[Spodeworld]

Interesting tutorial on how to get around the sync speed barrier with flash

You Tube

You Tube

[enoeske]

Interesting tutorial on how to get around the sync speed barrier with flash

Breaking The 1/250s Sync-Speed Trick! - YouTube

In case you want an explanation -- The flash is on full power because that means its "on" for a long time. It essentially becomes a normal always-on light source. When above the sync speed, the shutter moves in a slit down the sensor. The flash duration is usually so short that the sensor only sees it for part of this movement. This appears as a slit of the flash exposed in the image or dark bars where the flash didn't show up (as the movie shows).

If the duration of the flash is longer, more of the sensor "sees" the flash during the slit movement duration. If the flash duration is long enough, it can be on for the whole time the slit is exposing the sensor. Since the shutter always moves at the sync speed, this only works if the flash duration is greater than or equal to the sync speed, which doesn't happen on all flashes.

And, of course, for Pentax, the flash is totally disabled for shutter speeds beyond 1/180 unless you use HSS. So, you'd have to have a HSS flash on the camera, triggering a flash whose full power duration is 1/180 or slower.

[Oldbayrunner]

Or you can use an HSS flash on camera triggering a slave HSS capable off camera flash if light permitting or use something like the Aokatec HSS radio trigger system on both.

[mikeSF]

lol @ 2:00
"Understand Kung Fu"

[aleonx3]

Or you can use an HSS flash on camera triggering a slave HSS capable off camera flash if light permitting or use something like the Aokatec HSS radio trigger system on both.

I thought the trick was to use HSS mode on the flash mounted on the camera (pointing away) and M mode full power on the slave flash. I might have tried this before.... I think it is worth testing it out.

[Spodeworld]

I thought that this might be a way around using HSS totally (assuming one wants a way around it). But, looks like you have to have at least the flash on the camera in HSS mode. However, even if that were the case, you could still use off camera flashes that don't offer HSS in slave mode, and, in theory, this should work.

In case you want an explanation -- The flash is on full power because that means its "on" for a long time. It essentially becomes a normal always-on light source. When above the sync speed, the shutter moves in a slit down the sensor. The flash duration is usually so short that the sensor only sees it for part of this movement. This appears as a slit of the flash exposed in the image or dark bars where the flash didn't show up (as the movie shows).

If the duration of the flash is longer, more of the sensor "sees" the flash during the slit movement duration. If the flash duration is long enough, it can be on for the whole time the slit is exposing the sensor. Since the shutter always moves at the sync speed, this only works if the flash duration is greater than or equal to the sync speed, which doesn't happen on all flashes.

And, of course, for Pentax, the flash is totally disabled for shutter speeds beyond 1/180 unless you use HSS. So, you'd have to have a HSS flash on the camera, triggering a flash whose full power duration is 1/180 or slower.

---------- Post added 01-07-15 at 12:55 PM ----------

Yeah, he's pretty entertaining. Never saw his stuff before today, but it seems pretty good.

lol @ 2:00
"Understand Kung Fu"

[jake14mw]

His trick will work with other camera brands the way it was described in the video, but with Pentax cameras, since Pentax disables the flash firing with a shutter speed faster than 1/180(unless in HSS mode), you need to use an HSS flash on camera with Pentax.

We have been bitching for years to have Pentax change this by simply putting an override in the menus, but they have not done it. I don't understand why they won't do it.

[Spodeworld]

Bummer. Seems like an unnecessary obstruction. I get why they are doing this, but they should leave it to the discretion of the photograler.

His trick will work with other camera brands the way it was described in the video, but with Pentax cameras, since Pentax disables the flash firing with a shutter speed faster than 1/180(unless in HSS mode), you need to use an HSS flash on camera with Pentax.

We have been bitching for years to have Pentax change this by simply putting an override in the menus, but they have not done it. I don't understand why they won't do it.

[aleonx3]

His trick will work with other camera brands the way it was described in the video, but with Pentax cameras, since Pentax disables the flash firing with a shutter speed faster than 1/180(unless in HSS mode), you need to use an HSS flash on camera with Pentax.

We have been bitching for years to have Pentax change this by simply putting an override in the menus, but they have not done it. I don't understand why they won't do it.

The built-in flash currently does not support HSS, does other camera makers offer HSS in the built-in flash? would be nice to know...

[slowhands95128]

The key to this "fast flash" trick is to manually force a long duration flash which overlaps the very short duration when the focal plane shutter slit moves over the sensor. Pentax cameras won't permit flash for shutter speeds above 1/180th, unless the flash can do HSS - and is set to HSS, not manual, preventing this trick from working. It's just a firmware lockout. I'm sure the engineers thought this would help the average photographer who would complain when his flash pictures had slit lighting. For advanced users, this lockout should be optional.

I've been thinking about this. Could we use a radio remote trio (say, three Cactus V5s) to work around this? One is a transmitter to a receiver on the camera and to a receiver on the remote flash. The transmitter simultaneously triggers your camera and triggers the remote flash with maximum duration flash. You don't need an on-camera flash at all. [The camera has to be in Manual mode, so there is no "pre-flash delay" -- meaning auto mode think time in this case. Think time from shutter push to start of shutter movement is typically 20 or more milliseconds, an eternity compared to the 1 millisecond duration of the flash. It's so short we don't notice, but in auto modes the camera thinks a lot more, meaning delays that we don't want.]

One reason to do this is of course to replace one (expensive) HSS-capable flash in the Youtube video with cheaper radio remotes. Maybe the remote flash could just be on a Stroboframe with the camera, connected by radio, not wires. In fact it seems like the remote flash can be any old legacy flash, but with this trick it can simulate a more expensive HSS capable flash. Would this work? It sounds too good to be true.

[Class A]

Could we use a radio remote trio (say, three Cactus V5s) to work around this?

Your idea works with the Cactus V6 (and/or the Cactus RF60), but not with the V5 or any other trigger I know.

The reason is that even if you set the camera to manual focus, etc. its shutter lag will be way too long. The flashes will have fired already by the time the camera starts opening the shutter.

The V6 has a "delay" option, however, allowing you to delay the firing of the flashes. You'd have to set the delay to match the shutter lag of the camera. The latter may not always be 100% the same if you take several quick shots in succession and there is respective processing going on in the background, yet when using flashes at full power to make this technique work, this probably won't be a problem.

If you are using RF60s as off-camera flashes then you can set the delay on them instead of on the V6 receivers. The advantage of using RF60s would be that you could use true HSS (i.e. a long flash burst) instead of the HyperSync technique described here with the latter invariably leading to a graduated exposure acrosse the frame (since a regular full power pulse tails off in intensity rather quickly).

Let me know if you want me to validate your idea with my Cactus gear. I've been using an HSS-capable flash as a trigger for a V6 transmitter and am not sure anymore whether I ever validated the setup suggested by your idea.

[slowhands95128]

Ahh.. the camera shutter lag is too long for this simple implementation to work. Yes, I would be interested in whether the V6 delay function would compensate reliably for shutter lag. I always prefer to buy the latest --- that way instead of being obsolete next week, it's obsolete in two weeks.

Let's assume the camera is shooting in Manual exposure/manual focus, using JPEG only and not firing too often. That should keep shutter lag more consistent. I'm curious if this concept of achieving "HyperSync" can be implemented using V6s, and of course how many? Or maybe the camera could see an attached V6 as HSS capable by itself, without a flash installed? I'm going to have to read your detailed review of the V6 carefully.

[Class A]

Yes, I would be interested in whether the V6 delay function would compensate reliably for shutter lag.

I just tested it. With a K-5 II and an FA 43/1.9 at f/8 and 1/500s shutter speed, I consistently could illuminate the whole frame when I set the RF60 to a delay of 91ms.

Setting the RF60 to "HSS" mode, meant that I could also use flash powers less than "full" but still illuminate the full frame.

Hope this helps.

P.S.: You need one V6 for each off-camera flash (unless you use RF60, which have a V6 built in). As a remote trigger for camera and flashes a V5 will do instead of a V6, and the receiver for the camera could be a V5 only as well.