seeking some strobist advice guys :)

[lpphotography]

Hi people, I am new to this forum but seeking some (maybe obvious) advice.
I have been doing studio and outdoors fashion shoots, and have experimented in depth with off camera flash outdoors. having just aquired a flash meter im in need of advice..
if outdoors, my in-camera meter had metered the ambient for , lets say, 1/200 at F8 (iso 100). I would then want to underexpose the background, so i may (for sake of this post) drop to F11 or any other narrower aperture..
my question is basically, using a basic SB900 off camera and my flash meter, would i need to meter so the flash was at F8 or at the underexposed F11 (which would match the background ambient)? do you meter the flash at the original aperture (before underexposing by a stop or two) the ambient light gave the camera, or would i now match the F stop to match the F stop of the under exposed background?
I am sorry if the answer is silly and obvious, but something is keeping m stumped..
thanks for your help guys

[SpeedGraphicMan]

You would set your flash to render the foreground at f8.

This would darken the background... Setting your camera and flash for f11 would just give you a 1 stop underexposed shot!

[lpphotography]

thank you for clearing that up , and the quick reply., I was concerned about the change in F stop (to underexpose background) would also change flash exposure.. but i think I am just confusing myself. So would you recommend , as a rule, that after underexposing the ambient using F stop, I should then meter the flash to match the original Ambient F stop? thank you again for helping

[lpphotography]

can i also add one more question? .. If i have already metered the ambient (and underexposed to taste), would i need to just point the flash meter towards the flash to get the correct F8 flash power? or do i still need to do the "under the chin and facing the lens" flash meter placement?

[SpeedGraphicMan]

Originally Posted by lpphotography

So would you recommend , as a rule, that after underexposing the ambient using F stop, I should then meter the flash to match the original Ambient F stop? thank you again for helping

If that is the effect you want, yes!

You could underexpose the background even more if you wish (2 stops etc).

It is called "Overpowering the sun".
Lenses with "Leaf Shutters" allow you to just increase your shutter speed instead because they are not limited to "Sync Speed" like a focal plane shutter is.

I.E. Your ambient meter reading is f8 125...
You expose at f8 250, etc.

Most modern dslr cameras have fairly high sync speeds (250, 125, etc).
So you could try that also!

This might give you more info...
Overpowering the Sun Technique for Fashion and Portraits

As for your metering question, it would depend on whether your are using an incident or reflective metering.

Incident metering would have you place the meter near the subject and point it towards the flash...

[lpphotography]

ahhh! thank you so much that really cleared it up for me , i really appreciate it and i will check out that link

[Sailor Blue]

Originally Posted by SpeedGraphicMan

Incident metering would have you place the meter near the subject and point it towards the flash...

Sorry, but I disagree.

I answered the same question in lpphotography's other post.

The dome mimics the human head so you place it under the chin to represent the human face and so it will be illuminated the same as the face. You then point the dome right at the camera.

It is only if you are metering lights that don't illuminate the face that you point the meter at the lights. One example would be a hair light.

[lpphotography]

that makes sense, i will experiment with that and see what results i get. thank you both for your help

[jerryph]

Originally Posted by SpeedGraphicMan

You would set your flash to render the foreground at f8.

This would darken the background... Setting your camera and flash for f11 would just give you a 1 stop underexposed shot!

Uhm, no. If ambient is set to F/8 at 1/200th and the goal is to underexpose the background by one stop, you do that by increasing F/stop (that's one of 4 ways... HSS, ND filters and HyperSync being the other 3), then increase the flash power by 1 stop and the background is 1 stop darker and the subject is properly lit.

Setting camera to F/8 means you are setting the camera to the same as ambient and not lowering the ambient by a stop. The big issue is flash power, that is going to be your limiting item. Multiple flashes or studio heads are the answer.

BTW, the OP used the word, but are they visiting the site? Strobist and the strobist flickr site are where all this info is and has been for several years now.

There is something called the "Sunny 16 Rule" back from the film days. It is basically saying that on a clear sunny day, set the camera to 1/125th and set the aperture to F/16 and your exposures should be close. The problem is that at F/16, everything is in focus, what if you wanted to shoot at F/4? Then you need to cut down the light coming into the camera, either via increased shutter speed or ND filters.

Each, however, has it's own issues. Smaller apertures make everything in focus. ND filters cost money and introduce possible loss of sharpness or add colour casts. One normally cannot increase shutter speed past our max sync speed... until recently (like within the last 5-6 years recently). Today, with the right equipment one can use high shutter speeds, right up to 1/8000th and effectively get decent lighting. I am not talking about HSS which does work with high shutter speeds, but kills light power so much that anything beyond 2 feet is basically not possible to light.

My favorites are the ND filter and lately I have done a nice amount with HyperSync, which is a lot of fun.

A little info I gathered while playing with HyperSync:

http://jerryphpics.blogspot.ca/2012/...hypersync.html

http://jerryphpics.blogspot.ca/2012/...ic-how-to.html

[shuttereye]

Originally Posted by jerryph

Uhm, no. If ambient is set to F/8 at 1/200th and the goal is to underexpose the background by one stop, you do that by increasing F/stop (that's one of 4 ways... HSS, ND filters and HyperSync being the other 3), then increase the flash power by 1 stop and the background is 1 stop darker and the subject is properly lit.

Setting camera to F/8 means you are setting the camera to the same as ambient and not lowering the ambient by a stop. The big issue is flash power, that is going to be your limiting item. Multiple flashes or studio heads are the answer.

BTW, the OP used the word, but are they visiting the site? Strobist and the strobist flickr site are where all this info is and has been for several years now.

There is something called the "Sunny 16 Rule" back from the film days. It is basically saying that on a clear sunny day, set the camera to 1/125th and set the aperture to F/16 and your exposures should be close. The problem is that at F/16, everything is in focus, what if you wanted to shoot at F/4? Then you need to cut down the light coming into the camera, either via increased shutter speed or ND filters.

Each, however, has it's own issues. Smaller apertures make everything in focus. ND filters cost money and introduce possible loss of sharpness or add colour casts. One normally cannot increase shutter speed past our max sync speed... until recently (like within the last 5-6 years recently). Today, with the right equipment one can use high shutter speeds, right up to 1/8000th and effectively get decent lighting. I am not talking about HSS which does work with high shutter speeds, but kills light power so much that anything beyond 2 feet is basically not possible to light.

My favorites are the ND filter and lately I have done a nice amount with HyperSync, which is a lot of fun.

A little info I gathered while playing with HyperSync:

The Jerry Blog!: Sunny 16 and PW's Hypersync

The Jerry Blog!: HyperSync, the basic How-To

One thing that Jerry left out about the sunny 16 is that it's for ISO 100 if you have a camera that only goes down to 200 your going to have even a harder time cutting light....but if you can drop down to 50 it's going to help.
As far as ND filters if you are serious about using them you are going to spend some good money to get filters that degrade the image as little as possible. If you're just going to play around with them a little then you can get some rather cheap sets (that can help you decide if they are for you and if you want to spend the $$ or not)