Manual Exposure

[abik]

Hi Guys

I am quite new here, however not very new in photography business.

i own the Canon 6D and i am very happy with it.

I was learning a lot recently about metering and exposure issues and would like to ask you guys the following:

It is well known that once i press the shutter half way i activate metering and AF. the metering will determine the scene and according to scene will decide which exposure is the right one.

sometimes we lock exposure and recompose and then take the photo. since we want to take a photo with the appropriate exposure.

what i dont understand is where we use manual exposure and we set aperture and shutter speed which decides the right exposure. how can we nevertheless lock the exposure and recompose the picture? does it make sense to use exposure lock when we have manual exposure as our shooting mode?


thanks for answering

 

[480sparky]

Using exposure lock in Manual is meaningless. You set the shutter speed, aperture and ISO and it will not change until you change it.

Which settings to use for the shutter speed, aperture & ISO is purely the shooter's choice.

 

[abik]

and what about metering mode? if i change to spot metering in manual shooting does it make any difference?

 

[TCampbell]

and what about metering mode? if i change to spot metering in manual shooting does it make any difference?

The metering zone control simply affects where the camera takes it meter readings.

Your camera has a 63 zone metering system -- if it uses all zones. In "evaluative" mode it uses them all. In "spot" metering it uses only a single zone in the center of the frame. If you use "center weighted" mode then it "technically" uses all the metering points... but gives the greatest weight to the metering zones in a broad area (not a tight spot) in the middle of the frame.

HOWEVER... (and this is the important bit) your camera (as it is with all cameras that have built-in meters) is used a "reflected" meter reading. The other type of light meter is called an "incident" meter. This is the hand-held meter that you walk up to your subject, hold it in front of that subject, and take a reading as to how much light is "falling" on the subject. Since an "incident" reading is technically reading the actual amount of light landing on the subject, it is the most accurate.

A "reflected" meter can't measure the light falling on the subject... it can only measure the light that bounces off the subject (reflects) and into your camera's light meter. There's a problem with this... some subjects are more reflective than others and your camera doesn't know the difference. If you meter someone wearing all white in a snowy scene, the camera is going to get a LOT of light reflected off that subject. So much that it will believe there is more light than there actually is due to the highly reflective nature of all the "white" objects in your scene. On the opposite end of the spectrum, if you shoot a performer wearing all black in a dark theater, with black curtains in the background... the camera is going to tend to over-expose the subject (the few bits that aren't "black"). The scene reflects so little light that the camera believes there isn't much light -- when in reality, the parts that aren't black are actually get a ton of bright stage lighting.

I bring this up because if I shoot a concert event... I tend to put the camera into "spot" metering mode and take the meter exposure reading (and lock it in) while pointing the camera at the performer's face. If I point it randomly (or if I use "evaluative" metering) the camera will get it wrong. I've been doing this long enough that usually I sample the reading in "spot" mode, sample it in "evaluative" mode, check the difference (usually about 1 to 1-1/3rd stops) and then just use evaluative mode with exposure compensation dialed back a stop (or whatever the difference needed to be.)

My point is to give you an idea of WHY you'd choose one mode over another for metering.

The guidance given by the camera is always going to be on that reflected light value regardless of what shooting mode you are using. In other words, whether you use Program, Time value (Tv), Aperture value (Av), or Manual... the meter's "advice" is going to be based on the metering zone and the reflectivity of the subject. The difference is that in P, Tv, or Av the camera will automatically set the exposure (except in Tv or Av you dial in the shutter or aperture setting you want and the camera matches the rest). In Manual, the camera's meter in the viewfinder will indicate a "0" value if your exposure settings agree with what the camera believes is the correct exposure based on the metering mode and subject reflectivity. In other words... if you need to dial the exposure up or down and you're shooting manual, don't try to center the meter to the "0" position... just move it to that adjusted spot you wanted (e.g. "-1" for example).

Guidelines to remember:

Camera meters tend to underexpose when the image is dominated by whites.
Camera meters tend to overexpose when the image is dominated by blacks.

The meter is designed to expect "middle gray" values (which are generally between 12% and 18% gray depending on the specific camera. 18% used to be the standard years ago but today most cameras are set to something less than 18%.)

 

[pdq5oh]

What you have to learn when shooting in manual mode is 18% grey (neutral grey). Find something in your scene that represents this, and meter off of that. The beauty of manual is that once you learn this, you can get proper exposure, or very close. Keep in mind that whites can be 1-3 stops brighter in order for them to come out as white. Blacks can be 1-3 stops darker to get good blacks. You have complete control in manual. It's also the best mode for backlit subjects, IMO.

 

[Derrel]

SNIP>
Guidelines to remember:

Camera meters tend to underexpose when the image is dominated by whites.
Camera meters tend to overexpose when the image is dominated by blacks.

The meter is designed to expect "middle gray" values (which are generally between 12% and 18% gray depending on the specific camera. 18% used to be the standard years ago but today most cameras are set to something less than 18%.)

TCampbell gives you some good information with regard to using an in-camera light meter. Here's a memory device I developed years ago, to help me remember how to adjust my exposure settings when using an in-camera light meter.

If it's white, you need to add more light. (use the + aka the PLUS Exposure compensation dial settings)

If it's black, then dial 'er back. (use the - or MINUS Exposure compensation dial settings).

If it's gray, then you stay. (Stay on the meter's suggested settings.)