Sony has produced what can be described as a game-changer for the camera with the current flagship, the Sony a1. Although this camera offers quite a number of new features which impressed most of the reviews. One of its cool features has slightly disappeared from the radar. This feature is to increase the flash sync speed to 1/400th of a second shutter speed.
The Sony A1 It is one of the best unmatched full frame cameras on the market. Not only can it shoot 50MP high resolution files, it can also capture that much resolution at 30fps. Only until recently, we thought speed and high accuracy were an impossible combination, based on current technology. You can either have a high-resolution camera that captures a great deal of detail, or you can have a low-resolution camera that shoots super fast in high-speed situations. Sony manages to do both in one camera.
Additionally, Sony also managed to cram 8K 30p and 4K 120p into 4:2:2, 10-bit recording. Basically, the Sony a1 is a great camera system. However, these features are obvious and inevitable upgrades in the grand scheme of things. Almost everyone expected Sony to produce an 8K capable camera system, however, I doubt anyone would think Sony would improve the shutter mechanism and sync speed in the Sony a1.
What is a focal plane shutter?
A focal plane shutter is essentially the shutter mechanism found in almost all DSLRs and mirrorless cameras. The focal plane shutter is located in the camera and sits in front of the camera sensor. There are two sections in the focal plane shutter and they are called first curtain and second curtain.
The first curtain will open to reveal the full sensor after this point the second curtain will go down to close the shutters again. The time it takes for the shutter to open and close depends on your shutter speed.
The main advantage of focal plane shutters is their ability to manage faster shutter speeds than leaf shutter mechanisms (described below). Most high-end DSLRs and mirrorless cameras can manage shutter speeds of up to 1/8000 seconds, which is much faster than leaf shutter cameras.
Another advantage of focal plane shutters is that they work inside the camera. This means that almost any type of lens can be fitted and the shutter mechanism can still shoot. You can even use the pinhole body covers on the camera and the shutter will still be burning allowing you to expose the image.
The downside is that the focal plane shutter can remain fully open only at a certain speed. For most cameras, this shutter speed is 1/200 sec. Above this speed, the shutter blades will no longer fully open as they move down the sensor to reveal the image. The shutter aperture will become smaller as the shutter speed increases. This is not a big deal unless you are shooting with flash. If the aperture in the shutter blades is smaller than the sensor, the sensor will not be fully exposed when the flash is on.
As you can see in the comparison above, a large portion of the flash ends up hitting the shutter blades rather than the sensor when shooting faster than the sync speed. To solve this problem, you can use a feature called High Speed Sync. In this mode, the flash will fire several times quickly, in order to follow the shutter blades as they move along the sensor. Unfortunately, this feature greatly reduces flash power which makes it less than ideal in many situations.
What is a paper shutter?
Leaf shutters are relatively rare when it comes to camera systems. The biggest and most obvious difference between a leaf shutter and a focal plane shutter is that the leaf shutter operates inside the lens rather than the camera. This severely limits third-party compatibility. Another obvious difference is the structure of the leaf shutter.
Focal plane shutters move across the sensor in one direction, generally from top to bottom. The leaf shutters open and close in a circular motion somewhat similar to how the hatch blades open and close. It is this difference in design that makes the biggest difference. Unlike focal plane shutters, leaf shutter mechanisms do not have a limit on the flash synchronization speed. Paper shutter lenses can synchronize with the flash at any shutter speed they can manage.
For example, current Hasselblad lenses can sync flash even at a shutter speed of 1/2000s without the need for any kind of high-speed sync mode. The downside to leaf shutters is that the highest speed currently available is 1/2000s, which is far less than what focal plane shutters can achieve, which is 1/8000s.
How did Sony manage this?
The shutter mechanism generally works with a spring-loaded system. In a focal plane shutter camera, the two shutters are loaded and then fired when the shutter button is pressed. The spring-loaded system has worked extremely well in cameras for decades. However, this system has not been updated for a long time either.
Sony a1 comes with dual operation focal plane shutter. The shutter mechanism of this camera works with a spring system as well as a magnetic system. An active spring-loaded system will be for most fast and slow shutter speeds. The magnetic system is only active between shutter speeds of 1/320 sec and 1/400 sec.
These are the two fastest points that the Sony a1 can sync flash in full frame mode. The magnetic system allows the shutter curtains to move faster across the frame. The first curtain can open quickly enough that by the time the second curtain is ready to close, the full sensor is open for exposure.
This is the main difference. The magnetic system can move shutter curtains faster than a standard mechanism. This extra speed helps ensure that the sensor opens fully to exposure rather than parts that are blocked by shutter blades.
Why is this a big update
The Sony a1 is the only full-frame camera on the market today that can sync with flash at 1/400th of a second shutter speed. That’s twice as fast as most full-frame cameras, including Canon and Nikon mainframes. This sync speed can increase to a shutter speed of 1/500 sec if you shoot in APS-C mode. This kind of speed is on the same level as some leaf shutter lenses.
Interestingly, even with this high sync speed of the Sony a1, the shutter is durable enough to manage more than 500,000 cycles. Although it is important to note that Sony has not disclosed durability ratings for the shutter mechanism when flash sync priority is enabled.
However, for many working photographers, this increase in sync speed provides more real benefit than dynamic range improvements or increased resolution.
Having a lot of resolution can be great, however, after a certain point, a few pixels don’t make much difference to the way you shoot and the results you produce. Even with dynamic range, most cameras now offer enough flexibility that an extra half-stop doesn’t make too much of a difference or make any difference to the workflow. Features like megapixels and dynamic range may make great headlines, but in the grand scheme of things, it’s just marketing. Even smartphones can now capture up to 100 megapixels and higher.
An increase in sync speed is making a real difference to your workflow. You can shoot at a higher shutter speed no matter what type of flash you use. You can also delay the need for high-speed sync shooting with a full stop. This is especially useful when shooting in a controlled environment or in a studio.
For a long time, if you were shooting in a studio, the maximum shutter speed you could choose was 1/200 second. The ability to shoot at a faster shutter speed in a controlled environment will very likely reduce potential issues. If you’re shooting people for example, introducing motion into your shots is unlikely to cause motion blur.
This is without a doubt one of the best and most difficult leaps in technology we’ve seen in a long time, and Sony should be celebrated for doing so.
This is a huge leap forward for working professionals and the best thing is that it won’t be long before this feature starts showing up in less expensive cameras. As the cost of features becomes less expensive, we may start to see that this has become the standard sync speed for flash.
What is not clear at the moment is whether Sony can go ahead with this dual mechanism. It is arguably fair to assume that the magnetic system can probably manage faster shutter speeds. However, it may have been durability concerns that limited the sync speed to 1/400sec.
Hopefully we’re only in the early stages of what’s possible with magnetic shutter drives. Who knows, Sony’s next main camera may sync flash at 1/1000 second.