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Monito wrote:
Manual mode or an automatic mode or P mode, they will all get you to the perfect exposure at the same investment of thinking. Most of the time you have to alter the meter reading regardless of the mode, especially if you are shooting EttR (Expose to the Right) in Raw mode.
The automatic modes or P will get you to a good approximation of the right exposure the fastest, so I sometimes shoot in those modes, biased a bit for EttR.
Shutterspeed, F/stop and ISO all affect exposure equally. If you have the perfect exposure level, you can alter any two of them in an opposing way and retain the exposure.
ISO is usually chosen for image quality. I try to shoot landscapes at ISO 100. On the 5D classic I don't worry about going up to 400. I will think twice for ISO 800 and three times for ISO 1600. On your 60D, you should probably not worry in the 100 to 800 range and think twice for 1600, but I can't say from experience.
A "stop" is a factor of two for light. Shutterspeeds you multiply / divide by the factor, but since aperture settings are already "geometric" since they control an area, you multiply by the square root of 2 = 1.4. But the aperture has built-in settings to account for that.
I set my cameras to step by one-third of a stop. You can set it to half-stops, but for digital (and colour slide film) you can get slightly more precise by third stops. Thus a stop would be three clicks.
So assuming a fixed ISO setting, then if you open up the aperture one stop (smaller number) then you make the shutter speed faster by one stop.
Try this experiment: on a sunny day, fiddle with the ISO to get your camera exposing nicely at f/8 and 1/400 second, whatever the ISO needed to get that, with the meter set to Averaging mode or center-weighted, of an ordinary scene, not backlit or anything fancy or unusual. Fiddle with the ISO until you are getting the meter in the center at f/8 and 1/400.
Now make an exposure at 1/200 f/8. It will be lighter. Make one at 1/800 f/8. It will be darker.
Make another or use the same 1/400 f/8 exposure. Now expose at 1/400 f/5.6. It will be lighter. The smaller aperture number means a wider aperture which means more light. Make another at 1/400 f/11. It will be darker. The higher f/number means a smaller aperture and less light.
Now make three photos: A) 1/400 f/8; B) 1/200 f/11; C) 1/800 f/5.6. They should all be the same level of exposure, neither lighter nor darker.
So if you cut the speed in half (more light) you need to compensate by adjusting the aperture to the larger number (smaller opening, less light) to end up with the same level because they counteract each other.
The apertures go in a main sequence: f/1.0, 1.4, 2.0, 2.8, 4, 5.6, 8, 11, 16, 22, and 32. Each of those is one stop, related by a factor of 1.4 as mentioned before.
In between are third-stop settings. So one-third above f/8 is f/9 and one third below is f/7.1. Between f/4 and f/16 here are the third stop settings for illustration: f/4, 4.5, 5.0, 5.6, 6.3, 7.1, 8, 9, 10, 11, 13, 14, 16. The actual numbers are approximations to two digits of the exact numbers, but that is plenty accurate for photography.
In between shutter speeds are also 1/3 stop settings. So from 1/100 to 1/1600 second you go 100, 125, 160, 200, 250, 320, 400, 500, 640, 800, 1000, 1250, 1600. Note that 125, 250, 500, and 1000 form a whole stop sequence subset, and so do 160, 320, 640, and 1250.
Now ISO works the same way, in the same third stop sequence. Higher ISO numbers are more sensitive and need less light. So make an exposure at ISO 200, 1/400 sec, f/8 and compare it to one at ISO 100, 1/400, f/8 and the second will be darker because of lower ISO. Now shoot it at ISO 400 and it will be lighter.
Experiment and fool around....Show more →
I am printing all this, taking it out in the field to try all you said.. Thanks a LOT for your help!
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Note: Ironically you have posted a complaint about people who post complaints [even though my post wasn't a complaint].