M8 and Auto-ISO

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matthew-s

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Hi - I've had an M8 for a few weeks now, and have been playing w/ Auto-ISO.

It seems like it should be a great feature, but I find that it keeps using the MAX ISO setting (640 for me) even at high shutter speeds (1/250 for instance) - where the min speed is set for 1/30.

I've been using full manual exposure (setting Aperture & Shutter myself)

What gives? Could it be because I'm using an un-coded 50mm Summicron? Or is this feature just buggy?
 
matthew-s said:
Hi - I've had an M8 for a few weeks now, and have been playing w/ Auto-ISO.

It seems like it should be a great feature, but I find that it keeps using the MAX ISO setting (640 for me) even at high shutter speeds (1/250 for instance) - where the min speed is set for 1/30.

I've been using full manual exposure (setting Aperture & Shutter myself)

What gives? Could it be because I'm using an un-coded 50mm Summicron? Or is this feature just buggy?
Click to expand...

Then the light is too low for the camera to lower ISO. If you use manual mode in combination with auto iso then camera adjusts iso according to the light conditions. Take a close up photo of a light source and iso should go down to 160 again.
 
tom.w.bn said:
Then the light is too low for the camera to lower ISO. If you use manual mode in combination with auto iso then camera adjusts iso according to the light conditions. Take a close up photo of a light source and iso should go down to 160 again.
Click to expand...

I don't know why it would have selected ISO 640 in the first place though.

I would have expected the camera to not raise the ISO until I hit 1/30s. Until then it should retain the best/lowest ISO. I should have been able to hold at least 320, if not 160, in those light conditions.

This feature is not documented in the M8 manual. I guess it was added later?

Is it not working, or do I not understand the feature? :confused:
 
matthew-s said:
I don't know why it would have selected ISO 640 in the first place though.

I would have expected the camera to not raise the ISO until I hit 1/30s. Until then it should retain the best/lowest ISO. I should have been able to hold at least 320, if not 160, in those light conditions.

This feature is not documented in the M8 manual. I guess it was added later?

Is it not working, or do I not understand the feature? :confused:
Click to expand...

Didn't you say that you used it in full manual mode? Then the setting for the lower time is not relevant because you choose the time yourself. The lower time setting is only relevant in A-mode.

And you are right. The feature is not documented in the manual because it was added later.
 
ok - when in full manual mode, when does the camera decide to use a higher ISO?

In the example I used above, the meter was showing I was properly exposed at 1/250s @ ISO 640.

Why did the meter not encourage me to slow down to 1/60s, and use ISO 160?
 
When auto-ISO is on in full manual mode, the meter seeks to "correctly expose" based on your compensation setting.

It assumes you have set the shutter and aperture the way you need, and the camera's job is to set the "proper exposure." It will not encourage you to do anything.

The rangefinder patch is very close to being like a spot meter in practice. I set my exposure compensation to +2/3 of a stop and then point my patch to something I expect to be 2/3 of a stop over middle gray. I lock to that setting with a half press and recompose. The M8 is surprisingly good and exposing in an automatic mode IF you point it to the right subjects.
 
AncientCityPhoto said:
The rangefinder patch is very close to being like a spot meter in practice. I set my exposure compensation to +2/3 of a stop and then point my patch to something I expect to be 2/3 of a stop over middle gray. I lock to that setting with a half press and recompose. The M8 is surprisingly good and exposing in an automatic mode IF you point it to the right subjects.
Click to expand...

You really see that something is 2/3 over middle gray?
 
I also found that the auto-ISO tended go higher rather than lower. So I always manually set ISO now, depending on lighting conditions. I use the half-press shutter button to set shutter speed. I'm always on aperture priority.
 
I find Auto-ISO more bother than it is worth, as it takes control of the camera out of your hands. I only use it with a 135 lens to optimize shutterspeed. Are you sure you have all the settings right in the menu?
 
I'm pretty sure I've got the feature set up properly! Max ISO 640, Min Shutter Speed 1/30. Does not look like there are other settings.

Per Tom and others, I agree the manual only mentions aperture priority mode, so maybe in manual, it just uses the highest allowable ISO setting? I'll just manually set ISO when doing full manual.

I suppose I'd use aperture priority mode more if there was a quick way to perform exposure compensation, but there isn't (there should be!).

Maybe I need to play more with finding middle tone subjects to meter on - rather than guessing at adjustments.

This is the first manually-intensive camera I've used an a long time, so it's taking some getting used to.
 
Exposure compensation is extremely easy - if you just shoot manual. Basically this ia a manual camera wit AE thrown in for marketing reasons. ;)
 
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