Nikon D3100 Viewfinder

Nikon D3100 Viewfinder

As with most DSLRs, the Nikon D3100 has an optical viewfinder that lets you view your subject through the lens. Unlike the D3000, the Nikon D3100 also offers Live View mode which allows you to preview the current subject on the LCD monitor.

Nikon's main specifications for the D3100's optical viewfinder are pretty typical for an entry-level DSLR. It employs a less expensive pentamirror design (as opposed to a solid glass pentaprism) with coverage rated at 95% (our test results agree) and magnification of 0.8x (measured with a 50mm f/1.4 lens at infinity, -1.0 m^-1). Eyepoint is rather short at 18mm (at -1.0 m^-1), and the diopter adjustment range of -1.7 to + 0.5 m^-1 is not very generous either.

The Nikon D3100 does however offer more than the usual viewfinder information for its class, however the on-demand grid found in the D3000 and some other Nikons has been dropped. Also dropped are the reference circle for center-weighted metering, and the screen overlays for "no memory card" and the battery indicator (the information display across the bottom retains its battery indicator however).

Nikon has also updated the D3100's viewfinder autofocus point display. In the D3000, the approximate AF point locations were indicated with dense black marks in the viewfinder. For the Nikon D3100, these have been replaced with much fainter markings, illuminated by single red LEDs. The new LED indications are quite bright, but very small, and several of them have a tendency to "bleed" into other points. The worst offender is the center point, which causes the top and bottom points to glow quite noticeably. It's a little distracting, but the glow isn't as bright as a properly illuminated point, so it's still easy enough to tell which points achieved a focus lock.

One feature that owners of older AF lenses will appreciate is the Nikon D3100's exposure meter scale can act as a manual focusing aid, indicating which direction the lens needs to be adjusted to achieve focus. The option for the scale to behave this way is selectable in the Setup menu. This "Rangefinder" function as Nikon calls it, is not available in manual exposure mode as the scale then indicates exposure regardless of the Setup menu setting.

The graphic and table below shows what information is displayed in Nikon D3100's viewfinder.