Canon 7D Viewfinder

Canon 7D Viewfinder

The Canon 7D is a digital SLR design, so the optical viewfinder offers a true, through-the-lens (TTL) image. A dioptric adjustment dial at the top-right of the eye-piece accommodates eyeglass wearers, letting them adjust the viewfinder optics between -3.0 to +1 diopters. Viewfinder coverage is specified by Canon at 100%, and magnification is 1.0x (!) for a 50mm lens and -1 diopter, which is truly excellent. The viewfinder eyepiece has an eyepoint of approximately 22mm from the eyepiece lens center. This is a higher than average eyepoint, making the Canon 7D's viewfinder more comfortable for eyeglass wearers.

Like most other prosumer and pro DSLRs, the Canon 7D viewfinder uses an all-glass pentaprism design. The advantage of a pentaprism over a pentamirror design is that the pentaprism delivers more light to the viewfinder eyepiece, thanks to its more efficient internal reflection. As a result, the Canon 7D's viewfinder image is not only large, but bright.

The EOS 7D's viewfinder doesn't feature interchangeable focusing screens. Instead, it has a transmissive polymer network LCD display integrated into the prism assembly -- a design we've previously seen in Nikon's DSLRs. Illuminated by a light-emitting diode in low-light conditions, this display is embedded with patterns that allow it to display either the camera's AF points, metering areas or a grid to assist with precise image alignment. It's an interesting design that allows the user to select which information they want to see without needing to fiddle with changing viewfinder screens. One potential drawback is that in extremely cold (sub-freezing) temperatures, the AF point display in AI Servo Tracking mode may lag behind the actual performance of the AF system. Note that due to the transmissive display, when there's no battery in the EOS 7D, its viewfinder becomes dark and clouded.