Photo: Phil Askey

Clearly late August was traditionally considered a good time to launch a new camera, given we're able to mark the anniversary of a third historic announcement in the same week. As part of the twenty-fifth anniversary of DPReview, we're looking back at major events that occurred during the site's history. And they don't get much bigger than the arrival of the Canon EOS 5D.

Imaging sensors were expensive to produce in the early days of digital photography, meaning a lot of digital cameras were built around relatively small expanses of silicon. This was fine in compact cameras, where the lens was designed specifically to give a useful field of view in conjunction with those small sensors, but it presented a problem for SLR users.

The first mainstream DSLRs used APS-C sensors, which were less than half the size of the 36 x 24mm film negative used by the dominant 35mm format. This had all sorts of knock-on effects, including cameras with smaller, darker viewfinders. But perhaps the most significant was that these cameras only captured a central crop of the area SLR lenses had been designed to capture, effectively cropping the field of view. This meant that anyone continuing to use the lenses from their film cameras suddenly found they had narrower fields of view and less control over depth-of-field than they'd been used to.

The Canon EOS 5D changed all of this: bringing a 36 x 24mm "full-frame" sensor in a camera that amateur and enthusiast photographers could afford, rather than just the professionals. At $3299 ($5280 in today's dollars), it wasn't cheap, but it brought it within reach of a much wider audience.

At its heart was a 12.8MP CMOS sensor, at a time when most of the market was still using CCD chips. This next-generation tech applied in a sensor around 2.4x larger than its APS-C. Despite this, it's interesting to look back at our original review, which suggests that the 5D didn't seem to bring the degree of image quality improvement that that larger sensor would be expected to bring.

Read our original Canon EOS 5D review

The review concluded that "noise levels are essentially identical to the EOS 20D as is dynamic range." Which sounds like it must be a mistake. Perhaps a result of the site's then (understandable) focus on pixel-level output. But it turns out to be consistent with other testing.

With modern sensors, you'd expect around a 1EV dynamic range difference between an APS-C and a full-frame sensor if you view the output at the same size. But this is because modern sensors have so little read noise that shot noise (the inherent randomness of the light being captured) ends up as the limiting factor. This means the size difference, which dictates how much light the sensor experiences, ends up defining the IQ differences

With the 5D, we can see that read noise was blunting this potential benefit. As ever, though, dynamic range isn't an assessment of image quality as a whole, and neither is noise. Look at DxOMark's SNR 18% measurements (an assessment of the tonal quality of the midtones of the image), in 'Print' mode, and you see that there's an appreciable IQ benefit to the larger sensor, even if it's not quite the 1.3EV advantage over APS-C that we'd expect to see today.

Photo: Carey Rose

The EOS 5D went on to become beloved of a range of photographers, from wedding shooters to keen amateurs wanting the full range of their film lenses back. It also set in place the idea of an upgrade path, on which your APS-C camera was merely a stepping stone on the way to the full-frame promised land. Even at the time of review, Phil recognized distinct pro- and anti- full-frame camps becoming entrenched.

As a consequence of its mid-tier status, the original 5D wasn't as ruggedly built as Canon's pro-focused EOS-1DS models. While there are, no doubt, 5D 'classics' still providing good service, its popularity and workhorse image meant that many were worked into the ground. Stories of mirrors coming loose were becoming common currency more than a decade ago.

In many respects the EOS 5D's place in camera history is set: it would be nearly three years before Canon's rivals would introduce their own single-grip full-framers (including the similarly well-loved Nikon D700). But just as those competitors appeared, Canon would go on to introduce one of the few DSLRs that can challenge the EOS 5D in terms of historical significance: the EOS 5D Mark II.

Canon EOS 5D sample gallery