Bud Black

Okay, if I use a light meter to tell me the best aperture setting and shutter speed, why is this better than setting the camera on automatic and let it figure it out? I’m referring to not using flash.

Wingpilot Loc: Wasilla. Ak

The camera's light meter gives you what it thinks is the best setting for the scene being shot. Consider it a suggestion, though. You can either go with that or change the settings manually if you wish. Shooting in full auto mode takes away any control you might have or want to use. You have to use the aperture or shutter speed settings the camera gives you, which may or may not give you the result you want, especially if you want to control the depth of field/focus in a shot. If you like shooting in auto, give Program a try. In Program mode, the camera gives you its suggested settings, but you can shift those settings a bit to have control over shutter speed and aperture, and you can also choose your ISO and white balance settings, as well.

TBerwick Loc: Houston, Texas

Automatic metering determines what reading will balance out to 18% gray. That reading will frequently mute low areas and allow high areas to "blow out." Metering specific areas will allow you to "place" those areas that are important to you in a tonal range that will allow you to best interpret the photo as you wish it to be seen in post.

Google "Zone VI" to get an idea of the tonal ranges and general theory. Simply put, the zone range gives you the choice of placing very high or low tonal areas into an exposure range that will allow you to record their detail.

JohnSwanda Loc: San Francisco

In tricky lighting situations, the camera meter on auto can be fooled. If you learn to take manual readings, with the camera meter or a hand-held one, you can take readings from specific areas and determine the best overall exposure to get the best shadow and highlight detail. Also, if you let the camera decide both the shutter speed and aperture, it might not be the optimum combination for what you want to accomplish.

DirtFarmer Loc: Escaped from the NYC area, back to MA

I haven't used a light meter for about 50 years so things may have changed. The one I used to use looked at a very wide angle and pretty much took in the light from everywhere in front of it. On the other hand, a modern digital camera measures only the light that gets into it, so it's looking only at the field of view, which may be different from the overall scene.

I use the camera meter and it seems to work pretty well. Of course if you have a high dynamic range in the scene and if you're using a spot metering mode, you may have problems, but I don't think that scenario is what the OP had in mind. (please correct me if I'm wrong).

Photocraig

The automagic of the camera figuring it out is that it is a machine and doesn't SEE anything it just measures. The algorithms (a loaded word today) drive every photo toward average. In AUTO Everything, even the focus is selected by the camera. In a simple shot that's ok. But if there's anything between you and the subject (the one YOU, not the machine, picked to be the subject) most AUTO will pick the item nearest the camera as the subject, like a leaf, twig or park bench instead of the smiling face of your dearest.

There are lots of choices to allow the camera's exposure system to be a tool rather than the master of image making. As said above, Program, Aperture Priority, Shutter Priority. YouTube has many many tutorials on all of this. Spend some time with these with your camera in hand and leave behind (mostly) those "Da75N! why is my dearest's face blurry? And dark?" moments forever. While in the large number of photos it is amazing how good the Auto mode is, it is also amazing how reliance on it exclusively will lead to frustration.

Spend a little time experimenting with intentional photographs of specific subjects instead of pretty views and scenes. Then figure out what YOU want and how to use the camera as a tool for YOU to be the BOSS. Because, many times, as in life, average (exposure and focus) just isn't good enough!

Lucasdv123

This comes to old school photography where you had to tell the camara what you wanted and by taking a light reading you know that that picture was going to be perfect because back in the day of film photography you didn't know what you were going to get till you developed the film and there was only one time to get it right.with digital Camara you can shoot 20 or 30 shots in a matter of minutes and pick the one you like while still at the wedding, party,or wherever.

Golden Rule Loc: Washington State

To add to the above comments, automatic doesn't know if you want to show action blur or if you may want to freeze motion.

Amielee Loc: Eastern Washington State

The camera meter is a reflective meter. The hand held meter is both reflective and incident. Used as an incident meter the hand held measures the light falling on the subject. The reflective meter measures the light reflected by the subject and the background (usually). This can and often does make a significant difference. Most of the time the camera meter is "good enough" but for example it does not work if you want to photograph the moon. The large black night reflected to the camera meter causes it to over expose the moon. If the hand held is used as a reflective meter it probably does not make much difference but there are cases when the incident meter gives the best result.

Mac Loc: Pittsburgh, Philadelphia now Hernando Co. Fl.

burkphoto Loc: High Point, NC

Meters are stupid. They blindly average what they detect and ASSUME it is middle gray (12% to 18% reflectance, but i won’t get into that argument here). Some “matrix” meters are programmed to read different parts of the scene differently, so they can be more accurate, but every reflected light meter can be fooled.

Here’s a test. Set your camera on full auto. Set it to save only JPEGs. Photograph a Caucasian blonde in a white, full length dress leaning against a white wall. Then photograph an African American in a black dress leaning against a black wall. The exposures will be wrong in both cases!

Only an incident meter reading, or a reflective meter reading of an exposure target, or a Zone System calculation can give you an accurate exposure of either scene.

So... we meter manually for critical work, and for subjects that fail to meet the definition of “average”.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Bud, the best way to use either device to set your exposure is to understand how they work.

You can use a separate, hand-held meter, as long as you understand what it sees. It can read either reflected light from your scene or a light source. Many can do both. Some offer a narrow angle of view as a reflective meter so that you can be pretty specific as to what you are reading.

Meters don't get fooled, only photographers do. Cameras don't figure out anything. They just measure stuff. it's up to you to "figure" things out. A meter will not tell you the best exposure settings - but it will give you an exposure value, and a series of aperture/shutter speed settings that will give you a proper exposure, for that exposure value.

Take for example the commonly held view that meters read 18% gray. They don't. They are closer to 12% or 14% reflectance. Which means they are off by 1/2 stop on average.

https://marcschlueter.wordpress.com/2011/08/06/light-meters-grey-cards-and-the-ultimate-answer-its-12-not-18-and-42-is-totally-off/

https://en.wikipedia.org/wiki/Light_meter#Calibration_constants

The difference is close enough for most situations. But if you are at the threshold of overexposure, then the 1/2 stop can mean everything. It's best to understand your gear's limitations.

The other thing you'll hear is that the camera decides how to determine exposure. It does not have intelligence. It can't decide anything. It can only read what you point it at, and return a combination of shutter speed/aperture based on the ISO you dial in. Whatever it is pointed at, the meter will tell you how to set the camera. The result will always be "middle gray" whatever that actually means. If you have three cats in a picture - a white one, gray one and a black one - pointing a meter at each one will yield a different reading. In fact, there is one correct light value that will render each cat at the correct tonal value. Of course, the exposure value will give you a variety of shutter/aperture/ISO combinations.

Any decision-making is all on the camera's operator. Those who understand what is going on, will appreciate what the camera is reading and make the necessary adjustments to the reading to set the exposure, or if using auto exposure, how much to set the bias (compensation).

One exposure method that works for me 99% of the time is to measure the highlights where I want to record detail, using either a separate spot meter or the spot meter function in the camera, and adding up to two stops of additional exposure. This will ensure that the bright thing I am reading will be white/bright and not gray.

So cameras do have "evaluative" metering that tries to do scene recognition and it will compare it to a database of scenes, looking for something similar, adjusting the exposure to be similar. Other systems will look at the entire scene, and if the scene has a wide dynamic range, apply a rule that permits a percentage of overexposure (blown highlights), while keeping the rest of the image looking natural.

Incident light meters, while insanely accurate - fall short in a large number of situations. Be it a shot of the moon, a baseball game shot from the grandstands (where the shooter is in shade), or a blind where the birds are lit by open sky, and you aren't - these are situations that cannot work with incident readings.

However, when you are in a controlled lighting situation, usually in a studio or at a set on location - the incident meter reigns supreme.

srt101fan

Wingpilot's answer is on target. Some of the others seem to be wandering away from your basic question.

In Auto, you have zero control over the exposure settings. In the other "standard" modes you can go with the exposure settings indicated by the camera, or you can override those meter suggestions and make exposure adjustments if you want. In Auto you're stuck with whatever the camera selects.

Linda From Maine Loc: Yakima, Washington

Not a dumb question at all, as evidenced by the informative replies. But I'd like to touch on your choice of words, "best aperture and shutter speed..." which was also addressed by a couple of other folks.

Exposure is how light/dark the image is, and the same exposure can be achieved by several combinations of those "numbers" that many folks ask about. Out of context, a set of numbers is meaningless, not just because light is always changing, but because they don't take into consideration your subject (moving/stationary?) or your preferences for depth of field (blur background or have as much as possible in focus?).

So while the best exposure may sometimes be achieved by using a meter (of any kind), the best aperture and shutter speed are not known by the camera, only by you

BebuLamar

While I don't do it but I can leave the camera on P and make it set just about any exposure, shutter speed and aperture I want.