# Flash duration > How long a flash burst lasts; a very short flash freezes a moving subject sharply. Also known as: freezing motion, motion freezing. Category: Lighting and optics. Flash duration is the length of time a flash burst lasts. When the flash is the main light source, a very short duration, for example 1/10,000 s, effectively becomes the exposure time and freezes motion even if the subject is moving. ## How PhotoRobot uses it PhotoRobot relies on very short flashes of about 1/10,000 s to photograph products during continuous turntable rotation. The robot reads the table position 1000 times per second so the flash fires at precisely the right moment; PhotoRobot states this gives on average a four-fold productivity increase. ## Related terms - [Strobe](https://www.photorobot.com/glossary/strobe): A studio flash that emits a very short, powerful burst of light, freezing motion. - [Fast Spin](https://www.photorobot.com/glossary/fast-spin): PhotoRobot capture mode that photographs during continuous turntable rotation instead of stopping at each angle. - [Shutter speed](https://www.photorobot.com/glossary/shutter-speed): How long the camera shutter stays open; with flash, the flash duration usually freezes the motion instead. - [Rotary encoder](https://www.photorobot.com/glossary/rotary-encoder): A sensor that reports the exact angular position of a rotating part, such as a turntable plate. ## Where this term appears on photorobot.com Mentioned on 4 pages. Most relevant: - [PhotoRobot Control Units - Technical Documentation](https://www.photorobot.com/controller): To freeze the motion, a flash from high-power photographic lights with a duration of 1/10,000 s is used – with the robot providing an adjustable advance notification when reaching the defined position. - [Broncolor Siros 800 S WiFi / RFS 2 Operating Instructions](https://www.photorobot.com/manuals/broncolor-siros-800-s-operating-instructions): …ISO) with reflector L40 32 8/10 Aperture at 2 m (100 ISO) with reflector P70 45 6/10 Flash duration t0.1 (t0.5) – Min. - [Studio Lighting Overview for PhotoRobot Systems](https://www.photorobot.com/manuals/studio-lighting-overview): Instead, exposure is performed by a “freezing of motion” during a very short and intense flash. - [Mastering Product Photography: Shoes and Footwear](https://www.photorobot.com/blog/mastering-product-photography-shoes-and-footwear): …shutters will open and in what order to capture photos in the illuminated during the flash duration.