Plan – Master Light and Exposure
Getting exposure right was the mission. After reading online and a few books, it was clear that mastering light and exposure was one of the most important things I would need to learn.
I used the Olympus E-520 auto exposure setting for a few days, but then found that it’s OK as long as there’s no motion. I haven’t tried the programmed sports mode under “Scenes” because I’m not going to master exposure using pre-programmed camera modes. I quickly graduated to using Aperture and Shutter Speed modes. After a week taking a thousand photos with those settings, I moved to Manual mode yesterday.
Now, I certainly haven’t mastered exposure, that will probably take a long time. However, I have quickly graduated from complete Auto mode to Manual mode. I don’t think you can take properly exposed photos in manual mode without at least knowing the basics.
The Basics
Here are the basics as I understand them at this point:
- Full Sunlight – Aperture = f/16, Shutter Speed = 1/125 at ISO 100. This is the starting point.
- As light changes brighter or darker, adjustments are made in increments called stops.
- Decreasing a stop increases light sensitivity on the camera sensor, increasing a stop decreases light sensitivity.
- If you increase shutter speed one stop (from 1/125 to 1/250) decrease aperture by one stop (from f/18 to f/22). Note that increasing an aperture number decreases the aperture opening which decreases the light falling on the sensor.
- Doubling shutter speed decreases light sensitivity one stop, halving shutter speed is one stop in the other direction and increases light sensitivity.
- If you decrease shutter speed by one stop (from 1/125 to 1/60) increase aperture size by one stop (from f/16 to f/11).
- Full Aperture stops are f/1.4, f/2.0, f/2.8, f/4.0, f/5.6, f/8, f/11, f/16, f/22, f/32.
- Larger aperture openings result in loss of background detail or depth of field (DOF).
- If you increase ISO (film speed) from 100, increase your shutter speed to the reciprocal of the the film speed. ISO 200 at f16 = 1/200 sec. shutter speed. ISO 400 at f/16 = 1/400 sec. Note that increasing ISO will increase noise in the photo.
- Doubling ISO increases light sensitivity by one stop, cutting ISO in half reduces light sensitivity by one stop.
- In some modes, you can also adjust exposure with the camera. My camera allows adjustment +/- 5 stops in 1/3 stop increments.
That’s what I learned from books and magazines and that’s what I took to the field in an interesting way. I’m working in the Philippines on a consulting assignment and I have a 20 minute commute in the morning and afternoon. This commute is my exposure experiment.
I’ll start describing the experiement in the next post. But, before I go, here is the shot from this morning that is the culmination of the experiment to this point.
The shot was taken while moving at about 10 miles per hour, through the van window while the van was making a turn. I had just an instant to set exposure, compose and shoot. Settings are f/5.6, 1/125 sec, ISO 100, Zuiko 40-150mm lens at 58mm. Time was 7:45 a.m. so the sun was hot behind the building. You can see the sunlight in the window in the upper right hand corner.

Cheers
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