Underexpose or Overexpose

[unpopular]

I commend you in learning manual mode, and I cannot stress enough what a bad idea it is to start out on auto mode, semi-auto or otherwise. Learning manual mode is by far the best way to learn what exposure *actually is*, and in the long run will help you better utilize auto mode as well.

There are a few misconceptions about exposure that are pretty common. The most important is what a light meter does. A meter does not measure light, at least not intrinsically. What a meter does is compares a test subject to a known condition. When your camera's meter was being designed and calibrated they took a known standard and said that "this is what zero means". Zero on a meter does NOT mean "proper exposure". It means "this electrical signal matches the one at the lab where I was calibrated". It means you're letting the same amount of light in as the calibration target the meter was designed for - which is *completely arbitrary*.

Camera reflective meters are calibrated to 18% or 12% reflectance. So for every 100 photons that bounces off their calibration card, ideally 18 will bounce off. The human eye sees this as a sort of "middle grey" value. Not withstanding fancypants matrix meter modes, when you point you meter at a white wall and zero the exposure you get an under exposed image. The wall is rendered as if only 18 out of 100 photons are being reflected. If you point your camera at an interesting texture in the asphalt, again, it comes out too light. To overcome this, you need to bias the exposure accordingly. So for a darker subject, you'd need less exposure than for a brighter subject, you'd need to set the meter at -1 or -2. Likewise for brighter subjects you need to increase exposure, you'd need to set the meter to a higher EV. You do this using exposure/meter bias (look in your manual).

Despite what cliches you've heard, photography is NOT about recording light. It is about the *interaction* between light and materials. It's very important to get these cliches out of your head when thinking about exposure. Getting a good exposure is not so much about the quantity or quality of the source, but rather about the material quality of the *subject*.

I'd suggest that before you go about using average or matrix metering, really understand how your meter is reading the scene by using spot first. You may like spot metering (I do) or it might not really work well for you. But I think if you can use spot metering you'll have a better understanding of other modes as well since you have direct feedback as to how the area which you metered will look at a given exposure.

And by all means, read a basic overview of the zone system. It applies more now than it did with color film photography (though the application is reverse).

 

[unpopular]

The reason being...if you have to fix something post production, you have a better chance of being able to fix underexposure than you do overexposure. If you're at the beach shooting a portrait and skin has hot spots/highlights that are overblown, no matter what you do (other than clone other parts of skin) it's just going to be a gap in the photo...a spot with no detail.

Yes, but you also have more latitude to the right. A JPEG might come out blown beyond repair, but the raw data likely won't be unless the over exposure is significant. In fact, raw images that look good with gamma correction will appear vastly under-exposed with linear gamma.

OTOH (and for the same fundamental reason) because humans see more in the brighter regions than in the shadows we're willing to accept clipped shadows before clipped hilights. Images with very deep shadows tend to look "flat" to us, even when the histogram says otherwise. Obviously though if important information is in the shadows then clipping shadows cannot apply - though, for a newbie struggling with exposure, it is likely this scenario will over-expose rather than under.

 

[Dave442]

I have the 5d mark iii. please tell me how to easily zero the meter. I find that by the time i zero it any slight movement of mine or shift in the lighting changes it.

Often any large movements of the meter with only slight camera movement is when I am in Spot Metering mode. So usually I stay in Matrix metering mode (Evaluative metering mode on the Canon) and jump over to spot just when I might want to get some different readings in the scene. With Spot metering you do not want to just pick a subject and use that as the final meter reading; I might do that if I was looking at my hand, but a white shirt will end up being too dark in the final exposure.

 

[unpopular]

a white shirt will end up being too dark in the final exposure.

No. A million, billion trillion times infinity no!!

The shirt is too dark because you aren't compensating. The nice thing about spot metering is that *you* decide how the subject is rendered. You decide tonal placement. You decide how the exposure is made and how in conjunction how it will be processed!

If you want the shirt to be white with little detail, i.e. Zone 8-9, you just increase exposure 3 to 4ev (though digital cameras start to barf at Zone 9). If you want the shirt to be light with lots of detail, you increase exposure 2 to 3ev!!!

 

[KmH]

From your description you're using Spot metering mode. See pages 167 and 168 of your 5D III Instruction Manual.

The meter is calibrated on the basis of an average scene that has a 12% to 18% reflectance.
As mentioned previously if the scene you are shooting has more or less reflectance than that you have to compensate and can't use the middle of the metering scale.

Not too the in-the-camera meter can only measure reflected light

For portrait work I used a hand held meter that could measure reflected light, incident light, and flash.
If I was using flash I measured all 3 to decide what manual mode exposure settings I wanted to use.
If I was not using flash I measured both reflected and incident light to set the manual mode triad of settings shutter speed, lens aperture, and ISO.

In other words centering the meter does not always give you the correct exposure, based on how the camera works and your artistic and technical goals for the photo.
You can't solely rely on the camera to do all the work.

 

[Dave442]

a white shirt will end up being too dark in the final exposure.

No. A million, billion trillion times infinity no!!

I did not give the details, what I said is that you don't want to take a spot metering of just any part of the scene and use that as your final exposure - my examples were a hand and a white shirt. Of course you want to add two to three stops to the reading off the white shirt.

I was just throwing that out for the OP to think about and I completely agree with your more detailed explanation.

 

[Derrel]

If you had to choose one, which one would you choose?I finally made the switch to manual mode but am sometimes having trouble keeping the meter perfectly in the middle. Which way should I allow it to go? Over or Under expose? Which is safer?

Assuming that you are metering the most-important subject from a fairly close-up type position, one general operating procedure would be to use these memory-aiding devices of some simple rhymes.

Add more light to make things white. And conversely, Dial It Back to Make it Black.

For example, if you meter a white snowfield, you would most likely want to ADD some light (meaning over-expose deliberately) to make it render as white. The same goes for foggy days. When metering in the fog, you almost always need to add at least one full EV to the meter readings, or else it looks dingy and gray, and not like real fog.

If you shoot a photo of a black cat, you'd likely want to under-expose a bit, so the cat ends up looking black.

 

[Bebulamar]

To answer the OP if the OP has to choose between slightly over and slight under I would say for a digital camera it's better to slightly under expose.
But the real issue here is that the OP has the meter changing in basically the same lighting condition. Since the OP in manual mode, I would choose to point the camera in a way that the meter has the best chance to get the right exposure, set the exposure then point the camera where it gives you the best composition and don't care what the meter indicates then.

 

[unpopular]

A slightly under exposed image may look better sooc. However, a slightly over exposed image will have better data to work with.

 

[photografei]

Thanks. Learned.


Sent from my iPhone using Tapatalk

 

[dennybeall]

Being a Photoshop aholic I always shoot to underexpose just a tad because I can usually recover dark areas but once an area is overexposed you got nothing but white...................
Even when I scan an old dark snapshot it's remarkable that there is usually something to recover in the apparently dark areas.

 

[Jim Walczak]

This is just my own personal opinion here, however whether you're shooting manual or using modes (I'm usually in AP myself), with digital, a very good rule of thumb is to expose for the highlights. One very basic fact about digital is that you can often recover shadow information if you underexpose, however if you blow out the highlights by overexposing, there's generally no way to recover them.

BTW...film is the opposite - with film always expose for the shadows.

I will agree that where possible, it's usually best to get the correct exposure, however sometimes that can be dicey. If push comes to shove and your in a tricky lighting situation, don't be afraid to bracket your shots .