Live view

The Nikon D7100 inherits the live view functionality seen in recent Nikon DSLRs like the D600 and D5200. The most obvious improvement over the Nikon D7000 is a dedicated 'Lv' button on the rear of the camera surrounded by a lever that toggles between still image and movie mode.

The D7100 has a dual mode live view system. You can compose still images or preview framing for video with precision. A press of the 'Lv' button at the hub of the switch activates live view for either stills or movie mode.

When live view is activated, the camera's mirror flips up and a through-the-lens view is displayed on the rear LCD. The lens is automatically set to the aperture selected at the time live view was activated, giving you an accurate depth of field preview. It's important to note, however, that the actual Depth of Field preview button is inactive in live view. So should you change the aperture while in live view mode, you'll have to exit and then re-enter live view in order to preview its effect, behavior we saw and found fault with in our D600 review. Neither does the D7100 offer a histogram overlay in live view, a feature that is present in the high-end D800.

Manual exposure mode

You can set exposure compensation of +/- 5EV and the image preview will update to reflect the change in exposure, although Nikon cautions that values beyond +/- 3EV will not be previewed. Studio photographers who use strobes will be happy to know that in manual mode the D7100 - like the D600 - seeks to maintain a 'normal' exposure for the image preview rather than mimicking the brightness of the final image. This allows for composition and focus adjustments using a well-exposed onscreen preview in low ambient light scenes that will be illuminated by flash at the time of exposure.

The flip side of course, is that when shooting with continuous lights you cannot preview the effect that shutter speed or aperture adjustments will have on the final image. In these situations an exposure indicator scale - if enabled - is your only guide as to how far you've deviated from the camera-derived optimal exposure value. Whether this behavior is a plus or minus for you depends on the type of shooting you do while in live view. But we see no reason why Nikon simply could not have provided the option to choose between a 'normal' and simulated exposure view (as other manufacturers do).

Even more confusing - and as we've seen on previous Nikons - is that with Auto ISO disabled, adjusting exposure compensation changes scene brightness in the onscreen preview, even though the final exposure will (obviously) remain unchanged. Nikon's implementation of exposure compensation in manual mode is that it is used to change the metered target exposure, and it is precisely this target exposure that is simulated on the display. If you then adjust your exposure settings to match the camera's exposure compensation-enabled target exposure, the brightness level you see onscreen is indeed an accurate preview of the final image.

After taking an exposure in live view, the rear LCD remains blacked out until the image is written to the card, a delay that can last several seconds when shooting even single images in RAW+JPEG mode, let alone continuous bursts. While access to all of the menu screens is locked out during this period you can, however, change parameters available via the camera's top and rear plate controls such as shooting and drive modes, ISO sensitivity, white balance and exposure compensation. These can all be verified on the camera's top plate LCD.

In live view you also have the option of using the D7100's 1.3x crop mode. And we're pleased to report that unlike on the D600, you can toggle between standard and crop modes on the D7100 without having to disable live view, resulting in a much more efficient way of working.

Information displays

The D7100 offers four separate information displays. You cycle through these views by pressing the Info button. The AF rectangle turns green when the camera has achieved focus.

Here is the image only view. A grid view is available.
A single axis virtual horizon can be shown. An 'information' view displays key camera settings.

Live View autofocus

In live view mode the D7100 uses contrast-detection autofocus, which allows for a continuous live view feed that doesn't black out during focus acquisition. The trade-off, however, is that the D7100's contrast-detect AF is much slower than the phase detection AF used in its through-the-viewfinder shooting mode. In fact, like all current DSLRs, the D7100's contrast-detection AF acquisition in live view is sluggish compared to most every mirrorless camera we've used recently. To be fair though, we imagine that for many D7100 users, live view will be reserved primarily for critical focus applications like landscapes, still lifes and product photography, where maximum AF speed is much less important than accuracy.

The D7100 offers a choice of AF Area modes. You can choose between Wide... ...and Normal modes for a larger or smaller AF area box respectively...
 
or choose a subject tracking mode that attempts to follow the subject you've indicated inside the frame.  

The AF point can be manually positioned anywhere inside the frame via use of the multi selector arrows. You can choose between static and full-time AF modes, with the latter option allowing the camera to continuously adjust focus until the shutter button is pressed. In addition you can select one of four AF area modes. In Face-priority mode, the camera attempts to detect and lock focus on the face positioned closest to the camera. This works as advertised with faces that are fully turned towards the camera and can actually be quite useful for quick snapshots, although we doubt full-frame DSLR owners will be using live view in Auto AF mode much of the time.

A Wide-area AF mode provides a larger focus point than the Normal-area AF. A subject tracking mode allows you to identify an element of the scene for the camera to follow as it moves within the frame. With the slow autofocus performance we cited above, we find subject tracking to be eminently more useful in non-live view shooting modes. This matches our findings on the Nikon D800, which you can read on our AF performance page of that review.

Live view manual focus

As with image playback, in live view the zoom buttons on the rear of the camera can be used to change magnification of the image preview. You scroll through magnified areas of the image by using the multi selector's left/right up/down arrows. There are six levels of magnification available and unlike in image playback, the maximum zoom setting in live view (though a bit less magnified) does not show any pixelization.

Here is the image preview at normal magnification. This is the highest magnification, which offers the clearest view for critical focus adjustments.

As we saw with the D600, the D7100 does not offer live aperture control during live view viewing. When using live view, your lens is stopped down to the taking aperture at the moment live view is engaged. So if you want to shoot a scene at F8 for example, you're best off opening the aperture as wide as you can before entering live view, focussing at that aperture, then exiting live view and setting F8, and activating live view again to get the shot.

This is annoying, since it positively encourages focus errors until you realize what's going on. We'd much prefer the ability to accurately preview DOF adjustments without the time consuming steps of having to exit and re-enter live view mode.