Nikon D40 Flash

Flash photography has been a particular strength of Nikon SLRs for some time now, and the D40 follows suit, with its 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.

Flash capability is also an area where the D40 sheds some substantial capability relative to the D80, though, in that its built-in flash can't serve as a Commander in Nikon's Wireless Lighting System. You can still use the D40 with a Nikon SB-800 flash 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+Red-Eye Reduction, Slow Sync, Slow Sync+Red-Eye Reduction, and Rear Curtain+Slow Sync. 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. Red-Eye Reduction with Slow Sync works in a similar fashion, but 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. Finally, Rear-Curtain Sync 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 14.

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.)

As noted elsewhere in this review, the Nikon D40 sports a very fast 1/500 second flash x-sync speed (the maximum speed a normal strobe unit can be used with it).

Another note relative to the x-sync speed on the D40: Its built-in flash is not FP-capable. Basically, this means that the on-board flash can't sync at shutter speeds greater than 1/500 second. There also doesn't appear to be any support for external flash units that are FP-capable (eg, that can be used at higher than x-sync speeds), so the D40's maximum flash sync shutter speed seems to be 1/500, regardless of what sort of flash system you're using with it.

Besides the main flash modes listed above, the D40'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 D40's internal flash is fairly powerful, with a guide number of 17 meters or 55 feet at ISO 200 in auto mode, extending slightly to 18 meters (59 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 55 feet is the guide number, not the range. Divide the guide number by your lens' aperture setting to produce the actual range in feet.)

Also included on the D40 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 the D200. 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 D40 as well. Current Nikon flashes (the SB-800, SB-600 and new SB-400) will give you full capability in all exposure modes. Older models such as the 80DS, 28DX, 28, 27, and 22s will only offer a non-TTL (non through-the-lens metering) auto or manual flash modes.

To our eyes, the most natural partner for the D40 from Nikon's flash lineup is the new SB-400 model that was announced at the same time as the D40. Shown above, it's a very slim, trim flash unit with roughly double the range of the D40's built-in strobe.

The photo above shows another nice capability that the SB-400 offers over the D40's built-in flash: Its head rotates up to 90 degrees, so you can bounce the flash off the ceiling for a soft wash of light, rather than the harsh look of on-camera flash.

All in all, the SB-400 looks like a dandy little flash unit (the word "cute" keeps coming to mind) to accompany the D40, and at a list price of only $129, any prospective D40 owner should strongly consider buying one right along with the camera.

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 D40 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 D40 built-in flash can't act as a controller for remote strobes, it's perfectly compatible with the system if you slip an SB-800 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.