THE GOLDEN TRIANGLE > ISO > APETURE > SHUTTER SPEED
I have copied down some things from the web that I think you may
find helpful. Before you get to that I want to try and explain a couple
of things that we will be doing in our class.
SHOOTING At NIGHT WITHOUT A TRIPOD OR FLASH
First off let me give you this example of shooting at night without a
tripod and a flash. You’re walking down the street in YBOR and
you’re shooting in the Aperture setting. (Remember, the lower the
number i.e. f1.4, f2.8. f4.5 the more light in your camera. The higher
the number, f9, f11, f22, the less light.)
Set your camera in the Aperture setting to either f 4.5 if you want your
subject to be in focus and the background blurry, or f 9 or higher, if
you want everything in focus. Now you’re going to chase the light
exposure using only the ISO. Somewhere between 1600 and 3200
your shot will look like it was taken during the day! If it doesn’t keep
raising the ISO until it does. Remember, the higher the ISO setting
the more noise you will get and have to use a noise reduction
afterward in the editing process.
You don’t have to do anything with the Shutter Speed because when
you shoot in the Aperture Setting, the camera will automatically set
your shutter speed for you. Thank you camera!!!
LOW LIGHT WITH A TRIPOD, NO FLASH
You’re out and you are shooting the Tampa Skyline from Davis Island .
You always want to shoot in the Manual setting because the Aperture
setting will not give you a true color setting. When your camera is on
your tripod make sure that you turn off your shutter stabilizer or image
stabilization on your lens. Otherwise, your picture will be blurry when
you enlarge it.
Set your ISO on 100, you’re Aperture on say f-9 or f-11. You will
never touch them again as the only thing you’re going to move is your
Shutter speed. Depending on how dark it is you may set it for let’s
say 1 second. If your picture is too bright, turn it down less than one
second and keep going down until you have a properly exposed
picture. As the sky gets darker…., keep increasing the seconds to 2,
then, 3, then 4 as it gets darker and darker. That’s it!!! You now have
beautiful properly exposed night time low light photos!
STARBURST SPARKLE LIGHTS AT NIGHT
Again set your camera on Manual and then set your Aperture on f -14
to f-20 and above if you have anything higher. The higher, the better!
Let’s start at f-20 and then set your shutter speed to 30 seconds and
see what you get. If it’s too bright start lowering you shu tter speed to
25 seconds and keep going lower from there until you get the
exposure you want.
OR……
Go the other way….. keep your camera on 30 seconds and bring you r
Aperture down to say f-18 and keep going lower but do not go past f-
14 or you will lose the sparkle.
You can use a combination of both if you want as well. I prefer to
use the top one but practice this until you understand the results and
use whatever combination you like for your desired results.
FROM THE WEB.....
Adjustable elements that control the exposure - ISO, Aperture and
Shutter Speed.
1 What controls exposure?
ISO ratings determine the image sensor’s sensitivity to light, each value
of the rating represents a “stop” of light, and each incremental ISO number
(up or down) represents a doubling or halving of the sensor’s sensitivity
to light.
The Aperture controls the lens’ diaphragm, which controls the amount of
light traveling through the lens to the film plane. The aperture setting is
indicated by the f-number, whereas each f-number represents a “stop” of
light.
The Shutter Speed indicates the speed in which the curtain opens then
closes, and each shutter speed value also represents a “stop” of light. The
shutter speed is measured in fractions of a second.
When these three elements are combined, they represent a given
exposure value (EV) for a given setting. Any change in any one of the
three elements will have a measurable and specific impact on how the
remaining two elements react to expose the film frame or image sensor
and how the image ultimately looks. For example, if you increase the f -
stop, you decrease the size of the lens’ diaphragm thus reducing the
amount of light hitting the image sensor, but also increasing the DOF
(depth of field) in the final image. Reducing the shutter speed affects how
motion is captured, in that this can cause the background or subject to
become blurry. However, reducing shutter speed (keeping the shutter
open longer) also increases the amount of light hitting the image sensor,
so everything is brighter. Increasing the ISO, allows for shooting in lower
light situations, but you increase the amount of digital noise inherent in
the photo. It is impossible to make an independent change in one of the
elements and not obtain an opposite effect in how the other elements
affect the image, and ultimately change the EV.
I ISO Speed
ISO is actually an acronym, which stands for International Standards
Organization. The ISO rating, which ranges in value from 25 to 3200 (or
beyond), indicates the specific light sensitivity. The lower the ISO rating,
the less sensitive the image sensor is and therefore the smoother the
image, because there is less digital noise in the image. The higher the
ISO rating (more sensitive) the stronger the image sensor has to work to
establish an effective image, which thereby produces more digital noise
(those multi-colored speckles in the shadows and in the midtones). So
what is digital noise? It is any light signal that does not originate from the
subject, and therefore creates random color in an image. The digital
camera engineers have designed the image sensor to perform best at the
lowest ISO (just like with film). On most digital cameras this is ISO 100,
although some high end DSLRs have a mode that brings the ISO down to
50 or even 25.
A Aperture
A lens’s aperture is the opening in the diaphragm that determines the
amount of focused light passing through the lens. At a small f -stop, say
f/2, a tremendous amount of light passes through, even at a fraction of a
second; but at f/22, when the diaphragm is perhaps at its smallest, only a
tiny amount of light is let in (even at longer shutter speeds). An interesting
thing about the aperture and the f-numbers is that it doesn’t matter the
focal length of the lens as long as the f-number is held constant. This is
because the arithmetical equation that determines the f-number indicates
that the same amount of light passes through the lens on a 35mm lens as
on a 100mm lens, with a shutter speed of 1/125s. The size of the
diaphragm is unquestionably different, but the amount of light passing
through is the same.
S Shutter Speed
Shutter speed is measured in fractions of a second, and indicates how
fast the curtains at the film plane open and close. The shutter speed
controls how long light enters the lens and hits the image sensor or film
plane. The shutter speed enables you to capture the world in split
seconds, but it can also absorb the world at speeds upwards of three and
four seconds (or remain continually open up until the photographer wants
to close the curtain). Snapping the shutter in a fraction of a second, also
gives you control on how motion is recorded. If the shutter speed is faster
than the object or background, then the image will be tack sharp. If the
shutter speed is slower, then you’ll get blurred objects. Think about the
rain in a rainstorm, how fast is that water falling? Well, at 1/30th the
raindrops are streaks of undistinguishable white. But at 1/250th, the
raindrops hover in mid air and you can see the full swell of each water
drop.
2 What is "Auto Bracketing"?
Auto Bracketing is an exposure technique whereby you can ensure that
you have the optimal exposure by taking at least three (3) exposures of
the exact same composition with one at the metered EV, one at 1/3 of a
stop below the metered EV and one at 1/3 of a stop above the metered
EV. So “Auto Bracketing” is a function in which you set the EV value then
release the shutter and the camera automatically makes the necessary
up and down adjustments to the EV to give you the bracketed exposures.
Then you can review the three (or more) exposures, see the subtle but
critical differences in the images, and decide which one is the best image
for your purposes. In the three images on the right, you might prefer the
overexposed (by 2 stops) image because the setting sun is most brilliant.
Bracketing was a technique that was popularized from shooting slide film,
due to the limited ability to correct the image in the darkroom. Many
photographers still use the technique today, so they have the exposure
that they want. Having the three bracketed images lowers the amount of
post-processing time that they might have to spend.
3 Overexposure & Underexposure
How do you define overexposure and underexposure, since we said that
“correct” exposure is subjective? Simply put, overexposure is when the
information in the highlights is effectively unreadable. When there is this
type of excessive loss of image information there is no way to “retrieve”
that missing information in the digital dark room. Underexposure is pretty
much the same concept; except in this case there is no image information
contained within the shadows. This non-existent information cannot be
retrieved through post processing either. In digital photography, once that
image information is gone, there’s no way to retrieve it. This is not always
the case in the photochemical world of film photography. With film (as
opposed to digital) processing, it is possible to “find” image information in
an excessively underexposed frame, and perhaps “find” image
information during the printing process for seriously overexposed images
as well.
4 AE LOCK (AEL)
Auto Exposure Lock is a camera setting in which the EV is locked in (when
you’re shooting one of the semi-automatic or fully automatic modes, i.e.
Shutter-priority), so that no matter what changes there are to the lighting
in the scene, the camera locks in the ISO, Shutter and/or Aperture
settings, so you can continually achieve the same EV without having to
re-meter the scene.
C Conclusion
One highly practical advantage to digital photography is that it costs next
to nothing to experiment with the camera’s controls, so go out there and
shoot away. You want to become increasingly proficient with all three
elements of the exposure triangle, so that you can make adjustments on
the fly and know exactly what the resulting effect is going to be.