High Dynamic Range and the Quality of the Pixel

Sun, May 8, 2005

I wasn't going to upgrade to Photoshop CS2 because I didn't think that I need it.  But that was before I found out about the new support for High Dynamic Range (HDR) and 32 bits per channel floating point support.  Michael Reichmann over at The Luminous Landscape has an article talking about the new "Merge to HDR".  I was going to how current cameras only handle 6 stops and all (and what a stop is) but Michael does a good job of that in his article.

I'm excited about this feature because I think that it will enable me to capture images that I haven't been able to before.  I've often shot bracketed exposures with the thought that I would merge them together by hand later. The results rarely are as good as I imagined when I took the image.  For instance, shooting a sunrise of a mountain where the top of the mountain is in the sun but the rest is in shadow can be very difficult.  Having a tool that approaches this in a more methodical way is exciting.  On top of this, I'm excited by the possibilities of this combined with panoramic photography.  Wide angle and pano photography has a problem whereby you are taking in so much of a scene that you are much more likely to have parts of the image be very bright and others be very dark.  One of the skills that I've been developing is the ability to pick a scene where I won't run in to these problems.

But, as great as the new Photoshop might be, there are other parts of the digital photography system that need to catch up.  The first is on the display side.  While the data in a photograph might contain lots of dynamic range, today's displays can't show it all.  That is going to change over the next couple of years.  On the software side, there is plumbing being laid to support 32bpp through the Windows desktop and to the video driver.  (The 3D APIs and graphics cards are support a lot of this already because it can be useful in 3D rendering).  The displays are going to get better also.  Over the next couple of years, expect to see wide gamut and HDR screens coming out.  Sunnybrook is one of the companies that has been pioneering this LED based display technology.  Where normal LCD or CRT displays can get a contrast ratio of 300-400:1, they claim their LED technology can get 60,000:1.  That means the bright spots are brighter and the shadows are darker.  I haven't seen one of these displays myself, but I'm super excited by the technology.

The other side that needs to improve is on the image capture side.  I have not specific knowledge of any plans from any camera manufacturers, but it is obvious that the megapixel race is slowing down.  We are reaching the limits of the glass.  Another example is the fact that the new prosumer level Nikon SLRs are still only 6 megapixel.  It is clear that the camera makers are going to compete on more than just the number of pixels.  They will start competing on the quality of those pixels. This is going to be very exciting.  We are entering a world where digital cameras are not just matching the abilities of film cameras, but they are on the verge of surpassing them.  A camera that can capture higher dynamic range and a wider gamut?  Sign me up!

The big question in my mind is the print making side of the equation.  When I print my photos, I usually send them out (WHCC or WCI) to be printed on a Chromira printer.  This is a printer that uses LEDs to expose regular photo paper.  This photo paper is then printed traditionally.  The gamut of these devices (and that of the ink jet processes) can be larger than current displays but is still fairly limited.  The dynamic range of all of these output devices is pretty low compared to what can be done with an emissive display device.  The bottom line is that the printing technology isn't keeping up with the rest of the system.  What does this mean in the long term?  I'm not sure but we will start to see a vast divergence between the quality of an image when displayed on a good monitor compared to they quality of an image when printed.

It certainly is an exciting time for photography...