meter reading question

[Flash Harry]

I dont really care what lighting, I agree with you though, but if you do this for a living then presenting a client with browny colored shots of their black suits isn't going to get you much work. Adjust white balance. H

 

[netriaus]

When you spot metered the bag ... the meter will provide you with the exposure to render the bag as 18% grey ... which will over expose the bag since it is black.

In this situation you should know to under expose the shot to render the bag as black. So your meter was correct ... it was you understanding of what the light meter is doing that is throwing you off.

Same thing would go with a very white object (but in reverse).

If you really wanted to render the bag correctly ... put an 18% grey card in front of the bag and meter off it ... then take the shot.

[ OK, I have just repeated what MRogers stated ... hmm teaches me for not reading the thread closer before posting a reply ]

Well, this is a slight hijack, but I just wanted to say that your post finally made the concept of spot metering off of a grey card make sense in my brain. It was a concept that was *almost* connecting in my brain, but the wording of your post made it really click. It was one of those simple things that I should have figured out long ago but wasn't quite getting it. So... thanks!

 

[puyjapin]

so a grey card would have shown a exposure in the middle of the meter bar as correct but then after i move the card away it would show as an underexposure off the bag to get a correct exposure? so i need a grey card?

 

[JerryPH]

First... your meter has to be set correctly. It has to reference the correct ISO setting that your camera will be set at.

Second, incident and flash meters work differently. I assume we are talking about incident here becuase of the comment about a 5-second long exposure... unless you are using an incident meter set to a flash setting?


Third. All digital cameras try to expose everything to a medium tone. Blacks and whites *must* be compensated for to get accurate colour rendition. Cameras are basically stupid, human is smarter.

Fourth. Colour balance... been mentioned, but it should be adjusted before you start shooting, unless you are shooting in RAW and can adjust later.

Assuming that your meter is set to the same ISO as the camera, are using an incident meter, not a flash meter, that your are NOT using flash on the camera AND understand that the camera will try for an 18% gray on all tones... and you are STILL getting bad readings, the only possibilities left are:

1- meter is broke
2- camera is set to auto or exposure compensation is set away from a 0.0 setting.
3- camera is broke
4- user is not doing something right.

 

[dxqcanada]

Thanks Netriaus for the comment.

Puyjapin, yes.
Well, you do not really need a grey card. Very few photographers have them (... I actually have two that I keep in my camera bags). An incident Light Meter will do the same job ... but there again most photographers don't have that either (... I have a Sekonic L-328).

What most photographers have is their brain and experience.
You should learn to know that spot metering off of such a subject will provide you with an 18% grey exposure ... and that you should manually change the exposure to 1.5 to 2 stops lower in exposure.

Now some photographers have the advantage of having skin colour of the same exposure level as an 18% grey card ... or have taken a shot of their hand and remembered it's exposure to use as an almost grey card.

 

[puyjapin]

i still dont really understand. the meter i am reffering to is in the camera, not a seperate one

 

[puyjapin]

its the meter in the camera im referring to

 

[goodoneian]

In those two pics, where did you point the spot meter to take the reading ?
Also, I think on the D40, like my D90, each tic-mark on the exposure line is equal to .5 stop. So how many tics was the bottom shot reading underexposed, and compare that to how many stops difference between the two shutter speeds.
It should pretty much equal out so that if you increase shutter speed by 2 stops, your meter should read underexposed by 2 stops ( 4 tics ? ), all other things being equal, including that you meter on the exact same spot both times.

if i can recall correctly when i had a d40 each tick mark was 1/3 of a stop, not point .5. i could be wrong though but .5 of a stop tick marks on the d90 and d40 sounds wrong to me

 

[Flash Harry]

Yes we know, but all meters whether hand held or in camera work the same, its knowing when to under or over expose for correct rendition of the subject matter.

The bag is black, point your camera at it for a reading, this will show you the exposure, say 1/60 at F5.6, for what the camera says is correct. As we now know the camera is reading this as a mid tone 18% grey (not black) then we need to either dial in compensation or manually alter camera settings to achieve the black color, there are two ways, change shutter speed or aperture, switch the camera to manual and underexpose by a stop (sometimes 2 or even 3) by a stop I mean alter one of the settings, so you would end up with 1/120-125 shutter while aperture would remain at F5.6, for the same exposure, but for greater DOF, you would alter aperture, so your setting would be F8 at 1/60 for the same exposure. This for dark subjects only.

Overly bright subjects such as snow, white satin dresses etc, need overexposure, meter from the white would give say 1/1000 S. Speed at F5.6

(This all depends on the overall brightness of a scene and these numbers are for example only)

To overexpose in this case, you either lower the shutter speed, keeping the same aperture (IE=1/500 at F5.6) or for greater DOF again, reduce the aperture to F8 while keeping the SS to 1/1000 second.

All of this depends totally on the relative brightness or darkness of the overall scene, if its really bright sunny day photographing a snow scene then its possible you would need to overexpose up to 3 stops, similarly, dark subject dark scene you would underexpose by similar amounts.

Personally if unsure of the settings required for correct rendition, then do three shots at different settings, but only changing one of the values, overexposure settings would be from 1/1000 -1/500-1/250-1/125 second respectively, underexposure would be in the opposite direction.

ISO would need to be locked in whichever case and white balance set for the lighting in use at the time or, if shooting raw, alter this to suit in your software on computer H

 

[puyjapin]

i believe its a 1/3 stop for each tick. I just cant see the point in looking for a correct reading ie in the middle if that is not going to be correct

 

[puyjapin]

Yes we know, but all meters whether hand held or in camera work the same, its knowing when to under or over expose for correct rendition of the subject matter.

The bag is black, point your camera at it for a reading, this will show you the exposure, say 1/60 at F5.6, for what the camera says is correct. As we now know the camera is reading this as a mid tone 18% grey (not black) then we need to either dial in compensation or manually alter camera settings to achieve the black color, there are two ways, change shutter speed or aperture, switch the camera to manual and underexpose by a stop (sometimes 2 or even 3) by a stop I mean alter one of the settings, so you would end up with 1/120-125 shutter while aperture would remain at F5.6, for the same exposure, but for greater DOF, you would alter aperture, so your setting would be F8 at 1/60 for the same exposure. This for dark subjects only.

Overly bright subjects such as snow, white satin dresses etc, need overexposure, meter from the white would give say 1/1000 S. Speed at F5.6

(This all depends on the overall brightness of a scene and these numbers are for example only)

To overexpose in this case, you either lower the shutter speed, keeping the same aperture (IE=1/500 at F5.6) or for greater DOF again, reduce the aperture to F8 while keeping the SS to 1/1000 second.

All of this depends totally on the relative brightness or darkness of the overall scene, if its really bright sunny day photographing a snow scene then its possible you would need to overexpose up to 3 stops, similarly, dark subject dark scene.

Personally if unsure of the settings required for correct rendition, then do three shots at different settings, but only changing one of the values, overexposure settings would be from 1/1000 -1/500-1/250-1/125 second respectively, underexposure would be in the opposite direction. H

so are u saying i have to meter in an auto mode then go to manual. i have been metering in manual all the time, is this where im being misguided? are certain modes suited to take the reading?

 

[Flash Harry]

no, the meter reads the same in all modes 18% gray, its just darker/brighter subjects need compensating either one way or the other. H

 

[puyjapin]

so basically if there are lights and darks in a scene u cant expose both proprly?

 

[Steph]

You need to understand how your meter works. The light meter in your camera tries to expose the subject as if it was 18 % grey (that is meant to represent the reflectance of most common scenes). However your camera meter is not very smart and if you point it to a black object it will try to render it grey (hence over-exposing the picture). Conversely, if you were to point the meter at a white card, it will still try to render it 18% grey (hence under-exposing the picture). Try it for yourself: in auto mode, fill the frame with a white card and take a picture. Do the same with a grey and a black card and you will get three identical pictures.

If my explanation does not make sense, any book about photography basics should enlighten you. [ame="http://www.amazon.com/Understanding-Exposure-Photographs-Digital-Updated/dp/0817463003/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1235817699&sr=8-1"]Understanding Exposure by Bryan Peterson[/ame] is a good book.

 

[fwellers]

You need to understand how your meter works. The light meter in your camera tries to expose the subject as if it was 18 % grey (that is meant to represent the reflectance of most common scenes). However your camera meter is not very smart and if you point it to a black object it will try to render it grey (hence over-exposing the picture). Conversely, if you were to point the meter at a white card, it will still try to render it 18% grey (hence under-exposing the picture). Try it for yourself: in auto mode, fill the frame with a white card and take a picture. Do the same with a grey and a black card and you will get three identical pictures.

If my explanation does not make sense, any book about photography basics should enlighten you. Understanding Exposure by Bryan Peterson is a good book.

And to expand on that just a little for PJ, based on his last question, this is while in spot metering mode. If you go into another metering mode that takes more of the picture into consideration, then the camera takes averages of all the tones and tries to make them 18% gray.
You asked if you can't expose darks and whites correctly at the same time ? Yes, you can, but this is limited by the dynamic range of the camera. ( I think it's a limitation of the sensor itself but could be mistaken there )

btw, I guess I was wrong about that .5 stop between the tics. It probably is .3 but I think that is an adjustable parameter in the menu system.