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01-28-2011, 09:32 PM   #46
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QuoteQuote:
If flash photography is allowed, wouldn't a ND filter help in this case? Perhaps a convenient Cokin ND filter that you can pop in/out of its holder as needed without worrying about screwing it on/off.
ND filters would decrease all light; ambient and flash. So it really does nothing to help get us closer to the goal. ND Filters would help to obtain proper exposure in bright light with *longer* exposures. We're trying to get *faster* exposures.

QuoteQuote:
Pardon my ignorance, but my understanding is that flash duration is what freezes motion, not flash sync speed. So what the heck does sync speed have to do with stopping motion in a studio where the photographer has complete control over the ambient light?
Perhaps I was mis-understood or perhaps I mis-worded things (assuming this was directed at my comments?? -- hard to tell, no one was quoted or referenced)
Sync speed has no effect in a studio where you have control of your environment. You can set up an environment to fit almost any need.
Fast sync speed works where you cannot control the ambient light. The faster shutter speed will decrease ambient light while the flash is unaffected. Flash is almost always faster than shutter speed so it is not affected by the faster shutter. Thus ambient is easily balanced and offset by use of shutter speed.
Faster shutter speed also has the obvious effect of stopping motion without the use of flash. Thus with higher ambient light, (where not controllable in a studio), the faster shutter speed will still assist in freezing motion.


Last edited by amoringello; 01-28-2011 at 09:40 PM.
01-28-2011, 11:36 PM   #47
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QuoteOriginally posted by amoringello Quote
ND filters would decrease all light; ambient and flash. So it really does nothing to help get us closer to the goal. ND Filters would help to obtain proper exposure in bright light with *longer* exposures. We're trying to get *faster* exposures.
Flash output is user-controlled up to a point. Ambient light may or may not be. So if you can't bring down ambient light, then you can use a ND filter (same thing as turning down ambient light) and turn up flash output. Voila, subject lit, action frozen. In fact, I'm pretty sure the camera or flash's metering will do this automatically anyways. How does 1/2 a stop of flash sync speed affect any of this?

QuoteOriginally posted by amoringello Quote
Perhaps I was mis-understood or perhaps I mis-worded things (assuming this was directed at my comments?? -- hard to tell, no one was quoted or referenced)
It was a general comment regarding the OP's concerns and the gist of the thread which seems to imply that flash sync speed has any bearing on freezing action. I don't really need to directly reply to anyone to participate in a thread. Since I have no real experience with flash photography, the comments being made by some people were very confusing.

QuoteOriginally posted by amoringello Quote
Thus with higher ambient light, (where not controllable in a studio), the faster shutter speed will still assist in freezing motion.
Fine, but I don't see the relevance about the perceived "deficiency" of 1/180 vs 1/250 sync speed. Half a stop of shutter speed is mostly meaningless. When I photograph sports (like football), 1/250 isn't really adequate most of the time anyways. Sure, it may be the tiniest bit sharper than 1/180 if I compare closely, but it's still crap. My best results happen at 1/1000 and faster, although 1/500 may do in a pinch if I don't mind some motion blur from my subjects. I don't see how photographing football is any different from photographing martial arts, except that I can't actually use a flash at a football game,and I'm very surprised anyone can at a martial arts tournament.
01-28-2011, 11:40 PM   #48
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QuoteOriginally posted by Digitalis Quote
there are many cameras out there from the 35mm film era that used leaf shutters. Granted, almost all of them were range finder type cameras*. The fact is that some of them could synch up to 1/2000th
My Canonet rangefinder from the late 70's (which I've been using again lately) has a leaf shutter. It can flash sync at any speed, right up to its fastest 1/500 shutter speed. Pretty snazzy, considering it was marketed as a generic point-and-shoot
01-29-2011, 12:41 AM   #49
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QuoteOriginally posted by Wheatfield Quote
First, it would make no difference, since the shutter is moving at a finite speed (1/180th). All you would be getting is an unexposed band, with exactly the same exposure time as you'd get at 1/180th second.
This can be a hard concept to get one's head around, and most people seem to misunderstand it.
Second, they could add the moon to the camera, and all that would happen is there would be more things to go wrong, people would still complain, and they would also be complaining about the extra cost.
I think it would be nice to have it pop at every speed
1. You could put your subject in the flashexposed portion of the frame. Strobist calls this cheating the flashsync. Even as little as half a stop may be what makes the sky saturated to desired degree, and I think it would be possible in some situations to cheat to even shorter times.

2. Makes it possible to trigger a remote camera from a transmitter on the hotshoe.

01-29-2011, 02:23 AM   #50
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The main advantage of 1/250 vs 1/180 is the ability to use a half-stop less DoF in powerful ambient, that's all...
Both are not that freezing for sports.

So, this has meaning nearly only for portraits photogs that often have to deal with the sun and a small DoF.
But in this case, you can use a ND filter, or HSS...
01-29-2011, 06:26 AM   #51
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QuoteQuote:
Flash output is user-controlled up to a point. Ambient light may or may not be. So if you can't bring down ambient light, then you can use a ND filter (same thing as turning down ambient light) and turn up flash output. Voila, subject lit, action frozen. In fact, I'm pretty sure the camera or flash's metering will do this automatically anyways. How does 1/2 a stop of flash sync speed affect any of this?
People keep making an argument with NDs when these questions come up.
Easy enough to test. Try it. You'll see pretty quickly that ND affect both flash and ambient equally and therefore has no positive effect on freezing action. If you had the ability to turn up the flash to overcome ambient, shutter speed would not be an issue... and therefore neither would use of NDs.
Although, when you get the nuclear powered strobes to overpower the desert sun, and f64 isn't enough to keep your sensor from melting... then Yes, an ND or three would be helpful to bring the entire exposure back into range. :-)



QuoteQuote:
Fine, but I don't see the relevance about the perceived "deficiency" of 1/180 vs 1/250 sync speed.
I agree. I'd much rather have 1/500 1/1000 would be super! But for the lighting I am generally working in, that extra 40% increase in shutter speed (of 1/250 v.s. 1/180) would be helpful. Slightly.
01-29-2011, 06:56 AM   #52
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QuoteOriginally posted by amoringello Quote
People keep making an argument with NDs when these questions come up.
Easy enough to test. Try it. You'll see pretty quickly that ND affect both flash and ambient equally and therefore has no positive effect on freezing action. If you had the ability to turn up the flash to overcome ambient, shutter speed would not be an issue... and therefore neither would use of NDs.
???

The purpose of ND filters for freezing action is to lessen the ambient to the point it doesn't participate to the pic anymore... Then the action is lit by the flash only, which is quite instantaneous (usually 1/1000 for a full power blast, but even then the main part is more like 1/2000)...
You can indeed do the same by closing the aperture, or lowering the ISO, but if these two are already at their limits, ND filters are the only real way... HSS does not freeze the action (as it still takes 1/180s to expose the whole sensor), and higher sync speeds (with leaf lenses or digital shutters) are useful only up to 1/1000, where the flash starts to behave like a constant light source instead of a burst.

Granted, ND filters only work up to the maximal power of the flash...

Talking about deserts, Joe McNally once did a 7 strobes shooting in the desert using HSS.
Doing some simple calculation, he could have done the same shoot with only 5 strobes by using a ND filter. HSS does eat a lot of power...

Now, if you have to use a wide aperture, and you're already a min iso, then a ND filter will do more for you than a half-stop improvement of the sync speed.
As the only reason to use a faster sync speed is to further lower the ambient when iso cannot, it means you're in a well-lit situation, so the dimmer viewfinder should not be troublesome in this case.
01-29-2011, 07:16 AM   #53
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*** People, please... try these things and/or work out the math before you make such arguments.
Mathematically it doesn't make an ounce of sense. In practice it cannot and does not work.

Better get those NDs out and give it a go. Closing aperture and lowering ISO has the same effect... it affects *ALL* light; ambient and flash.

I would love to know how the aperture or ND is smart enough to let in flash and not the ambient light.
What part of physics tells these devices that the light is different?

e.g.; duration of flash is shorter than the shutter speed. So until your shutter speed approaches the flash duration, lets say 1/500 to 1/1600 or even 1/10000, depending on the flash, the flash is simply too short to be affected. Therefore higher shutter speed can cut ambient (constant) light and allow the flash to remain as metered.

There is *no* such physical property involved with aperture, ISO nor use of NDs that affect short duration light v.s. long duration or constant light.

01-29-2011, 07:21 AM   #54
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QuoteOriginally posted by kenyee Quote
No...the reason it has high sync speeds is that it's an *electronic* shutter. Same reason the Canon G series works at that speed and Nikon D40/D60.
No.

Because LX5 has 1/1000 limit for shutter speed when aperture is < 4.0. And 1/4000 when aperture is 4.0 or smaller (> 4.0).
This means it is a classic leaf shutter.

Electronic shutter is used in LX5 for video. Not for photo.
01-29-2011, 07:30 AM   #55
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QuoteOriginally posted by amoringello Quote
*** People, please... try these things and/or work out the math before you make such arguments.
Mathematically it doesn't make an ounce of sense. In practice it cannot and does not work.

Better get those NDs out and give it a go. Closing aperture and lowering ISO has the same effect... it affects *ALL* light; ambient and flash.

I would love to know how the aperture or ND is smart enough to let in flash and not the ambient light.
What part of physics tells these devices that the light is different?

e.g.; duration of flash is shorter than the shutter speed. So until your shutter speed approaches the flash duration, lets say 1/500 to 1/1600 or even 1/10000, depending on the flash, the flash is simply too short to be affected. Therefore higher shutter speed can cut ambient (constant) light and allow the flash to remain as metered.

There is *no* such physical property involved with aperture, ISO nor use of NDs that affect short duration light v.s. long duration or constant light.

I don't think anyone is arguing otherwise.

The point of adding the ND filter is to reduce ambient light you can't otherwise control, i.e. when iso as low as you can go, aperture as high as you already want it, at max sync speed, and no access to the light switch or it's the sun. Yes, the ND filters reduce your flash exposure as well, BUT you do have control over your flashes. Increase the flash power, add more flashes, move flashes closer, etc. to compensate for the ND filter. You can overpower ambient in any situation this way (given enough flashes and ND filters) and mimic a studio setup when the flash is the only noticeable contribution, thus effectively freezing action to your flash duration.

It would be better to have the extra sync speed available than have to whip out ND filters (and more flashes), but the ND filters can give you a little nudge and possibly get you the photo you are after.
01-29-2011, 07:36 AM   #56
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QuoteOriginally posted by amoringello Quote
*** People, please... try these things and/or work out the math before you make such arguments.
Mathematically it doesn't make an ounce of sense. In practice it cannot and does not work.

Better get those NDs out and give it a go. Closing aperture and lowering ISO has the same effect... it affects *ALL* light; ambient and flash.

I would love to know how the aperture or ND is smart enough to let in flash and not the ambient light.
What part of physics tells these devices that the light is different?

e.g.; duration of flash is shorter than the shutter speed. So until your shutter speed approaches the flash duration, lets say 1/500 to 1/1600 or even 1/10000, depending on the flash, the flash is simply too short to be affected. Therefore higher shutter speed can cut ambient (constant) light and allow the flash to remain as metered.

There is *no* such physical property involved with aperture, ISO nor use of NDs that affect short duration light v.s. long duration or constant light.
And, please, do read posts...

I said "ND filters work up to the maximal power of the flash"... You compensate for the ND filter light loss by upping the power of the flash. Of course, once you hit the flash's max power, there is nothing to gain anymore...

Okay, maybe I haven't made that clear enough in my previous post... I was of course implying that you must have some flash power left for the ND solution to work.
01-29-2011, 07:58 AM   #57
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QuoteOriginally posted by JohanBene Quote
I think it would be nice to have it pop at every speed
1. You could put your subject in the flashexposed portion of the frame. Strobist calls this cheating the flashsync. Even as little as half a stop may be what makes the sky saturated to desired degree, and I think it would be possible in some situations to cheat to even shorter times.
You are misunderstanding how focal plane shutters work.
Go back and read point 1 in the post you responded to.
01-29-2011, 08:27 AM   #58
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QuoteQuote:
I don't think anyone is arguing otherwise.
there is. :-)

QuoteOriginally posted by dlacouture Quote
And, please, do read posts...

I said "ND filters work up to the maximal power of the flash"... You compensate for the ND filter light loss by upping the power of the flash. Of course, once you hit the flash's max power, there is nothing to gain anymore...

Okay, maybe I haven't made that clear enough in my previous post... I was of course implying that you must have some flash power left for the ND solution to work.

It is quite possible I am mis-understanding what you're saying, it would not be the first time... but hopefully your agree that NDs have no different effect on ambient light than on light from flash.
If not,
- By what physical means do the NDs affect light only up to a certain power?
- How do you define "power" in terms where an ND filter will react differently?

The fact is that if you could up the power of the flash, there would be no need for an ND in the first place...
Unless doing so brought the entire exposure beyond the limits of your camera to properly expose the image. (as I also stated previously)
But if you are going to bring that much light into the scene, why not get a camera with higher shutter speed and save yourself some cash and hassles with setup. :-)
Or just wait until the sun goes down a bit where you do not need as much flash power?

If that is what you're getting at, we agree.
01-29-2011, 08:54 AM - 1 Like   #59
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Say you have the following ambient scene:
- f/2.8 (and you don't want to close it further).
- iso 80 (and you can't obviously lower it...)
- 1/180 speed...
- needed power from flash : 1/4th

Then you can cut down the ambient by using a ND filter. The needed power for the flash will have to be raised by as much as the ND filter used, so you can still use a 2-Stops ND filter before hitting the flash limits in the example given above...

And this will have motion-freezing capabilities, as your ambient is now 2 stops underexposed and does not participate that much to the pic. Still not a true 1/1000 sync speed, but near enough, as you now have a similar ambient exposure as 1/720, kept the flash exposure level (by upping its power), and have a 1/1000 flash duration that will freezes the motion.
01-29-2011, 12:05 PM   #60
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QuoteOriginally posted by dlacouture Quote
Say you have the following ambient scene:
- f/2.8 (and you don't want to close it further).
- iso 80 (and you can't obviously lower it...)
- 1/180 speed...
- needed power from flash : 1/4th

Then you can cut down the ambient by using a ND filter. The needed power for the flash will have to be raised by as much as the ND filter used, so you can still use a 2-Stops ND filter before hitting the flash limits in the example given above...

And this will have motion-freezing capabilities, as your ambient is now 2 stops underexposed and does not participate that much to the pic. Still not a true 1/1000 sync speed, but near enough, as you now have a similar ambient exposure as 1/720, kept the flash exposure level (by upping its power), and have a 1/1000 flash duration that will freezes the motion.
Thanks very much for the explanation - well done!
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