The recent spate of camera announcements has brought forth many half-informed comments about sensor sizes and pixel counts. Let's clear some stuff up.
You can make great, as in fully professional quality, photographs with small sensors. I'm not talking about artistic subjectivity, I'm talking about objective technical quality. Now, just as with small-format film cameras (read: 35mm) they're not going to be the best choice under every single circumstance. Some subjects or working styles simply demand a camera with humongous real estate. No argument. My disagreement is with those who say it's not possible to do professional work with small sensors, stating it like some law of nature rather than their personal preference. Plainly and simply wrong.
My current camera, an Olympus Pen EP-1, has a half-scale sensor (scale relative to 35mm/full-frame—nobody can remember what those damn video-format names mean). My camera before that, based on 4-year-old technology, which is forever in Internet years, was a Fuji S100FS with a quarter-scale sensor. Almost all the photographs I'll be talking about were made with that camera.
As I wrote in my original review, photographs produced by the Fuji at low ISOs were almost a dead ringer for those produced by a Nikon D200. I was very happy using that camera at anything between ISO 100 and 400. In fact, most of the digital photographs made from 2008 through 2010 that I'm selling 17x 22" prints of were made with that camera. Seventeen by twenty-two inches is not a small print, and my standards are not modest.
This picture is a good example. This photograph depends on low noise, a long exposure range, and well-rendered edge detail to succeed, all things that small sensor cameras are supposed to be unacceptable for.
You don't necessarily need a lot of pixels, either. I'm not saying more pixels aren't nice, just not necessary. On that "newer work" webpage, all the digital prints from 2008 through 2010 came from 9–12 megapixel files. I wouldn't print them bigger than 17x22", but they're fine up to there.
This panoramic photograph doesn't really violate that rule. Yes, it's a stitch of three frames and has a total of about 24 megapixels, but it looks best as a 40-inch wide print. You can't really see any of the detail. This JPEG is one third the resolution of the original file and begins to give you a sense of what there is in that photograph. For compulsive pixel-peepers, below is a full-resolution section. Keep in mind that looking at this on your monitor is like looking at a section of a 7-foot-long print.
In summary, you don't need a large sensor and you don't need a lot of pixels. You can do serious photography of demanding subjects with a double handful of megapixels and a sensor the size of your pinky nail. As the title reads, size doesn't matter.
On the other hand...
...Those who say that there's no point to having more megapixels and/or a larger sensor are equally wrong. Even in small prints (these days that's an 8x10), side-by-side comparisons will show that more pixels are better, up to some phenomenally large number. Think nine figures. Again, I'm not saying you need this. But there is a palpable, visible improvement, the same way that a contact print from 8x10 film would beat the pants off of anything enlarged from a smaller format.
Now, before people start posting comments to the effect that lenses aren't good enough to take advantage of lots of pixels in small sensors or that diffraction prevents you from getting good quality out of small pixels, save your breath. I've covered this in excruciating technical detail in previous columns. I don't need to flog that horse again. It's wrong, okay? You can go up to insanely high pixel counts and insanely small pixels before more pixels stop meaning more detail in the photograph.
Sometimes, there is no substitute for more pixels. Take this picture, also viewable here at about 50% scale. You might be wondering how Photoshop did such an incredible job of stitching the surf together. Well, it didn't. This isn't a stitched photograph, it's a cropped one! I started with a 5K by 6K file from a Phase One back and cropped out the top and the bottom, leaving me with a "mere" 18 megapixel photograph.
Not so incidentally, I can see a visible difference between an 8x10 print of this photograph and one made from a file with half the resolution. Eight megapixels will look plenty good filling an 8x10 inch sheet; 32 megapixels will look even better.
This panorama didn't require a large sensor, just a lot of pixels. Sometimes, though, one needs the acreage. The picture below would look okay if made with a (relatively) small-pixel-count, small-sensor camera, but it looks positively great coming from a Phase One back. Thirty megapixels, huge exposure range, and a lovely signal-to-noise ratio. What's not to like? (Well, for one thing, a camera heavy enough to anchor a modest-sized yacht.) Like the title says, size does matter.
As I said at the beginning, this isn't about your particular needs and working style. If you're one of the minority who's passionately in love with ultra-shallow depths of field, you need larger sensors and faster lenses. If life for you starts at ISO 1600 and goes up from there, your sweet spot is somewhere in the 2/3 to full-frame sensor range; smaller sensors—and larger ones—will usually not be as well-optimized for high ISO work.
But, for most of us, size and pixel count don't matter anywhere as much as some people claim.
Ctein's regular weekly column appears on TOP on Wednesdays. This one was written before today's CX-format announcement, although it surely pertains. —MJ
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Original contents copyright 2011 by Michael C. Johnston and/or the bylined author. All Rights Reserved.