How to avoid "ghosting" during daytime shoot?

[widowmaker]

I´m trying to get the hang of the use of flash off the camera, and I got one specific question. How do you avoid ghosting when you´re shooting for example mountain bike action during daytime? I know that it is the flash that freezes up the motion, but how do you avoid ghosting during daytime? Is is all based upon your aperture setting or what?

[turbodude]

example of what you are refferin to

[widowmaker]

http://img255.imageshack.us/img255/7184/final3lk0.jpg

something like this. How do you set up your camera for shots like this, where the rider is iluminated by flash, without ghosting?

[turbodude]

im still confused on what you mean by ghosting

[PacAce]

I´m trying to get the hang of the use of flash off the camera, and I got one specific question. How do you avoid ghosting when you´re shooting for example mountain bike action during daytime? I know that it is the flash that freezes up the motion, but how do you avoid ghosting during daytime? Is is all based upon your aperture setting or what?

What mode and camera settings are you shooting with?

[Connor P Price]

By ghosting, do you mean motion blur?

[sleibrand]

I´m trying to get the hang of the use of flash off the camera, and I got one specific question. How do you avoid ghosting when you´re shooting for example mountain bike action during daytime? I know that it is the flash that freezes up the motion, but how do you avoid ghosting during daytime? Is is all based upon your aperture setting or what?

Hard to see here at work but I'm guessing you're seeing movement of the rider. You are exposing for the background which means that ratio of ambient to flash is 1:1 or less (less flash than ambient.) The usual way to stop motion with flash is to have the flash overwhelm the ambient.

If you use second curtain synch, you'll at least get the ghost behind the bike rather than in front.

I'll be curious to see if anyone has some suggestions but I think this will be a hard one.

[turbodude]

oh i get what your are trying to say, stop the ambient exposure down 1/2 a stop and that problem will go away.

[sleibrand]

oh i get what your are trying to say, stop the ambient exposure down 1/2 a stop and that problem will go away.

Yes, reducing ambient will reduce it but the background will look dark.

[DSMITH131]

fast lens, fast shutter bump up ISO. use a little fill

[turbodude]

Yes, reducing ambient will reduce it but the background will look dark.

half a stop is not going to hurt the image, if anything if you set teh flash correctly it should actually help with contrast.

[widowmaker]

So, to take shots like that, I will have to meter for the ambient light, dial down my ambient exposure 1/2 a stop, and then set my off camera flash in manual and dial in the right amount of flash?
In other words, I want to override the ambient exposure with my flash?
I think this picture would need something like f2.8, and about 1/1000 sec to freeze the motion without the use of flash (ISO dialed up to get that shutter speed).
So if I wanted to use one or two flashes on a stand, using PW's, I would set my ambient to something like f4, and my shutter to sync speed (1/250), and then figure out how much flash I would need? Am I getting this, or at least getting close???

[Inspired Photography]

So, to take shots like that, I will have to meter for the ambient light, dial down my ambient exposure 1/2 a stop, and then set my off camera flash in manual and dial in the right amount of flash?
In other words, I want to override the ambient exposure with my flash?
I think this picture would need something like f2.8, and about 1/1000 sec to freeze the motion without the use of flash (ISO dialed up to get that shutter speed).
So if I wanted to use one or two flashes on a stand, using PW's, I would set my ambient to something like f4, and my shutter to sync speed (1/250), and then figure out how much flash I would need? Am I getting this, or at least getting close???

You must be working in pretty average light if you need to boost ISO to get 1/1000th at f2.8.

You have the theory pretty much right, but i would still leave the flash on ETTL since your rider is coming at you, so would need to be almost perfectly positioned distance from flash or you would under/overexpose anyway.

rob

Rob

[widowmaker]

I guess I could go with ETTL with the flash on camera, or with a sync cord, but I thought you lost the ETTL when using the flash off camera with pocketwizard triggers?

[DaveMcBride]

I would have thought that high speed sync would have been the way to go in order to freeze motion and avoid ghosting (double images)?

[widowmaker]

But again, don't you loose the ability to use high sync, when you put your flashes on a stand, firing them with PW's?

[Village_Idiot]

But again, don't you loose the ability to use high sync, when you put your flashes on a stand, firing them with PW's?

Yes. I belive some one said HSS works with the multimaxes, but I haven't read up on those.

[n1as]

I've been shooting basketball and having problems with ghosting. I shoot at 1/250 and set the ambient exposure to be 2 (yes, two) stops below the flash level. Even with 2 stops difference between the flash and ambient, I get motion blur and some ghosting since 1/250 is not enough to freeze the motion.

Shooting outdoors, I suppose you can use high speed sync provided you can still get enough light from the flash. You have to have the shutter speed fast enough to freeze the motion unless the flash is WAY above ambient.

[widowmaker]

Here's another example. It doesn't appear to me, that the ambient is dropped two whole f stops. Actually, it looks quite right. So how do they do it??






http://farm3.static.flickr.com/2326/2083429747_18806b9e9f_b.jpg

[NVcameraman]

I've been shooting basketball and having problems with ghosting. I shoot at 1/250 and set the ambient exposure to be 2 (yes, two) stops below the flash level. Even with 2 stops difference between the flash and ambient, I get motion blur and some ghosting since 1/250 is not enough to freeze the motion.

If you are getting ghosting with ambient 2 stops below flash and you are still getting ghosting then your flash does not have a fast enough duration to freeze the action. Look at this thread and you will see a test they did using a fan and shooting it with flash stops the blades from spinning with no ghosting.

http://photography-on-the.net/forum/showthread.php?t=454214&highlight=flash+duration

Fan blades spinning are way faster than any basketball player I have ever seen. Lowering the power on hotshoe flashes shortens the flash duration. It seems that with monolight strobes most Ive looked into it seems to increase the duration by lowering the power and shortest duration
at full power

Shooting outdoors, I suppose you can use high speed sync provided you can still get enough light from the flash. You have to have the shutter speed fast enough to freeze the motion unless the flash is WAY above ambient.

High Speed sync is worse for freezing action!!!

[n1as]

If you are getting ghosting with ambient 2 stops below flash and you are still getting ghosting then your flash does not have a fast enough duration to freeze the action.

Hmmm, that may be. I'm at work and can neither look at pics nor get to my page where I have pics but maybe you could.

Check out the pics from the most recent game at http://darwinphoto.zenfolio.com. What I see is the flash freezes the action but in the areas not illuminated by the flash there's enough ambient light that the motion get blurred ever so slightly.

I wonder if I really am 2 stops below the flash level? The shots where the flash doesn't fire (or hasn't recharged) sure do look dark. When shooting ambient in this gym, I shoot ISO 3200, 1/500, f/2. These flash pics were shot ISO 800, 1/250, f/2.8 which indeed is 2 stops.

[AB8ND]

For this shot, I think a little cross light would be nice. Put the flash on a lght stand about 180 degrees to the sun, maybe 6 to 7 feet away. Expose to give a nice exposure to the sunlit side, shooting at your max sync speed (1/250 or maybe if lucky 1/320) then with the flash on half power to start with, move it closer or farther to give fill to the dark side and light up the faces. While you want to shoot at the fastest speed you can to stop the action, you don't necessarily need to shoot at 1/1000.

Jack