Flash technique question


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Tweek

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#1
I've met with the following scenario many a time but still can't find a way to get around it. Let's say:

- I'm in an indoor environment. Ambient lighting is like a typical wedding dinner setting.
- I use flash but I want ambient light to show up, so I use high ISO like 400 or 800.
- I take a picture of my subjects who are about 2m away. Ceiling is too high so I use omnibounce/bounce card.
- However, due to the high ISO which increases the minimum flash distance, my subjects get washed out.

Any simple and easy way to diffuse the flash enough so that I can achieve a decent flash exposure while still letting sufficient ambient lighting to show up?

Thanks for any help rendered!
 

Prismatic

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#2
Go for lower shutter speeds, up to maybe abround +1 stop, adjust your flash output to maybe like -1 EV.

The idea is to fill in the exposure with flash first, then let the ambient lights fill in the rest of the exposure time.

This is a rough guide, good results comes from experimentation, since flash and camera characteristic varies from set to set.
 

Teddman

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#3
I have encountered similar problems before, and after, uh... several rolls of film, I think the best method is perhaps to use your flash guide number to assist you.

At ISO 400, set your aperture to maybe f 5.6, or larger.

Note down the guide number on the flash, ( normally 3m plus at 1/16 flash output.) This means that your subject has to be shot at that distance from the lens. Any further, you get underexposure. Any closer and you will get overexposure.

Leave it to the camera to decide the shutter speed. Note that the shutter speed should either be at your flash sync speed or slower. DON'T let the camera use TTL flash metering. Your camera should only trigger the flash, and nothing else.

The main problem in having this method is that you have to constantly take into account subject distance, and hence your response speed would be a bit slow... but your photos, generally will be pretty accurate in metering.

me 2 cents worth...

Derek
 

#4
I never had the problem when I shot film, even up to ISO 800 because of its large latitude. But when I went digital, I get the same problem when I wanted to shoot wide open. The only solution I guess is to know what your minimum flash distance is. If you get closer to that, stop down.

Regards
CK
 

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#5
May i know what the following:

1) What metering you choose? Spot, Centre weighted or Average?

2) Is your subject covered by the metering mode?

3) Is your subject darker or brighter than the ambient? example any strong light shining on them?

4) Is your shutter and aperture setting set for the ambient or the some other things?

Thanks.
 

kex

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#6
ISO 400 TTL flash straight on camera set to manual 1/30sec or abit higher if u can' hold at that speed,aperture 3.5 or 4.
you should get pretty good result at those setting.brighter room,set at the ambient reading.

regards
 

StreetShooter

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#7
In such situations, I would use Av mode to capture the ambient lighting, and use the flash pointed directly forward as a fill-in flash (ie no bouncing or anything). The E-TTL will moderate the flash output to prevent blowout. I have the benefit of LCD review and find this works best.

I've learnt NOT to use a bounce card in places with high ceilings. Very inconsistent. In places with a low white ceiling it works great.
 

Wolfgang

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#8
what i tried, with the S602 is basicaly set the ISo to 400, aperture to 2.8, shutter to 1/200, use an omni bounce but the main key is to tilt the flsh towards the ceiling.. abit trouble-some in the sense that if you switch orientation from landscape to portrait grip (hope i'm making sense here), you'll need to adjust the flash to aim towards the ceiling...

This should work. :)
 

Bluestrike

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#9
Originally posted by StreetShooter
In such situations, I would use Av mode to capture the ambient lighting, and use the flash pointed directly forward as a fill-in flash (ie no bouncing or anything). The E-TTL will moderate the flash output to prevent blowout. I have the benefit of LCD review and find this works best.

I've learnt NOT to use a bounce card in places with high ceilings. Very inconsistent. In places with a low white ceiling it works great.
That what I do for flashes.....

I oso uses the omni-bouce for direct if the subject is close to the camera. Abt 1-2m other then that, I'll take off the "tuberware"
 

tomshen

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#10
Partial metering (or spot metering if yr cam supports), FEL if you have time (would give u more consistent results). OK here is my usual setting FYI:

High Ceiling:
1. Evalutive metering: Tv, 1/30~60s with wide angle, flash -1~+1/3 depending on background;
2. Partial metering: lock the face if u can, Tv 1/30~60s with wide angle, flash at 0 or -1/3 (dark face). If u have no time to FEL and bridge in white, +1/3~+2/3 flash.
 

Zerstorer

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#11
How about switching flash to manual mode and select the lowest manual setting e.g 1/64 and see if it works fine. If so, you can then vary the flash power with distance if needed.
 

Zerstorer

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#12
Or you can also attempt to use a less relfective material for the bounce card, matt surface or even a neutral grey card as it would be less reflective.
 

Wai

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#14
Originally posted by StreetShooter
In such situations, I would use Av mode to capture the ambient lighting, and use the flash pointed directly forward as a fill-in flash (ie no bouncing or anything). The E-TTL will moderate the flash output to prevent blowout. I have the benefit of LCD review and find this works best.

I've learnt NOT to use a bounce card in places with high ceilings. Very inconsistent. In places with a low white ceiling it works great.
same here....
 

Java_Guru

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#17
Originally posted by StreetShooter
In such situations, I would use Av mode to capture the ambient lighting, and use the flash pointed directly forward as a fill-in flash (ie no bouncing or anything). The E-TTL will moderate the flash output to prevent blowout. I have the benefit of LCD review and find this works best.

I've learnt NOT to use a bounce card in places with high ceilings. Very inconsistent. In places with a low white ceiling it works great.
Almost exactly the same technique on my D60 except I will use the bounce card. With the bounce card, the guide number on the flash gun will auto adjust and up the power output.

Be aware of your minimum and maximum distance (after using the bounce card and from DSLR mutliplier). Use from experience.

Some wedding photos i took for my friend -> http://www.lionelsiau.com/photo/weddingofchrisandelsa

PS : Don't usually fool around with flash compensation as the results acutally are erratic and ETTL will get confused when changing scenes. But if same scene exactly, u can try to use flash compensation.
 

Tweek

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#18
Ok did some quick experimentations...

Tomshen's suggestion of using Tv has a good rationale, to control a good shutter speed. But I feel that one drawback is that if the minimum aperture is exceeded and the F number flashes, the camera doesn't say how much underexposure it'll be if the shot is taken. Not a big problem actually.

The idea of using Av, then fire with a head-on flash works well too, after simple experimentations in my room. From 1 to 1.5m away at ISO800, the exposure is almost always perfect. Any closer, I tried tilting the head up a little, and the exposure was fine too. Perhaps the result will be better if I try using a bounce card.

Just curious, I've seen many people use fill-flash with flash ev -1 to -2 for indoor shots, meaning in Av mode and E-TTL flash. But with your recommendations and confirmation in my own attempts, letting flash ev remain at 0 works well too. So what's the difference? Theoretically the difference is in the fill-flash ratio but physically I really don't see much difference in the final result.

In my normal-lit room, with ISO800, I could only get about 1/10s at f4 with Av. Underexposing ambient to -2 ev and using straight on flash, I can only get 1/40s which is just about nice for handheld. How did you guys achieve that with ISO400 (what most of you recommended)?

I also learn that omnibounce is a nuisance a lot of the time, esp of the fact that you lose about 2 stops of flash, and that it screws up ETTL sometimes. Maybe I haven't understand it enough to use it well, but perhaps ckiang is right, a bounce card may be easier. I'll make one for myself soon.
 

Java_Guru

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#19
Originally posted by Tweek
Ok did some quick experimentations...

Just curious, I've seen many people use fill-flash with flash ev -1 to -2 for indoor shots, meaning in Av mode and E-TTL flash. But with your recommendations and confirmation in my own attempts, letting flash ev remain at 0 works well too. So what's the difference? Theoretically the difference is in the fill-flash ratio but physically I really don't see much difference in the final result.
exactly. From my own testing, I would rather master ETTL and fool around with the flash compensation. I even don't touch the exposure compensation unless I consistently notice a requirement for that particular setting.

If u dial in flash or exposure compensation, u are actually allowing both auto ETTL and the compensation to interact. Double compensation. The results are erratic usually.

Curiously, what are u shooting at 1/10 - 1/30 sec? Won't the shots be blur esp with people/motion?
 

victor

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#20
Hi

A very interesting thread ! I am pretty new to flash photography so can I ask u guys rather simple questions like :

1) what's min flash distance ?

2) If we use Av in a dim room, won't the shutter speed sometimes be too slow for hand holding ?

Thx.
 

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