Using EV compensation with Flash

[sulhan]

Hiee Pals..

I have been getting some queries from fellow KM users on problem of not being able to do exposure compensation with the 7D - with flash photography (shold be the same for 5d I think).

Well, in the 7D, there are two modes for EV compensation:

1) Ambient Only - this will not allow you to change exposure and will seem no change if EV is changes from 0 to +1 or more...

2) Ambient and Flash - This is th emode you would want to use if using flash photography. Even the Sync speed for those using on board flash at 1/60 - this mode allows changes in exposure if EV is changed.

Hope this will help those hwo have enquired.

rgds,
sulhan

[TME]

Huh? Care to explain some more? I dun get it...

[zcf]

thought I was the only one who don't get it

Still don't understand relationship of +EV and increase in exposure well, is it by increasing EV through the increase of aperture size, ISO or reduce shutter speed? Thereby increase exposure?

[Drudkh]

I just looked through the manual.

EXPOSURE COMPENSATION SETUP
Exposure compensation setup is set in section 2 of the custom menu (p. 92). This custom function has two options:

1) Ambient & flash - when using exposure compensation with the flash, both the ambient.
and flash exposure controls can be adjusted.

This suggest that, when you set the camera to this option in the setup menu and you compensate EV and Flash EV, both affects the output on the photo.

2) Ambient only - the flash exposure is fixed and only the ambient exposure controls (shutter speed, aperture, and camera sensitivity) adjust the exposure.

This suggest that, when you set the camera to this option in the setup menu and you compensate EV and Flash EV, only the EV will affect the output on the photo. Flash EV when set to + or - will not change the flash output on the photo.

Am I right?

[sulhan]

Originally Posted by zcf thought I was the only one who don't get it Still don't understand relationship of +EV and increase in exposure well, is it by increasing EV through the increase of aperture size, ISO or reduce shutter speed? Thereby increase exposure?

HIee Bro...

I'm just putting it in simple laymans term dah....
If want to allow Ev compensation to take effect when using flash....then Use the Ambient & Flash option.




rgds,
sulhan

[UY79]

The settings allows you to link FEC to EC or for both to work independently.

Minolta cameras have a 1/focal length (1/60 or 1/125) shutter speed rule when using flash. If ambient Exposure Value (EV) is below what is set (e.g. 1/60 f/4), changing Exposure Compensation (EC) in Ambient Only settings do no affect anything as the camera's setting follow the rule instead of the metering and flash will fire with the set Flash Exposure Compensation (FEC). Whereas when using Ambient and Flash setting, it will affect the flash exposure which is the primary means of exposure in this case.

Only when ambient EV goes is above this rule (which forces the camera to use higher shutter speed) or when you are using slow sync, then you can control the overall exposure (ambient exposure and flash together) with Ambient and Flash setting or ambient and flash exposure individually using EC knob for ambient and FEC knob for flash with Ambient Only setting.

This 2 settings affect the way you set the EC and FEC when you want to say achieve a darkened sky in the day with your model illuminated by flash kind of shots. In aperture priority mode, with the Ambient and Flash setting, you will need to say -1.5EV on the EC to darken the sky (which brings the overall exposure to -1.5EV including flash because they are linked) and +1.5EV on FEC for proper illumination of the model (to bring the flash exposure back to 0EV). For Ambient Only setting, you will only need to set the EC to achieve the same result as the flash exposure is no linked and hence is still at 0EV.

Hope this helps.