Conventional wisdom says that the camera with the biggest sensor will be the best. That’s such a gross oversimplification as to be almost a lie. Conventional Wisdom Conventional wisdom says that the larger the pixel sensor element size, the cleaner and more noise free the image will be. Therefore, there has been a trend over the last few years to increase the sensor size. Almost all high end compact cameras now use 1/1.7” sensors at a minimum. The Lumix DMC-LX5, Canon G12, Nikon P7000, GR Digital III and Olympus XZ-1 all sport 1/7” sensors. Now we’re at the point where we have a whole new class of compact cameras with APS-C sensors. Cameras in the Super Compact class include Sigma’s DP1x and DP2x, Leica’s X1 and the new Fujifilm X100. Problems with Large Sensors Large sensors are not without their own problems. First they are expensive. APS-C compacts typically cost more than a thousand dollars. Secondly the whole optical system has to be physically scaled up so they’re hardly compact anymore. I can barely fit a Micro Four Thirds Lumix GF2 with even 14mmm pancake lens into my pocket. Likewise the X100 is a tight fit. For me portability is the whole point of compact cameras. Without compactness, I may as well leave it on the shelf next to the DSLR. The third problem lies with image quality. I can just about live with noise, but I can’t save a picture with poor focus. Slow and inaccurate focus is a bit of a problem with all the super compacts. The large sensor is compounded by fast lenses that give shallow depths of field and show up focusing inaccuracy. Compare this to the Ricoh GRDIII. You can be very sloppy with the focus and the wide lens, and smaller sensor is more forgiving. Small sensors are improving faster than large sensors. All would be forgiven if the super compacts made up for it in image quality. The X100 and its peers deliver in this respect. However, I’d be kidding myself if I said that most of my photos ever got printed or used at the highest resolution. At screen resolutions, it can be hard to justify the difference in price and size compared to the XZ-1 or GRD. I tend to use a DSLR for more serious shooting, technical shooting. A compact sits in my pocket as a backup or a walkabout camera. Viewed this way, the results are uncomfortably close between the ‘serious compacts’ and ‘super compacts’. Likewise, smaller sensor cameras seem to be catching up too. You can get much better performance from a 1/2.5” or 1/2.3” these days than I remember getting from my old IXUS 65. Amazingly this image quality advanced hand in hand with increased resolution. Sensor testing authority DxOMark explains it thus: “increasing resolution results in additional information that evenly balances the added noise due to smaller pixel size”. As a result, DxOMark says, small sensor cameras are beginning to catch up with large sensor cameras in terms of image quality. Yes, the X100 can take outstanding low light images, but I think that under the majority of real world conditions, I actually get better low light images with a smaller sensor. By a real world condition, I mean seeing something I want to photograph, whipping it out and quickly taking the shot. Some Parting Thoughts What does this all mean? Compact cameras are coming into their own. Over the next few years, I think we’ll see many DSLR owners come to rely more and more on their compact cameras. The new super compacts will grow as a class, but for many people the smaller 1/7” format is more practical and certainly cheaper.