3) Image Sensor and the new Expeed Processor
The most exciting new change for a gear-head like me, is the more powerful Expeed 2 camera processor, along with the new 14.2 MP (megapixel) high-resolution camera sensor. The D3100, by the way, was the first Nikon DSLR to have the Expeed 2 processor. Although I prefer better image quality over a higher number of pixels, the jump from 10.2 MP to 14.2 MP is certainly good for folks like me who are into landscape and wildlife photography. Higher resolution sensor means larger prints and more cropping opportunities. Nikon has been quite successful in keeping high ISO noise amounts low, while keeping image quality standards high in their latest generation DSLRs with more megapixels. A more detailed comparison between Nikon D3100 and other DSLRs is provided on page 1 of this review.
4) Autofocus Performance and Metering
The Nikon D3100 is equipped with the same 11 Point AF System with 1 cross-type sensor in the center, as in Nikon D3000 and Nikon D5000 cameras, so there is no change in AF performance. If you are interested in seeing how AF points and cross-type sensors impact the autofocus performance, please see my DSLR Autofocus Modes article. In short, the Nikon D3100 performs very well in daylight conditions and its autofocus performance might suffer in low-light conditions. If you experience autofocus problems in indoor/low-light situations, it might be a good idea to use the center (cross-type) AF point to focus instead of the 10 surrounding AF points for better accuracy. If framing and composition get difficult, simply switch the function of the AE-L/AF-L button to “AF-On” and use that button to focus and recompose instead. But be careful about doing this, because focusing with a center AF point and then recomposing might result in AF shifts, especially when focusing on nearby subjects. As for metering, the Nikon D3100 does a pretty good job just like its predecessor, giving pretty accurate results in most conditions.
5) Movie Recording
Although I personally do not shoot much video (except for occasional family videos), the high-def 1080p video mode on the Nikon D3100 was very tempting to try. I shot a series of videos of a Taekwondo competition indoors and the video quality was pretty impressive (see below). Live View/Video mode is super easy to switch to, thanks to the new lever on the back of the camera and I certainly like it much more than the “Lv” button on other Nikon DSLRs. The bad thing about shooting video on the D3100, is that there is no proper exposure control while recording video, which means that you cannot fully control your aperture, shutter speed or ISO during movie recording. You can set lens aperture before recording video and you can lock the exposure by holding the “AE-L/AF-L” button while recording, but that’s pretty much it. 1080p is limited to 24fps and 720p is capped at 30fps. In comparison, the Canon 550D has full exposure control when shooting video and can do 1080p at 30fps and 720p at 60fps. So if you are looking for a DSLR with good video capabilities, the Canon 550D is going to be a better candidate at a similar price point.
Here is a sample video of a Taekwondo tournament that I shot with the Nikon D3100 with the Nikon 70-200mm f/2.8G VR II lens:
Don’t forget to switch to 1080p and watch it in full screen.