What is the technical limiting factor for the maximum flash sync speed limit??

[Transposure]

So, I got to thinking today...
I know, I know, a rare occasion! LOL

My question has to do with flash sync speed limitations.....

The Schneider LS lenses I used with the 645DF body had a maximum flash sync speed of 1/1600s. The RZ67ProII has a maximum flash sync speed of 1/400s. These flash sync speeds are based on the use of leaf shutter lenses of course.

Canon and Nikon get around this with their focal plane shutters by pulsing their speedlites to simulate constant light during the shutter duration, albeit at greatly reduced power. I have used the Canon flash system routinely up to 1/8000s (high speed sync). I have ganged speedlites together to create an array that produces the appropriate light output needed, while also syncing at those speeds. I have even played with Profoto studio strobes wirelessly syncing at 1/8000s using the Radiopopper Jrx system (too much explanation to go into here).

My question, however, pertains to leaf shutters specifically....

What is the limiting factor in terms of flash sync speeds? I surmise it is the mechanical ability of the shutter blades to open and close reliably. Furthermore, I assume this is due to the weight of them, and the springs used to perform the work of opening and closing them. Schneider achieved it up to 1/1600s with the 645 lenses. Mamiya achieved it up to 1/400s with the RZ lenses. The Schneider lenses must use very light materials as well as being physically smaller than the RZ lens shutter blades.
Having said this, wouldn't stiffer springs and lighter carbon fiber or titanium blades allow greater sync speeds?

If anyone has any insight here, I would love to hear the theory. Besides being a photographer, I have a Masters degree in structural engineering.

Chime in!!

 

[Ed Hurst]

I cannot furnish you with a complete answer, just a supplementary question... Are the speeds you quote the faster shutter speeds available with those lenses/systems, or are they lower than the max (but simply the fastest speed allowing flash sync)? At least in the case of the RZ, i think 1/400 is the fastest speed they perform anyway.

Or, put differently, are you asking about fastest speed achieving sync or why leaf shutter speeds themselves can't be quicker (I think you mean the former)?

Ed

 

[Transposure]

Hey Ed,
I am referring to the fastest speed achieving flash sync.
Having read your reply, I realize that some of my theory is flawed.
So, let's start over, shall we? LOL

The goal.....finding an explanation for the limitations of flash sync speed.

The maximum shutter speed of the RZ is 1/400s. I am assuming I can wirelessly flash sync up to that speed using the Profoto Air system. I will find out tomorrow during my set up for a beauty photoshoot.

On the 645Df with the Schneider LS lenses, the Profoto Air system can wirelessly flash sync up to 1/1600s.

Both the RZ lenses and the Schneider lenses use leaf shutters.

Since the Schneider lenses can shoot faster than 1/1600 (where my original theory was flawed), there is something preventing a faster wireless flash sync speed. Now that I realize this, I suspect it is the radio system latency.

Food for thought....

Can anyone confirm this?

 

[Shashin]

Flash duration. Many flash units top out at 1/1000s or so. And why would you need a shutter speed faster?

 

[Transposure]

Hey Shashin,
Under their respective best settings, the flash durations of my collection of generators are:
Profoto 8A: 1/12,000s
Profoto B2's: 1/7000s
Profoto D4: 1/4500s
Profoto D1's: 1/2600

I will routinely shoot an array of four Canon Speedlites at 1/2000s to 1/8000s at midday, under bright sun, at f/2.8. This allows for creative choices for engagement sessions and editorial projects.

 

[SergeiR]

The goal.....finding an explanation for the limitations of flash sync speed.

materials used and electronic controls used. At time when original RZ was conceived 1/400 was pretty darn fast. Original focal plane shutters were syncing at 1/30th for years, btw. FP high speed syncing was designed quite recently and now its there. LS stepped up game with DF special control for new LS lenses (old ones are 1/400 as well btw). No one designed anything like that or new body for RZ system for a while.

I.e don't look for conspiracy where none is present. If RZ system will keep being revived - it will come.

 

[yaya]

To the OP I think you're mixing a few things here i.e. shutter speed, sync speed, flash duration, type of shutter and transmitter type. They are all different things!

By nature, leaf shutters are slower than focal plane shutters, because they have to open AND close whereas focal plane shutters move only in ONE direction (and two curtains)

However, leaf shutters can normaly synchronise at any speed; so if the RZ lenses can do 1/400 that's also their max sync speed

The Schneider designed Mamiya lenses can do 1/800 but in combination with a DF body and some black magic in the digital backs (Aptus-II, Credo, IQ, P40+ and P65+) we are able to double the speed

Wireless flash systems can have a limited sync speed; for example Pocket Wizards max out at 1/500...

Flash duration is a whole other thing and I'm not an expert in flash technology...

 

[fotografz]

There are a number of various sync speed Leaf Shutter lenses ... those you mention, as well as Hasselblad V lenses @ 1/500 and HC and HCD lenses @ 1/800, and some Rollie lenses that sync to 1/1,000. Other than the electronic "black Magic" Yair mentions, we may be at or close to the physical limits of shutters, and other methods will be employed to increase flash sync capabilities ... like no shutter at all, or better implementation of automated Hyper-Sync indicated at the end of my post with a link.

My limited layman's understanding:

Max sync speed for focal plane shutter cameras tend to be a considerably slower shutter speed, and that sync speed indicates when both shutter curtains are completely open (usually 1/125 for Medium Format, and 1/200 or 1/250 for 35mm type cameras), ... shutter speeds beyond that are a traveling slit. HHS with speed-lights pulses the light as that slit travels across the film or sensor to in effect produce a steady level of flash illumination. Pulsing the light greatly reduces the effective "collective" level of light reaching the film or sensor. HSS is possible because while the slit is traveling, it covers the remaining area, exposing only the revealed area with each pulse.

Leaf shutters open and close as a circular diaphragm, and can reveal the whole area quicker ... however, pulsed HHS isn't possible because as the leaf shutter opens and closes, some portion of the area is always exposed. The center of the image would be overexposed compared to the outer portions.

The next element in the process is flash duration. All speed-lights and studio strobes achieve proper levels of light by how long they stay on ... shorter duration = less light, longer duration = more light reaching the subject.

No matter how fast the duration is to the eye, all flash lighting ramps up to full illumination and then down to being off. This is measured in two ways called t.5 (duration above 50% maximum output) and t/1 (duration above 10% of maximum output). Manufacturers tend to use the t.5 number in their specifications for most practical applications of lighting, however, the t.1 specification is more relevant IF you are interested in freezing action. For example, a t.5 spec can be 1/1800 but the t.1 spec is 1/600 ... so a leaf shutter sync of 1/800 will clip a small portion of the light.

You really have to know the t.5 and t.1 specifications of your strobe system to use it effectively in all circumstances.

Then there are the triggers. A hard-wire connection to the light is generally the fastest. Radio triggers differ in specifications. Usually 1/200 or 1/250 for focal plane shutter camera use, and 1/500 for Leaf Shutter cameras. The Profoto AIR Remote touts a possible 1/1500 Leaf Shutter speed. In addition to Profoto AIR lighting, Hensel now also includes AIR receivers in select packs, so full sync is possible up to 1/1500 depending on the specific lighting tool specifications, settings and and the camera used.

The other wrinkle to all this is Hyper-Sync ... which may be the answer that the OP is looking for. HSS and Hyper-Sync are two completely different concepts, and Hyper-Sync is NOT limited to HSS enabled speed-lights and cameras. This starts getting well beyond my under-standing, and is better explained here:

PocketWizard® - HyperSync

-Marc

 

[Stefan Steib]

Hmmm, I think this is even more complicated:

first the lights. Most generators do state their output at T 0,1 which means that on a loss of a level smaller than 10 % to the peak the overall Guide Number is given. Now when you take a look at different system: Tube and LED Flashes, LED will probably have only nearly a peak and Tubes will also have a significant gain when coming to the maximum out put .

Put this in connection with electronic syncing, especially when you have a wireless connecion with a lag and then you will see that this is complicated.

now the leaf shutter: Imagine a classic strobe generator with tubes firing T 0,1 at the full open stage of the circular shutter/which is also at the same time an aperture. If the gain is very slow and the shutter opens fast but you use times about 2-3 times as long as T0,1 you may get color shifts, differing (higher) guide numbers . If you use shorter times you will cut guide numbers, run into syncing probs especially if you use several generators, so I guess what Canon does with the clustering and remote E-TTL of their flashes is quite an engineering achievement that regards highest respect.

Again , even a leaf shutter has syncing problems, so it would be much better to use a global shutter approach which takes the image always with wanted aperture and uniform and allows the flash just to fire right onto the full desired chip size without having to take care about a rolling blade-shutter/linewise read chip and or a leaf shutter with a linewise read chip.

As I said this is complicated, but it could be much easier !

regards
Stefan

 

[FredBGG]

To the OP I think you're mixing a few things here i.e. shutter speed, sync speed, flash duration, type of shutter and transmitter type. They are all different things!

Actually I think the OP has a very good grasp of those differences.

You then go on to state:

Flash duration is a whole other thing and I'm not an expert in flash technology...[/url]

But you still feel that it's right for you to say the OP is all confused......

 

[FredBGG]

Wireless flash systems can have a limited sync speed; for example Pocket Wizards max out at 1/500...

Hmmm my Pocket Wizards have no problem giving me synch speeds of 1/8000th with my Canon speedlights.

I can also achieve 1/2000th of a second using them with my Elinchrom AS3000 studio pack, but with S heads rather than A heads.

Things are simpler with leaf shutters, but it's somewhat flaunted as a big deal, but the truth is it is doable with 35mm dslr cameras. Hasselblad H cameras can go upto 1/800th and have more reliable shutters.

Also another important thing to consider is that a dslr is only really 3 stops slower than the maximum you can get out of the Phase system. Just adding a 3 stop ND filter and using more flash power from a studio strobe will pretty much get you the same result.

 

[yaya]

Hmmm my Pocket Wizards have no problem giving me synch speeds of 1/8000th with my Canon speedlights.

I can also achieve 1/200th of a second using them with my Elinchrom AS3000 studio pack, but with S heads rather than A heads.

You must have some custom made PW made by a US military lab....PW PlusIII Spec

Things are simpler with leaf shutters, but it's somewhat flaunted as a big deal, but the truth is it is doable with 35mm dslr cameras. Hasselblad H cameras can go upto 1/800th and have more reliable shutters.

So H is now lore reliable than DSLR? Can you point us to some stats that prove this?

Also another important thing to consider is that a dslr is only really 3 stops slower than the maximum you can get out of the Phase system. Just adding a 3 stop ND filter and using more flash power from a studio strobe will pretty much get you the same result.

And I guess that focusing and composing through a 3-stop filter makes it even easier, right?

 

[FredBGG]

By nature, leaf shutters are slower than focal plane shutters, because they have to open AND close whereas focal plane shutters move only in ONE direction (and two curtains)...

Let me elaborate on this.

35mm DSLR focal plane shutters are not actually slower... by that I mean that the shutter blades do not move slower, the issue is that they have to travel further.

With a leaf shutter even at high speeds the shutter has to open fully and then shut. While the shutter is fully open the whole image can be exposed by flash.

With a focal plane shutter high shutter speeds are achieved by sort of scanning across the focal plane.

At a 1/125th of a second this is what happens.

First curtain opens fully exposing the whole focal plane. Then the second curtain closes obscuring the focal plane.

This is what happens at 1/500th of a second.

First curtain opens, but before it fully exposes the focal plane
the second curtain starts to move. It follows the first curtain and completely obscures the focal plane 1/500th of a second after the first curtain finished moving. This means that the full focal plane is not uncovered completely at any given time and that the overall duration of the "scan" is longer than 1/500th, but no given part of the focal plane is exposed for more than 1/500th of a second.

Faster speeds are achieved by the second curtain chasing the first curtain sooner.

 

[fotografz]

Hmmm, I think this is even more complicated:

first the lights. Most generators do state their output at T 0,1

regards
Stefan

Not really, at least not until more recently, and certainly not consistently ... because t.5 sync specs look better for marketing. My point was to learn both if possible.

From a tutorial on Flash duration by Jerry Schmidt "The t.5 duration is generally the method used by manufactures in specifications of their lights".

Or if you prefer: a quote from Paul C. Buff, "There is nothing dishonest whatsoever about the use of the standard t.5 flash duration spec". His gripe was not stating both for full disclosure, which not all manufactueres do.

Buyers need to just do the homework.

-Marc

 

[FredBGG]

And I guess that focusing and composing through a 3-stop filter makes it even easier, right?

Absolutely no problem at all. When knocking 3 stops off sunlight you still have heaps of light for the AF systems on DSLR cameras.
Also I can use the live view if I want. I can even have my assistant remotely move the focusing point around following the models closest eye so I can concentrate on the subject.


Also whenever I shoot in bright sunlight with polarizing filter or nd filters I wear Kurtis surf goggles. They sit nice and light over you eyes and when you lift up the eyepiece you can catch the frame of the goggles and lift them out of the way as you peer into the eyepiece..... when your done they just plonk right down again..... learnt that one from a veteran oscar winning cinematographer.

But I also have a different setup for my Fuji GX680 is I want to overpower sunlight a bit and shoot wide open. I have a GX680 with a custom mount for a 4x or 8x nd filter mounted behind the mirror infront of the film back mount. It lets me have a bright viewfinder and shoot wide open in bright sunlight. With the flash sync of 1/400th it works quite nicely with powerfull strobe. The only problem I had is that I had to dedicate a body to this because I had to calibrate the focusing screen for the added glass surface behind the mirror.
The nd filter shifts the focus a wee bit.
Got the body for $150..... the titten ND filter cost more

This was shot with the Fuji GX680 "Midnight Shades" edition.

 

[FredBGG]

So H is now lore reliable than DSLR? Can you point us to some stats that prove this?

I did not mean that. What I meant is that at a maximum speed of 1/800th they are more reliable than faster leaf shutters.

Phase One, Leaf and Mamiya Official User to User Forum • View topic - SCHNEIDER 80MM LENS SHUTTER JAMMED

A couple of quotes from the phase one forum:

I am onto my third 80mm LS Schneider lens.

This weekend the shutter blades jammed closed and my camera was unusable.
This is the third lens of the same model to do this.
Phase One have replaced my lens every time but I am beginning to lose complete faith in the camera system?
I am shooting in the Maldives early March and I can't afford to have my kit breaking down or out of action.

The digital technician operating my camera and I were both at a loss to explain why the kit was breaking down so consistently.

I am interested to hear from Phase One or anyone with similar experiences?
thanks
Antony

I had the same issue 2 weeks into the new lens. The dealer replaced the lens no questions asked but amazingly annoying. Now that new lens doesn't auto focus to infiniti. Need to bring it in to be fixed. WTF?!

I have had very similar problems lately.
During my last job, the shutter in the df body destroyed itselt while shooting.
I rented a second body. Then the shutters in both my LS80mm and LS110mm would stick shut like once in 10 shots.
They make a strange noise and then open back up.
This went on during the whole shoot.
Both the body and the lenses were one and a half months out of warranty.
I sent the body in for repair and the shutter in the body was replaced at full charge.
When I asked about the lenses, phase one's answer was I would have had to pay €350 for them to look at them, with no guarantee that they would find a fix. In which case the shutters would be replaced at full charge.

That's about the worse service I've ever received in my life. And I'm stuck with two time bombs in my bag.

Anyone else have this problem?

 

[FredBGG]

You must have some custom made PW made by a US military lab....PW PlusIII Spec

More sarcasm from the Yaya......:thumbdown:

Nope.. no special military grade stuff, just the Pocket Wizard FlexTT5 for Canon.

Took a bit of testing to find the right calibration settings ...about an hour of so.

 

[fotografz]

You must have some custom made PW made by a US military lab....PW PlusIII Spec
So H is now lore reliable than DSLR? Can you point us to some stats that prove this?
And I guess that focusing and composing through a 3-stop filter makes it even easier, right?

Yair, if you have a moment, read the Pocket Wizard link in my post about Hype Sync. (1/8000 with PWs).

I use NDs or a Polarizer coupled with ISO-50 with the H4D when working with strobes outdoors for faster apertures when creatively desired ... in that bright of light seeing and focussing really isn't any problem.

All the best,

-Marc

 

[fotografz]

I did not mean that. What I meant is that at a maximum speed of 1/800th they are more reliable than faster leaf shutters.

Phase One, Leaf and Mamiya Official User to User Forum • View topic - SCHNEIDER 80MM LENS SHUTTER JAMMED

A couple of quotes from the phase one forum:

Hmmm, maybe this is why Leica is taking their sweet time getting the S2-LS lenses to market and why they're testing the living crap out of them ... no room for mis-steps.

-Marc