Shutter sync, ISO questions

Started May 23, 2012 | Discussions thread
UKphotographers
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Re: Shutter sync, ISO questions
In reply to kgbruce01, May 24, 2012

kgbruce01 wrote:

The reasoning is that if you need a faster shutter speed, then you can use it. There are many, many reason to need a faster shutter speed. For instance - I needed 1/1000th (and a 1.5 stop grad ND) here to bring the sky under control...

1/60th would have been far too slow.

Thats an interesting assumption, and I've been considering how it might be overcome. I've not worked out the NEED yet as any loss in flash output would put the 'bringing of sky under control' that much further away.

1/60s is only a perceived limitation because people are not familiar with working with it now. If they were there'd be all sorts of solutions around.

In that shot, you didn't HAVE 1/1000s sync, you had 1/250s sync - or whatever your camera was capable of. You only get 1/1000s sync by using FP mode or HSS or PW ControlTL.

FP mode or HSS loses 2-3 stops of output. Peak Hypersync with PW's wouldn't, but you wouldn't get even flash coverage at 1/1000s, so thats not applicable.

My old Olympus OM-1 had a maximum x-sync shutter speed of 1/60s, but it also had FP sync which retimed the sync exactly the same as modern Nikon and Canons do now to the beginning of the shutter cycle. Because the OM-1 would have no way to trigger the FP mode flash pulsing that the Nikon or Canons do, it would not lose any of the 2-3 stops which FP mode or HSS flash incur, instead it would retain the full flash output.

The difference between 1/60s and 1/250s is 2 stops, so in FP mode sync on the 1/60s x-sync Olympus - by the time you stepped the shutter up to 1/250s you would be at -2 stops (still better than the 1/250s sync) and by 1/1000s and opening your aperture by the same you would still have in theory an extra +1 stop of flash output available.

In reality, the +1 stop might even be greater as the 1/1000s shutter speed would use a longer duration of time and access the extra output previously described due to the older and slower shutter mechanism.

It could all go pear shaped, but certainly the FP mode sync is available so all you would need to use would be a suitable flash source with a long duration. Using a speedlight would be possible, but a flash bulb would be better and obliterate any speedlight and match many battery portables.

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Ian.

http://www.commercialphotographer.co.uk

Theres only one sun. Why do I need more than one light to get a natural result?

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