How to shoot in a big room?

settons · Nov 5, 2012

Hi Everyone,

I wanted some thoughts from you about how to shoot indoors with poor lighting and a high ceiling. Let me breakdown the scenario...Canon 40D, 430EX flash (with bounce card) and 50mm 1.8. I went to an awards presentation for my 3 year olds "little gym" class. It is probably a room that is 60'x70' and the ceiling is probably 20' high...similar to a elementary school gym.

I tried to bounce light off the ceiling, however it was too high and wouldn't produce enough light. When I directed the flash at my son, it gave the spotlight look, which obviously isn't what I am looking for.

My question is this, would a Gary Fong lightsphere had helped in that situation? Is there a better accessory out light that would be portable? It seems like I am in these situations often. Are there any pointers anyone can give me? Any advice would be appreciated.

2WheelPhoto · Nov 5, 2012

Bump the ISO a bit and bounce the light

I use available light in gymns but my ISO is screaming about 3200-4000, not sure if your body can handle that

Mully · Nov 5, 2012

Big rooms can not be lit with one light source ...shoot at 1.4 to 1.8 and start at ISO 1600 and see where you are

Designer · Nov 5, 2012

How about a clip-on soft-box attachment?

2WheelPhoto · Nov 5, 2012

Designer said:
How about a clip-on soft-box attachment?

and dim his little flash more?

KmH · Nov 5, 2012

If the ceiling is 20' high, the light will have to go 40' to bounce (20' up, 20' down).
The Inverse Square Law shows that if you double the distance only 1/4 of the light power reaches the subject. Inverse-square law - Wikipedia, the free encyclopedia

Next you may have white balance issues from mixed lighting (ambient/flash), unless you gel your flash to the same color temperature as the ambient lighting.
Bounced light produces 'racoon eyes' so it's good you have a bounce card for fill lighting.

When pointing the flash directly at your subject, manually setting the flash power to less than full power, or setting a minus flash compensation value, can alleviate the 'spotlight' look.

Big Mike · Nov 5, 2012

My question is this, would a Gary Fong lightsphere had helped in that situation?

The Fong Dong (and similar accessories) are the WORST thing in that type of situation. Think about what it does...it spreads the light out in all directions. That means less light is available to bounce in the directions that would actually help if you did have enough power. And the light going directly to the subject won't be any better than direct flash. The end result is that it likely wouldn't have enough flash reaching your subject, but the flash would be firing at full power, thus taking longer to recycle and killing the batteries faster.
Something like that is only useful in a small/close room where there are surfaces suitable for bouncing the light off of.

Actually, I would think that 20' ceiling aren't too high. 20' up and 20' down is 40', but your flash (being a 430EX) is rated at 43 Metres at ISO 100. So if we factor in the loss of light from the bounce surface absorbing some of it (usually about two stops), I think you still have enough power...especially if you up the ISO and use a large aperture.

It may not be a whole lot of light after the bounce, but it should be adequate. The issue may be that if you are trying to overpower some existing type of light, you may not have enough for that, and your WB may not work out well.

On the other hand, ISO 1600 and F1.8 might get you a fast enough shutter speed to shoot without flash.

settons · Nov 5, 2012

Thanks for the replies everyone. I have always been hesitant to increase my ISO past 400 due to noise. I think I need to become more educated on how to adjust the settings on my flash. I understand everything related to the camera, however I have never taken the time to understand the settings on the flash. Does anyone know of any good sites that explain the 430EX?

It's really disappointing/frustrating when you get in a situation and can't figure out how to get a picture that is close to acceptable. I have learned lots from many people on this site and will continue to read and improve.

TCampbell · Nov 5, 2012

Don't try to bounce of diffuse -- and for two reasons.

A softbox or even a shot-through umbrella will eat about 1 stop worth of light (so you'll only get about half the light making it through the fabric.) This isn't a problem when using the diffuser as intended because the working distance to the subject will be short -- you'll still have plenty of light even after losing half of it. The point of a diffuser is NOT to spread the light around... it's to make the light appear to originate from a broad area. When you're well back in a gymnasium or other large, long room your light source will still seem to originate from a tiny point (diffusers only work when you are reasonably close to the subject.)

This topic really calls for an understanding of "guide numbers". A speedlight flash (dedicated flash strobe) has it's power rated as a "guide number". This is a bit misleading because guide number isn't an indicator of the flashes power (well... not directly anyway). Its an indicator how much light it can deliver at a given distance. It turns out the shape of the reflector in the flash head will have a big influence on this. You'll notice lots of flashes have a zoom setting. Some dedicated flashes electronically zoom the head to focus the light. Some allow you to manually move the reflector in or out to focus the beam.

The guide number is usually listed in either feet or meters. This number is the distance at which the flash can deliver an adequate amount of light to create a proper exposure WHEN the camera is using ISO 100 and f/1.0.

At this point you should instantly realize that your camera can shoot at ISO 100 and also realize that you do NOT have an f/1.0 lens. Sounds crazy that they should use f/1.0? Not really. They do this because it makes the math VERY easy. Since they used f/1.0 as the baseline for the guide number, it means you simply divide the guide number by the f-stop you are using. If you use f/5.6 then you divide the guide number by 5.6 and you're done.

You've got a Canon 40D. You said you had a 480 flash... did you by chance mean 580? The 580EX has a bounce card. The next model down is the 430EX (no bounce card). They did make a 430EG (years ago) but I suspect that's probably not the model you have.

In any case, I'll assume you meant 580. It has a guide number of 58 meters (about 190'). Divide that by 5.6. 190 ÷ 5.6 = 34' (rounded off).

Now... imagine that instead of having a white ceiling (which probably reflects less than half the light that hits it) that your ceiling is a highly polished mirror and you have virtually no light loss... it's 20' up and another 20' down. Ignoring the fact that we'd need to do some quick math using Pythagorean triangles to calculate the true distance that the light has to travel from flash to subject, we've already got AT LEAST 40' of travel on a flash that can only provide adequate lighting to 33' in a straight line assuming no light loss when you have an f/5.6 lens.

What to do?

Adjust your ISO. Each time you double the ISO it's the same as shaving off a stop of aperture. That means if you shoot at ISO 1600 which is FOUR full stops up (100 -> 200 -> 400 -> 800 -> 1600) you are allowed to pretend that you've lowered your focal ratio by the same number of stops (5.6 -> 4 -> 2.8 -> 2 -> 1.4) There you have it... shooting at ISO 1600 at f/5.6 is the same as shoot at ISO 100 at f/1.4. Now when you divide 190' by 1.4 you get 190 ÷ 1.4 = 136' (rounded off) and that's pretty good. Possibly you can get away with shooting at only ISO 800 (for less noise) -- the answer depends on where you are in the room. But just remember that if you try to "bounce" off the ceiling, you're going to lose a TON of light and add a lot of distance. Bouncing really works best when the ceiling is relatively low.

gsgary · Nov 5, 2012

You would have been lucky if your flash had reached the ceiling

settons · Nov 5, 2012

Tim, thanks for the detailed explanation. It makes lots of sense. The flash I have is actually the 430EX...that was my mistake.

How would you have shot it? Assuming that your ISO 1600 f/5.6 still wasn't giving you enough light without flash, would you adjust the flash in the settings and shoot directly? A little direction would be greatly appreciated.

TCampbell · Nov 5, 2012

settons said:
Tim, thanks for the detailed explanation. It makes lots of sense. The flash I have is actually the 430EX...that was my mistake.

How would you have shot it? Assuming that your ISO 1600 f/5.6 still wasn't giving you enough light without flash, would you adjust the flash in the settings and shoot directly? A little direction would be greatly appreciated.

The 430EX II has a guide number of 43 meters (or 141'). So now the math is 141 ÷ 5.6 = 25'. At ISO 1600 (4 stops up) you get to pull 4 stops off f/5.6 or pretend you're using 1.4. 141 ÷ 1.4 = 100'.

That means your 430EX II can take the shot as long as you are within 100' and the flash is fully zoomed in (the 430EX II electronically zooms the reflector on the flash head. At the 105mm zoom point is where it's giving you the max guide number of 43 meters). That means if you're camera lens is 50mm and the head is matching the lens you wont get the same distance (light will be dispersing about twice as much in all directions and this impacts the light by the SQUARE of the difference (which means you'd get about 1/4 of the light)). You can either take over the zoom control on the flash (press the "Zoom" button, then press the "+" button a bunch of times until the display reads "M Zoom 105mm" then press the Sel/Set button (and don't forget to undo this when you're done shooting or it'll stay in that mode forever -- it even remembers it after power off and back on. So press "Zoom", then "-" a bunch of times until the "M" (for manual zoom control) disappears, then press the "Sel/Set" button.))

If you were actually using the 50mm f/1.4 lens at f/1.4 then the natural math gives you 100' even at ISO 100 (because you really have an f/1.4 aperture... not at f/5.6 aperture as you'd have with most variable focal ratio zooms). Only the central area of the shot is going to be illuminated. If the flash head matches the camera then you only get 1/4 of the light (which means you have to pretend you are shooting 2 stops up to compensate... shooting at f/1.4 with a 50mm angle of view is like shooting at f/2.8 with a 100mm angle of view. The light would only carry to about 50' for an adequate shot (instead of 100')

Keep in mind that the 50mm lens is "full frame". On the APS-C camera you don't need to illuminate the full frame.

Using a 50mm lens, your camera will have the angle of view that a full-frame camera would have with an 80mm lens. This means that if you "zoom" the flash-head to 70mm you'd still actually cover the entire area that your APS-C camera can capture. That saves you 1 stop and THAT means you can now be about 70' away.

To sum up:

The math is pretty easy when using the 430EX II with a lens at f/1.4 because the 141' (lets just round that to a nice neat 140) works out to provide effective flash coverage at 100'. BUT ... this assumes the flash head is zoomed all the way to the 105mm length. If we "round" this to 100mm for 100' then the focal length and flash distance actually MATCH UP! The flash will handle a 50' distance if you have to illuminate a 50mm angle of view.

Since you've got an APS-C sensor camera, a 50mm lens actually provides the angle of view of an 80mm lens on a full-frame camera. That means if you manually zoom the flash head to the 80mm setting you can adequately get a subject 80' away (and we're still talking about using ISO 100. If you boost the ISO then you go even farther.)

Keep in mind that anything closer will get a lot more light. Assume you're well back in the audience... you'll get quite a bright amount of light on the backs of the heads of audience members in front of you. You could try to baffle that (this is why we use "barn doors" on studio flashes) -- basically some flaps that keep light from going into places where we don't want it to go.

All of this will create "adequate" lighting. For better lighting, you do want some shadows (to have good light, you need good shadows... "good" shadows are shadows that you control). For that I'd use a 2nd flash which is off to one side (a side-light) but remotely triggered to go with the main light. This helps avoid the "flat" light appearance of the straight on flash. You're too far away to use diffusers or to think about bouncing off the ceiling. A 2nd light is, of course, more expensive. A 430EX II cannot act as a "master" (commander) to remote trigger another flash. But it can act as a slave. You could use a 580EX II on the camera and a 430EX II off camera and the 580 will remotely trigger the 430. That's more money of course, but it will improve the look.

The nice thing about flash photography is that it only 'seems' mysterious. I tell people it's kind of like a magic trick. It only seems like magic when you don't know how it works. Once you learn the trick you realize it wasn't so tough after all. "It's easy once you know the secret." Full stops on cameras alter the exposure based on the SQUARE ROOT OF 2 (i.e. 1.4) and it turns out lighting distances work on the exact same number (the inverse square law of light).

So here's something to think about... if you've learned the basics of the "exposure triangle" than you know that when you change one setting you are allowed to change either of the other 2 settings to compensate. E.g. change the shutter speed down by 1 "stop" (half as fast) then you can increase the aperture by 1 "stop" and you'll get the same exposure. That means you ALREADY KNOW how to use flash. But instead of an "exposure triangle" you've now got an "exposure square" (there are four things that impact the exposure. Changing the light power by halving or doubling it is the same thing as changing the shutter speed or aperture or ISO by a stop.) The only difference is that it's not just the light power output level that impact the light... it's also the physical distance from the light or the rate at which the light is allowed to disperse (beam angle). I can double the distance of a light bulb if my reflector allows me to concentrate the light into a tighter beam which is half as wide.

I actually do have both the 580 and 430 speedlights, so sometimes I will use that 2nd off-camera flash so that each flash helps fill the shadows created by the other flash. This provides a nice 3D look and the shadows are weak instead of dark. The edges aren't as soft but the only way to create a "soft" edge is to diffuse the light and the only way to diffuse the light is to make it appear to originate from a broad source (not a pinpoint source). That would require being close - which is not an option in a lot of shooting situations. The cross-wash of two flashes is the next best thing.