Taking the Mystery out of Exposure

March 31, 2014  •  1 Comment

Hi all, one of the things I get asked about most is exposure and why people's photos do not come out like they saw the scene they photographed.  Probably the most important factor in getting what you see recorded (wow I am still getting used to not saying something like down on film) is to understand what the meter in your camera is trying to do.

Light meters try to get the exposure to come out to a perfect 18% gray. This doesn't mean that it will make photos gray but that it will try to find a neutral tone that corresponds to that tonality one gets with the 18% gray card that we used to use to set our meters and exposures back in the film days. Well many people still use it today many professionals still meter to get that perfect exposure to begin work with.

I guess what I am saying here is lets say you go out and take a photo of a street and night. You see the very dark or black night sky, the bright lights and the way their light plays off the buildings or the street. You like the contrast and find the mood appealing. The shot is taken and it comes out kind of a wishy washy gray tone with no real darks or whites. That is the meter going for the 18% Gray.

To get the photo you saw in your head you are going to have to adjust your exposure.  On a dark scene and as counter intuitive as it may seem you will need to underexpose sometimes a couple of stops.  Many of the modern digital cameras have a meter control that will say plus or minus then a 1,2,3 after it so you can still use auto exposure and set the camera to underexpose up to the limit of the control

If you do not have this option or the degree you may want to alter the exposure is beyond what it will allow you will need to go to manual exposure.  I know many people who dread this but it really is very easy once you get the concept down.  If you set your camera on M you will have complete control of what it does exposure wise.

T

Check the meter in your view finder and when it shows perfect exposure (check your manual to see how it will display this) your exposure is set for 18% gray, then you can under or over expose as needed you will see the markings on the meter in your view finder. Now the good thing about digital is that you can shoot and chimp or look at your screen and see if the exposure is what you are looking for if not adjust it and since you are shooting digital it costs nothing to do. In  the old days many people bracketed the exposure shooting a stop over and under and steps in between to get that perfect exposure that will have information in all the lights and darks of the photo so a nice print can be made. That got expensive but now you can do it and it wont cost a thing but a bit of effort and time. Some people do this instead of meter they just shoot and adjust, it works but metering is better and especially when you begin to want to control all shades in the photo.

One other thing I would add here is that I always shoot in RAW, this will give you a greater latitude in exposure and dynamic range, the range of light to dark that the sensor will capture.  The human eye captures around 11 stops of light. A stop is a measurement for photography and the aperture and shutter speed combination will allow you to adjust that.  Anyway the cameras I use are able to capture 8 stops of dynamic range and most digital cameras are around this maybe a stop or two shallower.  Film captures about 3 stops of dynamic range which is why those of us who shot it for years really had to learn to expose correctly to avoid blown out or black spots in the photo. Sometimes the black looks great but I rarely see a blown out portion that looks good and they do not print well at all.  Nikon has come out with the D800 this camera will grab to 9.5 of dynamic range. It is almost approaching the human eye. I am sure in a few years we will be there and that will be amazing. 

To get the best dynamic range out of your camera shoot RAW if you shoot JPEG the camera processes the photo for you and you loose stops of range. Of course if you are not processing your photos then shoot JPEG and let the camera do the work for you but you loose control.

As far as a processing program I would recommend Lightroom, I use Lightroom 5 and it is amazing. I also use some plug ins for it as well as Photoshop CC and I will get into that later but if I were forced to choose one processing program that is the one I would go with.

Well this is a good start and I will add some tips specific to certain photographs to show how they were metered in my next Post.


Comments

Janice(non-registered)
Thanks for a very good article Rick. I have two of the cards for metering and I have to admit, I've never used one. I "chimp", lol, but I will try I and I'm sure it will produce a better picture.
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