<a href=showthread.php?s=&postid=13688903#post13688903 target=_blank>Originally posted</a> by Pmolan
I meant camera settings.
I did research for RAW. The opinions seem to be that its too much trouble to work with the large files as they take up too much room on the memory card. Some swear by it.
I think RAW is the way to go to slightly edit a photo but I think I need to learn to take decent photos first.
You need to learn the basics of exposure and metering.
In an above statement, mentioned 18% grey. Your camera takes a measurement of light to come up with an estimated exposure. The meter sees the world as 18% grey. It is your job as the photographer to decide whether the object you are metering from echos an 18% grey reflection.
On a very very very basic level:
Your camera sees very dark surfaces as grey. The meter will give an exposure too bright, trying to match a black car to grey.
Your camera sees very light surfaces as grey. The meter will give an exposure too dark, trying to match snow to grey.
So, again on a very basic level, you want to -subtract- exposure when metering off of dark surfaces. You want to +add+ exposure when metering off of light surfaces.
As you experiment and learn, choosing whether to lessen or add to an exposure's "brightness" will become second nature. For example, a leafy green tree in the bright sun will generally correctly expose -negetive 2/3 of a stop".
What is a "stop" anyway you may ask. Each of the three major exposure components are separated into basic increments.
Aperture is measured by a circular opening in the lens. the square root of 2 is ~ 1.41
f/2.8 is generally the widest opening of high quality zoom lenses. 2.8 X 1.41 ~ 4. So, f/4 is the next stop. f/4 will allow TWICE as much light as f/2.8
4 X 1.41 ~ 5.6, so f/5.6 is the next stop and so on. These stops are often measured in 1/3 increments in modern DSLR cameras:
f/2.8 f/3.2 f/3.5
f/4 f/4.5 f/5
f/5.6 f/6.3 f/7.1
f/8 ect.
The main thing to observe is that each stop doubles the last.
Shutter speed is measured in seconds, or more commonly fractions of a second. No circular openings or trigonometry to deal with here, shutter speed is very straight forward.
1/100 1/125 1/160
1/200 1/250 1/320
1/400 1/500 1/640
1/800 ect.
ISO measures how sensitive your sensor is to light. The side effect of extra sensitivity is interference or "noise". ISO always starts as 100. It goes in increments very similar to shutter speed.
100 125 160
200 250 320
400 500 640
800 ect.
Some advanced cameras allow ISO 50, effectively making the sensor LESS sensitive to light. This would be useful for attempting longer shutter speeds in bright light for example. Even though ISO 50 comes before 100, ISO 100 is the starting point.
------------------------
Now above are the basic increments of exposure. I could not pull EXIF data from your images to see your actual exposure setting, so I will make one up. This will be NO WHERE NEAR what the actual exposure in your image was, I am using these numbers for demonstrational purposes only.
Lets say you take an image and it comes out way to bright. Your exposure was as follows:
Aperture: f/5.6
Shutter Speed: 1/400
ISO Speed: 400
To bring the "brightness" of the image down, you could lessen any of these settings by one stop.
Changing the Aperture to f/8 OR the Shutter Speed to 1/800 OR the ISO speed to 200 will all have the same effect on the brightness of your sandbed. It is up to you whether to change the exposure by 1/3 of a stop, 2/3 of a stop, an entire stop, or more.
Don't forget to correctly interpret your metering. If you metered off the live rock, the camera would likely make the image too bright. If you metered off the sand, the camera would likely make the image too dark.
So now your thinking...I'm really new to this. How in the heck am I supposed to have a 6th sense about what the camera is thinking?! Enter the histogram. There are several types of histograms but we will just worry about the basic brightness graph here.
A histogram is a bar graph showing the range of brightness the camera can see. Off the scale to the left will be completely black. Off the scale to the right will be completely white (like your sand). Adjust your exposure -negative- until everything shifts to the left. You can experiment with the results and get creative with them. Sometimes you might WANT parts of the graph off the scales. Either way, with a histogram, you can know what you are going to get.
