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10/19/2007 12:45:23 PM · #1 |
I have a Canon 40D and my external flash is a Sigma EF500DG Superflash E-TTL II.
I want to use fill flash on my subjects for brightly back-lit outdoor shots, but don't want to blow the background/sky/clouds.
I thought, OK, full manual... but whenever I turn on the friggin flash the POS camera won't allow me to use a shutter speed faster than 250, the synch speed. WTF? I absolutely want to keep the aperture wide. I want to control the exposure via shutter speed.
This pissed me off and I nearly threw the camera and flash into the lake.
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10/19/2007 12:49:43 PM · #2 |
You need to use a high speed sync mode on the flash. The 40d won't sync naturally faster than 1/250".
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10/19/2007 12:52:13 PM · #3 |
Page 18 in the manual tells you how to use high speed sync.
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10/19/2007 01:00:14 PM · #4 |
And while you're thinking about it .... I recommend this thread to learn a bit more about what it means to be using High Speed Sync mode.
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10/19/2007 01:04:06 PM · #5 |
I think you should box the POS camera up and donate it to me! PM me for the address!
Just kidding |
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10/19/2007 01:06:42 PM · #6 |
You might want to look into getting a reflector. Another option is to get some ND filters and powerful strobes, but that's costly :-/
You could also just simulate the DOF in post processing, but it probably won't look as good. |
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10/19/2007 01:22:14 PM · #7 |
Doh, RTFM! Thanks guys. Thanks for the link David!
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10/19/2007 01:35:29 PM · #8 |
Originally posted by kyebosh:
You might want to look into getting a reflector. Another option is to get some ND filters and powerful strobes, but that's costly :-/
You could also just simulate the DOF in post processing, but it probably won't look as good. |
Well, Hi-speed synch is the right way to do it, but it needs an E-TTL flash and a type A camera to work.
A reflector is of no use, it just delivers less light to the subject but doesn't help with overexposed BG. Powerful strobes, likewise, don't help; they deliver MORE light to the subject but don't help with the overexposed BG.
ND filters will help, of course, assuming they are dense enough for the desired effect.
If slippy wants to shoot at, say, f/2.8 at ISO 100, then he needs a shutter speed, in bright daylight, of 1/2000 or so. If he is forced to synch at 1/250, then he'd need 3 stops of neutral density, a LOT.
R.
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10/19/2007 01:36:58 PM · #9 |
Hey, I like that the manual at least took the time to describe what is going on ... that the flash "keeps firing" while the shutter is running, and that the "guide number will be lower".
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10/19/2007 01:38:50 PM · #10 |
Originally posted by Bear_Music:
If slippy wants to shoot at, say, f/2.8 at ISO 100, then he needs a shutter speed, in bright daylight, of 1/2000 or so. If he is forced to synch at 1/250, then he'd need 3 stops of neutral density, a LOT. |
Yeah, and a mighty powerful flash to punch through 3 stops of ND! (that's when you stick the flash right next to the person's face and let them "feel the burn")
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10/19/2007 01:47:11 PM · #11 |
I don't know about your flash, but my flash for my Pentax has a mode that mixes the high sync mode and the normal flash mode. That is what I always use. So if there isn't enough light it works like the normal flash mode, but when there is plenty of light, it switches to high sync mode, allowing the camera to choose the shutter speed and it acts just like a fill flash. I like using this setting so I don't have to remember to switch modes based on lighting conditions. See if your flash does something similar. If not, just like everybody else has said, you just need to set it to high sync mode to get what you want.
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10/19/2007 03:07:22 PM · #12 |
Originally posted by Bear_Music:
Well, Hi-speed synch is the right way to do it, but it needs an E-TTL flash and a type A camera to work.
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Doesn't he have an A type camera and an E-TTL flash?
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10/19/2007 04:36:42 PM · #13 |
I remember from somewhere that High-sync had some disadvantages.
Here's my search.
Apparently, it uses more power and won't stop action. Also something about the guide numbers being off.
I use it a lot for fill myself, but I have the sync safety shift enabled just in case. (If you hit the threshold of the shutter sync, the aparature is adjusted.) |
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10/19/2007 07:00:09 PM · #14 |
Originally posted by Bear_Music:
Well, Hi-speed synch is the right way to do it, but it needs an E-TTL flash and a type A camera to work.
A reflector is of no use, it just delivers less light to the subject but doesn't help with overexposed BG. Powerful strobes, likewise, don't help; they deliver MORE light to the subject but don't help with the overexposed BG.
ND filters will help, of course, assuming they are dense enough for the desired effect.
If slippy wants to shoot at, say, f/2.8 at ISO 100, then he needs a shutter speed, in bright daylight, of 1/2000 or so. If he is forced to synch at 1/250, then he'd need 3 stops of neutral density, a LOT.
R. |
Of course a reflector would help. It doesn't take away light from the subject it adds to it, effectively balancing the lighting of the foreground (subject) and backround. If you can reflect enough light onto the subject you can keep the AV the same and just adjust with the shutter speed.
The same is true for the strobe with ND filters. The ND filters would balance out the backround and the strobes light up the foreground to balance to the backround.
Sure, the high speed sync is a good idea if your flash is strong enough, but depending on just how bright it is, you might need more power.
edit: then again, at 2.8 it should have the power lol
Message edited by author 2007-10-19 19:01:00. |
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10/19/2007 07:35:34 PM · #15 |
Originally posted by kyebosh:
If you can reflect enough light onto the subject you can keep the AV the same and just adjust with the shutter speed. |
That was the problem in the first place as 1/250s was the MAX that he could sync up to and since he wants to use f/2.8 the sky's going to be blowing out. Other than the 2 options listed above (High-speed sync and ND filters) you could also try one of the following.
Know anyone with a D40/D50/D70(s)?(not sure about the canons) borrow their camera and use the flash in manual and you should be able to sync up to 1/1250 no problem without seeing any flash cutoff due to their use of an electronic shutter.
Find out which part of the frame gets flash cutoff if you manually sync faster on your camera and how much of the frame is cut off at each given shutter speed. If you find that the right 1/2 of the frame is cut off @ 1/1000 you can try placing your subject on the left half and he should still get lit. Not an optimal solution but it should do the trick if you absolutely need that extra shutter speed. |
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