Using flash on overcast days

csedgbeer

csedgbeer

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Chris
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Hi

I'm starting to do event photography and I mainly shoot in Av and use fill in flash from a 550ex which works well. But i'm never sure how to use flash "properly" when the light is too low for Av on it's own without silly high ISO.

Example, was out the other day covering a student protest march, it was a grey overcast morning, and using f4 (biggest i've got on my 17-85) unless I went up to ISO 1600 i was only getting a shutter speed of 1/30 or slower which seeing as i was walking wasn't fast enough.

So I put the camera on P and let it sort itself out, most of the shots where then 1/50 or faster which still wasn't quite enough on some shots when i was zoomed into around 80mm. The flash was in e-ttl so it was figuring itself out.

I guess manual mode is what I need for shots like that, is there a general rule or is it a case of experimenting and checking the histogram to see if the photo is correctly exposed?

I'm also out doing some photography at the Sunseeker Rallye in Bournemouth next month, and in the evening at the finish podium which will be in the dark the same question applys. I know going to P works well ish, but I feel i should be doing it the proper way really!

thanks

Chris
 
If you are zoomed in to 80mm on the 17-85 lens you will be at F5.6...

This is a bit slow, would be better to get a F2.8 lens... or use your nifty fifty...

If you are moving try changing to AF Servo mode rather than one shot, this will continuously focus as the subject moves....

:thumbs:
 
markw08 said:
If you are zoomed in to 80mm on the 17-85 lens you will be at F5.6...

This is a bit slow, would be better to get a F2.8 lens... or use your nifty fifty...

If you are moving try changing to AF Servo mode rather than one shot, this will continuously focus as the subject moves....

:thumbs:
Click to expand...

sure i know it's not very fast at up to 5.6 but it's all i have! , should have mentioned the flash is a 550ex so should be good and powerful enough just to fill in enough, guess i just need to experiement with manual!
 
All the camera can do is try to balance the flash with the ambient light. If that light is very low, you'll get a long shutter speed regardless of whether it's in Av, P, or M.

If raising the ISO is not enough, you need a lower f/number. Fiddling with different modes won't change the light.
 
HoppyUK said:
All the camera can do is try to balance the flash with the ambient light. If that light is very low, you'll get a long shutter speed regardless of whether it's in Av, P, or M.

If raising the ISO is not enough, you need a lower f/number. Fiddling with different modes won't change the light.
Click to expand...

sure, if your in manual will the flash expose for the background or subject as it does in P?

guess what i'm saying is is it better to leave the camera in P and let it work it all out!
 
csedgbeer said:
sure, if your in manual will the flash expose for the background or subject as it does in P?

guess what i'm saying is is it better to leave the camera in P and let it work it all out!
Click to expand...

Are you talking about manual camera exposure control, or the flash?

If the flash is in auto, it will tend to expose for the nearest subject, depending on where it thinks the subject is. Off-centre subjects can fool it, which is what the FEL* button is mainly for.

P is pretty foolproof. With Canon I think that in this mode the shutter speed will track the ambient down to 1/60sec, but will then stop. The thinking here is that longer than this would allow too much background blurring and the better option is just to let the background go dark.

If you don't want it to do that, then shoot on Av and the shutter speed will keep on dropping for as long as it thinks it needs - several seconds if needs be.

If you want something inbetween, then manual lets you lock any shutter speed you like while the flash on auto will still match the f/number.
 
I shoot a lot of outdoor stuff for magazines and I haven't found anyting wrong with using manual flash with wither manul mode on the camera or Av. Like Hoppy says, the camera can usually do a pretty good job in automated modes but I do think that if you're in pretty static light levels that don't really change you can just set the exposure and balance the flash to it. Obviously, changing flash power will be done manually and sometimes it's not the most ideal way of working if you are under pressure, but if you have abut of time, then I find it as easy as pie.

I did a shoot today; ISO 500 was giving me roughly 1/60th at f/5.6 - that's pretty dull and dingy - so I just pushed in a little flash here and there to just add a bit of oomph. It needn't be a massive blast of flash - little amounts can just pep up a photo and fill-in the shadows.

Don't be afraid to shoot at high ISOs though; a 20D was never the greatest camera at handling ISO 1600 but ISO 100 on a 20D is okay I think. You'll obviously see the grain at lager print sizes but if you're doing web or small print stuff then there's no hassles. I regularly shoot at ISO 800 and 1000 for A4 magazine work - doesn't worry me one bit. :)
 
thanks for the replys guys, i've got a better understanding now

Cheers

Chris
 
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