Exposure!!

I learned the mechanics of proper exposure many, many years ago – back before digital was even invented, back when I shot with film with my old Pentax K1000.  So when I picked up my first DSLR a few years ago, I was ahead of the game somewhat from most.  People are buying DSLR’s today, and really don’t know how to use them beyond Programmed Auto mode.  As a matter of fact, until recently, I still relied on one of the semi-auto modes myself when doing my photography.

For action photography, like barrel racing, I knew I needed a fast shutter speed to “freeze” the action. So I would use Shutter Priority mode on the camera (“S” on Nikons, and I believe “Tv” on Canons) and manually set the Shutter Speed to 1/500 of a second, and then let the camera automatically adjust the Aperture.

For portraits, I was more concerned about the proper depth of field that the Aperture controls, so I would use Aperture Priority mode (“A” on Nikons, and I believe “Av” on Canons) and set the aperture to around f5.6, and then let the camera automatically adjust the Shutter Speed.

Recently however, I’ve been shooting strictly in full Manual mode.  Manual mode give me more control and allows me to set the exposure the way I want, to get the results that I want to see.

Anyway, I had been planning on writing a post about proper exposure for a while now.  But there are literally hundreds of videos about the subject on YouTube – so it seemed kind of pointless to do anything more than just link to some of those videos. Below are two of the videos that I like the best. He explains how ISO, Aperture, and Shutter Speed are all related…

The most important things to grasp and remember are the following;

Adjusting the Aperture one full f stop open, doubles the amount of light hitting the sensor.
Adjusting the Aperture one full f stop closed, halves the amount of light hitting the sensor.

Doubling the Shutter Speed, halves the amount of light hitting the sensor.
Halving the Shutter Speed, doubles the amount of light hitting the sensor.

Doubling the ISO setting, makes the sensor twice as sensitive to light hitting it.
Halving the ISO setting, makes the sensor half as sensitive to light hitting it.

Thus, with nothing else considered, from a pure exposure standpoint, the following are all identical:

ISO 100, f4, 1/100 is equivalent to;
ISO 100, f2.8, 1/200, which is also equivalent to;
ISO 200, f2.8, 1/400, which is also equivalent to, etc, etc, etc….

(NOTE: full f stops are: 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32 there are also 1/3 stops and 1/2 stops between each of those!!)  O_o

If you are interested in more, like the “whys” and “how comes”, then just watch the videos!  🙂

(NOTE: These videos are not mine! They came from YouTube Channel MyStudio® Table Top Photo Studios
 

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