Canon - Fill in Flash issues - advice?

[Photogaz]

I must admit to finding flash usage very difficult. I'm ok with it for indoor shots or very low light situations. I've never really used fill in flash with my 580EX II during daylight though, but I read its a great idea and i've seen some excellent examples. The other day I thought i'd try it out but failed quite terribly.

If I set the camera to Av mode at say f4 on an overcast day, the camera wants to sync at a higher speed, so I turn on high speed sync. However, the shots come out way too over exposed with the flash. I dialed it down to -3 but it still had problems. Another photographer (Nikon) was saying he has his to f8, shutter 250 and showed me examples and there's no overexposure at all. Not even using high speed sync!!

What was I doing wrong? Any advice?

 

[david1701]

aperture will affect both flash and ambient exposure, shutter only affects ambient

so if your ambient exposure is like 1/125 f10 then set up the flash at f10 then you can over or under expose the ambient by changing the shutter.

1/250 of a second under exposes the ambient by a full stop

1/60 of a second over exposes the ambient by a full stop (this will also over expose the subject as it is lit by ambient also)

 

[Gofer]

I must admit to finding flash usage very difficult. I'm ok with it for indoor shots or very low light situations. I've never really used fill in flash with my 580EX II during daylight though, but I read its a great idea and i've seen some excellent examples. The other day I thought i'd try it out but failed quite terribly.

If I set the camera to Av mode at say f4 on an overcast day, the camera wants to sync at a higher speed, so I turn on high speed sync. However, the shots come out way too over exposed with the flash. I dialed it down to -3 but it still had problems. Another photographer (Nikon) was saying he has his to f8, shutter 250 and showed me examples and there's no overexposure at all. Not even using high speed sync!!

What was I doing wrong? Any advice?

Is your flash set to ETTL? If it is there's no reason why it shouldn't work perfectly in the scenario you describe. I've just taken a picture through my study window with the aperture set to f4, shutter speed at 2000, flash in ETTL/HS mode and the picture is perfectly exposed - the outside is exposed correctly and the (relatively dark) room has also been exposed correctly via the flash).

 

[Denisw]

I must admit to finding flash usage very difficult. I'm ok with it for indoor shots or very low light situations. I've never really used fill in flash with my 580EX II during daylight though, but I read its a great idea and i've seen some excellent examples. The other day I thought i'd try it out but failed quite terribly.

If I set the camera to Av mode at say f4 on an overcast day, the camera wants to sync at a higher speed, so I turn on high speed sync. However, the shots come out way too over exposed with the flash. I dialed it down to -3 but it still had problems. Another photographer (Nikon) was saying he has his to f8, shutter 250 and showed me examples and there's no overexposure at all. Not even using high speed sync!!

What was I doing wrong? Any advice?

As you are probably aware in AV mode the Canon camera is set up for fill in flash but if you set aperture to wide it will over expose your shot. Try setting Safety Shift to enable on your Camera this will ensure you dont over expose your photo. Hope this helps

 

[Photogaz]

Thanks for the advice. I re-tried this weekend with my new 5D Mark II and it seems to handle it much better. It could have just been the conditions on the day.

What do you recommend for the metering mode if you're using people as subjects, spot metering?

 

[tdodd]

To set an exposure for the ambient light (ignoring flash for the moment) try using manual exposure. Spot meter off your own palm and then set an exposure for +1 1/3 stops on the meter. Adjust a little up or down from there as necessary to get the background as you would like. Adding in fill flash should then be simpler since your ambient exposure won't be jiggling all over the place as you adjust your composition. Start off with fill at maybe -2/3 and, once again, adjust to taste. If the background is especially bright - backlit sky, for example, then you will probably have to dial down the ambient exposure to avoid blowing the sky and then boost the fill.

Of course, unless you want to use high speed sync for the flash you will be constrained by the max flash sync speed, so bear that in mind when setting your ambient/background exposure. Remember the sunny 16 rule as a guideline for shooting in bright sunshine - f/16, 1/100, 100 ISO. If you want to open up that aperture for shallow DOF you will not be able to go far without exceeding the flash sync speed - f/11 and 1/200 or f/10 and 1/250. You can see why f/4 might be a problem in bright conditions.

If you must open up the aperture for creative effect then either....

- you need lower ambient/background light levels;
- or you need to add an ND filter;
- or you need to use high speed sync.

 

[CScottMcQueen]

Thanks for the advice. I re-tried this weekend with my new 5D Mark II and it seems to handle it much better. It could have just been the conditions on the day.

What do you recommend for the metering mode if you're using people as subjects, spot metering?

If you have a 5D Mk II then go into the custom functions and set the 'safety shift in AV or TV' to on. This will make sure the camera never goes above 1/200 shutter speed (the maximum sync speed).

Never use high speed sync in Ettl for fill flash! The camera cheats like buggery in this mode and afaik will never get the maths right for fill flash.

if you dont want to change the custom functions keep the shutter speed below 1/200 in AV mode by manually turning the wheel

you can still use FEC to adjust the amount of fill light the flash puts out.

 

[Chappers]

Don't forget you can use the FEL option to try and balance both flash and ambient. If it;s the same as the 5Dmk1 then pressing the * button of the back of the camera will cause the camera to fire a preflash and adjust the exposure accordingly. However you may( probably will) need to adjust the flash power dependent on the subject and the lighting ratio you are after.

Like all these things its a question of experience. ( Even then you can get it wrong sometimes )