Nikon D5100 Flash
Flash photography has been a particular strength of Nikon SLRs for some time now, and the D5100 retains the company's implementation of Nikon's 3D Color Matrix II metering for flash exposures. This advanced exposure metering system takes advantage of subject-distance information relayed by the lens to compute more accurate flash exposures than more conventional systems based on reflected light alone.
Like 2008's Nikon D60, flash capability is an area where the Nikon D5100 shed some substantial capability relative to the D90 and higher models, though, in that its built-in flash can't serve as a Commander in Nikon's Wireless Lighting System. You can still use the Nikon D5100 with a Nikon SB-700, SB-800 or SB-900 flash or SU-800 wireless Speedlight Commander to control multiple remote flash units, but the built-in flash doesn't have that ability on its own.
The flash modes available vary depending on the setting of the mode dial, with some of the more automated/programmed modes restricting your choices. The full list of flash modes includes Auto, Auto+Red-Eye Reduction, Auto+Slow Sync, Auto+Slow Sync+Red-Eye Reduction, Fill, Red-Eye Reduction, Slow Sync, Slow Sync+Red-Eye Reduction, Rear Curtain, and Rear Curtain+Slow Sync. Slow Sync combines the flash with a slower shutter speed for night portraits. (This reduces the harsh effect of nighttime flash shots, allowing more of the ambient illumination into the picture.) Slow Sync mode works with shutter speeds as slow as 30 seconds to preserve color in night shots. Red-Eye Reduction mode fires the (very bright) AF-assist light before the main flash exposure, to reduce the Red-Eye Effect in shots of people. Finally, Rear-Curtain fires the flash at the end of the exposure, producing light trails that appear to follow (rather than precede) moving subjects. A Manual flash exposure mode is available via Custom Settings Menu option e:1.
Flash exposure can be set over a range of -3 to +1 EV by holding the Flash and Exposure Compensation buttons down simultaneously, while rotating the Command Dial. (Flash exposure can also be adjusted via the Shooting Display and Multi-Controller arrow keys, which some users may find more straightforward.)
The Nikon D5100 has a 1/200 second maximum X-Sync speed, and its built-in flash is not FP-capable. Basically, this means that the on-board flash can't sync at shutter speeds greater than 1/200 second. There also doesn't appear to be any support for external flash units that are FP-capable, so it seems that 1/200 second is the fastest shutter speed you'll be able to use with the flash, regardless of mode or flash source.
Besides the main flash modes listed above, the Nikon D5100's onboard speedlight can also be used in manual mode, in which you can set its power output to fixed levels of full, 1/2, 1/4, 1/8, 1/16, and 1/32 power. The Nikon D5100's internal flash is reasonably powerful, with a guide number of 12 meters or 39 feet at ISO 100 in auto mode, extending slightly to 13 meters (43 feet) in manual mode. The greater range in manual mode is because it doesn't have to expend energy on the metering pre-flash. (Novices should note that 39 feet is the guide number, not the range. Divide the guide number by your lens' aperture setting to produce the actual range in feet.) Guide numbers at ISO 200 are 17 meters (56 feet) in auto mode, and 18 meters (59 feet) in manual mode.Also included on the Nikon D5100 is an external flash hot shoe, just behind the pop-up flash compartment, but there's no separate PC-style sync terminal as found on professional models. Nikon does however sell a sync terminal adapter (Part Number AS-15) that converts the hot shoe to a sync terminal. The hot shoe accommodates Nikon accessory flash units, as well as a wide range of third party flashes. The full range of flash sync modes remains available for compatible flash units, but third-party models may not support all modes. Different Nikon speedlights offer different features when used on the D5100 as well. Current Nikon flashes (the SB-900, SB-800, SB-700, SB-600 and SB-400) will give you full capability in all exposure modes. Older models such as the SB-80DX, SB-28DX, SB-28, SB-27, and SB-22S will only offer non-TTL (non through-the-lens metering) auto or manual flash modes.
3D Color Matrix II Flash Metering
As noted above, the "3D" aspect of the Nikon metering system is that it uses subject distance information from the lens (only available with G or D-type lenses) to guide its exposure decisions. This is particularly key with flash exposures, because flash illumination falls off quite strongly as the subject gets further from the camera. The "Color Matrix" part of the name refers to the use of a 420-segment RGB sensor for exposure determination, which significantly improves the accuracy with which the camera can determine various scene types, for lookup in its 30,000-image exposure database. We at IR are huge fans of Nikon's flash technology, it's really a case of technology working perfectly in the service of creativity. The camera just quietly does its job, so you can focus on composition, color, interacting with your subjects, etc. It doesn't remove the creative decisions of how you want to light your subject, it simply removes the technical legerdemain from the equation. It won't by any means turn a duffer into a pro photographer, but it'll certainly take an average shooter a long way in that direction.
The Nikon D5100 with Nikon's Creative Lighting System
Nikon has long been a leader in flash technology, but in late 2003, they significantly upped the ante with their Creative Lighting System. This system of flashes and supporting camera bodies lets the photographer control up to three separate groups of remote flash units, with an essentially unlimited number of individual strobes in each group. The exposure and operating mode of each group of flashes can be controlled independently, and exposure is metered through the lens (TTL) for all units.
While the D5100 built-in flash can't act as a controller for remote strobes, it's perfectly compatible with the system if you slip an SB-700, SB-800 or SB-900 flash, or an SU-800 commander into its hot-shoe. The control and creative freedom Nikon's Wireless Lighting system offers is truly amazing: See our Nikon Creative Lighting System review for more info.
Flash Test Results
Coverage and Range
Slightly weak flash with uneven coverage at wide-angle. Our standard shots required a slightly above average amount of compensation.
|Flash coverage, at 18mm||Flash coverage, at 55mm|
+ 1.0 EV
Coverage and Exposure. Flash coverage was rather uneven at wide-angle (18mm), but more uniform at telephoto (55mm). Some of the light fall-off in our test images above is no doubt due to the lens itself, though. (We measured about 3/4 EV falloff at wide-angle and about 1/2 EV at telephoto when we tested the same lens on SLRgear.) For our Indoor Portrait scene test, the Nikon D5100's flash required +1.0 EV exposure compensation adjustment to get bright results, which is a little higher than average among the cameras we've tested. (The average is +0.7 EV for this shot.) The camera's Slow-Sync flash mode produced very bright results without any compensation, though with a stronger pinkish-orange cast from the abient room lighting.
ISO 100 Range. At wide-angle, the Nikon D5100's flash exposures started out dim at 6 feet, though brightness increased before decreasing, peaking at 8 feet which was still a little dim. Image brightness gradually dropped-off from there but was acceptable out to about 11 feet. At the telephoto end, flash intensity also started out dim at 6 feet but didn't drop-off noticeably until about 9 feet, and became gradually dimmer from there on.
|Manufacturer-Specified Flash Range|
Manufacturer Specified Flash Test. The Nikon D5100's flash Guide Number (GN) is 12 meters in auto flash mode at ISO 100, which translates to a range of about 11.3 feet at f/3.5 and 7 feet at f/5.6, the maximum apertures of the kit lens at full wide-angle and telephoto respectively. The flash shots above were taken at 11 and 7 feet respectively, and are both underexposed by a little more than 0.5 EV, indicating the D5100's flash output doesn't quite perform to Nikon's specification in our tests. Our standard test method for flash range uses a fixed setting of ISO 100, to provide a fair basis of comparison between cameras. We've now also begun shooting two shots using the manufacturer-specified camera settings, at the range the company claims for the camera, to assess the validity of the specific claims.