- I, uh, I said in the last movie
that I wasn't going to do any recap of what we
covered in the first part of this series,
but I just can't help it.
I feel like there's one thing that I have
to go over again to kick off this chapter,
and that is the importance of checking
shutter speed to ensure a sharp image.
As you should now know,
when you half press the shutter button
to meter the light in your scene,
your camera calculates a shutter speed
aperture combination that will yield
good, overall brightness.
And then shows you those settings
in the cameras viewfinder.
Now if you're working in dim lighting,
it's possible that the shutter speed that the
camera chooses will be too slow to effectively
use when you're shooting hand held.
When the shutter's open for a longer time,
any tiny motion in the camera can cause
an overall softening in your image.
Now, you may think you have a very steady hand,
or that a 30th of a second is still a really
fast shutter speed,
but it just doesn't take much motion
to soften an image.
In part one of this series I recommended
that once your shutter speed drops below
a 60th of a second,
you should take action to speed it back up.
And so we looked at using program shift
to switch to an equivalent combination
of shutter speed and aperture,
but an equivalent combination at a faster
shutter speed and corresponding wider aperture.
We also looked at raising ISO.
I also mentioned that there's a guideline you can
follow for computing the slowest shutter speed
that you can use with a given lens.
I covered that guideline in my
Photography Foundations: Lenses course.
In that course, you'll also learn about the
effects of image stabilization and how it can
dramatically ease hand held shooting.
Now you might think,
I'll just avoid this whole risk of camera shake
thing by always trying to keep my shutter
speed really high.
But as you accelerate your shutter speed,
you'll be preventing more light from getting
to the image sensor,
that will require you to use higher ISOs
which will result in your final images
having more noise.
What's more, faster shutter speeds will require
you to use wider apertures,
and, as you'll learn in the next chapter,
a wider aperture has a huge impact
on your final image.
One that can cause some parts of your image
to go out of focus.
So when you go to a wider aperture
to prevent motion blur,
you've possibly exchanged one sharpness
problem for another.
Choosing exposure settings is a balancing act.
How much brightness do you want?
How much motion?
How much ISO noise are you willing to tolerate?
And so on.
There are a lot of decisions involved,
but if you are someone with a tendency
towards analysis paralysis, don't worry.
Most of the decisions you have to make
will be bounded by practicality.
I can't shoot with a shutter speed this low
because my image will be shaky,
or I can't shoot with a shutter speed this fast
because I don't want the moving water
in that fountain to get frozen, and so on.
The more you learn about exposure,
the easier it will be to juggle all
of these competing creative
and practical decisions.