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Old Feb 14, 2004, 11:14 AM   #11
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NHL...

Thanks for the info; if he has these lights mounted above then why would he need a third to control the shadow? Why would he even need to worry about shadow if he's shooting horizontally? The picture here http://dipictures.free.fr/sports/bas...L/ab2d8712.htm

demonstrates that shadow control is non-existent when the shot is from the wrong direction (above).

I appreciate your observation on aperture setting; I neglected to read that myself. As well, could you comment more on the 1/500 setting...is that overkill?
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Old Feb 14, 2004, 11:27 PM   #12
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Quote:
Originally Posted by Normcar
NHL...

Thanks for the info; if he has these lights mounted above then why would he need a third to control the shadow? Why would he even need to worry about shadow if he's shooting horizontally? ....
Look carefully at : AB2D8649.JPG, AB2D8612.JPG, and AB2D8677.JPG, the shadows come from the side as well, and not just down to the floor particularly on the other links where the bottoms of the player's chins, or neck, are not affected at all... when shooting from the side (or may be his 2nd strobe is positioned low enough to the ground)

Quote:
I appreciate your observation on aperture setting; I neglected to read that myself. As well, could you comment more on the 1/500 setting...is that overkill?
Unlike theses studio strobes which can provide their full power for the whole 1/500s duration, the external Canon's Speedlites has to modulate their output at fractional power to follow the shutter slit at high speed limiting your range to only short distances... This makes high-speed sync @ f/5.0-6.7 un-practical with the 550/420EX at theses distances even @ ISO 400!
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Old Feb 15, 2004, 12:03 AM   #13
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NHL said: This makes high-speed sync @ f/5.0-6.7 un-practical with the 550/420EX

What about at f4? I'd appreciate some information on how you work out the details on high speed sync pooping out at this specific aperture. Since I use the 420 and sometimes find it nice to use a faster shutter than 200, I'd certainly appreciate being able to work out some sort of maximum possibility, especially with respect to shutter and aperture.

I understand the general idea of what you are saying but I'm not the most capable with numbers and things of that sort. What would you say could be my maximum shutter and aperture stop-down combination for high speed sync to remain effective?

Thanks
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Old Feb 15, 2004, 1:36 AM   #14
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The back of your 420 manual should give you the guide numbers for normal and high speed sync (at least the 550ex does.) If you know how guide numbers work, that should be all you need. If you don't, do a little google searching and you should be able to find something that describes it.

I looked it up once, but I don't remember now.
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Old Feb 15, 2004, 7:32 AM   #15
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Quote:
Originally Posted by Normcar
What about at f4? I'd appreciate some information on how you work out the details on high speed sync pooping out at this specific aperture. Since I use the 420 and sometimes find it nice to use a faster shutter than 200, I'd certainly appreciate being able to work out some sort of maximum possibility, especially with respect to shutter and aperture.
Normcar

The problem with the Speedlites is not the apertures! It is the shutter speed at high-speed (FP) sync: the 550/420EX are not designed for long flash duration from tiny batteries and they must simulate this by outputting multiple 50kHz bursts at lower output! which make them ideal for close range photography only.
http://eosseries.ifrance.com/eosseri...k_synchfp.html

A normal flash pulse at X-sync of 1/200s or less is incredibly brief (refer to the figure in the link) but more powerful and can also freeze the picture if it's powerful enough... and you have to take this into consideration based on this formula:

1. Guide Number = Aperture x Distance
For the 420EX, the GN is 42 at ISO100 at the 105mm tele position. It's less at wider focal lenght, and the pictures posted were @ 70mm so you have to factor this in as well.

2. Using the above formula 42 = f/4.0 x Distance -> Distance = 42/f4 = ~10m (max) and only 42/f6.7 = ~6m (max) at f/6.7; However you can increase this range by going to ISO400 or higher.

3. If you use FP sync for 1/500s with the Speedlites instead your GN decrease by more than 1/2, hence your distance as well... BTW it's also not a good practice to set the flash on FP if you're not going to use it: Check the flash manual, but it also lowers your flash output even at 1/125s (ie you're much better off using X-Sync @ 1/200s)!

4. Closing the aperture down on the 70-200 f/2.8 not only increases the DOF, but also bring the lens to its most optimum(sharpest) position... So wide open may not be the best for the kind of shots you want...

Bottom line if you want both higher shutter speed from a smaller opening for sharper pictures -> you need MORE light! :lol: :lol: :lol:
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Old Feb 16, 2004, 1:29 AM   #16
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NHL...

All of your wonderful math gave me a headache but I certainly appreciated your input. Your last sentence made the most sense to me, "you need more light!" That I can understand. So, what I plan to do is make the best, for now, of the light that is available to me at the moment, because most people who know nothing about photography don't even notice some of the stuff that some of us here notice. With a good bit of Neat Image processing and some sharpening and increase in contrast and light with PSP, I can live with what I'm getting at the moment. I appreciate your comments because they certainly are helpful to me (the stuff that I understand) for future goals.
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