A photo like this is about ambiance and to capture any ambient light the ISO needs to go up that way we do not get a scene blasted out by flash. The exposure ideally needs to capture the fire and the flash is just used to raise the lighting on the faces and to achieve this without vast camera shake you up the ISO. If the exposure is right for the fire iyt wil most likely be wrong for the faces, hence a blip of fill in flash for them.
Mike
I see where you are coming from Mike but lets look at this 'blasting out by flash'. What you're describing here is generally whats going to happen when you stick a flash on a camera and use TTL mode. If we take this scenario (
the camp fire) then the camera will see the world in darkness and 'blatt' out a huge flash looking like the subject has been caught in a nuclear blast as it will try to over-compensate for the darkness. Even the most intelligent flashes are not that intelligent at time times and the results are unflattering and less than impressive.
As you say, the camp fire and subject is all about creating an atmosphere. Whilst I take your point about turning up the ISO, You'll certainly get a result, but it won't nececarilly be the best result as it will lead to more noise. I'm not a great advocate of sorting noise out in PP as I want to get the highest quality image I can in-camera. However, more importantly, using a high ISO makes the camera's sensor more receptive to available light, increases the shutter speed range and increases the flash range. This is the exact opposite of what I don't want when doing this type of photography ! For this reason I'll use a low ISO between 100-400.
Balancing Ambient light and Flash (
and fill-in) , if you break it down is a two-stage process. You expose for the flash (
distance / aperture) and you expose for the ambient light (
shutter speed / f-stop). It's essentially a blend of two exposures that occur simultaneously, no wonder TTL gets confused and gets it wrong. It does not see what you are seeing and doesn't know what you're trying to achieve. I'll try and bring this all together in context and explain my approach which I didn't explain very well the first time round due to time restraints.
For this scenario, I'll select an aperture to achieve the depth-of-field I want to obtain using either the Aperture Priority Mode or Manual setting and select a slow shutter speed, this is where I'm going to start the exposure to capture the ambient light . Any movement of people is going to get frozen the moment the flash goes off 'Bang' at that moment in time, but it will capture the ambience and atmosphere. If I want to get really creative then I will decrease the shutter speed to 1/30 or lower, use a tripod and use rear curtain sync to show movement / motion blur and freeze the subject giving a natural and pleasing effect - but I'm going off on a bit of a tangent here !
Back on track if the flash on the subjects faces are overexposed I'll dial in a bit of flash minus(-) flash E/V if in AP mode, or if shooting In manual mode dial down the power output on the flashgun. One particularly useful accessory for this type of photography is a handheld flash meter. Taking an incident light reading from the subject takes all the guesswork out and is more accurate than the internal camera meter.
For individuals there are many ways of achieving similar results, this is just my approach and why it works for me. None of this is an exact science well 'it is' - it's just that I can't explain it and if I could it would be extremely tedious. Hope this helps just bring a few things into context and explain my rationale.