Like a person’s nose, the viewfinder prism is the central integrating part of an SLR’s design, and consequently it is the most distinguishing visual trait. Ideally, it articulates the essence of the forms around it. Unfortunately, the prism is often the subject of “creative expression” for marketing purposes. To encourage the acceptance of planned obsolescence, they must approach the prism as an area for decoration of dubious quality. Just looking at the example of Canon, it’s easy to see that this phenomenon generally has a direct relationship with the camera’s price: as the cost goes down, so does the quality of the prism’s design.
 |
| The Canon 1Ds Mark II (4/04) and III (11/07). |
The current stylistic trend in camera design has been toward linearity and simpler geometry, a shift embodied most subtly in Canon’s 1-series. The blobby, NURBS-enabled design of the original 1D (December 2001) through the 1D MkIIn (October 2005), whose prism always reminded me of an elephant’s forehead, was supplanted by the slightly less blobby design introduced by the 1D MkIII (May 2007). Apart from it’s pronounced sloping shoulders, the key differences are the two edges that run down the face of the prism, formed by a curved plane and saddle surfaces which intersect. The concave shoulders sweep down from the flattened, convex band of the prism’s center. Personally speaking, this post-2007 prism is one of the classic SLR prism designs along with the Nikon F’s eye level finder, Pentax Spotmatic, Topcon RE, Contax RTS, and Leica S2.
 |
| Elephant's forehead. |
 |
| Some kind of frog or toad. |
In these three-quarter views, note how the rounded edge on the right side of the MkIII has a smaller radius and creates a more distinct line.
 |
| Canon 1Ds MkII (November 2004). |
 |
| Canon 1Ds MkIII (November 2007). |
The trend toward linearity can also be seen in the 5D series. It’s a shame that Canon hasn’t produced a version of the 1-series without the vertical grip since the design, interface, autofocus, and weather sealing are not quite as nice in their other cameras.
 |
| Canon 5D (October 2005). |
 |
| Canon 5D MkII (November 2008). |
 |
| Canon 5D MkIII (March 2012). |
Rather than settling on a strong design for several generations, each iteration of the 5D series has shifted from one uninspired, noncommittal design to another, just like the x0D series. The original 5D’s prism oddly resembles a pig’s nose, while the MkII needlessly departs from the 1Ds MkIII’s basic design by adding chamfered edges (a bit like the Pentax 645D) and an angular throat. In trying to slim down the body, the buttons in front of the top LCD jut out from the edge a little bit, which clutters up the design. The exaggeratedly chamfered edges on the MkIII make the prism look fairly rounded from the front, which has really only worked on the Leica S2 and Sony A99 because they both have raised shoulders that minimize the viewfinder’s protrusion.
 |
| Prism of the Canon 5D MkIII. |
That said, the Canon 6D deserves mentioning for its admirably plain design.
 |
| Canon 6D (November 2012). |
The design of the x0D series has been the most erratic, leading to an occasional hit but mostly misses. The 10D should remind you of the Nikon D4 and D800, Sony A100, Panasonic G and GH series, and Samsung Galaxy NX (along with a handful of bridge cameras) since the motif of a single contoured surface that blends the front of the top plate with the front of the prism was, I think, introduced by this camera. I would have to dig further to be sure. My favorite is the straightforward 30D. It’s the Platonic ideal of an APS-C DSLR. The 7D would look better if it didn’t seem overinflated, and I’m not sure what happened with the 40D and 50D. They tried to add a touch of hardness to it, but chiseling some facets on the prism’s beak did not work out in this case.
 |
| Canon 10D (March 2003). |
 |
| Canon 20D/a (September 2004/February 2005). |
 |
| Canon 30D (March 2006). |
 |
| Canon 40D/50D (September 2007/September 2008). |
 |
| Canon 7D (October 2009). |
Given the higher specifications and stronger designs of higher end cameras in general, it is tempting to look at new upgrades in a lower end series and see a connection between internal improvements and the quality of external design. Of course, no such correlation exists within a series, only between them. A better looking design is a matter of chance when it comes to mass market consumer cameras. It is only at the high end and in niches where standards of good design are maintained. An obnoxious fact of modern life.
