Focus point selection and spot metering

Mohan Apte wrote:

ThrillaMozilla wrote:

Mohan Apte wrote:

Now suppose I am shooting a portrait

For that you should use manual exposure with a manual ISO setting. The exposure shouldn't change when you move the camera around. And now you can focus wherever and whenever you want, without worrying about the exposure being tied to the focus.

Ok noted. I have so far experimented with auto exposure in manual mode - I mean the only variable I keep automatic is the ISO. Everything else is manually adjusted. It makes taking a photo a bit quicker. If everything is in manual mode, it means I will need a lot of time to figure our what combination of aperture, shutter speed, ISO, metering etc I need to use for a particular shot - not suitable to candid photography or impatient subjects who want me to "get it on and get done quickly"

It sounds like Thrilla is interpreting "a portrait" to mean a portrait session (with the subject posing for multiple shots under controlled conditions, and constant image brightness a desirable outcome). His advice makes perfect sense for that. I don't think he means if the main subject of a single shot is a face you must use manual settings.

Don't make the mistake of thinking that centring the meter should or will give a perfectly bright image, and therefore that the way to fix image brightness problems is by changing the metering mode. The right way to fix image brightness is by compensating the exposure (shutter and aperture) and image processing (ISO) settings away from the meter's guess of what might work. Exposure compensation is not a meter calibration setting, it's a per-shot setting to get the image brightness you want. Use any metering mode you like since any guess is fine to start from. Then use the histogram and blinkies to determine if you captured good data, not the appearance of the shot on the monitor.