Histogram vs. Light meters

Histogram vs. Light meters

In the following paragraphs I make an argument in favor of using a light meter over the histogram. Please feel free to correct.

1. Your camera need not be moved from a tripod, or even need to be turned on.

2. A histogram will not show you the intensity of light per flash so that you can make creative decisions in the shadow/highlight sections of your final image. A histogram shows spikes. Which spike applies to the section of the image your interested in? The LCD on the back of the camera will lead you astray for overall image brightness and can not show you fine details in the shadows or the desirability of the highlights.

3. You can completely meter a scene before your subjects arrive. The only way to do this without a light meter is with a grey card and a white towel.

4. You don't need white towels and a gray card or even a working camera.

5. You can walk around a venue and read each spot to see what the light will be for those sections of the building. This is even more useful if you will not be using flash but still good to know if using bounce flash.

6. You will be so close to the correct exposure you won't need to do image damaging exposure changes in software.

In favor of the histogram:

1. You don't care about graduations of light and shadow just one specific part of the image. Maybe the face for example or a white dress. As long as you don't have clippies the client will be happy!

That is the only benefit I can see to the histogram. To guarantee you have a printable image, that your within the dynamic range of your camera for the overall image.

But if you desire more control in what and how something is going to be lit your going to find the light meter indispensible.

Just to be fair you could take a camera, white towel, and WhiBal card to each spot of the image and do the work of a light meter... but why?!?!?!?

1. Sure.
2. Light meters are great for setting flash ratios. LCDs show how it really looks.
3. You can use a histogram before your subject arrives, you don't need a grey card.
4. Huh? I've never used a white towel, and a working camera comes in handy when you want to take photos.
5. That's useful for room lighting too, as light intensity varies around the room.
6. Light meters get you pretty close to the correct exposure, but I trust my histogram more.

pcunite wrote in post #6066644
In favor of the histogram:

1. You don't care about graduations of light and shadow just one specific part of the image. Maybe the face for example or a white dress. As long as you don't have clippies the client will be happy!

2. $300 saved.

You are right. I get by with spot meter and chimping but a light meter would be better.

I have a light meter in my bag at every wedding, I use it only to meter room lights/studio strobes, but rarely any other time. I find if I use it for ambient light I have to tweak the results it gives me to get a good histogram anyway.

My light meter has been gathering dust since I learned how to use a histogram.
Need an exposure crutch?

My 1-cent flash "meter" in images 5S & 6S.
Simple 2 Light Portrait Set-up

Would anyone debate the merits of a screwdriver vs. a pair of pliers? No, because they understand that each does a very different job and sucks at what it is not designed to do! Same with histograms vs. handheld light meters.

Wilt wrote in post #6068431
Would anyone debate the merits of a screwdriver vs. a pair of pliers? No, because they understand that each does a very different job and sucks at what it is not designed to do!

That explains why i'm having problems with my DIY I guess

OK, here's what each does...

Incident light meter tells you the exposure for the inherent brightness of light falling on a scene. It cares not what your subject is. For example, ISO 100 might yield 1/100 f/16 with the incident meter.

Histogam tells you where the brightness of the frame area lands in the distribution of pixels, as captured.

Where does the incident meter 'fall down'? Only when you might be able to record a scene at a higher exposure (more light) so that shadow areas can record in greater number of levels (more details captured).

Where does a histogram fall down? It can cause you to bias a scene's exposure in spite of unwanted detail! For example...let us assume our subject is a green ficus tree and the inherent brightness of the light falling on the scene is 1/100 f/16 at ISO 100. If the green tree was in front of a white background, we would have lots of pixels on the right and we might bias the exposure to 1/100 f/11 because the white pixels of the background fall off the histogram otherwise -- but wait, the subject is the ficus tree and we are NOT exposing the leaves to best advantage by dropping the exposure -1EV for the background and and we do not need (in fact we do not want) detail in the white background! Similarly if we remove the white background and replace it with a black background, we might bias the exposure to 1/100 f/22 -- but wait, the subject is the ficus tree and we do not need (in fact we do not want) detail in the background. Yet why are we shooting to the histogram in either of these cases???

If the subject was the ficus & the bride in her gown, we WOULD want to preserve detail in her $3000 gown, so we WOULD want to shoot to the histogram in this case. But NOT in the case of the white background behind the ficus!

A histogram is a tool, and like all tools there is a RIGHT time and a WRONG time to depend on it!

tim wrote in post #6068472
That explains why i'm having problems with my DIY I guess

It probably also explains why my sex life is going nowhere when I suggest a jackhammer for a marital aid!

Really only works for Godzilla!

Histogram leaves you guesstimating proper exposure, Albeit a good guesstimate if you know how to use it.

A light meter tells you the actual proper exposure.

Even franks link is titled "Crutch"....Dosen't that infer it is an aid.

And a Jackhammer would improve my marriage....My wife want's me to remove the sidwalk and build an addition.

If you learn to use the meter properly, you don't need a histogram.

Histogram is a crippled method of judging exposure because I often take photos with large while or black areas and it's hard to imagine what the proper histogram is going to look like.

Second, I feel more in control when I meter and know how it's going to come out.

Potentially, I can do it with a histogram, but the whole: "Click, chimp, adjust" ad infinitum gets old fast.

DocFrankenstein wrote in post #6070607
Potentially, I can do it with a histogram, but the whole: "Click, chimp, adjust" ad infinitum gets old fast.

And it suffers the time overhead of shooting and then chimping to determine what to do! Oftentimes there is NOT time to shoot and chimp, we have to simply shoot...and in this case the incident light meter avoids issues of subject brightness (or other non-essential things in the background that throws off the exposure.) So, for example, at the cake cutting at a wedding reception, there is not time to take a photo and chimp and adjust...but you can arrive at the cake a few moments before the B&G, take an incident reading and put that into the camera on manual, and be confident about the exposure being correct.

Put it another way, relative to the validity of the exposure...
You are shooting sports on a bright sunny day. One soccer team is wearing white, the other soccer team is wearing black. The histogram method would have you moving exposures back and forth and back and forth simply in response to the number of white jerseys in the frame vs. the number of black jerseys in the frame for any given shot (and this is perpetually changing!). Incident meter gives you ONE reading to use, regardless of the white jerseys or the black jerseys filling the frame!

I'd be surprised if several old fogies on the forum besides myself can't think back to when we were making near-perfect exposures all the time based on readings from our handheld meters. We didn't even have meters built into most of our cameras. We certainly didn't have histograms to look at. We didn't even have the ability to "chimp" an image until the film was processed, and then we had to look at it sort of "backwards". Nonetheless, we seldom had exposure problems and didn't feel that time was against us in getting decent images.

Skip,

Lightmeter? Way too posh. No way I could afford one of those when I started. I was one of the "Sunny 16" generation.

As in, using ASA 64 film, shoot at 1/64s at f/16 if its sunny, adjust if its not.