Canon 5DmkIV exposure question

Is there anyway I can be in manual and have the Auto ISO work while using external 600 speed lite.
Basically can I set say 1/125 or 1/200 so flash is not in high speed sync and aperture F2.8 and have the Auto ISO work? I tried this and the ISO ALWAYS went to 400. It was not the correct exposure. Is there settings on camera or flash that allows this?

Auto-ISO with flash will always go to ISO 400. Every Canon camera I've ever had does that. Manual exposure with auto-ISO and ETTL flash is a far cry from manual.

If you have the flash turned on, and a manual over-exposure dialed in, you're going to get over-exposure. You do realize that manual ambient and flash are two entirely separate and distinct exposure right? Perhaps an example, with intact EXIF will help us help you.

I was on another site where someone was having this exact same issue so I'm interested. I've never used auto ISO for anything. Why does it default to 400? Why is that the base number and not 200 or 800?

Auto ISO with flash will always default to 400. Why 400 was chosen, I have no idea. Perhaps it was considered a good compromise.

Interesting. Thanks.

The reasons for not having the ISO still be "automatic" with flash, are all about how ISO effects a flash image. It can be DRAMATIC. Like two entirely different images going from ISO 200 up to ISO 1600,..

eg: A person standing in front of a black background with only the subject lit, vs. a subject in front of a very visible well lit background.

Which did the photographer want? Auto ISO mixed with flash would take that choice away.

So here is what I am looking for.
Lets say I am using 135 F/2 lens.
I am outside
Subject is in the shade
Let's use sunny 16 rule for shade so
1/125 (close enough to 1/100) at F 5.6 ISO 100
So I want to shoot at F/2
That's 3 stops from 5.6
So 1/125=1/1000 at F2
If I want to use Fill Flash for catch lights providing I don't have any other ways but natural lighting
I have to put the speedlight in high speed sync (that reduces flash power) and if I use a flash card like a Rogue bender in bounce there doesn't seem to be enough flash as the catchlights are barely visible.
What is the solution when you can't bring other equipment along and you want some fill and/or catchlights??

Post a photo with EXIF, including all camera and flash settings.

The reason Auto ISO gets fixed when used with a flash is because it has to.
If you are using the flash with a manual setting, then you have to know the ISO beforehand, or you don't know how to set the flash.
If you are using E-TTL II, then you run into the conflict that you get a measurement for ambient light first, giving a certain combination you can see in the viewfinder. Aperture, time and ISO, it's all there. Then you press the trigger button and the camera finds out that the ISO chosen doesn't work with the flash. It's either too high or too low. Thus the ISO has to be changed, but there's no time to tell the user that the camera has changed one of the conditions used to determine the proper time and aperture for the ambient light.

Thus Canon has chosen to give you fixed value for ISO, in case (to be brutally correct) you are stupid enough to use Auto ISO with flash. They give you ISO 400 for all cases except if you set the camera to P mode, thus probably indicating you want as much automation as possible. In that case you get ISO 400 with the flash aimed directly at the subject, but ISO 1600 if bouncing the flash.

Anyway, I can't see how auto ISO would have solved the issue you outlined above.

You have 1/125 s, f/5.6 and ISO 100, but you want to use f/2. Thus you have to go to 1/1000 s, which in turn requires high speed flash sync.

I fail to see how auto ISO would have solved that problem for you? Aren't you looking for the auto ISO function to solve an issue it can't, even if one would disregard the problems with auto ISO with flash I outlined above?

apersson850 wrote in post #18223885
The reason Auto ISO gets fixed when used with a flash is because it has to.
If you are using the flash with a manual setting, then you have to know the ISO beforehand, or you don't know how to set the flash.
If you are using E-TTL II, then you run into the conflict that you get a measurement for ambient light first, giving a certain combination you can see in the viewfinder. Aperture, time and ISO, it's all there. Then you press the trigger button and the camera finds out that the ISO chosen doesn't work with the flash. It's either too high or too low. Thus the ISO has to be changed, but there's no time to tell the user that the camera has changed one of the conditions used to determine the proper time and aperture for the ambient light.

Thus Canon has chosen to give you fixed value for ISO, in case (to be brutally correct) you are stupid enough to use Auto ISO with flash. They give you ISO 400 for all cases except if you set the camera to P mode, thus probably indicating you want as much automation as possible. In that case you get ISO 400 with the flash aimed directly at the subject, but ISO 1600 if bouncing the flash.

Anyway, I can't see how auto ISO would have solved the issue you outlined above.

You have 1/125 s, f/5.6 and ISO 100, but you want to use f/2. Thus you have to go to 1/1000 s, which in turn requires high speed flash sync.

I fail to see how auto ISO would have solved that problem for you? Aren't you looking for the auto ISO function to solve an issue it can't, even if one would disregard the problems with auto ISO with flash I outlined above?

Good explanation.

gqllc007 wrote in post #18223767
So here is what I am looking for.
Lets say I am using 135 F/2 lens.
I am outside
Subject is in the shade
Let's use sunny 16 rule for shade so
1/125 (close enough to 1/100) at F 5.6 ISO 100
So I want to shoot at F/2
That's 3 stops from 5.6
So 1/125=1/1000 at F2
If I want to use Fill Flash for catch lights providing I don't have any other ways but natural lighting
I have to put the speedlight in high speed sync (that reduces flash power) and if I use a flash card like a Rogue bender in bounce there doesn't seem to be enough flash as the catchlights are barely visible.
What is the solution when you can't bring other equipment along and you want some fill and/or catchlights??

If you want to use F/2 and not use HSS then you wiil need to use a ND filter to keep your shutter speed down...this will avoid the need for HSS and will give you more power available from your speedlight.

gqllc007 wrote in post #18223767
So here is what I am looking for.
Lets say I am using 135 F/2 lens.
I am outside
Subject is in the shade
Let's use sunny 16 rule for shade so
1/125 (close enough to 1/100) at F 5.6 ISO 100
So I want to shoot at F/2
That's 3 stops from 5.6
So 1/125=1/1000 at F2
If I want to use Fill Flash for catch lights providing I don't have any other ways but natural lighting
I have to put the speedlight in high speed sync (that reduces flash power) and if I use a flash card like a Rogue bender in bounce there doesn't seem to be enough flash as the catchlights are barely visible.
What is the solution when you can't bring other equipment along and you want some fill and/or catchlights??

I don't know what that has to do with auto iso with flash?
Is this an actual question that is unrelated to our current topic? (solution being ND filter as Don mentions)

Or are you trying to make a point which is going over my head?

No not trying to post something irrelevant lol.
I accepted ISO 400 in M mode and the explanation makes great sense
I had totally brain farted on ND filters so instead of posting a new thread I posted my question in here. I should have stated that first! My bad. Again I completely forgot about my ND filters

Putting on an ND filter will eliminate the need for high speed sync, provided the filter is dense enough. But it will still require (in this particular example) four times as much power from the flash, if we presume we go down from 1/1000 to 1/250 to avoid high speed sync demand.
It's probably still better than using HSS, but it's not for free, so to speak. Actually the difference may be so small that using HSS and not bothering putting on the ND filter may still be the sensible remedy, at least in some cases.

I haven't seen any mention of upping the flash power, either through manual flash or Flash Exposure Compensation...?

I'm not a flash expert, but would that be a useful consideration in using fill light with a shady subject, if not using an ND filter?