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04/29/2008 10:41:03 AM · #1 |
I have two hot shoe flashes which can go off at the same time. I'll slowly up the power to the slave and the image starts to become overexposed (naturally). My problem is if I continue to raise the f-stop on my slave (1/64...1/32..1/16...etc), at some point my image then becames darker. If I lower it back one, the image is bright again; up one and we're back to dark. This example is with all other things remaining constant.
My only guess is that the camera has an overexposed protector where it's designed to protect the sensor if it senses too much light??? yes/no? Is this supposed to happen?
Great site!
Thanks, Pete.
Canon 30D, 2 lens, 2 flashes. |
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04/29/2008 05:18:05 PM · #2 |
Let me see if I can explain this.
The more flash power you add, you start to loose ambient light and your background starts to get darker. This is because your flash becomes your light source. If you slow down your shutter speed (dragging the shutter), you'll pick up more ambient light.
I still haven't gotten images for my flash tutorial:
Canon Flash Tutorial
I'll have to find time this week to shoot the images I need for this tutorial.
You also post some of your examples, it'd be easier to help troubleshoot. |
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04/29/2008 07:22:33 PM · #3 |
Well, hurry up with it, will you???? ;)
Originally posted by Nullix:
Let me see if I can explain this.
The more flash power you add, you start to loose ambient light and your background starts to get darker. This is because your flash becomes your light source. If you slow down your shutter speed (dragging the shutter), you'll pick up more ambient light.
I still haven't gotten images for my flash tutorial:
Canon Flash Tutorial
I'll have to find time this week to shoot the images I need for this tutorial.
You also post some of your examples, it'd be easier to help troubleshoot. |
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05/01/2008 06:52:52 AM · #4 |
Nullix, I understand what you're talking about, although I have a different problem that I can't figure out...
In other words...camera and two strobes are set. Everything stays the same EXCEPT the power to my slave. I take a pic at 1/128=an ok shot; at 1/64=a slightly brighter pic; at 1/32=an even brighter pic; at 1/16=an overexposed shot; at 1/8=it becomes dark (the whole picture, not just the foreground). If I go back to 1/16, it's that same overexposed shot...back to 1/8 and I get dark again.
There's no steady number at which it happens (ie.-it happens once the slave flash gets to 1/4). It all depends on the surroundings, but it does happen at some point.
Sorry I can't post any examples (I'm a newbie and don't have an url). I can email what I'm talking about to anyone willing to view and listen.
Thanks,
Pete.
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05/01/2008 07:04:37 AM · #5 |
just to throw an idea out there. If you use TTL mode for your flash (not sure what its called in Canon-land) it may alter the power of the flash. If you go to manual mode then you get the control you are looking for. Just an idea anyways...
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05/01/2008 07:07:30 AM · #6 |
What flashes are you using and how are they connected, IE, one on camera, one on optical trigger etc...?
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05/01/2008 07:08:54 AM · #7 |
Originally posted by Citadel:
If you use TTL mode for your flash it may alter the power of the flash. If you go to manual mode then you get the control you are looking for. Just an idea anyways... |
Part of what I am getting at, but also, flash modes if on camera could be firing pre flashes? |
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05/01/2008 08:56:51 AM · #8 |
OK, HERE IS YOUR ISSUE
The canon preflash will trigger and the slave will fire before the picture is taken so ttl can get a good reading....NOW, At a low power rating on the flash, the flash will have enough power to fire again immediatly. If you go full power on your flash, there will not be enough time to recharge and when the picture is being taken, the flash on camera goes off the the slave has no power left in the cap. Take a picture of the flash itself to see if it is the slave not fireing.
If you hit the * with your right thumb (FEL), Then the preflash will be fired well before you take the picture and you have no issue with recharge....things will work right.
If you are trying to save battery's in your slave...cover your flash when hitting the FEL button so the slave will not fire and discharge on the prefire.
Let me know if this helps -Fred |
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05/02/2008 07:45:50 AM · #9 |
Thank you all for responding...
The culprit was the TTL. I took my flash to Manual and the higher I put up the power, the brighter the image got (with no dark images at any point). Live and learn. Definitely more control while flash is on Manual (even though the camera was on manual throughout).
Again, thanks! |
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