Using flash to freeze action

Abstract · 01-06-2011, 02:10 AM

Originally posted by patriotap

Strobist: Welcome to Strobist.

Looks interesting, thanks.

newarts · 01-06-2011, 05:27 AM

Originally posted by hoanpham

As I saw your pic with the water drop, the solution is simpler: use ND filter(s) to kill the ambient.....

Good answer.

Stacking a linear polarizer (or a backwards circular polarizer) on top of another polarizer will make a density filter adjustable between about 1 & 10 stops.

SOldBear · 01-06-2011, 12:55 PM

Originally posted by patriotap

Its actually the opposite

you actually dont want a full power flash.

You need to lower your flash duration, so set it to 1/4 or less power.

The lower you drop the power the faster the strobe and the more stop motion you will get since the MINIMUM power creates the shortest flash duration and thats what you need.

I think you missed the point.

Other posters and I suggest a powerful flash. That's not the same as "full power flash."

For the same amount of light, the pulse duration from a powerful flash will be shorter than from a weak flash. Since the duration is less, it freezes the action better.

Ira · 01-06-2011, 01:12 PM

Originally posted by SOldBear

I think you missed the point.

Other posters and I suggest a powerful flash. That's not the same as "full power flash."

For the same amount of light, the pulse duration from a powerful flash will be shorter than from a weak flash. Since the duration is less, it freezes the action better.

Wow--this actually sunk in for me.

Thanks for explaining the concept.

**Ash** · 01-06-2011, 01:50 PM

Originally posted by SOldBear

I think you missed the point.

Other posters and I suggest a powerful flash. That's not the same as "full power flash."

For the same amount of light, the pulse duration from a powerful flash will be shorter than from a weak flash. Since the duration is less, it freezes the action better.

Which is why I suggest that if you can't get access to a more powerful flash, then high sync speed may be the answer - full power will be more likely be used, but a faster shutter speed will stop action more effectively.

patriotap · 01-06-2011, 02:03 PM

Originally posted by SOldBear

I think you missed the point.

Other posters and I suggest a powerful flash. That's not the same as "full power flash."

For the same amount of light, the pulse duration from a powerful flash will be shorter than from a weak flash. Since the duration is less, it freezes the action better.

I read it again, and I think I understood it. But regardless, to freeze the action doesnt really on a powerful flash, it has to do with overpowering ambient light and having a quick flash duration, all you have to do is move the flash closer to the subject until it overpowers the ambient AND dial down the flash power manually to get a quicker flash duration.
Full power or powerful flash, however you want to state it isnt the determining factor. So instead of 1/1 go to like 1/4, 1/8th etc will give you faster flash durations. You can use a 10yr old flash to accomplish this and its being done all the time like that. There are many sites to explain just that.

patriotap · 01-06-2011, 02:08 PM

Originally posted by Ash

Which is why I suggest that if you can't get access to a more powerful flash, then high sync speed may be the answer - full power will be more likely be used, but a faster shutter speed will stop action more effectively.

Not true, dont need a more powerful flash and definitely dont need HSS. I can freeze action with my off camera nikon sb-28 and my k5 at the x of 1/180th, dont have a flash that is even capable of HSS nor do i need it.

**eccs19** · 01-06-2011, 03:20 PM

Definitely a lot of information. Thanks everyone. I wouldn't have even thought of trying a ND filter to kill the ambient light. Cool idea. As someone suggested about using HSS, I don't think I would be able to try it with my old flash, but I could of course be wrong. I don't know much about flash, and even if it did work on the camera, I don't know if it would work with my cheap Chinese wireless units.

tuco · 01-06-2011, 04:06 PM

Outside in the Sun and snow you could be looking at f11 or f16 and 1/180th (OP's flash sync) of ambient light. More powerful flash to cut the ambient light by stopping the lens down? How many more stops do you have or willing go? The ND approach sounds like the solution in that sort of scenario and you'd need flash power to make up for what the ND took away.

**Ash** · 01-06-2011, 04:35 PM

Sorry, didn't realise your flash wasn't P-TTL - shouldn't have assumed so.
Scratch the HSS idea.
Though a more powerful flash does make sense, and the ND filter should do the trick (if the flash's full power output is strong enough to overcome the ND filter's effect).
See how you go in that situation - and choose a cloudier/more subdued ambient lighting environment to retry.

hoanpham · 01-06-2011, 04:37 PM

Hi eccs19,
I think with your current equipment will be ok to try with ND filter. I use cheap chinese triggers too. You may need 2 nd8 filters, or stacking 2 CPL as newarts stated which is a very good point. Place your flash 1-3 inches from your subject. The closer the more powerful is the light. This is a kind of macro shoot, and can be setup with one flash.

My move is to add enough ND and flash power to get: 1/125s, iso100/200, f5.6, w half power flash, very close. Just black out the background and get the freeze you want. Flash duration is about 1/1000s. I will also set another flash to lit up the background in controlled manner. f5.6 will blur out the background.

I will definitely try this. Seems fun. Currently where I live, there is still too cold and I cant find a similar 'scenario' with white snow/ice melting, but soon. Can you post some image when you try yours?

philbaum · 01-06-2011, 05:14 PM

Originally posted by Ash

I'd have done a HSS exposure at 1/500sec or so - that would have frozen action better.

I was thinking similar, in addition to boosting the ISO to 200 or more to allow even faster shutter, and less susceptibility to ambient. HSS allows higher shutter speeds than 1/180.

patriotap · 01-06-2011, 06:46 PM

Originally posted by philbaum

I was thinking similar, in addition to boosting the ISO to 200 or more to allow even faster shutter, and less susceptibility to ambient. HSS allows higher shutter speeds than 1/180.

Take a look at this

HSS Test

**Ash** · 01-06-2011, 07:06 PM

Originally posted by patriotap

Take a look at this

HSS Test

That makes sense, those examples were done in settings where ambient light was less of a factor - but the problem of ambient light at flash-sync shutter speed still exists in the setting concerned here, so either stopping down or applying a filter to make ambient light negligible is required.

patriotap · 01-06-2011, 08:18 PM

Originally posted by Ash

That makes sense, those examples were done in settings where ambient light was less of a factor - but the problem of ambient light at flash-sync shutter speed still exists in the setting concerned here, so either stopping down or applying a filter to make ambient light negligible is required.

You can move the flash closer to over power the ambient, if possible. You could even hand hold the off camera flash and hold it inches fm the subject, even in frame and crop it out later, again, if possible depending on the situation.

01-06-2011, 04:35 PM	#25
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Sorry, didn't realise your flash wasn't P-TTL - shouldn't have assumed so. Scratch the HSS idea. Though a more powerful flash does make sense, and the ND filter should do the trick (if the flash's full power output is strong enough to overcome the ND filter's effect). See how you go in that situation - and choose a cloudier/more subdued ambient lighting environment to retry. Last edited by Ash; 01-06-2011 at 04:43 PM.

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01-06-2011, 02:10 AM	#16
Abstract Inactive Account Join Date: Sep 2010 Location: New York Photos: Gallery Posts: 388	Originally posted by patriotap Strobist: Welcome to Strobist. Looks interesting, thanks.

01-06-2011, 05:27 AM	#17
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Originally posted by hoanpham As I saw your pic with the water drop, the solution is simpler: use ND filter(s) to kill the ambient..... Good answer. Stacking a linear polarizer (or a backwards circular polarizer) on top of another polarizer will make a density filter adjustable between about 1 & 10 stops.

01-06-2011, 12:55 PM	#18
SOldBear Veteran Member Join Date: Feb 2009 Location: Alameda, CA Posts: 3,206	Originally posted by patriotap Its actually the opposite you actually dont want a full power flash. You need to lower your flash duration, so set it to 1/4 or less power. The lower you drop the power the faster the strobe and the more stop motion you will get since the MINIMUM power creates the shortest flash duration and thats what you need. I think you missed the point. Other posters and I suggest a powerful flash. That's not the same as "full power flash." For the same amount of light, the pulse duration from a powerful flash will be shorter than from a weak flash. Since the duration is less, it freezes the action better.

01-06-2011, 01:12 PM	#19
Ira Inactive Account Join Date: Mar 2009 Location: Coral Springs, FL Photos: Gallery \| Albums Posts: 5,216	Originally posted by SOldBear I think you missed the point. Other posters and I suggest a powerful flash. That's not the same as "full power flash." For the same amount of light, the pulse duration from a powerful flash will be shorter than from a weak flash. Since the duration is less, it freezes the action better. Wow--this actually sunk in for me. Thanks for explaining the concept.

01-06-2011, 01:50 PM	#20
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Originally posted by SOldBear I think you missed the point. Other posters and I suggest a powerful flash. That's not the same as "full power flash." For the same amount of light, the pulse duration from a powerful flash will be shorter than from a weak flash. Since the duration is less, it freezes the action better. Which is why I suggest that if you can't get access to a more powerful flash, then high sync speed may be the answer - full power will be more likely be used, but a faster shutter speed will stop action more effectively.

01-06-2011, 02:03 PM	#21
patriotap Senior Member Join Date: Oct 2009 Location: South Jersey Photos: Albums Posts: 159	Originally posted by SOldBear I think you missed the point. Other posters and I suggest a powerful flash. That's not the same as "full power flash." For the same amount of light, the pulse duration from a powerful flash will be shorter than from a weak flash. Since the duration is less, it freezes the action better. I read it again, and I think I understood it. But regardless, to freeze the action doesnt really on a powerful flash, it has to do with overpowering ambient light and having a quick flash duration, all you have to do is move the flash closer to the subject until it overpowers the ambient AND dial down the flash power manually to get a quicker flash duration. Full power or powerful flash, however you want to state it isnt the determining factor. So instead of 1/1 go to like 1/4, 1/8th etc will give you faster flash durations. You can use a 10yr old flash to accomplish this and its being done all the time like that. There are many sites to explain just that.

01-06-2011, 02:08 PM	#22
patriotap Senior Member Join Date: Oct 2009 Location: South Jersey Photos: Albums Posts: 159	Originally posted by Ash Which is why I suggest that if you can't get access to a more powerful flash, then high sync speed may be the answer - full power will be more likely be used, but a faster shutter speed will stop action more effectively. Not true, dont need a more powerful flash and definitely dont need HSS. I can freeze action with my off camera nikon sb-28 and my k5 at the x of 1/180th, dont have a flash that is even capable of HSS nor do i need it.

01-06-2011, 03:20 PM	#23
eccs19 Site Supporter Join Date: Jul 2008 Location: Lisle, Ontario Photos: Gallery Posts: 1,510 Original Poster	Definitely a lot of information. Thanks everyone. I wouldn't have even thought of trying a ND filter to kill the ambient light. Cool idea. As someone suggested about using HSS, I don't think I would be able to try it with my old flash, but I could of course be wrong. I don't know much about flash, and even if it did work on the camera, I don't know if it would work with my cheap Chinese wireless units.

01-06-2011, 04:06 PM	#24
tuco Pentaxian Join Date: Jul 2009 Location: Pugetopolis Posts: 11,029	Outside in the Sun and snow you could be looking at f11 or f16 and 1/180th (OP's flash sync) of ambient light. More powerful flash to cut the ambient light by stopping the lens down? How many more stops do you have or willing go? The ND approach sounds like the solution in that sort of scenario and you'd need flash power to make up for what the ND took away.

01-06-2011, 04:37 PM	#26
hoanpham Veteran Member Join Date: Nov 2009 Location: Strand Photos: Gallery \| Albums Posts: 1,366	Hi eccs19, I think with your current equipment will be ok to try with ND filter. I use cheap chinese triggers too. You may need 2 nd8 filters, or stacking 2 CPL as newarts stated which is a very good point. Place your flash 1-3 inches from your subject. The closer the more powerful is the light. This is a kind of macro shoot, and can be setup with one flash. My move is to add enough ND and flash power to get: 1/125s, iso100/200, f5.6, w half power flash, very close. Just black out the background and get the freeze you want. Flash duration is about 1/1000s. I will also set another flash to lit up the background in controlled manner. f5.6 will blur out the background. I will definitely try this. Seems fun. Currently where I live, there is still too cold and I cant find a similar 'scenario' with white snow/ice melting, but soon. Can you post some image when you try yours?

01-06-2011, 05:14 PM	#27
philbaum Veteran Member Join Date: Oct 2007 Location: Port Townsend, Washington State, USA Posts: 3,659	Originally posted by Ash I'd have done a HSS exposure at 1/500sec or so - that would have frozen action better. I was thinking similar, in addition to boosting the ISO to 200 or more to allow even faster shutter, and less susceptibility to ambient. HSS allows higher shutter speeds than 1/180.

01-06-2011, 06:46 PM	#28
patriotap Senior Member Join Date: Oct 2009 Location: South Jersey Photos: Albums Posts: 159	Originally posted by philbaum I was thinking similar, in addition to boosting the ISO to 200 or more to allow even faster shutter, and less susceptibility to ambient. HSS allows higher shutter speeds than 1/180. Take a look at this HSS Test

01-06-2011, 07:06 PM	#29
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Originally posted by patriotap Take a look at this HSS Test That makes sense, those examples were done in settings where ambient light was less of a factor - but the problem of ambient light at flash-sync shutter speed still exists in the setting concerned here, so either stopping down or applying a filter to make ambient light negligible is required.

01-06-2011, 08:18 PM	#30
patriotap Senior Member Join Date: Oct 2009 Location: South Jersey Photos: Albums Posts: 159	Originally posted by Ash That makes sense, those examples were done in settings where ambient light was less of a factor - but the problem of ambient light at flash-sync shutter speed still exists in the setting concerned here, so either stopping down or applying a filter to make ambient light negligible is required. You can move the flash closer to over power the ambient, if possible. You could even hand hold the off camera flash and hold it inches fm the subject, even in frame and crop it out later, again, if possible depending on the situation.