confused on something

went to a lighting class with A master photog last week. awesome experience as only 3 people showed up for this class. we basically had 4 hours in her studio having her show us how she does things,lighting and posing

here is the question.

she only shot in manual mode and her lights in the studio were set at f/11. she used a 5d ,an 85L and the 24-105L for the demonstrations. all shots were shot under 200 shutter speed. many were in the 30-60 range inside and up to 125. we shot inside and outside.

when we were outside she frequently had to shutter speed at or near 200 for MORE DETAIL AND COLOR in the background. im thinking maybe i didnt hear this right or im confused. what does as faster shutter speed with flash say at 125-200 do to the color and background as opposed to 30-125??? havnt tried it yet since the class and i think im probably misunderstanding some of her points.

thanks in advance

Assuming the flash could synchronise with the shutter at any speed the only difference the shutter speed makes when the flash is the main light is the brightness of the background. The brighter it is the more color there'd be, I expect. I suspect she misspoke when she said she uses 1/200th for more detail and color.

In the studio it usually makes no difference whatsoever if the shutter is 1/10th or 1/200th, assuming again the flash can sync properly. I was recently shooting at ISO100 F11 1/125th, when the lights didn't fire the frame was complete black. Even dropping the shutter to 1/10th there was only a vauge outline of anything. So shutter speed is irrelevant.

tim wrote in post #6193084
Assuming the flash could synchronise with the shutter at any speed the only difference the shutter speed makes when the flash is the main light is the brightness of the background. The brighter it is the more color there'd be, I expect. I suspect she misspoke when she said she uses 1/200th for more detail and color.

In the studio it usually makes no difference whatsoever if the shutter is 1/10th or 1/200th, assuming again the flash can sync properly. I was recently shooting at ISO100 F11 1/125th, when the lights didn't fire the frame was complete black. Even dropping the shutter to 1/10th there was only a vauge outline of anything. So shutter speed is irrelevant.

Well, if she was deliberately underexposing the ambient scene, that would help to improve color saturation (particularly of the sky) and then using flash she could expose the subject at the usual levels! For example, if using ISO 100, the fundamental Sunny 16 exposure could be 1/100 f/16, so 1/200 f/16 would underexpose the ambient by -1EV, then the flash at full power might permit the exposure of the subject via the flash at f/16, too.

Yeah there is that. Given the OP said "background" I didn't think "sky".

now that ive heard the work SKY,, that may clear some things up. like i say,,im just a tad confused. when we were outdoors, she definately had a faster shutter speed(200-250 ??) because she didnt want the background to be washed out and wanted more color. we were talking about shooting towards the sky at magic hour,lakes,,ect. sooo,, outdoors,,with a flash,,magic hour,,use higher shutter speeds 200 v/s 50-80 and why i havnt experimented with yet,,,but i will this weekend. anything else i should be aware of

inside in studio light im thinking under 125 depending on what im going to shoot.

thanks guys for trying to help clear this up,,advise always appreciated

When you are shooting with flash the way to control ambient light is with the shutter speed. If you think of flash photography as taking two pictures it makes more sense. The first image is the ambient image metered with the camera for ambient light (underexposing a bright day a bit brings out the colors) and the second is the flash image which is either metered with a flash meter or via ETTL with Canon EX capable flash units and only covers the subject being hit by the flash.

slowdad wrote in post #6195540
now that ive heard the work SKY,, that may clear some things up. like i say,,im just a tad confused. when we were outdoors, she definately had a faster shutter speed(200-250 ??) because she didnt want the background to be washed out and wanted more color. we were talking about shooting towards the sky at magic hour,lakes,,ect. sooo,, outdoors,,with a flash,,magic hour,,use higher shutter speeds 200 v/s 50-80 and why i havnt experimented with yet,,,but i will this weekend. anything else i should be aware of

inside in studio light im thinking under 125 depending on what im going to shoot.

thanks guys for trying to help clear this up,,advise always appreciated

As Titus213 stated, the 'two exposures in one' is the key concept to take away, for indepedently altering different parts of the scene. The use of 1/60 vs 1/250 is inherently nothing magical, it is in the reduction of the amount of light to that aspect of the scene, the portion exposed by ambient light.

OK, now I'm confused. So how do you independently meter for both ambient and subject (flash) in ETTL mode? If I use the camera to meter the ambient and set shutter speed accordingly, how do I set the flash intensity/duration for the subjects without doing it manually? I guess I'm asking, because I've never tried it, can I do a flash exposure meter and lock and then an ambient meter and lock, and then take the picture and have both set correctly?

sdipirro wrote in post #6198057
OK, now I'm confused. So how do you independently meter for both ambient and subject (flash) in ETTL mode? If I use the camera to meter the ambient and set shutter speed accordingly, how do I set the flash intensity/duration for the subjects without doing it manually? I guess I'm asking, because I've never tried it, can I do a flash exposure meter and lock and then an ambient meter and lock, and then take the picture and have both set correctly?

Here is an example which is generic (not dependent upon ETTL)...
1. meter the ambient light, get a reading like 1/400 f/8
2. convert the reading from #1 into one which is shutter speed-compatible with your flash unit...e.g. 1/200 f/11 (I am ignoring the availability of HSS for this example, especially since no studio flashes support HSS!)
3. meter just the flash exposure with a flashmeter, e.g. f/16
4. Now you have two exposures, 1/200 f/11 is ambient, and f/16 is flash
5. Adjust #4 to balance the two halves of the exposure.

• for example, to underexpose the ambient relative to the flash, simply set 1/200 f/16 on the camera and shoot, with the flash.
  
• for example, to overexpose the ambient relative to the flash, if you increase f/stop to f/16 (for the flash), you need to compensate to shutter speed 1/100 simply to achieve equal exposure. Instead, change to f/16 and 1/50

I'm still learning this, but I'll take a stab at it. The "two pictures" is accurate. Shooting flash, you have 4 adjustments available: shutter speed, aperture, ISO, and flash power. Shutter speed does not affect the flash and the flash power does not affect the ambient. Aperture and ISO affect both. So, in general, you adjust the ambient with shutter speed and flash with flash power. If you run out of adjustments, you can change aperture or ISO, but you will affect both pictues and some adjustments will need to be made.

She probably tried to balance ambient & flash. It's a combo thing, or highspeed sync for digital if they want to keep their Aperture constant on a sunny day.

lefturn99 wrote in post #6198567
...snip...Shutter speed does not affect the flash and the flash power does not affect the ambient...snip...

Partially correct. Flash can overpower ambient if you have enough power, and depends on the sync speed of your flash with your camera. Most works up to 1/250 only, unless you have the option to turn on high speed sync or you shoot range finders.

Follow along the 2 exposure analogy:
You need to meter the background ambient, then balance the foreground with the background using your flash to prevent blown outs.

Simple example: sunny day and you want to keep your sky / clouds clear & crisp instead of a blob of white. You'll meter off the sky, then dial your flash up to match it for your subject (also called fill-flash). That's what your teacher was probably trying to do.

Fairly simple to do if you work with Canon. Here's the lazy way with eTTL.
Use manual, spot meter of the sky, dial up your Aperture or Shutter to get an appropriate exposure (I normally underexpose this by 1/2 or 1 stop), then let the flash do the fill using eTTL. Adjust the flash output to your liking for your subject.

Here's an even lazier way...if it works. I guess that's what I'm asking, although I could probably just find out through experimentation. Suppose you have the background sky setting with puffy clouds that you want exposed correctly, and a subject in front of you who is partially in the shadows. Here's what I'm wondering. If I shoot in AE mode with the aperture I want, meter off the background, hit AE to lock the exposure, recompose on my subject with flash in high-sync mode, press shutter button halfway, what will the camera use for exposure information to decide on the flash output (ETTL mode)? Will it use the locked exposure information or recompute for the subject when I press the shutter halfway?

Lots of good information here. I don't know if this will help anyone but here's how I set my exposure for this photo.

good info everyone. im going out this weekend with my lightmeter and im gonna to do some spearmenting:p