Auto iso: why does my speedlight choose ISO400 ?

WHY...

WHY IN THE WORLD WOULD ANYONE USE AUTO-ISO?

ISO, is the one variable that I would want to control not let the camera control it for me.

I am really asking this question because, perhaps there is something I have missed...

RPCrowe wrote in post #13096928
WHY IN THE WORLD WOULD ANYONE USE AUTO-ISO?

ISO, is the one variable that I would want to control not let the camera control it for me.

I am really asking this question because, perhaps there is something I have missed...

I don't think you've missed anything, at least in my opinion. If auto ISO was fully programmable I would use it, otherwise I don't shoot anything where I need the current implementation. I not saying others may have a use for it.

RPCrowe wrote in post #13096928
WHY IN THE WORLD WOULD ANYONE USE AUTO-ISO?

ISO, is the one variable that I would want to control not let the camera control it for me.

I am really asking this question because, perhaps there is something I have missed...

If I could pick shutter speed and f/stop, and the camera would then choose the right ISO to permit me to use that specific combination even as the light changed up or down in intensity, then Auto ISO capability has value...since I monitor camera choices for f/stop and shutter speed, even when I relinquish control of one of the settings, I have not totally given up creative control. Similarly, I would continue to monitor what the camera would choose for ISO value, and decide if it an acceptable value (to me) or not.

But since Auto ISO does not do what I described, it is of no current value at all to me.

RPCrowe wrote in post #13096928
WHY IN THE WORLD WOULD ANYONE USE AUTO-ISO? ISO, is the one variable that I would want to control not let the camera control it for me.

For the same reason someone might want Av mode or Tv mode.

Aperture priority is really aperture and ISO priority. You let the camera choose the shutter speed.

Shutter priority is really shutter and ISO priority. You let the camera choose the aperture.

What's missing is an aperture and shutter priority mode, where the camera chooses the ISO.

I know what aperture I need for the DOF I want. I know what shutter speed I need to avoid motion blur. If I'm going to give the camera any control at all, I would rather have it choose the ISO than let it choose one of the other two variables.

ISO has less impact on image quality and is the only corner of the exposure triangle that doesn't affect DOF or motion blur.

Depends on your settings.

If you're on Av, Auto-ISO will work by adjusting your ISO to the LOWEST POSSIBLE while keeping your shutter speed to 1/focal length. For example; if you're zoomed in at 50mm, Auto-ISO will select the ISO that you need in order to keep your shutter speed at 1/60.

In Tv mode, Auto ISO will select the proper ISO that will still expose the camera correctly while the lens is wide open during darker conditions, and stopped down in brighter conditions.

If you're on M (Which i suspect that you are), Auto-ISO will automatically select ISO400 REGARDLESS OF EXPOSURE/METERING.

Also, please not that your camera meters the exposure WITHOUT the flash in the equation.

Auto ISO is a pretty useful function for those who knows how it works.

emdzey01 wrote in post #13108665
If you're on Av, Auto-ISO will work by adjusting your ISO to the LOWEST POSSIBLE while keeping your shutter speed to 1/focal length. For example; if you're zoomed in at 50mm, Auto-ISO will select the ISO that you need in order to keep your shutter speed at 1/60....Auto ISO is a pretty useful function for those who knows how it works.

If that first statement were true, I would not have seen this happen...

•in low light and f/4.5 in Av mode it suggests shutter of 0"4 and ISO value of 800...why the heck didn't it selected ISO 1600 or 3200 instead, permitting a more handholdable shutter speed?!

•in bright light and f/8 in Av mode it suggests shutter of 1/2000 and ISO value of 400...why the heck didn't it select 100 along with shutter speed of 1/500?!


What camera model do you have, which might account for why my 40D does not behave like your camera is described?! This 5DII owner describes its auto ISO as pretty simplistic in the ISO value chosen... https://photography-on-the.net …p?p=12494061&po​stcount=19

Actually, I think several of the Canon bodies behave differently with auto ISO. The 1D4 allows me to use M mode, set the aperture and shutter speed, and it will float the ISO between 100-12,800 when NOT using a flash. I find this very useful when I'm shooting indoor sports, for example. I just have to watch out for bumping up against the ISO limit and underexposing the shot. But pop a flash onto the hotshoe, and auto ISO locks the ISO at 400. This seems like something that could be fixed in firmware. When shooting in ETTL, if the flash is at full power and still underexposed, it could float the ISO to get a proper exposure. And if it could do that, it could start at ISO 100 and work up from there the way it does when there's no flash on the hotshoe.

sdipirro wrote in post #13109165
Actually, I think several of the Canon bodies behave differently with auto ISO. The 1D4 allows me to use M mode, set the aperture and shutter speed, and it will float the ISO between 100-12,800 when NOT using a flash. I find this very useful when I'm shooting indoor sports, for example. I just have to watch out for bumping up against the ISO limit and underexposing the shot. But pop a flash onto the hotshoe, and auto ISO locks the ISO at 400. This seems like something that could be fixed in firmware. When shooting in ETTL, if the flash is at full power and still underexposed, it could float the ISO to get a proper exposure. And if it could do that, it could start at ISO 100 and work up from there the way it does when there's no flash on the hotshoe.

i agree with this statement about how it should be. ISO should only move up if the flash doesent have enough power to expose the shot. i think canon made ISO lock to 400 to save the batteries and make their speedlights seem better than what they really are

I can vary the ISO

Using P, AV or TV mode, I can on my x0D and 7D cameras vary the ISO by simply moving my finger over to the ISO button and rotating the main dial with that same finger. It takes no time to do this and I see the ISO value in my viewfinder. I don't have to move my eye from the viewfinder.

I DON'T LIKE MY CAMERA SELECTING VALUES FOR ME....

I love Auto ISO for those times when I'm doing on-location ambient light shooting. I set the limits where I want and let the camera choose the ISO.

The 5DIII and 1Dx have the ability to set the lower limits of shutter speed way better than older cameras.

I liken it to this... Years ago a friend had the Konica T3 (I told you it was years ago!) That camera was an early adopter of auto exposure. I was skeptical but then he asked me how I adjust the exposure setting on my camera. I replied that I do what the in-camera meter tells me to do. He replied... My camera does that same thing for me... faster!

Same with Auto ISO... one less thing for me to have to mess with. Obviously there are times when I don't use it. But it's a handy feature to have.

BTW, I too wish that the flash wouldn't switch to ISO 400 when in Auto ISO. Annoying. I'd rather be able to use the Auto ISO feature with the limits I preset.

FuzzyDuenkel wrote in post #15796721
I love Auto ISO for those times when I'm doing on-location ambient light shooting. I set the limits where I want and let the camera choose the ISO.

The 5DIII and 1Dx have the ability to set the lower limits of shutter speed way better than older cameras.

I am curious about how the 5DIII and 1Dx behave in low light and bright light conditions where my 40D would behave like this...

•in low light and f/4.5 in Av mode it suggests shutter of 0"4 and ISO value of 800...why the heck didn't it selected ISO 1600 or 3200 instead, permitting a more handholdable shutter speed?!

•in bright light (about Sunny 16 ambient) and f/8 in Av mode it suggests shutter of 1/2000 and ISO value of 400...why the heck didn't it select 100 along with shutter speed of 1/500?!

...which I complained about 1.5 years ago in this thread?

Wilt, I'm hazy on the problem. Does your 40D give you the option to set the limits of shutter speeds, or can you set parameters on the available ISO range?

FuzzyDuenkel wrote in post #15796756
Wilt, I'm hazy on the problem. Does your 40D give you the option to set the limits of shutter speeds, or can you set parameters on the available ISO range?

No the 40D provided zero control of range of shutter speed...the newer bodies are better in that regard. However the issues that I have with Auto ISO in the 40D are the 'less appropriate combinations' that it chose, not the selection of a 'bad shutter speed' per se. As my bulleted behaviors indicate

•in low light and f/4.5 in Av mode it suggests shutter of 0"4 and ISO value of 800...why the heck didn't it selected ISO 1600 or 3200 instead, permitting a more handholdable shutter speed?!

•in bright light (about Sunny 16 ambient) and f/8 in Av mode it suggests shutter of 1/2000 and ISO value of 400...why the heck didn't it select 100 along with shutter speed of 1/500?!

The issue:
In the first case, it had higher ISO values available, but some odd logic prevented it from choosing them.
In the second case, it has lower ISO values available, but some odd logic prevented it from choosing them.
So is the ISO selection logic any less impaired in the newer cameras?

I see. I was confused. So what you're saying is that it has two variables, and you didn't like the choice it made in favoring one over the other.

I know what you're saying. When I had an old Nikon FA, it had a P mode. If I shot in P mode, I didn't like that the camera would close down the aperture instead of speeding up the shutter speed.

I dunno. I don't know if a newer body would shift that bias toward hand-holdability. But I bypass that problem by setting the limits on the shutter speed.

Not to side-step your concern... but the new cameras are really superb! The 5DIII is their best value ever. It does everything it should and more (finally! The older 5D versions... not so much. The 1Dx is great too, but kind of pricey unless you need its features.

FuzzyDuenkel wrote in post #15796803
I dunno. I don't know if a newer body would shift that bias toward hand-holdability.

The issue is less about handholdability, but that it seems odd to constrain the range of ISO speeds available in Auto ISO, rather than permit the full range to be selected by the camera logic. I might understand high ISO noise being a consideration, but what explains why ISO 100 and 200 are outside the selectable range of the Auto ISO logic?

It is analogous to setting a fixed ISO and choose Tv (auto aperture) mode with shutter set at 1/100, and the lens aperture is somehow constrained (with a f/2 through f/16 lens aperture range) to only select from f/2.8 through f/11 ...neither the fastest aperture nor the slowest aperture are available. One might speculate that the logic is "f/16 has diffraction considerations, f/2 wide open similarly has less detail resolution, so don't let those apertures be available" in Auto Aperture mode?!

So are the newer cameras any less brain dead in this regard (contraining the range of Auto ISO to less than the full range of ISO which can be set manually)?