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Introduction

Photography has undergone some seismic shifts in the last decade. The digital camera has dealt large blows to the fortunes of many companies. Kodak is bankrupt. Minolta has vanished into the hands of Sony. Pentax and Olympus are struggling. Yet with all of that, it looks like the digital compact camera is being killed also. The camera phone has now taken off. Two of the three most popular cameras on Flickr are iPhones. Not one of the top 5 is a digital compact.

Digital compacts are going to take another hit from another new technology. This is the mirrorless camera. It produces DSLR quality photos in a compact body. Now while it might be assumed that the mirrorless camera is kind of a halfway house between a compact and a DSLR, this misses the point. The mirror-less camera is really a completely different way to take pictures. Its portability means it’s much easier to take with you (e.g. it now comes with me when I’m cycling) so you end up trying and experimenting with more kinds of photos.

I know finally, have the answer to the question I often get asked. That’s what camera someone should buy. The answer is a mirrorless camera. I’m pretty enthusiastic about the Sony NEX system, as it uses a larger sensor than the rival micro-4/3 (MFT) system used by Panasonic and Olympus. Your mileage may vary. There’s no such thing as ‘the best’ camera system. All have different strengths and weaknesses.

Sony Nex-5 with 18-55mm kit lens


So what are the main differences? Compared to a compact camera the biggest difference is the size of the sensor. A Sony NEX camera uses an APS-C sensor that has an area of 370mm2. Most compacts have an area of 28.5mm2 and camera phones have smaller sensors than that. This means that even at 14-16 megapixels (MP) a mirrorless camera is using pixels that are individually much larger. This means it can extract more information from the light hitting the sensor. This translates into better colours, better detail and much better low light performance. It doesn’t matter how much processing power you throw at a digital image, if there’s a not a lot of information there, you can’t do much with it. This is the main reason I’ve never bothered getting a compact before. The images just aren’t that good when you start looking closely.

The other important differences are that mirrorless cameras have interchangeable lenses, and that they allow for full manual control over the exposure and focus. Being able to use a lens that is optimal for a scene, and being able to place the focal point exactly where you want it, makes a critical difference.

Compared to an SLR camera the obvious difference is the mirror mechanism is redundant. This means the camera can be made much more compact. Because the mirror doesn’t have to flip up and down when you take a picture, it also means that you can get a high frames-per-second, and video functions are much easier to implement. In fact, because these cameras use much larger sensors than many video-cameras and you can employ high-quality SLR lenses, you can get very high quality video clips also.

The big disadvantage is that the mirror-less camera has to use contrast detection for autofocus. This isn’t a big issue for landscape shots, but makes a big difference for action shots (wildlife, sports etc). SLR cameras use phase detection which is better at predicting movement and focuses faster.

An aside on autofocus.

Phase detection: image is split and then projected onto sensor via semi-transparent points on mirror. Images are compared and measured to see if subject is correctly focused. Is better at continuous focusing and in low light conditions than contrast detection.

Contrast detection: focus is adjusted until image achieves greatest contrast. The camera cannot tell if low contrast is a result of the lens focusing in front of, or behind, the subject. This makes it less effective for moving subjects and in low light (not enough contrast). It has to do a lot more focus-hunting to find the subject.



As a result I’m not ditching my SLR kit just yet. In a recent trip I was still using 2 cameras, but this time one of them was my NEX-5. The DSLR had my 300mm prime lens and was used for the bird and wildlife photography. Whenever I wanted to take a landscape shot I used the NEX-5. It was much easier than having another DSLR with me and the larger lenses this requires.

…In the next blog piece, a beginner's guide