no one tone mapping algorithm that works for all images.

+1
My advise is to go easy on the 'Strength' and 'Light Smoothing' sliders (eg. if you're using Photomatix) unless you absolutely want that unholy halo look!



My mate's Model T in the 'tunnel' at Kirribilli. Early morning sun was highlighting the hood and inside canopy with everything else pretty dark. This would have been impossible without resorting to HDR. 5 exposures from a tripod.

slt

Which version of PhotoShop has Merge to HDR? My version 7 doesn't.

I'm using CS3 (= Version 10), and it has. Dunno about earlier ones.