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'M' mode vs 'P' and the Exposure Indicator Help Please

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Adam George

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Hi,

I have been using my DR for a short time now but would like some information regarding how the 'Exposure Indicator' works in the 'M' mode. For example I shoot most things using 'M' and accept that the 'Exposure Indicator' works well in giving me an idea on the type of exposure I will achieve (and I understand this is not used for exposure compensation in this mode etc), however this indicator does not appear to take into account whether I am using the in-built flash where it still indicates a massive underexposure on my settings.

For example:

In 'M' mode I might select 1/15 f1.8 and this indicates perfect exposure (without flash), however if change the settings to 1/60 f4.0 it obviously indicates massive underexposure but continues to inform me of the problem even if I pop up the flash????

In comparision the same shot using 'P' mode would use 1/15 f1.8 (without flash) or automatically change to 1/60 f4.0 with the flash selected and indicate a perfect exposure.

Do you think this has to do with the different metering methods used by the two modes???

Thanks for your help

Adam
 
I also noticed same problem but got used to it after three months. The flash will do right thing in M (but 9 of 10 shots underexposed well-covered in other topics) regardless of indicator position. M has center weighted metering i.e. very much bias toward the small focal point while P has evaluative, i.e. some consideration of light at other points.
Adam George said:
Hi,

I have been using my DR for a short time now but would like some
information regarding how the 'Exposure Indicator' works in the 'M'
mode. For example I shoot most things using 'M' and accept that
the 'Exposure Indicator' works well in giving me an idea on the
type of exposure I will achieve (and I understand this is not used
for exposure compensation in this mode etc), however this indicator
does not appear to take into account whether I am using the
in-built flash where it still indicates a massive underexposure on
my settings.

For example:

In 'M' mode I might select 1/15 f1.8 and this indicates perfect
exposure (without flash), however if change the settings to 1/60
f4.0 it obviously indicates massive underexposure but continues to
inform me of the problem even if I pop up the flash????

In comparision the same shot using 'P' mode would use 1/15 f1.8
(without flash) or automatically change to 1/60 f4.0 with the flash
selected and indicate a perfect exposure.

Do you think this has to do with the different metering methods
used by the two modes???

Thanks for your help

Adam
Click to expand...
 
Would like to add that in all M, Tv, Av the exposure indicator does not include the build-in flash.
Nhat Dinh said:
Adam George said:
Hi,

I have been using my DR for a short time now but would like some
information regarding how the 'Exposure Indicator' works in the 'M'
mode. For example I shoot most things using 'M' and accept that
the 'Exposure Indicator' works well in giving me an idea on the
type of exposure I will achieve (and I understand this is not used
for exposure compensation in this mode etc), however this indicator
does not appear to take into account whether I am using the
in-built flash where it still indicates a massive underexposure on
my settings.

For example:

In 'M' mode I might select 1/15 f1.8 and this indicates perfect
exposure (without flash), however if change the settings to 1/60
f4.0 it obviously indicates massive underexposure but continues to
inform me of the problem even if I pop up the flash????

In comparision the same shot using 'P' mode would use 1/15 f1.8
(without flash) or automatically change to 1/60 f4.0 with the flash
selected and indicate a perfect exposure.

Do you think this has to do with the different metering methods
used by the two modes???

Thanks for your help

Adam
Click to expand...
Click to expand...
 
As I understand it, the exposure indicated is for the background only, regardless of flash. When the flash is up, it will do the ETTL metering, by firing the preflash at the power required to properly expose the subject (the area under the focus point). The background will be exposed as indicated on the EC meter. So, if you have 1/60 second with flash, the subject will be exposed, but the background underexposed. To expose both properly, the flash will fire to fill the subject, but leave the shutter open for the background at whatever exposure length is required.
Adam George said:
Hi,

I have been using my DR for a short time now but would like some
information regarding how the 'Exposure Indicator' works in the 'M'
mode. For example I shoot most things using 'M' and accept that
the 'Exposure Indicator' works well in giving me an idea on the
type of exposure I will achieve (and I understand this is not used
for exposure compensation in this mode etc), however this indicator
does not appear to take into account whether I am using the
in-built flash where it still indicates a massive underexposure on
my settings.

For example:

In 'M' mode I might select 1/15 f1.8 and this indicates perfect
exposure (without flash), however if change the settings to 1/60
f4.0 it obviously indicates massive underexposure but continues to
inform me of the problem even if I pop up the flash????

In comparision the same shot using 'P' mode would use 1/15 f1.8
(without flash) or automatically change to 1/60 f4.0 with the flash
selected and indicate a perfect exposure.

Do you think this has to do with the different metering methods
used by the two modes???

Thanks for your help

Adam
Click to expand...
--
--------------------------------------------------------------------
http://www.jordansteele.com
 
Jman13 said:
Adam George said:
Hi,

I have been using my DR for a short time now but would like some
information regarding how the 'Exposure Indicator' works in the 'M'
mode. For example I shoot most things using 'M' and accept that
the 'Exposure Indicator' works well in giving me an idea on the
type of exposure I will achieve (and I understand this is not used
for exposure compensation in this mode etc), however this indicator
does not appear to take into account whether I am using the
in-built flash where it still indicates a massive underexposure on
my settings.

For example:

In 'M' mode I might select 1/15 f1.8 and this indicates perfect
exposure (without flash), however if change the settings to 1/60
f4.0 it obviously indicates massive underexposure but continues to
inform me of the problem even if I pop up the flash????

In comparision the same shot using 'P' mode would use 1/15 f1.8
(without flash) or automatically change to 1/60 f4.0 with the flash
selected and indicate a perfect exposure.

Do you think this has to do with the different metering methods
used by the two modes???

Thanks for your help

Adam
Click to expand...
--
--------------------------------------------------------------------
http://www.jordansteele.com
Click to expand...
So are you saying the in 'P' with the settings given by the camera 1/60 f4.0 then the background will not be exposed correctly? because it indicates that the exposure is spot on but not on when using the same settings / subject in 'm' mode???

Also the preflash thing for me seems pretty random I obviously get it if I use FEL but hardly ever other times.

I will need to do some more testing and some with various distances from subject to background since at the moment I am happy with exposure and not finding it underexposed at all (hence the reason I use 'm' mode to allow full control over what I expose)
 
Nhat Dinh said:
Adam George said:
Hi,

I have been using my DR for a short time now but would like some
information regarding how the 'Exposure Indicator' works in the 'M'
mode. For example I shoot most things using 'M' and accept that
the 'Exposure Indicator' works well in giving me an idea on the
type of exposure I will achieve (and I understand this is not used
for exposure compensation in this mode etc), however this indicator
does not appear to take into account whether I am using the
in-built flash where it still indicates a massive underexposure on
my settings.

For example:

In 'M' mode I might select 1/15 f1.8 and this indicates perfect
exposure (without flash), however if change the settings to 1/60
f4.0 it obviously indicates massive underexposure but continues to
inform me of the problem even if I pop up the flash????

In comparision the same shot using 'P' mode would use 1/15 f1.8
(without flash) or automatically change to 1/60 f4.0 with the flash
selected and indicate a perfect exposure.

Do you think this has to do with the different metering methods
used by the two modes???

Thanks for your help

Adam
Click to expand...
Click to expand...
Thanks for the response.

What sort of subjects / conditions are you getting with your under exposures, I use 'm' to prevent any problems to ensure I have full control over what I exposure (although I still learning a lot on the flash side of things)
 
Most likely, at 1/60 second, with a dark scene, the background will not be properly exposed unless the flash reaches it. (outside, you won't illuminate buildings 60 feet behind you without blowing out your subject).

However, realize that the meter in P mode doesn't show you what the exposure will be, but rather the the exposure compensation for the image....that you set. The camera is going to set the exposure to properly expose your subject with flash. That's it. It isn't going to think about the background at all. To get the camera to properly expose the background with flash, shoot in Av mode, and expect shutter speeds that are pretty slow (must use a tripod).
Adam George said:
Jman13 said:
Adam George said:
Hi,

I have been using my DR for a short time now but would like some
information regarding how the 'Exposure Indicator' works in the 'M'
mode. For example I shoot most things using 'M' and accept that
the 'Exposure Indicator' works well in giving me an idea on the
type of exposure I will achieve (and I understand this is not used
for exposure compensation in this mode etc), however this indicator
does not appear to take into account whether I am using the
in-built flash where it still indicates a massive underexposure on
my settings.

For example:

In 'M' mode I might select 1/15 f1.8 and this indicates perfect
exposure (without flash), however if change the settings to 1/60
f4.0 it obviously indicates massive underexposure but continues to
inform me of the problem even if I pop up the flash????

In comparision the same shot using 'P' mode would use 1/15 f1.8
(without flash) or automatically change to 1/60 f4.0 with the flash
selected and indicate a perfect exposure.

Do you think this has to do with the different metering methods
used by the two modes???

Thanks for your help

Adam
Click to expand...
--
--------------------------------------------------------------------
http://www.jordansteele.com
Click to expand...
So are you saying the in 'P' with the settings given by the camera
1/60 f4.0 then the background will not be exposed correctly?
because it indicates that the exposure is spot on but not on when
using the same settings / subject in 'm' mode???

Also the preflash thing for me seems pretty random I obviously get
it if I use FEL but hardly ever other times.

I will need to do some more testing and some with various distances
from subject to background since at the moment I am happy with
exposure and not finding it underexposed at all (hence the reason I
use 'm' mode to allow full control over what I expose)
Click to expand...
--
--------------------------------------------------------------------
http://www.jordansteele.com
 
Hi,

I would belieave the diffirence in m&p modes are because of the metering mode, if I remember correctly in m mode it's spot metering and p mode has partial metering, or the other way around, or something, dig it up :D
 
Sandman said:
Adam George,

See if these help:

http://forums.dpreview.com/forums/read.asp?forum=1031&message=6949576

and

http://forums.dpreview.com/forums/read.asp?forum=1031&message=8560040

Cheers,

jim

Oh yeah, and the P mode mystery is addressed here:
http://www.videodirecteoscameras.com/canonspeedlitestechnology.html

Good luck

jim
--
Shoot more, ***** less!
galleries at: http://www.pbase.com/sandman3
Click to expand...
Thanks for the links. I have been searching the forums and found a few posts confirming that in 'M' mode that exposure guide does not account for the flash and I now believe it uses this information to guage the power required for the flash. Now as pointed out in 'P' mode the guide is used to adjust compensation and not correctness of exposure.

Great fun this hobby.

Adam
 
Malt said:
Hi,

I would belieave the diffirence in m&p modes are because of the
metering mode, if I remember correctly in m mode it's spot metering
and p mode has partial metering, or the other way around, or
something, dig it up :D
Click to expand...
In M it´s center weight average. That is not the same as spot metering. It´s overall metering, with a bias towards the center.

In P, Av and Tv it´s a matrix metering, with a bias towards the active focus point.
 
Adam George said:
So are you saying the in 'P' with the settings given by the camera
1/60 f4.0 then the background will not be exposed correctly?
Click to expand...
What is ´correct exposure´ for the background when you´re using flash? The same using no flash? The normal ambient metering, like done in Av mode, will give you very long exposure times... And you might actually WANT the background dark.

That´s actually how I use M mode... I can tune the background brightness. Very usefull for flowers. Much more effective for isolating the subject than just DOF.
Adam George said:
because it indicates that the exposure is spot on but not on when
using the same settings / subject in 'm' mode???
Click to expand...
P mode doesn´t care about background.
Adam George said:
Also the preflash thing for me seems pretty random I obviously get
it if I use FEL but hardly ever other times.
Click to expand...
You don´t see pre-flash. It´s so quickly followed by the main flash, that you don´t notice it. What you probably see is the autofocus assist. With the build-in flash, that is done by strobing the flash.
With most external flashes, it´s (infra)red, and hardly noticable.
 
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