FEC and Manual output...What the diff ?

[singlesnipershot]

Hi

Can anyone tell me in simple languag what is the difference between FEC and manual output and when the two options are generally used ?

[Octarine]

Originally Posted by singlesnipershot Can anyone tell me in simple languag what is the difference between FEC and manual output and when the two options are generally used ?

FEC: Flash Exposure Compensation
This only works properly if you cam and your flash are using the same communication (Canon: ETTL. Other brands label it differently). The communication is proprietary and limited to equipment of the same brand or 3rd party equipment suitable for that communication. Read the manuals of the flash equipment whether they support the flash communication protocol of your cam.
Flash exposure (the necessary amount of flash light for normal exposure) is calculated by the camera according the given exposure settings (Exposure Mode, aperture, shutter, ISO etc.) and the ambient light. Then the necessary amount is transmitted to the flash (that's why you need the communication!) and not only the trigger signal "flash now".
But this might not always be the best setting and the metering of the camera can also easily get fooled. Also, if you want to balance ambient light and flash light ("fill flash") you might need to adjust the flash output. In such cases you can increase or decrease the amount of flash light by using FEC. It leaves the camera settings untouched but changes the flash output.
Read your camera / system manual carefully on how the metering is done and how flash exposure is calculated. Here a link for Canon: Photonotes.org: Flash Photography with Canon EOS Cameras

Manual: Manual flash output adjustment
Useful (or rather necessary) when there is no proper communication between camera and flash and the only signal transmitted is the trigger signal "flash now". This is the case when using simple radio-triggers in off-show setups or a flash of different brand / manufacturer on hotshoe.
Here you need to carefully measure the necessary output (or you need a lot of trial and error) and adjust the output accordingly.

[singlesnipershot]

Originally Posted by Octarine FEC: Flash Exposure Compensation This only works properly if you cam and your flash are using the same communication (Canon: ETTL. Other brands label it differently). The communication is proprietary and limited to equipment of the same brand or 3rd party equipment suitable for that communication. Read the manuals of the flash equipment whether they support the flash communication protocol of your cam. Flash exposure (the necessary amount of flash light for normal exposure) is calculated by the camera according the given exposure settings (Exposure Mode, aperture, shutter, ISO etc.) and the ambient light. Then the necessary amount is transmitted to the flash (that's why you need the communication!) and not only the trigger signal "flash now". But this might not always be the best setting and the metering of the camera can also easily get fooled. Also, if you want to balance ambient light and flash light ("fill flash") you might need to adjust the flash output. In such cases you can increase or decrease the amount of flash light by using FEC. It leaves the camera settings untouched but changes the flash output. Read your camera / system manual carefully on how the metering is done and how flash exposure is calculated. Here a link for Canon: Photonotes.org: Flash Photography with Canon EOS Cameras Manual: Manual flash output adjustment Useful (or rather necessary) when there is no proper communication between camera and flash and the only signal transmitted is the trigger signal "flash now". This is the case when using simple radio-triggers in off-show setups or a flash of different brand / manufacturer on hotshoe. Here you need to carefully measure the necessary output (or you need a lot of trial and error) and adjust the output accordingly.

Thanks.... you had actually gotten the essence of my question as I was benturing into strobe photography and wanted to know why we needed to use manual and if manual carries the same effect as FEC when the flash in on shoe.

[singlesnipershot]

Originally Posted by singlesnipershot Thanks.... you had actually gotten the essence of my question as I was benturing into strobe photography and wanted to know why we needed to use manual and if manual carries the same effect as FEC when the flash in on shoe.

new question to my old question...understand now that there is a new version of radio transmitters that can allow you to use ETTL even when it is off-shoe? Does that mean i do not need to be in manual mode and still shoot off shoe ? what happens when I got mutiple flashes and wanted to adjust the FEC separately for these off-shoes flashes ?

[Octarine]

Originally Posted by singlesnipershot new question to my old question...understand now that there is a new version of radio transmitters that can allow you to use ETTL even when it is off-shoe? Does that mean i do not need to be in manual mode and still shoot off shoe ? what happens when I got mutiple flashes and wanted to adjust the FEC separately for these off-shoes flashes ?

Yes, with any radio transmitter supporting ETTL you will be able to use the ETTL functions. If we phrase the condition as "wireless" (which includes radio types) then you can start with the Canon Speedlite Transmitter ST-E2 working with IR. Since it uses IR light there are some drawbacks (needs line of sight between trigger and flash, harsh daylight might affect transmission).
For multiple flashes in wireless setup I'd recommend you continue reading on http://www.strobist.blogspot.com/ Since I only have one flash and no wireless trigger my knowledge is very limited here. What I have read so far: most people use manual settings in order to manage the light output exactly as they want it.

[J-Chan]

you can set the slave flashes into groups A B or C and set the ratios accordingly, FEC would affect the whole setup's lighting and the ratios tell each flash how much to output..

[singlesnipershot]

Originally Posted by Octarine Yes, with any radio transmitter supporting ETTL you will be able to use the ETTL functions. If we phrase the condition as "wireless" (which includes radio types) then you can start with the Canon Speedlite Transmitter ST-E2 working with IR. Since it uses IR light there are some drawbacks (needs line of sight between trigger and flash, harsh daylight might affect transmission). For multiple flashes in wireless setup I'd recommend you continue reading on http://www.strobist.blogspot.com/ Since I only have one flash and no wireless trigger my knowledge is very limited here. What I have read so far: most people use manual settings in order to manage the light output exactly as they want it.

Thanks for sharing bro

Originally Posted by J-Chan you can set the slave flashes into groups A B or C and set the ratios accordingly, FEC would affect the whole setup's lighting and the ratios tell each flash how much to output..

Cool...Appreciate the clarification on the groups. Now I can appreciate what that is for

Anyone knowsif I can use a Sun pal mounted on my camera to trigger (using flashes) my 430 EX off-shoe ?. How to do this ? I willalso be getting a Vivitar 285 as a 3rd flash perhaps with a PT04m receiver but need to find a way top trigger this (since my hot shoe is already tied up with the sunpak - incidentally, this is the small cute RD 2000)

[J-Chan]

Nope, you can't use the sunpak to trigger the 430EX, unless you mount an optical slave eye to the 430EX.. I believe the trigger has a mini-jack to PC sync port connection, you can just connect that to the PC sync if your cam has.. if not, you'll need to find those hotshoe adaptors with a PC sync port at the side..

[singlesnipershot]

Originally Posted by J-Chan Nope, you can't use the sunpak to trigger the 430EX, unless you mount an optical slave eye to the 430EX.. I believe the trigger has a mini-jack to PC sync port connection, you can just connect that to the PC sync if your cam has.. if not, you'll need to find those hotshoe adaptors with a PC sync port at the side..

I see....no probz...What I will try to do is to put a PT04m transmitter on my cam and then attach my 430 EX and 285 HVs to PT04 receivers then. SHould work right ?

I am just ahobbyist and hope to take those beautiful sunsets with subject photos when on holiday with my GF. Not wanting to spend hours setting up my shot, I got myself a manfrotto super clamp and a hot-shoe-unbrella adapter that can connect to my tripod (max height of 5+ feet) with a 33" bounce umbrella. You think will do ?