MDI Mainer

A little-discussed feature of Sony's flagship A1 is its 1/400 flash sync capability and dual drive shutter. This from a recently published article in Fstoppers by Usman Dawood:

A camera shutter mechanism generally operates with a spring-loaded system. In a focal plane shutter camera, the two curtains are loaded and then fire when you press the shutter button. The spring-loaded system has worked extremely well in cameras for decades. However, this system hasn't been updated for a long time either.

In comes the Sony a1 with its dual-driven focal plane shutter. The shutter mechanism in this camera operates with a spring-loaded system and also a magnetic system. The spring-loaded system will be active for most shutter speeds fast and slow. The magnetic system is only active between shutter speeds of 1/320s and 1/400s.

These are the two fastest points that The Sony a1 can synchronize flash in full-frame mode. The magnetic system allows the shutter curtains to move faster across the frame. The first curtain can drop open fast enough that by the time the second curtain is ready to close, the full sensor is open for exposure.

This is the key difference. The magnetic system can move the shutter curtains faster than the standard mechanism. That extra speed helps ensure the full sensor is open for exposure as opposed to portions being blocked by the shutter blades.

Why This Is a Big Update

The Sony a1 is the only full-frame camera on the market right now that can synchronize with flash at 1/400th of a second shutter speed. This is double the speed of most full-frame cameras, including flagship systems from Canon and Nikon. This sync speed can increase further to 1/500s shutter if you shoot in APS-C mode. This kind of speed is on the same level as some leaf shutter lenses.

And the comment from Tony Northrup:

Agreed that this is a practical and useful improvement, especially for portrait photographers weighing the a1 against the Nikon Z9 @ 1/200. I didn't know the mechanics of it, so thanks for teaching me about the use of magnetics!

anotherview Loc: California

Interesting discussion of the A1 flash device.

uhaas2009

Today’s cameras can handle high speed sync but it needs to be adjusted in the camera. So it’s not a problem to use 1/200- 1/8000 sec with the flash……I try to understand what is the different….

wireloose

Their point was that you could sync at 1/400 without HSS

uhaas2009

Thank you, but what is the difference or why is good to use 1/400 vs high speed sync?

wireloose

Sounds like its mostly in the studio, but here's a link to the article
https://fstoppers.com/gear/sony-made-huge-leap-technology-and-no-one-talking-about-it-610337

autofocus Loc: North Central Connecticut

The one disadvantage of high speed sync is that it pulses the flash many times over the shutter cycle which will consume some of the battery life, and often provides a bit less light contributing to the overall exposure. HSS, on the other hand has it's advantages with it's use in freezing action.

With flash photography you have two sources of light that influences the overall exposure and the shutter speed controls the ambient light part of it. So, if you want a darker ambient, or you want your flash to freeze action you will need to use a faster shutter speed which will kill more of the ambient light. It's often misunderstood that flash will always freeze action, but that's not true. In trying to do that while use of a slower shutter speed can cause what's known as ambient blur. That happens because the flash fires a very quick burst when the shutter curtains are full open, but with slower shutter speeds, say 1/40 second, the shutter is still allowing light to come in after the flash has fired, and that's what can cause the blur. A while back I was explaining this to someone and I created a little video to demonstrate it, you can see it here if you wish: https://flic.kr/p/2neCGQB

User ID

Unfortunately theres no short explanation of the difference. I can make it simple, but not short :-(

High Speed Synch is not truly high speed (aka "strobe") flash. Its not actually flash synch at all. Its not synch and is not even flash. It was introduced decades ago by Olympus who called it by a more honest term, "FP Synch" (FP=focal plane). One could reasonably view HSS as no different than an old time flash bulb ... except its reusable instead of disposable.

Electronic flash has an extremely short duration. HSS lighting is long duration. Its actually continuous light and is NOT flash.

The important difference is whats sometimes called "synchro sun" flash. HSS does not allow for synchro sun.

With continuous light, whatever you do to adjust exposure affects both the ambient light and the additional light equally, thus you cannot alterr the balance between the two sources by adjusting the camera. The only method available is changing distance or adding physical attenuators to the HSS light.

With an actual high speed flash you can control the flash power via the flash controls and separately control the ambient light exposure via the camera controls. Thus you can directly control the flash-to-ambient lighting balance.

Whether using synchro sun or HSS, aperture affects the exposure of both sources equally. HOWEVER !!! high speed electronic flash duration is so short that its unaffected by the shutter speed while acoarst the shutter speed ALWAYS affects the ambient light exposure. THAT (!) is the whole key to using synchro sun for controlling the ambient-to-flash exposure balance.

The key point is that HSS is NOT actually flash. Its a CONTINUOUS source exactly the same as an LED video panel, except it uses a xenon gas tube instead of LEDs.

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If the above makes no sense to you, then just dont buy a Sony a1. That saves you 3 to 4 thousand $$ which you can spend on exotic lenses that will make you the envy of your entire camera club :-)

MDI Mainer

Thanks. I didn't post it originally, so that the topic wouldn't be moved to Links and Resources.

gwilliams6

HSS greatly reduces the duration (thus power output) of your strobe's power to enable pulsing the flash at a very fast rate, so you DO NOT have as much light illuminating your scene as with a single full power flash. .

The A1 with its 1/400 sec flash sync allows you to use the full power of your flash, better to light dark subjects, and better to light larger areas and subjects at greater distances , and better to overpower the sun. This is a huge advantage .

FYI, I am a longtime pro and I currently own Sony A1, A7RIV, A7SIII. And yes I have done all types of flash photos in my 48+ year pro career using all types of flashes and all brands of camera and flashes. This is truly a breakthrough for digital cameras.

Cheers and best to you all.

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Architect1776 Loc: In my mind

Grahame Loc: Fiji

Here's a practical example demonstrating 'differences'.

Lets assume an indoor situation using a Z6 (flash sync speed 1/200) and an SB-5000. Camera is set at 1/200, f/4.5, ISO100, approx. setup for a portrait and these settings are allowing no ambient to affect the result.

a) At 1/200s (sync speed) the resulting subject exposure/brightness is correct with the flash set at 1/16 power.

b) At 1/400s (HSS/FP) the resulting subject exposure/brightness is underexposed.

c) At 1/400s (HSS/FP) the resulting exposure/brightness is equivalent to that in a) when the flash is set to 1/2 (-2/3EV).

In this example there would have been no downside to using HSS at 1/400 disregarding battery drain/recycle time that may or may not be a concern.

Now, if to get correct exposure/brightness of the subject in a) it had required 1/2 flash power there would have been a problem unless ISO was increased or aperture widened (both being detrimental to your goal).

As for the value of the advantage between syncs of between 1/200 and 1/400 outside I'm not really conversant with this, I use HSS only outside for action shooting with shutter speeds between 1/800 and 1/1600.

gwilliams6

Folks need to understand the loss of flash power when you use HSS (high speed sync). It can be significant and you have to factor that when shooting in HSS, especially in bright sunlight. Here is a video to help explain it.

This is How Much Light You LOSE w/ High Speed Sync!
https://www.youtube.com/watch?v=E2LtZ7g2pR8

You do not lose this flash power when shooting flash at 1/400sec. or 1/500 sec. (APS-C mode) with the A1. You can choose to use the full power of your strobe and still shoot at a fully-synched high shutter speed without using HSS.

HSS can be useful in some shots, but it is not the answer when you need to be able to use the full power of your strobes, but still want to use a high shutter speed.

Cheers and best to you all

Hemp Imagery

As a studio photographer, using lights, that synch @1/60 & getting excellent results , the 1/400 ,just has no relevance for my studio use. Even for outdoor sports leagues, 1/200 is plenty fast to stop any movement expected. so it's a non issue for me ( It's like a lot of features on the Z9-I'll probably never use them. )

User ID

The greater control one can exercise over their working situation, the less flexibility one requires from their basic camera and lens. Thaz always the no brainer trade off.

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