How to shoot group indoors with flash

[sfogel2]

Hi, all...

I would like some advice, please, on how to balance all the tradeoffs when shooting a group indoors.

• The scene: 8 high school girls dressed up for homecoming dance.
• The victim: Dad, trying to get the best indoor shots of the group
• The equipment: Canon EOS Rebel T2i, 18-135mm f/3.5-5.6 USM IS lens, Speedlite 580EXII with diffuser
• The settings: Av mode, f/11, ISO 400, 1/60sec (Custom setting for shutter speed in Av with flash = 1/60 to 1/200)

I wasn't that happy with the results. Everyone was in focus, but exposure was just OK and needed tweaking on computer. Sometimes not enough detail in shadows, like a black dress. (Couldn't move group and they were in a narrow alcove with glossy white paint on walls and ceilings.)

How do you balance these tradeoffs?

• Shutter speed needs to be faster than 1/30 to avoid camera shake
• ISO must be kept low to avoid noise
• Aperture must be f/8 or narrower to keep everyone in focus
• Want as much ambient light as possible to avoid flash glare

That last one is a new revelation of mine. I believe that when shooting in Av, the T2i tries to meter for the background. So maybe adjusting so more ambient light can get in would be a good idea. Maybe because I have an IS lens I could go to 1/30.

Any advice would be welcome.

Steve

[Colin Southern]

Hi Steve,

I'm just about to head out to a studio shoot, but in a nutshell ...

- Use a tripod if at all possible

- Use a higher ISO. High ISO settings don't create noise per se - they just limit the dynamic range the sensor is capable of recording. It's the combination of high-ISO with under-exposure that creates the noise - so DON'T UNDER-EXPOSE (not even a little bit!).

- You could probably have got away with F5.6 (depending on distance) - you'd really need to check with a DoF calculator beforehand. Unfortunately, with limited lighting, you need to push things like aperture & ISO to the limit.

With regards to using the flash, a flash bounce is usually the best approach (but it depends on the characteristics of the room you're in). If the walls are light coloured and the room isn't too big then I usually turn the flash around and fire it behind me. The type of diffuser also makes a BIG difference. Stofen type diffusers are useless as they don't do anything to increase the effective size of the light source. The likes of the Gary Fong Lightsphere can work well because they basically spread the light around everywhere. The 580EX II has a lot of grunt, so I'd be pointing it behind me to maximise the size of the effective light source in the scenario you mentioned (and you'll eliminate the glare).

[krispix]

Hi Steve,

Very little to add to Colin's response.

You mention ambient light. Are you talking about daylight through windows etc., or artificial light? If it's the latter I wouldn't recommend mixing that with flash as the colour temperature of the two light sources are miles apart. Your shutter speed is largely irrelevant because the exposure is created by the flash which will be operating at anything from 1/5000 sec or faster. Like Colin, I would go for a bounce flash as well unless you've got access to a large umbrella or similar.
With flash exposure is paramount. Under-exposure will result in black dresses being lost in the shadows. Similarly, over-exposure will blow out faces etc. It's a bit of a juggling act, but it's normally easier to tease detail from under exposure than over.
Talk to a wedding photographer who struggles with black suits and white wedding dresses all the time!

[Colin Southern]

Not to gloat or anything, but I would just like to add how nice it is for me to be able to walk in to that kind of situation these days with enough fire power to light up a stadium; if I've done my calculations correctly, I think I can output a momentary pulse of light somewhere in the order of 6 million watts

... I don't miss the "good old days" of a solitary 580EX one little bit

[Geoff F]

You may have already read this post, Steve How does my flash work? which gives a lot of good advice about using flash.

I will just repeat that when I started using a Speedlite flash I had similar disappointments to you.

At first I was selecting Tv and 1/60 (as I had done with film cameras and simple flash units) but although this worked I was shooting with the lens fully open (auto set by the camera) and getting a lot of over exposed images.

Eventually, I realised that I could set my camera in Manual Mode to suit the scene and allow this new 'self thinking' flash to choose a suitable flash output to match my settings.

Although originally used for macro work I now find this usually gives me the best results. There is a bit of limitation in deciding which settings will both suit the scene and flash but I find there is normally quite a bit of leeway here. And the High Speed flash option can extend the options to higher shutter speeds than 1/250.

I have tried a Stofen flash difuser but although it is capable of producing better colours I find that I have to increase the Flash Compensation to allow for it (the flash unit doesn't know that it is fitted) so it doesn't always produce better results than simply selecting a little negative flash compensation.

Shooting in Av mode can produce excellent results where you need a good background but the shutter speed is often too slow for hand held shots; or subject movement.

[Colin Southern]

I have tried a Stofen flash difuser but although it is capable of producing better colours I find that I have to increase the Flash Compensation to allow for it (the flash unit doesn't know that it is fitted)

ETTL should already compensate for it, as it also attenuates the preflash by the same amount.

[Geoff F]

I'm not sure about that, Colin. But when trying to use a Stofen for macro shots I had consistently dark images which required extra flash compensation. As soon as I removed the unit, shooting the same scene, I needed a little negative flash compensation to counter over exposure.

But this was with full manual camera settings.

I seem to remember reading something about problems using a Stofen with the flash head pointing directly towards the subject, it needs to be angled upwards by around 45 degrees to give best performance.

This angling of the flash head also produced poor results for outdoor macro shots; in fact it was worse than the straight ahead method.

Since then I put the difuser away and haven't tried it again. But my initial trials with the device, at a 45 degree angle, did give better colour with general indoor photography, in a small room.

[Colin Southern]

I'm not sure about that, Colin. But when trying to use a Stofen for macro shots I had consistently dark images which required extra flash compensation. As soon as I removed the unit, shooting the same scene, I needed a little negative flash compensation to counter over exposure.

But this was with full manual camera settings.

I seem to remember reading something about problems using a Stofen with the flash head pointing directly towards the subject, it needs to be angled upwards by around 45 degrees to give best performance.

This angling of the flash head also produced poor results for outdoor macro shots; in fact it was worse than the straight ahead method.

Since then I put the difuser away and haven't tried it again. But my initial trials with the device, at a 45 degree angle, did give better colour with general indoor photography, in a small room.

Hi Geoff,

Anything that reduces the flash output also reduces the preflash, so the only reasons I can think why you'd need to change the compensation are if the pre-flash was attenuated to such a degree that the camera mis-read it, or the flash was in a manual mode. Other than that, "who knows". It's my personal opinion that Stofen-type diffusers are a waste of money and plastic; the flash is a 2 square inch light source without one, and is still a 2 square inch light source with one, so it's not going to do a darn thing to change the relative size of the lightsource. At best, all they're going to do is attenuate the flash and (perhaps) spread it around the room a little -- at which point somethig like a lightsphere is going to do that a gazillion times better.

I guess that for macro photography they might have more of an effect, but I still think there are far better ways of lighting a macro subject.

Just my 10c worth

[Geoff F]

I guess that for macro photography they might have more of an effect, but I still think there are far better ways of lighting a macro subject.

Well I certainly returned rather quickly to just using a little negative flash compensation.

My hope with a Stofen was that it wouldn't be too large to scare the subjects and would still enable me to shoot through 'holes in the foliage'.

Maybe one day, if I can remember where I threw it, I will have another go.

[Colin Southern]

Maybe one day, if I can remember where I threw it, I will have another go.

Yeah - they're good for holding gels in place

[jonnywaz]

Just so you know you are not alone, I too had the problem of the Stofen causing under exposure when forward facing but fine when bounced. I shoot with a 7D and EX580II, and I really can't explain it. My thinking always being the same as Colin's that the pre-flash is with the Stofen on, so it should account for it.

I gave up on it, and generally haven't miss it. Bouncing when appropriate, and using direct for fill-in. Since buying the 580, I pretty much always use for outdoors or in for portrait's of my children - great bit of kit when balanced with the ambiet light well.

[Colin Southern]

Hi Jonny

Just so you know you are not alone, I too had the problem of the Stofen causing under exposure when forward facing but fine when bounced.

The only difference electronically is that facing forward, the flash uses focusing distance in the exposure calculation, so I'm at a bit of a loss to explain why it's happening, other than it's affecting the spread of light slightly resulting in a different calculation.

PS: Welcome to CiC - great to have you with us!

[Geoff F]

I'm not really sure of what I'm talking about here (situation normal) but the Stofen doesn't fit tightly against the Speedlite glass, there is about a 1 inch gap, and has transparent sides, unlike many other difusers which contain and prevent 'light leakage' sideways.

This may be the cause? Shooting at an angle in a room with a low ceiling means that you are getting a bounce flash plus direct light from the Stofen sides.

Does that make any sense?

[Colin Southern]

I'm not really sure of what I'm talking about here (situation normal) but the Stofen doesn't fit tightly against the Speedlite glass, there is about a 1 inch gap, and has transparent sides, unlike many other difusers which contain and prevent 'light leakage' sideways.

This may be the cause? Shooting at an angle in a room with a low ceiling means that you are getting a bounce flash plus direct light from the Stofen sides.

Does that make any sense?

It still shouldn't affect the flash portion of the exposure though, because when ever it does to the flash, it also does to the pre-flash -- so regardless, the ratios stay exactly the same.

[jonnywaz]

This got me thinking, and led to an interesting experiment and result. My theory being that the pre-flash is weak, hits a small amount of the internal diffuser when on low power, and perhaps with the Stofen fitted more forward light in that configuration (when compared to fuller power). Hence the miscalculation.

As an experiment I tried one shot as normal (Stofen fitted) for a portrait ~75mm focal length, 1.5 meter from subject. The shot was about 1.5stop underexposed as usual. I then tried with the wide angle diffuser flipped down (Stofen again fitted). This forced the flash to spray light wide in the Sofen, both via the flip down filter, and because the flash 'zooms out' to 14mm. Result, perfectly exposed photo! I repeated each three times to make sure it was consistent and it was.

Of course there is a whole lot of power being wasted in this setup, and to be honest the softening of light from the Stofen in forward facing wasn't significant. Never the less, an interesting result.

Geof, may be of use to you.

[Geoff F]

It is certainly something I will try, Jon.

As I said previously, I was experimenting with a difuser for macro shots of insects, to try to reduce the glare which sometimes occurs, and didn't want to add anything too large or too far forward which may scare the insects.

Also something which wasn't too bulky, complicated or expensive. But in reality, so far, I still find that using negative flash composition is the best all round answer for rugged, in the field, photography.

[Dismayed]

I think of a flash photo as two separate exposures. Ambient light is controlled by the combination of aperture and shutter speed. So play around a bit before your models arrive so that you know how you want to set up your ambient exposure. The flash exposure, on the other hand, is controlled solely by the aperture (assuming all else, such as ISO, remain the same). The reason is that the pulse of light from the flash is very short (much shorter than the shutter speeds at flash sync or slower) so the entire pulse gets into the camera. That also means that you can use the flash to freeze motion at slow shutter speeds, as long as the flash exposure is a few stops above ambient light levels.