Mental Sync speeds :)

:O I thought you could only get that from cables

not tried it but really wanna buy a g series so I can
 
Sadly with all these various high speed sync workaround tricks, the downside is a huge loss of light which makes it effectively impractical. The best option by far is to use an FP/HSS enabled flash gun.
 
HoppyUK said:
Sadly with all these various high speed sync workaround tricks, the downside is a huge loss of light which makes it effectively impractical. The best option by far is to use an FP/HSS enabled flash gun.
Click to expand...

Rubbish ;)

I get a consistent flash exposure all the way to 1/1500s using rear curtain sync.

From 1/125 - 1/1500s in a dark environment the histograms are absolutely identical, no loss of flash power at all until the shutter speed gets up to 1/2000s. Nothing other than the shutter speed is changed. No drop off in exposure, no loss of light or power they're identical. Which makes sense since the flash duration is around 1/15,000 second at 1/16th power.

In an environment with ambient, the flash exposure's consistent so I can pull ambient way down. Just got to wait for a free sunny day now.

I now know that with a speedlight I can sync at up to 1/1500s, I'll try the Safari gear tomorrow but I think the limitation is probably in the Skyports, and maybe I should retest using first curtain sync and just a cable.
 
D70s are great. Not sure how you are managing to get that sync though. With pocketwizards, the fastest you can go before you get crazy moire patterns and other odd anomalies is 1/800th.
 
HoppyUK said:
Sadly with all these various high speed sync workaround tricks, the downside is a huge loss of light which makes it effectively impractical. The best option by far is to use an FP/HSS enabled flash gun.
Click to expand...

with this one is an electronic shutter so it works anyway :p
 
ruvor said:
D70s are great. Not sure how you are managing to get that sync though. With pocketwizards, the fastest you can go before you get crazy moire patterns and other odd anomalies is 1/800th.
Click to expand...

Elinchrom Skyports consistently upto 1/1500s (Elinchrom claim 1/1000s so can't expect more)

I've just tried a cable and it comfortably goes to 1/4000s.

Not seen any strange effects yet.
 
JasonRS said:
Rubbish ;)

I get a consistent flash exposure all the way to 1/1500s using rear curtain sync.

From 1/125 - 1/1500s in a dark environment the histograms are absolutely identical, no loss of flash power at all until the shutter speed gets up to 1/2000s. Nothing other than the shutter speed is changed. No drop off in exposure, no loss of light or power they're identical. Which makes sense since the flash duration is around 1/15,000 second at 1/16th power.

In an environment with ambient, the flash exposure's consistent so I can pull ambient way down. Just got to wait for a free sunny day now.

I now know that with a speedlight I can sync at up to 1/1500s, I'll try the Safari gear tomorrow but I think the limitation is probably in the Skyports, and maybe I should retest using first curtain sync and just a cable.
Click to expand...

The D70 has a CCD instead of a CMOS sensor which uses electonic switching to achieve high shutter speeds, as opposed to a mechanical shutter. In that way, it gets around the normal focal plane shutter sync problems.

However, it cannot increase the power of the flash. Say for example that a full power flash pulse lasts for 1/1000sec with a typical hot-shoe gun, if your D70 shutter speed is 1/2000sec (and your synching is perfect) you're only going to get half the light (that's absolute maximum, optimum result) and a quarter the light at 1/4000sec and so on. The reality will probably be less than that. There's nothing you can do about it - the flash only has so much power and you are slicing that up into smaller pieces with the shutter switching.

TBH it's a pretty cool trick and is a good substitute for FP/HSS enabled guns, but the power losses are similar. Plus there are the downsides to CCD sensors which is why they're not used any more.

You can have a go at battling with sunlight, but you'll really struggle at anything but very close range. You might have solved the sync issue, but in doing so you have increased the power problem.
 
JasonRS said:
Elinchrom Skyports consistently upto 1/1500s (Elinchrom claim 1/1000s so can't expect more)

I've just tried a cable and it comfortably goes to 1/4000s.

Not seen any strange effects yet.
Click to expand...

hmm, i found my skyports to be far slower, 1/640 without power loss. They were the RX models though and triggering a el. Ranger, so perhaps it is a little slower than small strobes. I'll have a play around sometime with my pw+IIs/MMxs and see what I can sync to with a speedlight.

Either way, it's an incredible handy feature to have, being able to use fill light on action shots in bright light without having to worry about ghosting is great.
 
HoppyUK said:
However, it cannot increase the power of the flash. Say for example that a full power flash pulse lasts for 1/1000sec with a typical hot-shoe gun,
Click to expand...

It's also 1/1000s for my Safari heads.

That is firing at full power though.

If you drop the power the duration drops quite dramatically too so that around 1/4 power you're at 1/5,000s flash duration. It's not a linear tail off and the first few drops in power have the biggest impact on duration. 1/64 should be around 1/30,000s. That's on a hotshoe flash, not sure if it will tail off in a similar manner for the Safari as it's got bigger and better tubes, so may go to an even lower duration.

This extra sync speed also opens up the option of much lower flash power being required to control ambient because I don't need to overpower it so much and recycle time gained too. It also allows for larger apertures, and hence even lower flash power.

It's not so much about having the ability to fire full power shots of light into a scene but I've now got a lot more leeway for certain scenarios without needing extra w/s.

Even at 1/1000s, I have 2-3 stops extra gained over a typical sync speed (my other body maxes at 1/180) whilst still allowing me to benefit from a full power flash output. So that's 3 stop bigger aperture, 3 stops less power from the flash or 3 stops better ISO (Disappointed that Nikon only goes down to ISO 200 though).

1/1000s is probably where my working limit will be as it's a sweetspot of camera, skyport, full power duration all wrapped up together.

The D70s isn't my main body, it was bought with the sole purpose of getting access to these much higher sync speeds with studio / portable gear and to allow for experimentation.
 
JasonRS said:
It's also 1/1000s for my Safari heads.

That is firing at full power though.

If you drop the power the duration drops quite dramatically too so that around 1/4 power you're at 1/5,000s flash duration. It's not a linear tail off and the first few drops in power have the biggest impact on duration. 1/64 should be around 1/30,000s. That's on a hotshoe flash, not sure if it will tail off in a similar manner for the Safari as it's got bigger and better tubes, so may go to an even lower duration.

This extra sync speed also opens up the option of much lower flash power being required to control ambient because I don't need to overpower it so much and recycle time gained too. It also allows for larger apertures, and hence even lower flash power.

It's not so much about having the ability to fire full power shots of light into a scene but I've now got a lot more leeway for certain scenarios without needing extra w/s.

Even at 1/1000s, I have 2-3 stops extra gained over a typical sync speed (my other body maxes at 1/180) whilst still allowing me to benefit from a full power flash output. So that's 3 stop bigger aperture, 3 stops less power from the flash or 3 stops better ISO (Disappointed that Nikon only goes down to ISO 200 though).

1/1000s is probably where my working limit will be as it's a sweetspot of camera, skyport, full power duration all wrapped up together.

The D70s isn't my main body, it was bought with the sole purpose of getting access to these much higher sync speeds with studio / portable gear and to allow for experimentation.
Click to expand...

That sounds about right and workable Jason :thumbs: However, all the D70 does is solve the sync speed problem - up to about 1/1000sec should be okay but you'll be cutting power pro-rata after that, and that is asssuming that the x-sync timing is optimum.

And of course you need a D70 to do it. I think the D40 has a similar switching CCD sensor and some other older Nikons. They limit this feature to 1/500sec without the workaround hack because it becomes inconsistent and unreliable, depending on the flash used. You will probably get colour shifts too.

Also bear in mind that studio flash works quite differently to hot-shoe guns. Hot-shoe thyristor flashes reduce the power by cutting the duration, whereas studio flashes reduce the brightness of the flash but maintain a similar duration. The shape of the flash pulse is also different with a long tail to the studio pulse which falls away relatively slowly but at a very low level. Which part of the studio flash pulse you actually get, especially at higher speeds, depends of the sync timing and will be different with different triggering methods and different flash units.
 
Finally got around to having an opportunity to play with this, images shot today, not for artistic merit just to share the results of an SB25 and high sync speed.

1,2 & 3 shot directly into the sun 1/1000s at 17:00 today.
SB25 zoomed to 85mm, handheld about 6ft from my son's head.

#1 - f16 SB25 at 1/2 Power
op1.jpg

#2 - f16 SB25 at 1/2 Power
op2.jpg

#3 - f11 SB25 at 1/4 Power
op3.jpg

#4 - f11 SB25 at 1/8 Power 24mm, 3ft FTS distance held high and left.
Shot at 12:30, so the sun was pretty much direct overhead. You can see where the light would have been from the shadows on the house in the background (and the double shadow from the little fella's head....)
op4.jpg


BTW, I've noticed the exif dates are out by 2 years shows I've not touched this body since the first experiments earlier in this thread....Must go and correct it now!!
 
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