Pentax K-7 Flash
The Pentax K-7 features a built-in, pop-up flash, which operates in either Auto, Flash On (forced flash), Auto + Red-eye reduction, Flash On + Red-eye reduction, or Wireless mode. First and Second Curtain sync modes are available, as well as Slow-sync. The flash is not auto pop-up. To release the flash from its compartment, press the Flash button on pentaprism housing. Close it again by pushing the flash head back down.
The Pentax K-7's built-in flash has a guide number rating of 13 meters (43 feet) at ISO 100, translating to a range of about 15 feet at ISO 100 with an f/2.8 lens. A Flash Exposure Compensation feature controls the flash exposure -2.0 to +1.0 stops in 1/2 or 1/3-stop increments. Maximum sync speed is 1/180 second, though if an external flash that supports high-speed sync is used, such as the Pentax AF540FGZ or AF360FGZ, maximum shutter speed with flash is 1/8,000 second.
In Wireless mode, the built-in flash can be used as a controller to multiple wireless slave flashes (including the Pentax AF540FGZ and/or AF360FGZ flash units). The built-in flash can be set to contribute to the exposure, or to act only as a controller. The Pentax wireless flash system offers four control channels, so up to four camera/flash setups can be used in the same area without interfering with each other. The K-7 can connect on any of the four control channels: You program it by setting a flash unit to the desired channel, attaching that flash to the camera and then half-pressing the shutter button. This sets the camera to the channel the flash was set up for. After this, the flash may be removed and used as a remote unit, controlled by the camera.
Normally, all flashes used (whether on-camera or remote) contribute equally to the exposure, however each external flash can be set to one of the following ratios: 1/1, 2/3, 1/2 or 1/3. Additionally, each flash can be adjusted to under- or overexpose in 0.5 stop increments from -3.0 stops to +1.0 stop. All of this is relative to the overall flash exposure that can be adjusted on the camera by from -2.0 stops to +1.0 stop. Alternately, the Pentax flash units offer a Contrast-Control-Sync mode (CCS for short), which drops a flash's power. Units set to CCS mode can thus be used to provide "fill" illumination. When used with the K-7, and when the K-7's internal flash is also contributing to the exposure, the external flash in CCS mode will cut its output to two-thirds, while the K-7's built-in flash will cut its exposure contribution to one-third.
The Pentax K-7 also has a top-mounted hot shoe for attaching an external flash unit. A dedicated PC-sync terminal is also provided.
Flash Test Results
Coverage and Range
Fairly powerful flash at close range, with uneven coverage at wide-angle. Lower than average exposure compensation required.
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| 17mm | 70mm |
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| Normal Flash +0.3 EV |
Slow-Sync Flash Default |
Coverage and Exposure. Flash coverage was uneven at wide-angle (17mm) with the 17-70mm lens, and also casts a shadow from the lens at the bottom. Coverage was much more uniform at telephoto (70mm), if a bit dim. In the Indoor test, the Pentax K-7's flash required a less than average +0.3 EV exposure compensation adjustment to get good results. (Most cameras we've tested required about +0.7 EV for this scene.) We did notice that increasing the flash exposure compensation above +0.3 EV had little effect. The camera's Slow-Sync flash mode produced slightly brighter and more even results with no exposure compensation, though with a stronger pinkish-orange cast from the room lighting.
ISO 100 Range. Since the 17-70mm lens is constant aperture (f/4), and the manufacturer specified range is at ISO 100 (see below), we didn't shoot our usual ISO 100 wide-angle and telephoto series.
| Manufacturer-Specified Flash Range |
|---|
| Telephoto |
 10.7 feet ISO 100 |
Manufacturer Specified Flash Test. The Pentax K7's flash is rated with a GN of 13 meters at ISO 100. That translates to 3.3 meters or 10.7 feet at f/4. In the shot above, the K-7 performs about as Pentax says it will, producing a good if slightly dim exposure at the rated distance. 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.
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