Every summer I face the challenge of remembering AE Lock and FEL implications, ? 5DS R.

Apologies but as a 98% manual studio shooter, every summer I find I am a little confused regarding AE lock, and fill flash.
Would some kind expert confirm or tell me the best way to expose for the background and also using ETTL2 fill flash for the face of the subject.
My process
If in Manual mode, use partial metering and point the centre of the lens at the area of landscape I would chose to expose the scene for. And then adjust the shutter to keep F8 to F11 (my lenses sweet spot.). Then point the centre of the viewfinder, at the subjects face and set FEL. Then shoot.
There is no need to use AEL, as I effectively lock this anyway by adjusting the eposure and being in manual mode its effectively locked.
I am pretty sure FEL uses a spot metering mode to set the flash expose in ETTL2. Is this right.

If this is right then I can pretty much survive tomorrow.

Other than if its bright, I may have to use HSS ( not so keen on that as it really gobbles flash power, but with 4x 600s I should have enough). I also do have 2 other manual YN560s that are just triggerred off the main flash for exposing some background areas if needed.

It appears to me if one sets HSS, and the determined sync speed is lower than 1/200 (the 5DSRs max sync speed) then HSS wont operate and flash will be normal. But is this right? I never did understand this, because if so, why not always set HSS?

OK so thats survival mode stuff for tomorrow solved? But what if I want to use AV or TV mode. Can I use AELock and FEL at the same time?
And if so is this following logic for AV mode right?
Set metering to partial, in this mode exposure is not locked until the picture is taken, ( half pressing the shutter only locks exposure in Evaluative mode if focus is achieved?) , so I have to use AEL?
When using AEL I must point the centre of the lens on the area I want exposure set for, as only in Evaluative mode will it lock expose on the selected AF point.
Assuming I have effectively locked the correct exposure for the background ... Can I then point the centre of the lens at the face of the subject and use FEL to achieve the correct level of flash in ETTL2 for the subjects face.
I guess the summary question is in AV or TV mode, can I use both AEL and FEL at the same time?


Other ?
If I used Av mode, and Evaluative metering then I must set AEL at the manually selected AF point, that achieves focus with a 1/2 presssed shutter button, rather than the centre of the lens.
Is this right ?

In Evaluative mode, it appears that not only is exposure locked with a 1/2 shutter press but also focus? Whereas the in other metering modes the exposure Is actually set when the image is taken, ie not on the 1/2 shutter press?

Am I thick or is this quite a lot to retain in ones head?

[Basic gear .. 5DS R, Canon STE3 Commander, 4x 600EX RTs with 1m shoot through brollies].
All scenarios are in one shot AF)

Cameras that have a button that can be programmed to execute FEL, or has a dedicated FEL button, can use both AEL and FEL at the same time.
Simpler cameras, which have a * button only, will implement AEL on that button when no flash is active, but revert to FEL if there's a flash in use.

FEL is always spot metering, that's correct.

When combining One Shot AF with evaluative metering, you get focus and exposure lock on half press. When you think about it, you realize that this has to be like that.
All other combinations of focus and metering modes will give exposure metering at the moment of taking the picture, unless you use AEL explicitly.

AEL when using evaluative metering should normally be executed with the active AF point on the target. This is of interest only when using Servo AF, as it's implied when using One Shot AF.

And yes, if you don't remember this when you wake up in the morning, you're thick!

A very extensive read about using Canon Flash can be found here:

http://photonotes.org/​articles/eos-flash/

Very technical and informative.

apersson850 wrote in post #18095838
Cameras that have a button that can be programmed to execute FEL, or has a dedicated FEL button, can use both AEL and FEL at the same time.
Simpler cameras, which have a * button only, will implement AEL on that button when no flash is active, but revert to FEL if there's a flash in use.

FEL is always spot metering, that's correct.

When combining One Shot AF with evaluative metering, you get focus and exposure lock on half press. When you think about it, you realize that this has to be like that.
All other combinations of focus and metering modes will give exposure metering at the moment of taking the picture, unless you use AEL explicitly.

AEL when using evaluative metering should normally be executed with the active AF point on the target. This is of interest only when using Servo AF, as it's implied when using One Shot AF.

And yes, if you don't remember this when you wake up in the morning, you're thick!

Feeling pretty thick, lol
But appreciate the info

Canon Amateur wrote in post #18095859
A very extensive read about using Canon Flash can be found here:

http://photonotes.org/​articles/eos-flash/

Very technical and informative.

Thanks