Speedlite 420EX fill in flash

[ian_walker2]

This may be a dumb question to some � apologies if it is.

 

I have just purchased a 420EX flash and am trying it out in the

various modes to see how well it works. I have always relied upon

natural light before and never used flash before.

 

The user manual talks about fill in flash for the Full Auto and

Program AE modes but not Shutter Priority, Aperture Priority and

Manual. Can the flash do fill in in these modes to soften harsh

shadows in daylight etc?

 

Thanks in anticipation.

[george_kuldhardhis]

Wonderful documentation by Nk_Guy... If you have not seen it already

--> http://photonotes.org/articles/eos-flash/

[digitmstr]

YES - if your camera allows FEC, only. Simply put, you can use flash anytime you want to whatever ratio you like by using FEC. My favorite is to set the camera to M and measure the ambient light. I can then choose the ratio of ambient/flash as I wish. If the resulting shutter speed is ABOVE your camera max sync speed you'll have to set the 420 to 'H', for high speed sync.

[bill_goldman]

In Av and Tv modes, the camera will set exposure for the ambient light regardless of whether flash is used or not. In these modes the flash will provide fill only. In Program mode, the flash will provide the main source of illumination in dim light and automatic fill in bright light.

[jimstrutz]

In addition to what's been said so far, you should keep in mind that with most EOS cameras the flash exposure will be reduced by a stop or two as the ambient lighting increases past EV10. This makes the flash act as a fill light instead of the main light. This happens in Av, Tv & M modes, and in some situations in P mode as well. Any Flash Exposure Compensation (FEC) you add or subtract will be in addition to this auto reduction of flash exposure.

 

You don't mention what EOS camera you are using, and some do not have FEC as an option. Also, some EOS cameras can disable the auto fill flash reduction with a custom function.

 

More details are provided in the link to the PhotoNotes site mentioned above.

[ian_walker2]

Thanks to everyone for swift and easy to understand answers.

 

I have a EOS 300 which does not have FEC - never mind. The long term plan (wife and family permitting) is to get a EOS 3 which does have FEC.

 

I have shot a couple of rolls of film with it in various modes and light conditions and should get the prints back today to compare with the notes i took whilst playing.

[simonpg]

Read the photonotes web sit on EOS flash - read it from cover to cover - it is everything that Canon should produce to fully let users get the best out of their flash gear.

Basically you need to understand how flash differs from natural light - unlike natural light exposures are not a link between f stop and shutter speed. F stop in flash determines how much flash illuminates the subject. Shutter speed determines hom much natural light illimunates the background.

So program modes limit the camera to the standard synch shutter speed eg 60-125th sec on the EOS 33/30 and 60-250 on the 1v. In A mode you determine the balance and the shutter speed will be set accordingly and unless you select high speed synch the max shutter speed will be 125 or 250 sec accordingly. In high speed synch mode you'll have access to all shutter speeds depending on the f stop selected and the ambient light available. Some recommend manual mode so you select both f stop for the subject and amount of background light. Sounds complicated but Photonotes material will clarify it. Then practice and take lots of shots.