Off camera flash

Hi all.

I would be grateful for a little advice and guidance as i venture in to the world of off camera flash.

I have decided that this is the year for me to take the next step and learn a little more about flash, especially off camera to try and get the most from my wedding pics.

I am using Canon kit and currently have the 5D Mark 2 (yes the noise is as good as they say) and 2x 580 EX II speedlites.

Lets say i have a B&G stood in the church lit from behind by a large stained glass window. You know the scene, we all do this pic.
My thoughts are that i meter the entire scene and maybe close up by one stop to make sure i don't blow out the beautiful window. Then i use the flash to light the couple.
The flash is going to be in e-ttl mode thanks to the canon transmitter.

Now, i have a couple of questions.

Lets say i am in AV mode, to stop down i will just adjust the exposure compensation by one stop. BUT will this cause the flash to under expose the couple by one stop too? Or will the ettl still try to light the couple to the correct exposure?
If it does underexpose ( i think it will ) do i just up the FEC by one stop to compensate?
does it work like this?

OR

If i was in fully manual and the scene metered to f8 and i then stopped down to f11 (for the window) would the flash guess that i am trying to underexpose and thus do the same to the B&G with the flash?


I am hoping the wireless ettl will work well and hopefully negate the need to constant adjusting of flash power but i am not too sure how it really knows what you are trying to achieve.

You are making things more complicated than it should be.
I do this type of shot manually as I don't trust ttl and it tends to make things more complicated.

You'd need to meter twice, one for the background (stained glass) and one for the couple. Assuming the glass is brighter than the B&G:

1. If you want an evenly lit scene, expose for the glass, use your flash to fill / balance the B&G.
2. If you want a silhouette couple, under expose the B&G a couple of stops.

Jonny wrote in post #7205728
Hi all.

I would be grateful for a little advice and guidance as i venture in to the world of off camera flash.

I have decided that this is the year for me to take the next step and learn a little more about flash, especially off camera to try and get the most from my wedding pics.

I am using Canon kit and currently have the 5D Mark 2 (yes the noise is as good as they say) and 2x 580 EX II speedlites.

Lets say i have a B&G stood in the church lit from behind by a large stained glass window. You know the scene, we all do this pic.
My thoughts are that i meter the entire scene and maybe close up by one stop to make sure i don't blow out the beautiful window. Then i use the flash to light the couple.
The flash is going to be in e-ttl mode thanks to the canon transmitter.

Now, i have a couple of questions.

Lets say i am in AV mode, to stop down i will just adjust the exposure compensation by one stop. BUT will this cause the flash to under expose the couple by one stop too? Or will the ettl still try to light the couple to the correct exposure?
If it does underexpose ( i think it will ) do i just up the FEC by one stop to compensate?
does it work like this?

OR

If i was in fully manual and the scene metered to f8 and i then stopped down to f11 (for the window) would the flash guess that i am trying to underexpose and thus do the same to the B&G with the flash?


I am hoping the wireless ettl will work well and hopefully negate the need to constant adjusting of flash power but i am not too sure how it really knows what you are trying to achieve.

viet wrote in post #7205794
You are making things more complicated than it should be.
I do this type of shot manually as I don't trust ttl and it tends to make things more complicated.

You'd need to meter twice, one for the background (stained glass) and one for the couple. Assuming the glass is brighter than the B&G:

1. If you want an evenly lit scene, expose for the glass, use your flash to fill / balance the B&G.
2. If you want a silhouette couple, under expose the B&G a couple of stops.

So when you say 'manually' do you mean:

Meter the window and then adjust the flash manually, ie: 1/1, 1/2, 1/4 etc....
Does this take long to get the balance right? i am assuming there will be a lot of + and - before you get the perfect balance?

Jonny wrote in post #7205823
So when you say 'manually' do you mean:

Meter the window and then adjust the flash manually, ie: 1/1, 1/2, 1/4 etc....
Does this take long to get the balance right? i am assuming there will be a lot of + and - before you get the perfect balance?

Yup, that's what I meant by manual. It shouldn't take more than a couple of test shots to get it right. If you know your flash power at a set distance, it takes one test shot to get it right. Here's what I mean.

Let say we are photographing your B&G at a distance of 10 feet, and you know at this distance, your flash will properly expose them at 1/4 power @ 400 ISO & F4, then it only becomes a matter of adjusting your flash power up or down to match the glass, or if you don't want to adjust your flash, then move it back or forward.

http://photonotes.org/​articles/eos-flash/ (as listed in the stickies for this section) is your friend. Read it, read it again, go out and shoot with a flash some, then read it again. It will all make sense at some point in there, and sooner or later becomes automagic.