RAW converters at ISO 3200

February 24, 2008 | Filed Under Uncategorized 

The Story in a Nutshell

With the release of Aperture 2.0, one thing I was looking forward to was to see if a disturbing trend I noticed on some of my photos would be corrected or improved on. Now that I’ve had time to review specific images, I thought I’d write up an report to pass on to the development teams at Apple and Adobe, because my consensus is that there clearly is room for improvement.

High ISO performance on modern-day digital SLRs are simply amazing, compared to the film days. You can get images from ISO 3200, or even higher that exceed anything you ever saw on film. A whole new world of photography becomes possible.

One of the areas of interest I pursue is shooting candids in night clubs. I am an available-light purist. I don’t like using a flash. So in those dimly lit night clubs, I am forced to push everything to the absolute maximum. I use a Canon EOS 5D, 35mm f/1.4L, ISO 3200, (sometimes underexposed 1-stop for ISO 6400 effective) and of course, RAW.

(Please note that the pictures exhibited below were selected only to illustrate the problem I am reporting on, not on their artistic merits, so don’t tell me the pictures suck, because I already know that!)

So when I started doing this work a little more than a year ago, I started to notice that certain pictures I took would exhibit posterization or blooming. An extreme example here:

At first, I did not suspect the RAW converters because both Aperture and Photoshop gave me nearly identical output. I was led to believe that it was a problem with the 5D itself, perhaps with the ISO sensitivity pushed so high that the extremes in light (areas of darkness and subjects in spotlights) were just overwhelming the camera’s ability to give smooth graduations.

That part I could live with, perhaps, but there were also images, more disturbingly, where *new* information was being added. Example below:

There are strong yellow bands distrupting the areas of falloff on the skin colors. This was even more bothersome to me than the first example, because it just looks all wrong! Again, both Aperture and Photoshop were rendering the image like this.

Where is the problem occuring?

I was starting to have doubts about using my 5D at ISO 3200 with results like this. Granted, it didn’t occur very frequently, only in certain extreme examples, and that 90% of my other images where there wasn’t a strong contrast in colors or for specific colors, the image would be just fine. Like the image below.

But still, I didn’t want to capture the killer shot, and have it ruined with some posterization. But I couldn’t really back down to ISO 1600 either. ISO 1600 wouldn’t give me the shutter speeds I needed.

Its Not The Camera, Stupid

It was only by accident, one day when I was reviewing some shots on my 5D on a photo shoot when I realized I had not formatted the memory card and it still had old shots from a nightclub shoot from a week previous. A few of those pictures from that night had posterization issues, and so I decided to check them out on the camera, and see what the preview showed me.

And to my complete surprise. The preview image was just fine! No posterization at all!

So, where do things stand now?

With the release of Aperture 2.0, and its new RAW decoder, I eagerly checked out to see what, if any improvements. The results are mixed. Some things got vastly better, some were improved slightly, and some stuff, in my opinion, got worse. I realized I couldn’t just sit here and do nothing about it. I’m probably one of those extreme margin cases, and only by making my observations known, I can help the development teams at Adobe and Apple improve their RAW decoding for those examples.

The Good

In this example below, both Aperture 1.5 and Photoshop CS3 rendered skins with that mysterious deep yellow banding/blooming.

(Aperture 1.1 RAW)

(Photoshop CS3)

Aperture 2.0’s RAW dramatically improves the image. There is no more posterization in the picture anymore.

The Bad

Unfortunately, the above example is the only one I have observed that resolved the posterization/blooming issue completely. The majority of pictures I reviewed were improved slightly, but not completely, with the Aperture 2.0 RAW decoder. The Aperture 2.0 RAW example exhibits less posterization, but the color shifts are still rather apparent. Examples below:

(Aperture 1.1)

(Photoshop CS3)

(Aperture 2.0)

The Worse

In some of the pictures that I reviewed, I actually think Aperture 2.0 did worse. Those examples seem to be where magneta or purple posterization occurs. Examples below:

(Aperture 1.1)

(Photoshop CS3)

(Aperture 2.0)

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