marike6 wrote:
rakore wrote:
I like to use the E-M5 in manual mode with auto ISO. It lets me control the two variables of the exposure triangle I'm most concerned about, and at the same time releaves me from having to factor in ISO as a third factor.
However, I haven't found a way to set exposure compensation on the E-M5 in this mode. I think Pentax allows it in its TAv mode (aperture and shutter mode), and I think some high end Nikons allow it too. This would be a very useful feature and should be doable with a firmware fix.
EV Compensation is
only for AE modes like A and S, not M. There is no reason to have EV Compensation in Manual exposure mode as it's already there - all you have to do is change either the aperture, shutter speed (or ISO) to compensate.
In the AE modes like A or S, the meter always produces the correct exposure, and changing the aperture or shutter speed gives you an equivalent exposure, but doesn't effect the current EV reading. This is why EV compensation is needed in this instance (A or S), and not in M mode.
You're at a concert or stage show with your camera. From your seat you decide on a 100mm FL and wide open your lens limits you to F/4.5 as your brightest Aperture at this FL. But you know your lens and you know it's a little soft at F/4.5 and will be better stopped down to F/5.6. You decide you need at least 1/200s to freeze motion of the singer and in particular that manic drummer.
So you decide you want to fix the lens at F/5.6 and not let the shutter drop below 1/200s.
Which mode do you shoot?
- Aperture priority on F/5.6
- Shutter priority on 1/200s
- Manual on F/5.6 + 1/200s
Let's assume for now you answered 3, manual.
Now as the singer dashes about the stage, going from blackness with a solitary spot, to full on background Pyro, how do you capture this light varying from shot to shot?
- Meter and change the ISO manually for every shot
- Allow the camera's Auto ISO feature to give a 'correct' 'exposure'
Choosing option 1 will cause many missed moments as you meter for a singer who has since moved on.
Choosing option 2 lets you concentrate on framing and predicting the performers motion. But the problem with 2 is, in this tricky light the metering is going to get fooled and give you lots of blown highlights when the singer in solo spotlight. You perhaps want to under-expose by 1.5 stops.
If you have a camera that supports EC in 'manual' mode, you set your EC to -1.5 (perhaps switch to raw for extra latitude) and then fire away, capturing lots of great stage performance.
If you have the Olympus, you either put the camera down and enjoy the show, or fix your ISO and accept having more noise than needed on some shots, and over/under exposure on others.
Perhaps you have another solution that works better in this scenario? And the other scenarios that need fixed (or have limited) Aperture, and a minimum shutter speed, with a constantly changing light source?
Note 1: The mode that let's you set both Aperture and Shutter independently is called
Manual on many cameras, but unfortunately the use of this word causes lots of debate, such as this one. The name of the mode does't matter, it is the ability to set both Aperture and Shutter independently that is important. But when an un-compensatable Auto ISO is used in this mode, you are stuck with whatever ISO the meter decides to give you.
Note 2: The word 'exposure' above is inside these '' marks because, as the pedants rightly like to tell us, exposure is not really affected by ISO. Technically it is the resulting image brightness that is affected by ISO. However so many people use the term under/over exposed for dark/bright images, being too pedantic about it only detracts from the actual issue being discussed.
Note 3: Sometimes, some cameras let you work around the problem in other ways, for example being able to specify a minimum shutter speed in some circumstance. But these vary and can be burred in menus, and as the EC is used in the other semi-auto modes, it just makes sense to some people to allow it in the semi-auto mode known as M+AutoISO.
-Najinsky
