# Flash setting on my camera



## Goldcoin79 (Sep 17, 2012)

I have a canon sx30 is camera and I have been reading in the manual about the flash settings but not 100% sure if I fully understand them so hoping one of you may be able to fill me in.

I can controll the flash output which has 3 settings low medium and high, would I be right in thinking that if I wanted a fill flash I would use low and if taking a picture in dark area then I would use high?

One of the settings is flash exposure comp from -2 to +2 not entirely sure of this function hope some one can help, seams to have a similar effect to adjusting flash output and also what is the difference between this and adjusting the normal exposure compensation camera function?

Shutter sync, options are first curtain or second curtain where flash fires after shutter has open on first curtain or fires before shutter closes on second curtain. When should either of these functions be used and what is the idear of them?

Hope someone can help.

Thanks, James


----------



## Tiberius47 (Sep 18, 2012)

Goldcoin79 said:


> I can controll the flash output which has 3 settings low medium and high, would I be right in thinking that if I wanted a fill flash I would use low and if taking a picture in dark area then I would use high?



For the most part, yes.

Fill flash isn't meant to bring the shadows to the same exposure as the highlights (such as a sunlight part of your subject's face).  Fill flash is just to put a bit of light into the shadows so they are inky blackness.  The exact power setting will vary depending on your situation though.



> One of the settings is flash exposure comp from -2 to +2 not entirely sure of this function hope some one can help, seams to have a similar effect to adjusting flash output and also what is the difference between this and adjusting the normal exposure compensation camera function?



Flash exp comp alters the strength of the flash based on what the camera thinks the correct flash exposure should be.  Setting it to -1 means the flash fires a stop lower than what the camera thinks is right (a stop is doubling or halving the amount of light).  So a setting of -1 means the camera fires the flash at half power.  -2 is 1/4 power.  -3 is 1/8 power.  Likewise, +1 is double power, +2 is four times and +3 is eight times.



> Shutter sync, options are first curtain or second curtain where flash fires after shutter has open on first curtain or fires before shutter closes on second curtain. When should either of these functions be used and what is the idear of them?



First curtain flash is when the flash fires at the beginning of the exposure.  It can lead to a bit of ghosting in front of the image.  For example, let's say you are taking a picture of a car driving along.  You take the photo and the flash fires, creating a bright image of the car.  But the car continues moving forwards during the exposure, and as a result, any lights on the car will appear to streak out in front of it.  This streaking in front of the car can give the impression the car is moving backwards.

Second curtain flash fires the flash at the END of the exposure, just before the shutter closes.  This means that any such streaking of lights will end up looking like it is behind the car, giving the impression that it is moving forwards.



> Hope someone can help.
> 
> Thanks, James



I hope what I've said will be of use.


----------



## Goldcoin79 (Sep 18, 2012)

Thank you very much this does help a lot. Could you answer one more question for me, if I wanted to use a fill flash and I  lower the power of the flash to low for example would it have the same effect if I changed the flash exposure compensation to -2 instead of adjusting the flash power?

I have understood all what you have written but not sure when you would adjust flash power and when you would adjust flash exposure compensation.

James


----------

