Camera Shutters Are Extremely Fast as The Slow Mo Guys Capture Focal Plane Leaf and Flash Sync on a Phantom TMX 7510

Gavin Free first pointed a high-speed camera at a shutter in 2015, using a Phantom Flex and a cropped square to reach 10,000 frames a second on a Canon EOS 7D. In September 2026 he brought the same battered 7D back, now with a Phantom TMX 7510 that holds full resolution at 80,000 frames a second, and the extra speed showed details the older clip never caught.

First curtain on that 7D travels a little faster than the second. A 1/2000 second exposure means that the slit between them widens slightly as the duo moves down the sensor. It’s a two-curtain focal plane design, similar to what film cameras use. When the mirror flips up, the first curtain opens and light hits the plane, followed by the second curtain and the mirror descends. With super-fast shutter speeds, however, the second curtain must begin before the first has even cleared the frame. As a result, flash sync is often limited to 1/250 second. Try shooting a strobe with only a slit open, and part of your image will remain dark.

Sony’s A7R IV showcases the current hybrid system. Unlike traditional cameras, the sensor is constantly visible since exposure begins electronically, eliminating the need for a mechanical initial curtain to close. However, in order to complete the shot, the motorized second curtain must swing higher. The shutter is essentially snapping shut, as aperture blades snap into position when you begin to capture and then spring back open again. On the A7R IV, those blades broaden slightly near the end of travel to compensate for the curtains’ increased speed, keeping the frame level from top to bottom. The electronic-first-curtain mode reduces lag and wear compared to the whole mechanical cycle.

Then there’s the Hasselblad X2D, which pursues its own path. Leaf shutters are housed within the lenses themselves, and are just a collection of blades that open and close completely across the frame at the same time. The strange thing is that the blades are so distant from the sensor that even a small opening illuminates every pixel, just like a regular aperture. Plus, full-power flash allows for extremely fast shutter rates. However, when the blades slam shut, they judder slightly, a little wobble that becomes most noticeable when the frame rate reaches 80,000. Speaking of which, one of their 38mm lenses completed its whole open-close cycle while the frame was being shot at 50 frames per second. Old-style leaf shutters were slower than focal-plane shutters because the mechanical pieces had to slow down and reverse themselves. These Hasselblad units are definitely keeping up.

In contrast, electronic shutters simply skip over the mechanical bit and scan the sensor line by line, however this rolling readout produces issues with quick subjects and high-speed sync pulses, resulting in a slew of brilliant bands. Global shutters, the kind inside the Phantom TMX 7510 and Sony A9 III, expose every pixel together. Phantom can fire 1.75 million times a second with an exposure as short as 95 nanoseconds. A9 III tops out at 1/80,000 second but does so 120 times a second. Hasselblad’s own readout still takes hundreds of milliseconds, so closed periods remain visible in slow motion. Stacked sensors are shrinking that gap.