Argghhh! When do you use EV comp? Metering nightmare

wildviper

Hi All,

Seems like I am having a brain freeze for the past few days. I think I just have read too much not practiced enough.

Anyways, when do you guys/gals use EV comp using Av mode? Here is my problem.

From what I understand of Zone system, a yellow would most likely be a +2/3 comp or even a +1.

So I tried to do a test with the four pictures below:

All Spot Metered.

1. Grey Card



This came in at 1/40, f 5.6, ISO 200

It is not a straight line up in the middle of the histogram though for some reason.

2. This is -1 exposure comp. Spot Metered on the yellow head.


This came in at 1/60, f 5.6, ISO 200.

3. This is at 0 EV. Spot metered on the same spot.



This came in at 1/30sec, f 5.6, ISO 200.

and finally

4. This is at +2/3 EV Comp. Same Spot Metering.



This came in at 1/20, f 5.6, ISO 200.


As you can see my confusion. I like the -1 EV comp picture the best due to the richness of color. However, going by Zone System, the proper expo should be the last one with +2/3.

So how do you guys meter???? I am completely confused. For a Caucasion person, would you put the skin tone at +2/3 EV or not?

pathfinder

Your card gave a reading of 1/40th f5.6 ISO 200. Why didn't you try that exposure in Manual Mode for one of your shots? Sounds like you might have liked the results.

Many folks agree with 1/2 to 3/4 of stop of +EC for a Caucasian complexion - depends on the degree of fairness, swarthyness to an extent, High key or film noir, light or dark.

Nikolai

As you probably know, any automated camera system is trying to bring ANY your image as close as possible to your #1. It cannot tell what's important and what's not. Even all the recent face recognition woodoo can be - and often is - easily fooled.
So it's up to you, really, to tell the camera what exact exposure you want. With a lot of experience you can nail it almost each time. For less experiences (or less talented, like the most of us) there is a RGB histogram. Yet still it's only a technical tool, glorified gray void. It's only you who knows HOW you want this image. And I agree, your #2 is the best. You like it. I like it. I think most of the viewers will like it it over more exposed ones, too.
The question is: why do you care if it's -1 or +2/3? There is no universal setting...
And for your last question: Caucasian skin has nothing to do with flowers, so don't expect -1EV to work for all white male portraits...
HTH

wildviper

Nikolai wrote:

The question is: why do you care if it's -1 or +2/3? There is no universal setting...
And for your last question: Caucasian skin has nothing to do with flowers, so don't expect -1EV to work for all white male portraits...
HTH

I care because I would like to know by looking at a scene what settings should be. I know it takes practice, but this exercise just threw me off today. I was fully expecting to see the -1 EV as being way underexposed not good. I expected the +2/3 to be vibrant with color.

I asked about Caucasian skin only cause I have it hard wired in my brain that it should be +1/3 to +2/3. With the above example I am confused.

wildviper

pathfinder wrote:

Your card gave a reading of 1/40th f5.6 ISO 200. Why didn't you try that exposure in Manual Mode for one of your shots? Sounds like you might have liked the results.

Many folks agree with 1/2 to 3/4 of stop of +EC for a Caucasian complexion - depends on the degree of fairness, swarthyness to an extent, High key or film noir, light or dark.

Pathfinder, I am not sure why I didn't try the grey card settings. I thought I did, but obviously I didn't. The question is though, the flower is not middle tone in my mind. So, the setting wouldn't have worked anyways no?

Don't you always have to make an adjustment if the tone is not middle tone. What the heck is middle tone anyways???

pathfinder

If you are using a true grey card, then there should be no need for adjustment for the proper exposure for light or dark tones, as the 18% grey card is supposed to always give a reflected light meter reading in the middle of your histogram.

Think of an incident light meter, rather than a reflected light meter. There is no need for adjustment of the meter reading because it reads the incident light falling on the subject, not light reflecting from the subject, which could be very light or dark.... When you use a grey card, the grey card is defined to be a middle tone, so in essence, you are getting the correct exposure whether the subject is white or black or yellow. If you meter off a light tone or a dark tone, yes, then you need to compensate for a reflected light meter. But you read off a middle grey tone hence no compensation needed.

The truth of this can be seen by the fact that the exposure reading from the grey card seems more likely correct than any of the three images you shot too.

A middle grey reads 128,128,128 by definition

Purchase a Kodak grey scale and photograph it and see if you can capture the entire grey scale with the center tone at 128,128,128 when you shoot in camera jpgs. Your exposure will have to be within 1/3 of a stop accurate to even come close.

wildviper

Got it. Thanx for that explanation. I think this is where I was thrown off a lot of times too.

I metered the grey card and then I would adjust from that point to compensate for white or black or yellow. Per your explanation, I SHOULD NOT be adjusting as long as I had the grey card in the same light.

Makes sense.

Ok, I have another problem...the grey card is a true grey card..not Kodak, but off brand from a camera shop. When I shoot it, sometimes I get the middle values lined up right, but most times I have a histogram that is going -1/3 to +1/3 and spiking in middle. I have noted that my lens (18-70DX) has vignetting...could that be the reason why I have the weird histograms? I usually ensure I don't have any shadows or things.