Sony NEX-5 Flash

Sony has made a decision in the design of its NEX-5 that's likely to prove just as divisive for the company as it was for with two recent cameras from rival Olympus. Playing up to the strengths of the single-lens direct view camera format, namely its extremely compact size and weight, Sony has forgone an internal flash strobe. Olympus followed the same route in the design of its first two Micro Four Thirds SLDs, the Pen E-P1 and E-P2, and the decision split public opinion -- not to mention causing some debate in the IR labs. On the one hand, there were those who felt that the absence of a built-in flash was a curious decision, for two reasons. It meant bringing along a bulky external flash strobe everywhere you went, if you had the least concern about ambient light conditions. Since the hot shoe shared double duty as a mount for the accessory port, it also meant that flash couldn't be used at the same time as the external viewfinder accessory. On the other hand, some observers argued that much of the time, they simply didn't need to use flash photography -- and that the ability to pare off a little more bulk from the camera was more than worth these trade-offs.

With the Sony NEX-5, those on both sides of the argument may find themselves digging trenches and preparing to escalate the battle, because new ammunition has been provided for both arguments. There are a couple of reasons for this, and they both relate to how Sony has chosen to implement external flash. Like Olympus before it, Sony has introduced a diminutive external flash strobe to accompany its NEX-series cameras. Sony's HVL-F7S flash is even smaller than that provided by Olympus, however -- and it even folds flat against the top of the lens mount when not in use. It's also reasonably powerful for its size, with a useful range extending out as far as sixteen feet. Sony officially lists the guide number as being seven meters (23 feet) at ISO 100 -- which while it's rather less powerful than the strobes on most digital SLRs (typically rated at 12 or 13 meters), is equal to the built-in strobe on the Olympus E-PL1, and actually a little more powerful than the built-in strobe of the Panasonic GF1. The folding design makes it surprisingly compact even when attached to the camera. Once safely packed in its protective plastic case, it's dimensions are barely under 2" x 1.5" x 1", easily small enough to slip in a pants pocket and forget you're even carrying it, until you have a need for it.

One could be forgiven for thinking that the compact size of the flash strobe entirely solved the problem, were it not for a couple of other features of its design. Firstly, the coverage is rather narrow, leading to pretty uneven illumination with the 16mm prime kit lens, and at wide angle with the 18-55mm zoom kit lens. The same will apply to the 18-200mm kit lens, and vignetting will likely prove an additional concern with that combination, given the modest height of the HVL-F7S strobe when extended, and the significantly larger dimensions of the lens itself. Perhaps more of an issue, though, is that the HVL-F7S is your only choice for on-camera flash, full-stop. The reason for this is that Sony's NEX-series models -- unlike every other current SLD camera -- don't include a standard flash hot shoe. Instead, Sony has instead adopted a proprietary accessory connector, shown at right above, that accepts either the HVL-F7S flash strobe, an external stereo microphone accessory, or an optical viewfinder.

A small thumb screw in the base of the strobe and other accessories allows them to be tightly fixed to the camera, safe from being accidentally bumped off, while two small pins on all the accessories mate into holes on the camera body to keep everything steadily aligned. The decision to adopt this proprietary port doubtless has helped Sony to keep the camera size and weight down, and enables the NEX-5's smooth, clean top panel (once the accessory port door is closed). Unfortunately, it also means that there's no way to mount any more powerful, third-party flash strobes on the camera, though. Nor is there any provision for bounce flash, a feature not offered by the tiny HVL-F7S strobe. Unless Sony releases a larger and more capable flash strobe compatible with the mount, or another manufacturer licenses or reverse engineers the connection, this is likely to remain the case. Given the modest size of the thumb screw and alignment pins, there's likely a fairly strict limit on the size and weight of accessory that the cameras could accept. If you're willing to accept these quirks, though -- and many photographers will be -- then there's no denying that the size of the HVL-F7S strobe beautifully complements that of the NEX-5 body.

The HVL-F7S flash strobe folds down against the top of the lens mount when not in use, keeping the overall package more compact. Unfortunately, the accessory port door sticks out when the flash is attached, so you wouldn't want to store the camera in a bag this way lest you accidentally break the door off. The flash is automatically disabled when folded.

When raised, the HVL-F7S flash stands proud about an inch above the camera's top deck, and when lowered once more, the  flash is automatically disabled. The Sony NEX-5's has six flash modes: Auto, Fill, Slow Sync., Rear Sync., and Off. Through a separate menu option, red-eye reduction can be enabled, which function by adding several bursts of preflash to contract your subjects' pupils, in addition to the regular metering and exposure flashes. Flash modes are changed in the Camera menu, Flash Compensation in the Brightness / Color menu, and Red-Eye Reduction in the Setup menu. Available settings vary depending on exposure mode. X-Sync (the maximum shutter speed with the flash enabled) is 1/160 second by default -- a bit below average these days, but identical to the X-sync speeds of the Olympus Pen E-PL1 and Panasonic Lumix DMC-GF1.

The Sony NEX-5 allows you to adjust flash and ambient exposure independently of each other, by providing flash exposure compensation between -2 and +2 EV in one-third EV increments.

Unlike the Sony NEX-3, the accessory port cover on the NEX-5 is small enough to mate nicely into a recess in the back of the HVL-F7S flash strobe. It's a small difference, but it makes the two seem better integrated. Where the accessory port cover on the NEX-3 seems at risk of accidental damage if the camera's placed in a bag with the flash strobe attached, the NEX-5's cover seems destined to live a longer life.

Flash Test Results

Coverage and Range
A powerful flash given its size, but with very narrow coverage. Our standard flash shots required less than average amount of exposure compensation.

18-55mm: 18mm	18-55mm: 55mm
16mm
Normal Flash +0.3 EV	Slow-Sync Flash Default

Coverage Flash coverage was quite uneven with the 18-55mm kit lens at wide-angle (18mm), resulting in dark corners when shooting our flash coverage target. Flash coverage was much more uniform at telephoto (55mm). As you'd expect, coverage was even more uneven with the 16mm lens, with very dark corners.

Exposure. In the Indoor scene test, the Sony NEX-5 required +0.3 EV flash exposure compensation adjustment, which is less than average among the cameras we tested for this shot. (The average among cameras we've tested is +0.7 EV). The camera's Slow-Sync flash mode produced good results without any flash exposure compensation, though with a strong pink-orange cast from the ambient room lighting.

18-55mm Flash Range: Wide Angle
6 ft	7 ft	8 ft	9 ft	10 ft	11 ft
1/60 sec f3.5 ISO 200	1/60 sec f3.5 ISO 200	1/60 sec f3.5 ISO 200	1/60 sec f3.5 ISO 200	1/60 sec f3.5 ISO 200	1/60 sec f3.5 ISO 200
12 ft	13 ft	14 ft	15 ft	16 ft
1/60 sec f3.5 ISO 200	1/60 sec f3.5 ISO 200	1/60 sec f3.5 ISO 200	1/60 sec f3.5 ISO 200	1/60 sec f3.5 ISO 200

18-55mm Flash Range: Telephoto
6 ft	7 ft	8 ft	9 ft	10 ft	11 ft
1/100 sec f5.6 ISO 200	1/100 sec f5.6 ISO 200	1/100 sec f5.6 ISO 200	1/100 sec f5.6 ISO 200	1/100 sec f5.6 ISO 200	1/100 sec f5.6 ISO 200
12 ft	13 ft	14 ft	15 ft	16 ft
1/100 sec f5.6 ISO 200	1/100 sec f5.6 ISO 200	1/100 sec f5.6 ISO 200	1/100 sec f5.6 ISO 200	1/100 sec f5.6 ISO 200

18-55mm ISO 200 Range. We normally test flash range using ISO 100, but the Sony's minimum ISO sensitivity is 200. With the 18-55mm kit lens, flash exposure started out bright at 6 feet at wide-angle, and generally became brighter up to about 10 feet, where it started to decrease gradually as distance increased. Exposure wasn't always consistent with distance however, with the 8 foot exposure being slightly dimmer than 9 feet. Flash images were still usable all the way out to 16 feet, though. At full telephoto, flash exposures started out slightly dim at 6 feet, but exposure didn't drop off appreciably until about 10 feet. Good results here, but keep in mind results are not directly comparable to cameras that have a base ISO of 100. (ISO 200 provides roughly 1.4x the flash range as ISO 100.)

16mm Flash Range
6 ft	7 ft	8 ft	9 ft	10 ft	11 ft
1/60 sec f2.8 ISO 200	1/60 sec f2.8 ISO 200	1/60 sec f2.8 ISO 200	1/60 sec f2.8 ISO 200	1/60 sec f2.8 ISO 200	1/60 sec f2.8 ISO 200
12 ft	13 ft	14 ft	15 ft	16 ft
1/60 sec f2.8 ISO 200	1/60 sec f2.8 ISO 200	1/60 sec f2.8 ISO 200	1/60 sec f2.8 ISO 200	1/60 sec f2.8 ISO 200

16mm ISO 200 Range. Since the Sony NEX-5 is also available bundled with the 16mm f/2.8 lens, we did a flash range test with it as well. Here, flash exposures where bright all the way out to 16 feet, the limit of our test, though some inconsistency compared to distance can be seen.

Note: the 16mm f/2.8 flash shots above were taken with a preproduction version of the lens. We didn't think the changes to the production version would affect flash coverage and range, so we didn't reshot those with the replacement lens.

Manufacturer-Specified Flash Range
Wide Angle	Telephoto
9.3 feet ISO 200	5.8 feet ISO 200

Manufacturer Specified Flash Test. Sony rates the NEX-5's flash with a Guide Number (GN) of 7 meters at ISO 100. At ISO 200, that works out to about 9.3 feet at an aperture of f/3.5 and 5.8 feet at an aperture of f/5.6 with the kit 18-55mm zoom lens. In the shots above, the Sony NEX-5 produced a bright exposure at wide-angle (about 1/4 EV overexposed, and slightly reddish), but telephoto was just a touch dim (about 1/10 EV underexposed). Pretty good result here. 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.

Follow Imaging Resource