bluefacedpixie

I discovered HDR last week.

HDR is High Dynamic Range photographs. There are many flickr groups and images, a wikipedia entry, an FAQ, and a recent NYT article. All of which happened nigh simultaneously to me last week.

HDR is intriguing – it offers the ability of combining digital images to expand the range that can be viewed. This is important as the human eye is more subtle in its distinction of light and detail and can see more in a glance than a photograph can reproduce – the classic example is viewing a house with an open door. The human eye will see some detail through the door and the detail of the house, even in bright light. A photograph would have to choose, as it would not have the range to do both. The photographer, camera and ‘film’ choose the image. Ironically enough, although digital has a smaller range than film had, it can capture images that can be merged into a greater range than film. Almost as good as the eye.

The photos taken can be unsettling – not really photograph like, and often compared to paintings. We’re just not used to seeing photos with this many “shades of gray” i.e. ranges of colour. Indeed sometimes the simple photo seems better.

This weekend, while hiking in the North Cascades, I decided to take one set of photographs of Mt. Baker to experiment. You have to buy HDR merging software; there are plugins for Photoshop (which I don’t have) and standalone programs e.g. there is one for Windows and Mac called Photomatix. I used the demo version of Photomatix for experimentation and will probably bite the bullet to produce more HDR photos.

For the example I took 3 shots using exposure bracketing on my Nikon D50, 2 stops apart (one very bright, one ok, one very dark). All shots were taken with the 18-55mm lens, using a polarizing circular filter on the same position. I took the shots in NEF (Nikon RAW) but used Preview on the Mac to make them TIFF as Photomatix doesn’t understand NEF. I then proceeded to HDR merge the shots in four different ways, choosing values mostly at random and making gratuitous use of automatic settings.

Before we leap into the examples, one final comment: apparently the computer screen doesn’t necessarily do HDR full justice and you need to print for the full effect. I’ll do that later.

A typical JPG shot

Now I think the above shot is cracking. Great colour, nice interaction, good rich feeling. There’s a little detail lost in the foreground and clouds, but I’m not looking there.

My first HDR - a straight automatic average merge

Wow. Admittedly, for the HDR’s I’ve zoomed out a little from the JPG, but the trees are so green. But the sky is a little wishy-washy, not really as deep as the JPG. But wait, there’s detail in the cloud. And if I take my Smith’s off, what do I really see.

HDR - Tonemapped

An alterative merging process, I don’t think this is the best shot to play with. Too bright, but that unrealistic watercolour effect that people complain about is creeping in.

HDR - Automatic Mode

This shot is the one used at the head of the blog entry.

Once the colour difference with the JPG is accepted, the detail is amazing. This is the same camera. It’s only 6MP, the detail differences can’t be explained with JPG/NEF because it’s mostly about colour. I am now officially intrigued.

HDR - Manual Adjustment

I didn’t know what I was doing with the manual settings. There are a lot of sliders and settings. My objective was to find a midpoint between tone and auto and I kinda like it. I think that for this mode, you need a vision and then try and get there with digital merging.

and now…

To wrap up, what do you think – which one looks best, the most realistic? I’m a far shot from this flickr group, which claims to be My First HDR. Leave comments here, or on flickr. In my geeky way, I’ll be watching.

[Photomatix branding on some presented images due to demo software. Good, easy to use, runs well but not sparky on my older Powerbook G4 on 35Mb images]