fill flash and metering and bright sunshine

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Just a little confused on this one...

I want to do some outdoor portraits with my wife and newborn son. I've read and been told that its better to take the photo with the sun behind your subject. I know a reflector would be ideal in this situation, but if I wanted to use fill flash with a bounce card or diffuser of some sort, what would be the metering process? If I wasnt using the fill flash, and just metered for the subjects, I would most likely get an extremely blown out background. My logic and understanding tells me to meter the background and then use enough diffused flash to illuminate the subjects, but part of me tells that may not work and how would I know how much flash to use. I know I can chimp my way there, but I am interested in understanding and learning the technique. :thumbs:
 
hsuffyan said:
Just a little confused on this one...

I want to do some outdoor portraits with my wife and newborn son. I've read and been told that its better to take the photo with the sun behind your subject. I know a reflector would be ideal in this situation, but if I wanted to use fill flash with a bounce card or diffuser of some sort, what would be the metering process? If I wasnt using the fill flash, and just metered for the subjects, I would most likely get an extremely blown out background. My logic and understanding tells me to meter the background and then use enough diffused flash to illuminate the subjects, but part of me tells that may not work and how would I know how much flash to use. I know I can chimp my way there, but I am interested in understanding and learning the technique. :thumbs:
Click to expand...

Your logic is correct, though it doesn't usually need to be diffused light - direct flash is fine, and - unusually - close to the lens axis. The trick is to balance the exposure so that the flash effect is pretty much invisible to the untrained eye, so it shouldn't be casting any shadows of its own. It's purely fill-in.

The hard way is to set the ambient exposure manually and then balance the flash output manually and chimp it until it's right. Then when the subject distance changes even a little, do it all again ;)

A better way is to put the camera on Av with the 430EX, put that on E-TTL and to high speed sync just in case, point and squirt. Adjust the background exposure with +/- compensation on the camera, and adjust the flash with +/- compensation on the gun. E-TTL takes care of distance changes which are very critical with flash used quite close.

If the ambient light demands a shutter speed faster than 1/200sec, the HSS will automatically engage. It's (almost) foolproof ;) :thumbs:
 
Hoppy's point about AV and using the +/- exposure comps on both camera and flash is the most reliable I'd say. Personally I prefer to do i the former though - everything in manual, both camera and flash - but I know after doing shots of my baby boy that young uns don't keep still for long so fiddling with cameras and flashes isn't great.

I hatev to say it that in bright sunlight I have been known to whack it on P (with -2/3), set the flash to TTL (with no more than +1/3rd or so) and get a good shot - I rarely trust the camera fully but now and then it does surprise me. Saying that, you have any hint of large tonal range and it can panic and really blast things out.

Stick with AV and TTL flash ;)
 
My understanding of fill flash in a backlit environment was to use 1/3 or 2/3 negative exposure compensation.
And then a positive of 1/3 or 2/3 of flash exposure compensation.
This ensures the background is well exposed and also the foreground/ subject is well exposed.

And using Av to select your required aperture but also using High Speed Sync on the flashgun incase it selects a shutter speed higher than 1/200
 
It's interesting to see a mix of opinions on this one - I guess the methods suggested are all the same really, but without being able to see the outcome on the back of the camera it would be a bit hit and miss - how did they manage in the days of film! :)
 
Jchaplin said:
It's interesting to see a mix of opinions on this one - I guess the methods suggested are all the same really, but without being able to see the outcome on the back of the camera it would be a bit hit and miss - how did they manage in the days of film! :)
Click to expand...

They probably used a light meter??;)
 
onform - sounds sensible, but what would you meter exactly? (sorry, maybe I'm being dumb but I need it explaining to me!) :)
 
one question regarding using exposure compensation in AV mode. When we dial in negative exposure in camera and positive exposure on flash, shouldnt we clarify where to point the camera's meter at and to be using spot metering for optimum results? My logic tells me to dial in negative and meter background, exposure lock, recompose and shoot with positive compensation on flash. Does that make any sense?
 
There are many factors to take into account when using fill flash with backlight subjects. Using slower shutterspeeds and wider apertures have an influence. Best way is to keep it simple. My method is to set shutter to 1/60 @f5.6. Set ISO to compensate for these settings (maybe 200-400). Set flash to -2/3 and take a test shot and adjust flash output accordingly. As mentioned the effect you are trying to create is a well exposed shot with no obvious signs of flash, except for catchlights.
 
Some more interesting responses. No one has referred to the Canon system whereby FEC is automatically introduced in bright conditions, ie. the flash behaves as fill when its brighter than 11-13ev I believe. So is it necessary to still dial in -1/3 to -2/3 of a stop on top of this automatic compensation??
 
hsuffyan said:
one question regarding using exposure compensation in AV mode. When we dial in negative exposure in camera and positive exposure on flash, shouldnt we clarify where to point the camera's meter at and to be using spot metering for optimum results? My logic tells me to dial in negative and meter background, exposure lock, recompose and shoot with positive compensation on flash. Does that make any sense?
Click to expand...

I'm not sure that your logic is entirely right there, but your basic understanding is sound I think.

When the camera is set to auto-TTL flash and one of the auto exposure modes, the camera tries to balance the background (ambient) light with the foreground (flash). It's aiming to get them both optimum and uses various tricks that it doesn't tell you about. Some have been alluded to above, but there are more in it's calculation algorithms.

There are two common problems. The first is that flash is very distance sensitive and gets caught out with off-centre subjects. That's when you use the Flash Exposure Lock button - FEL* and to help that along even more, theortetically centre-weighted metering is a better fit with that (using spot is risky though). Handbook explains.

The other thing is that what looks 'balanced' in terms of fill-in flash varies and is also somewhat subjective. Usually the camera does a pretty good job IMO but there is sometimes a tendency for it to overdo the flash a bit, and it needs minus compensation.

You'll just have to give it a try but bearing in mind that all situations are different and the kind of result you want might not be what the camera has in mind, a bit of chimping and tweaking is sometimes unavoidable.
 
I honestly believe the best way to do this is to manually meter for the background. Then under expose it by approx 2/3 to 1 stop.

In bright conditions your shutter speed will be faster than 1/250th sec so you'll almost certainly need your high-speed sync mode selected.

Put the flash in TTL mode but be prepared to dial in flash exposure to suit. You want the shadows lifting but not so much that you end up with an obviously flashed picture. Generally the flash will be under powered when the sun is behind the subject. So don't dffuse it and don't get too far away from the subject. High-speed sync is fine but the flash power is seriously reduced.

Graham - I think you've assumed we're in low light situations. Out doors at 1/60th sec at F5.6 will blow everything out :eek:
 
HoppyUK said:
When the camera is set to auto-TTL flash and one of the auto exposure modes, the camera tries to balance the background (ambient) light with the foreground (flash). It's aiming to get them both optimum and uses various tricks that it doesn't tell you about. Some have been alluded to above, but there are more in it's calculation algorithms.
Click to expand...

And for this reason Canon will always tell you you may need to make some manual corrections.


You'll just have to give it a try but bearing in mind that all situations are different and the kind of result you want might not be what the camera has in mind, a bit of chimping and tweaking is sometimes unavoidable.
Click to expand...

Exactly
 
Thanks everyone for the replies on this, its something I'm keen to understand better so I'll get out there and take some pictures based on the suggestions made. :)

Jeremy.
 
ryanyboy said:
Graham - I think you've assumed we're in low light situations. Out doors at 1/60th sec at F5.6 will blow everything out :eek:
Click to expand...

Nope which is why I said alter the ISO accordingly. With backlit subjects there may be a big exposure difference from background to subjects face, less so if say when sun is at its highest in high summer.

Using lower shutterspeeds and wider apertures will create a "more balanced" shot anyway as opposed to (say) 250 @f16. There is no exact formula for fill in and proberbly most methods suggested will work but test shot will be required to fine tune. Its really down to trial & error to find the best method for you.

In film days we rarely used anything above ISO400 due to increased grain. Now with modern digital more common speeds are 250th with high f no. and high ISO. We need to look at how to use various settings combinations to achieve different results. As there wasnt any preveiw with film cameras we had to know how to achieve results and get it right, with digital we can check and adjust as we go along. Is this a good thing or a redundancy of knowledge?
 
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