Viewfinder specs and view
The SD1's viewfinder is large by APS-C standards - its 0.95x magnification places it on a par with the likes of the Canon EOS 7D, Nikon D7000 and Pentax K-5. However this is noticeably smaller than the large electronic finder on Sony's SLT-A77, which is close in size to the optical finders of full-frame SLRs. It offers 98% coverage of the captured scene both vertically and horizontally, while its main competitors all claim 100% coverage.
The SD1's fixed matte screen gives a good indication of focus, making manual focus relatively straightforward. A corollary of this, though, is that the view can get somewhat dark when using lenses with small maximum apertures in the F4-5.6 range. It's also worth noting that focusing in the OVF can never be quite as accurate for really critical work as magnified live view, which the SD1 regrettably doesn't offer.
One figure hidden away in every SLR's spec is the size of the viewfinder (often in a format that makes comparison between competing models impossible). The size of the viewfinder is a key factor in the usability of an SLR - the bigger it is, the easier it is to frame and focus your shots, and the more enjoyable and involving process it is.
Because of the way viewfinders are measured (using a fixed lens, rather than a lens of equivalent magnification), you also need to take the sensor size into account, so the numbers in the diagram below are the manufacturer's specified magnifications divided by the respective 'crop factors'.
|The Sigma SD1 has a viewfinder magnification of 0.95x, placing it in line with other high-end APS-C cameras such as the Nikon D7000 and Pentax K-5.|
Many SLRs crop the frame slightly when you look through the viewfinder - in other words you get slightly more in the final picture than you see through the viewfinder. The SD1 shows 98% (vertically and horizontally) of the frame. This may seem like a disadvantage compared to other high-end APS-C cameras which offer full 100% coverage. Unless you spend all of your time working extremely critically with the camera on a tripod, however, it's pretty well irrelevant in practice, as the example below illustrates.
|The white frame overlaid on the image simulates the 98% coverage you have of the captured scene when looking through the SD1's viewfinder.|
The SD1's viewfinder display includes exposure mode and metering pattern, alongside shutter speed, aperture, exposure compensation and available buffer depth. But full-time display of ISO is conspicuous by its absence - you can only see it by pressing the awkwardly-placed ISO button. Instead the SD1 displays the much-less-useful number of shots remaining on the card, which in these days of multi-GB storage tends to say little other than 'lots'.