Bigger is Different. / by Edward Crim

In a previous post I stood the risk of being misunderstood by some of my readers. I am fully aware that all other things being equal, sensor size does make a difference in the way your image looks, but, hey, this is not the same as saying “bigger is better”, it’s more like “bigger is different”, and, of course, you may like that “different”, better. So how are the bigger sensors different? There are quite a number of ways in which these differences show, actually. Let’s list them.

1) Depth of Field – as I mentioned in my previous article, the larger the sensor (or in the days of film, the film size) the shallower the depth of field (the zone of acceptable focus) of the image. This is a physical law and technological change will not affect this part of the equation.

2) Pixel size – assuming we have 4 different sensors all with the same pixel count, i.e., the same Megapixel value, the largest sensor has the largest pixels. The larger the pixel, the more photons reach it and the stronger the signal it emits. The stronger the signal, the greater the dynamic range (contrast, basically – shadow and highlight detail retained), and therefore the better it performs under low light situations, and the greater the color accuracy will be. This is assuming, of course, that the sensors are all of the same vintage and level of technology. The current rate of change in the field of technology is phenomenal, and improvements to sensors and data processing chips are enabling today’s small sensor cameras to outperform yesterday’s full frame units. Therefore, large sensors are theoretically able to out-perform small sensors under low light conditions and they usually do; usually, but not always.

3) Lens Size – One of the promises made to photographers in the early days of the crop sensor cameras was that lenses could be made smaller for the same f value as their 35mm (full frame) counterparts. Several manufacturers have actually followed through on this, such as Fujifilm, Olympus and Panasonic. These systems offer great low light performance, wide selections of large aperture lenses, and the benefits of small size and light weight. Independent lens manufacturers such as Sigma, Tamron, and Tokina, have followed suit with such great lenses as Tamron’s 18-400, Sigma’s 18-35 f1.8 and Tokina’s 14-20 f2.

4) Camera size & weight – This should be obvious, but many people don’t think about it much. My Canon 5D Mk II is a full frame camera that weighs 810 grams without a battery, and about 1550 grams with battery and my 24-105 lens. My Fujifilm XT-20, a crop sensor camera like the Canon Digital Rebel series, weighs 333 grams without battery and 713 grams with 18-55 lens and battery. In other words, the Fujifilm camera weighs less than half as much as the Canon.

So which camera is better? It depends entirely on the job to be done. When I shoot professionally, I use my Canon cameras. I like the responsiveness of them, I like the larger size, I don’t mind the weight (a rolling bag helps there), I prefer an optical viewfinder to an electronic one, I sometimes need the shallower depth of field that the larger sensor affords, and I sometimes need specialty lenses that are simply not available for my Fujifilm camera. Lenses such as the 17mm and other tilt/shift lenses, which are ideal for architectural work, are only available for Canon and Nikon camera lines. Full disclosure, though; I have both full frame and crop sensor Canon cameras in my tool kit. Why? I have both because they are each useful in different circumstances. I don’t have a 24mm tilt/shift, but when I use the 17mm lens on a crop sensor Canon, it gives me the same angle of view as a 24mm would on a full frame Canon. The camera was much less expensive than the 24mm lens and it also comes in handy for telephoto shots where it gives me extra reach (giving a 200mm lens the reach of a 300 on a full frame camera) and sports shooting, where it gives me much greater frame rate than my full frame camera.

Which camera is better? My Fujifilm offers an articulating screen that allows waist-level or over the head viewing, which none of the full frame Canon cameras allow (Nikon and Sony do, though). My Fujifilm camera incorporates a completely silent electronic shutter (only Sony offers that in a full frame camera), which with its small size and waist-level viewing make it great for street photography and any other candid shooting. It is also great in low light and the images it creates are equal in quality to my full frame Canon cameras.

Which camera is better? Sony has a great series of super zoom cameras built around their one inch sensors (which are actually just about 9x12mm, less than half an inch in each dimension). Their RX10 IV is a heck of a camera, incorporating a 25x zoom lens (greater than anything available for a DLSR, crop or full frame), super fast autofocus, and outstanding image quality. In the tests I did for my previous article (I used the RX10 II) I was amazed at the quality of the images produced by the one inch sensor when compared directly to the full frame Canon. For some uses, the Sony RX10 IV would be a better choice than either my Canon 5D MKII or my Fujifilm XT-20. What would those uses be? When we want to travel light, spend a weekend hiking, hang out at the park with friends, or blend in with the amateurs. But this camera is also good enough that we could use it for product photography, portraits, sports, wildlife, and landscapes. It wouldn’t be my first choice for any of those purposes, but not because of image quality. The image quality of this camera is excellent and well suited to all of these uses.

The point of all this is that the state of the art of digital cameras has advanced so greatly that the image quality of almost any current camera is good enough to take to press in a magazine or make a huge print for wall display, and is plenty good enough to illustrate an article on the internet, which is more than 99.44% of digital photos will ever actually do. Image quality should not be your primary criteria for purchasing a camera because almost all of them produce great image quality. Consider size, weight, available lenses, handling and cost as more important.