Nikon D5100 Performance

Average to good speed overall for a consumer digital SLR.

The Nikon D5100's startup time is about average for an SLR, and shutdown is quite fast and difficult to measure despite the fact that sensor cleaning occurs at startup and shutdown by default. (Sensor cleaning is preempted by the shutter release, and likely continues briefly after the camera is shut off.) Buffer clearing times are pretty good with a fast card, considering the buffer depths and file sizes. The Nikon D5100 supports newer Ultra High-Speed (UHS-I) cards, so buffer clearing may be even faster than what we measured with our 30MB/s card.

Mode switching is pretty good for a consumer SLR: Play to record and displaying a captured large/fine JPEG image were so fast they were difficult to measure, though switching from Record to Play immediately after capturing an image was about average.

The Nikon D5100's speed in determining that it's properly focused when shooting the same target multiple times is about average for a consumer SLR. The D5100 required about 0.27 second for full AF using the center focus point. Enabling the flash raised the lag to 0.29 second, which is pretty good, with very little delay added for the metering "preflash" there. Shutter lag increased to 0.41 second in Auto-area AF mode. Continuous autofocus and manual focus lag times were both around 0.25 second. When prefocused, shutter lag dropped to 0.11 second, which is a little slower than average these days, but still pretty fast.

Full autofocus is much slower in Live View mode, as expected. The Nikon D5100 only offers contrast-detect AF in Live View, which took about 1.3 seconds to focus in our tests. (How fast the lens can adjust focus makes a big difference here.) Prefocused shutter lag is also slower in Live View mode, at about 0.49 second.

To minimize the effect of different lens' focusing speed, we test AF-active shutter lag with the lens already set to the correct focal distance. We also use the same Sigma 70mm f/2.8 macro with every camera (on all platforms except Four Thirds/Micro Four Thirds and Nikon consumer models lacking an in-body focus motor), to further reduce variation, and because our tests showed that focus-determination time with this lens was close to the fastest, across multiple camera bodies from different manufacturers. Being an older design with a non-ultrasonic motor, it wouldn't be the fastest at slewing from one focus setting to another, but that's exactly the reason we measure focus determination speed, which is primarily a function of the camera body, vs focus adjustment speed, which is primarily a function of the lens.

Shot-to-shot cycle times were a somewhat slower than average for an SLR, at 0.73 second for large/fine JPEGs, and 0.77 second for RAW or RAW + Large/Fine JPEG frames. Continuous speed are good for a consumer SLR these days, at 3.9 to 4 frames per second depending on the image type. Buffer depths are pretty good for a consumer model, at over 50 large/fine JPEG frames, 13 RAW frames and 9 RAW + Large/Fine JPEG frames. (We use a difficult to compress target, so results with typical scenes should be better; Nikon claims bursts of 100 JPEGs are possible.) The flash takes 4.0 seconds to recharge after a full-power shot, which is good.

Connected to a computer or printer with USB 2.0, download speeds are reasonably fast, though not as fast as some recent models.

Bottom line, the Nikon D5100 is about average when it comes to autofocus and shutter lag, with slightly faster than average continuous mode, but slightly slower single-shot performance. It should be fine for most family situations, including some action shots.

Battery
Good battery life for a lithium-ion design.

The Nikon D5100 uses a custom rechargeable lithium-ion battery for power, and ships with a charger. Battery life when using the optical viewfinder is above average for a consumer SLR. Nikon does not specify battery life for Live View mode, but it will certainly be a lot lower, so we recommend you pick up a spare battery and keep it freshly charged and on-hand for extended outings or when using Live View.

The table above shows the number of shots the camera is capable of (on either a fresh set of disposable batteries or a fully-charged rechargeable battery as appropriate), based on CIPA battery-life and/or manufacturer standard test conditions.

(Interested readers can find an English translation of the CIPA DC-002 standards document here. (180K PDF document))

Storage
The Nikon D5100 accepts SD/SDHC/SDXC memory cards, and no card is included with the camera. Nikon recommends cards with a speed rating of at least Class 6 for shooting HD movies. The Nikon D5100 also supports UHS-I cards.

We strongly recommend buying a large capacity SDHC card, at least a 4GB card, preferably an 8 or 16GB one, to give yourself extra space for extended outings or when shooting RAW or video. (Check the shopping link above, cards are really cheap these days, so no reason to skimp.)