Friday, November 25, 2005

So why did I decide to get a big new dSLR? What can it do that the other pont-and-shoot digitals can't do?

I was a keen photographer when I was younger - I used to develop my own black-and white films at home, and I had set up a darkroom in the loft. I also toyed with colour photography: both slide processing and colour printing. I found that colour photographic chemistry was very difficult to control: the slides came out ok-ish, but it seemed almost impossible to get the colour right for prints. I stopped developing my own photos about half-way through university. It's only now that digital SLRs have become reasonably affordable, offering the sort of flexibility that I was trying to acheive by developing my own photos. I'm not much good at music drawing or painting: photography is a great art form for someone into gadgets and technology.

The first reason for choosing a dSLR is the quality and range of lenses available. There's always a compromise to be made when designing a lens. Cheaper cameras have smaller aperture lenses, and will have more distortion or aberration at either end of the zoom range.

The next reason is the quality of the sensor. The dSLR doesn't just have more megapixels, it has a larger sensor. With four times as much silicon behind each pixel, it's mich less prone to random noise: smaller cameras show more noise when you turn up the amplification in the sensor.

Another feature of this sort of camera is the ability to save raw images: this is the image digitised from the sensor, without any other processing. No jpeg compression artifacts, and 16 bits per pixel. The raw image is sometimes called the 'digital negative'. This gives much greater leeway for 'digital darkroom' work: adjusting brightess levels, colour balance, etc.

Other features of the new camera include very fast startup, very fast autofocus, continuous shooting at 3 frames per second, and lots more control over focus, metering, whitebalance, etc.

My little pentax pocket camera is great for simple snapshots, really lightweight and compact: it has a 3x zoom lens (giving a 35mm-equivalent range of about 36-107mm focal length), but it is fully auto: there's not much manual control. The effective film speed is 80-400asa.

The Kodak has much larger zoom, equivalent to 38-380mm; sensitivity 80-800asa, with good manual control over shutter speed, aperture, manual control: but I have never been particularly happy with the image sharpness at the long end of the zoom, the wide end of the zoom isn't really wide enough, and it is sometimes very poor at acheiving autofocus.

My new Nikon D50 has an effective fim speed of 200-1600asa. Even at the top 1600asa sensitivity there's virtually no noise visible in the image. The sensor is smaller than a 35mm frame, so the lenses give a field of view equivalent to a 1.5x longer lens: I chose a 18-70mm lens, (giving the equivalent field of view of 27-105mm on a 35mm camera). I have also bought a 35mm f/2 for low-light use.

So what does all this mean in terms of the actual photos taken? A wider wideangle means it's easier to get in all the people in a group, it's also good for certain types of scenery shots, architecture, etc. A fast lens and high-speed sensor means it's easier to take low-light shots, eg in museums where flash is not allowed. A wide aperture also means you can throw the background out of focus in a portrait.


Sunday, November 20, 2005

Grantchester Meadows


Grantchester Meadows, originally uploaded by hchalkley.

I decided in the end to get a new Nikon D50, rather than a D200: the money I save can go towards some decent lenses instead!
Here's a great photo taken with the new camera.


Tuesday, November 01, 2005

First official news of the Nikon D200:
Kodak europe; dcresource;
engadget; dpreview
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