EV – EXPOSURE VALUE

1. EV – EXPOSURE VALUE

2. Why you may need to adjust the ev • Changing the EV will ensure your photos are correctly exposed. • On “AUTO” setting your camera chooses an exposure setting about mid-way between the brightest and darkest areas. Most of the time this works well. Where the problem arises is when your image is very bright (like snow or beach scenes) or very dark (like forest depths)

3. MORE ABOUT LIGHT • There is about 1000 times more light outdoors on a sunny day than in an indoor room with average lighting. • Our eyes can simultaneously process a sunlit meadow and a log in the deep shadow. • Cameras are getting better but still have nowhere near the capability of the human eye. • So, what to do?

4. CHECK Your camera settings • You may have a setting on your camera which will allow you to adjust the EV. • If your camera does not have this capability, do you have “special” modes which adjust exposure? Try this exercise with those. • You will probably only be able to adjust the EV in certain camera modes, likely not in “automatic”. EXPOSURE VALUE can be usually be adjusted in 1/3 steps from -3.0 to + 3.0. Your camera may have different values. • Take a few photos. Set the EV to it’s lowest (-) setting and go as high as it’s highest (+) setting and see what happens to the light in your image.

5. SO, WHAT DOES THIS EXERCISE PROVE? • The following samples will demonstrate that by adjusting the EXPOSURE VALUE you can lighten or darken your image without changing the location or available lighting. • These photos were taken indoors with minimal lighting. The white balance was set to automatic and the ISO to 400

6. EV +2 EV +1

7. EV 0 EV -1

8. EV -2 Now the photo is way too dark

9. SO, WHAT DID YOU LEARN? • if your image appears too bright, simply adjust the EV to the minus value (-). This adjustment is often necessary with a bright sky to keep the sky from washing out to white. • And, if your image appears too dark, adjust the EV to the plus value (+). Adjusting the EV value upward can improve the appearance of flowers, food and snow.

10. Sunset & sunrise • Changing the exposure value is a great way to capture stunning sunsets and sunrises. • The sun can mess with the exposure in a darker sky. On automatic settings, the camera will set a higher exposure to compensate and this results in the rest of the image being darker and the sky colours can be destroyed. • In a snow scene, the camera is fooled because there is too much white and your image may appear gray. • Set the EV to +1 or +2 and bring back the colours or the whites!

11. THE HOLY TRINITY OF PHOTOGRAPHY –iso, aperture & shutter speed For the purpose of this discussion on EV, we will focus mainly on ISO. ISO refers to the “speed” at which a camera sensor absorbs light. Obviously then, your camera’s ISO setting is very important when discussing “Exposure Value”. We have discussed Aperture Priority and Shutter Speed in the past, and without a doubt, we will discuss them again in depth but today they only get a brief mention.

12. MORE ON ISO • ISO is the electrical charge that affects the sensor – or speed. It was called ASA on film. • Outside on a bright day you would use an ISO of about 100, maybe 400 for a cloudy day& much higher at dusk or after dark. • A slow (low) ISO gives minimal “noise” & so is preferable for sharper photos. But, you will have to use a faster (higher) ISO, maybe 1600 at dusk or after dark. Here’s where your tripod becomes important. • If the light remains constant, you needn’t change the ISO setting.

13. You may have a setting on your camera which will allow you to adjust the ISO. • Again, you may only be able to adjust the ISO in certain cameral modes such as “manual” ISO settings differ from camera to camera but often can be adjusted from 100 to 25,600 – there is no automatic setting in this mode. • Take a few photos. Set the ISO to 100, then go as high as ISO of 3200 and see what happens to the light and noise of your image. • So, that’s what ISO is!!

14. ISO 100 Note the shadow - another lesson learned, remove the hood from the lens when using flash photography ISO 200

15. ISO 400 ISO 800

16. ISO 1600 and now the photo is too light

17. BECAUSE IT ALSO AFFECTS “EXPOSURE VALUE” WE will MENTION “APERTURE PRIORITY” • PUT CRUDELY, APERTURE IS THE SIZE OF THE HOLE THROUGH WHICH THE LIGHT PASSES ON THE WAY TO THE SENSOR. IT LIVES IN THE LENS. • MAKING THE APERTURE LARGER ALLOWS IN MORE LIGHT, MAKING IT SMALLER ALLOWS IN LESS. IT IS MEASURED IN “f STOPS”. • SOUNDS BACKWARD, BUT THE HIGHER THE F STOP #, THE SMALLER THE DIAMETER OF THE LENS OPENING. • APERTURE NOT ONLY ASSISTS WITH EXPOSURE, BUT DETERMINES THE DEPTH OF FIELD.

18. BECAUSE IT ALSO AFFECTS “EXPOSURE VALUE” WE will make MENTION of “SHUTTER SPEED” • THE SHUTTER IS LIKE A DOOR. IT ONLY OPENS WHEN WE PRESS THE SHUTTER BUTTON. • THE LONGER THE SHUTTER STAYS OPEN, THE MORE LIGHT IT LETS IN. • SHUTTER SPEED NOT ONLY ASSISTS WITH EXPOSURE, ADJUSTING THE SHUTTER SPEED ALLOWS YOU TO “BLUR” OR “FREEZE” MOTION.

19. IN SUMMARY • SO, AS AN EXAMPLE, IF YOUR SHOT LOOKS TOO DARK, YOU CAN TRY THE FOLLOWING ADJUSTMENTS TO IMPROVE YOUR EXPOSURE VALUE. • A) INCREASE (+) your EV setting (e.g. from +0.0 to +3.0) • B) LOWER the ISOsetting (e.g. from ISO 400 to ISO 100) • C) Open up the APERTURE (DECREASE your F stop #) to allow more light in. (e.g. from F8 to F4) • D) Slow down the SHUTTER speed to allow shutter to stay open longer, letting in more light. • Or, if you cannot make these adjustments on your camera, do you have special modes for “beach” or “snow”?

20. A final word on EV • As with everything to do with photography PRACTICE….PRACTICE….PRACTICE • Most cameras today do have the ability to adjust the exposure setting, but not in every shoot mode. A lot of cameras today (not only DSLR’s) have the ability to adjust ISO, Aperture, and shutter speed as well. • Some point and shoot cameras will instead have special “scene” modes such as for “beach” or “snow”, which will set the appropriate EV for these bright scenes. These settings are often good enough. THE END