Welcome to the forum!
As an adjunct to the Tangents blog, the intention with this forum is to answer any questions, and allow a diverse discussion of topics related photography. With that, see it as an open invitation to just climb in and start threads and to respond to any threads.
Trouble determining correct flash distance to subject using Pocketwizards.
So i set up my camera to expose a scene say it goes something like this:
1/160
f4.5
ISO 800
I want to remotely position my flash at around 3 metres away from my subject (Side light) and zoom the head to 105mm which my flash when on camera tells me it should be set to a manual setting of:
1/128 power
Zoom: 105mm
Which supposedly gives me a correct flash-to-subject exposure distance of 2.7m (close enough to 3m).
My question is: Why is it that when i put my flash onto my pocketwizard, the flash-to-subject distance now changes to .8m?
Why does this happen? It seems so much easier to just have my flash already on my pocketwizard, set the flash correctly according to what distance it will be away from my subject and start shooting away... But doing it that way gives me an incorrect flash-to-subject distance...
by the way i have a Nikon D3s and 2x SB900 with a mini TT1 and 2x TT5
Comments
This is in regards to using pocketwizards with flashes: This intelligent system (Pocketwizards) takes note of any changes that you make to your ISO, shutter speed or aperture and makes any necessary changes to ensure perfect exposures...
Now try this scenario with a remote flash on a pocketwizard (mini tt1 with a flex tt5) and let me know why the distance doesn't work correctly:
1) Set both your camera and shoe flash in manual mode
2) Adjust your camera exposure to your ambient light. For argument sake let's say it's F/5.6, 1/60th, at ISO 200
3) You should see F/5.6 on the LCD screen of your flash unit along with a distance scale in feet or meters
4) Now you want to judge your distance to your subject… let's say you are six feet away from your subject
5) Now, dial up or down your flash power with the controller on the back of your flash while looking at it's LCD screen so that the flash output power lines up with your calculated distance to your subject (6 feet in this example)...it may say 1/4 power, or 1/32 power, or some other number. That will give you the proper amount of flash at that distance to your subject and will be pretty balanced with your ambient light.
cheers
For example, if you zoom your lens does the flash head zoom like it would if it were on your camera? The FlexTT5/MiniTT1's claim to fame is being used to handle TTL flash, not as a manual dumb trigger.
Quin
Put the flash on camera in manual mode, choose an aperture of f11, then write down what 1/1 will give you in distance; 1/2 power; 1/4 power; etc.
then change aperture to f8, do the same and so on with as many aperture settings you commonly work with.
so it would look something like this:
f11 - 1/1 6m; 1/2 3m; 1/4 1.5m; etc.
f8 - 1/1 8m; 1/2 5m; or whatever you get.
f5.6 - and so on.
That way, you just have a laminated printed small business size card in pocket and pull it out and set flash power/distance to suit.
this will get you into the ball park very quickly.
However, I personally, do not bother, since with experience comes a very rough idea of what to set and it will only take a few seconds to take some tests and get it right.
Distance information isn't communicated to a remote flash. GN and Manual distance scale operation is not the same as it would be on the camera without any radio.
Best regards, Dan Cirillo
Actually, now that I think about it, you can also reprogram the Flex to be a "dumb" trigger through the configuration tool. Then trigger your flash in Manual mode to your heart's content.