《Practicing low-light landscape shooting》 【更多lynda教程字幕，尽在www.iacrobat.com】 All right. By now, you should know the drill.
【如果喜欢该教程，请购买正版！】 You come out in the dark, you stand around, you look for the shot, you frame the
【更多lynda教程字幕，尽在www.iacrobat.com】 【作品只能交流学习，不得用于任何商业盈利用途】 shot, you focus the shot, you think about your exposure.
Now what I have got here now is this big railroad tie that has washed ashore.
And way out over there are the cliffs and the sea and the rocks
offshore, so I am thinking this railroad tie makes a good anchor for a shot.
It's not that it's some kind of fascinating subject, but it's a place to hold the
viewers eye while I frame a larger shot around this entire scene here.
And I want some sky in the shot because I want some stars.
So again, I'm going to start by framing my shot, and it's bright enough out here
with the moon that I have ballparked it just by looking through the viewfinder,
but I still can't quite see the edges because it's dark.
I'm going to now take a shot as quickly as possible, just for the sake of
visualizing here and hence checking my framing.
So to get that as fast as possible, I am going to up my ISO to 12,000--not an
ISO that I am going to shoot at, but one that will allow me to just very
quickly capture an image.
I am in Program mode. I am in Manual Focus because I don't care about focus right now.
I am going to ask the guys to turn off the lights.
We have got though some lights on me right here, just so that you can see me.
I have still got mirror lockup enabled and I am liking this framing just as it is.
I had fiddled with this before we started this video.
I didn't just nail it right the first time.
So we have got the framing that I want.
Now I need to think about focus.
And in this case I am going to need really deep depth of field, because I want
this railroad tie in focus, and I want the stuff in the distance in focus.
Now I don't have to have a depth of field that covers that entire distance.
The stuff in the distance, if it's a little soft, that's not going to matter, but
we really, really need the railroad tie to be sharp.
So I am going to set a focus point on it and let my manual focus go to work here.
I am switching to Manual Focus.
I am getting out my flashlight again.
I don't actually need them to turn off the lights for this; in fact, the more
light in the scene the better.
And what I am doing now is inside my camera I have a choice of a number of focus
points and it turns out that there's one sitting just about in the middle of the
railroad tie, so I am going to manually select that focus point and half-press
the Shutter button and it is auto-focusing, so focus is locked.
Turn off my flashlight, switch the lens to Manual Focus because I don't want it
to try to focus again, when I half- press the shutter button, because without my
extra light around it's not going to find anything, and I am going to lose this
focus that I have set.
Now I can think about exposure. And we are going to do two different things with this shot.
We are going to start just by trying to get the shot.
I am going to dial my ISO down and just see what kind of shutter speed and
aperture the camera thinks we need.
I am going to go down to 800.
Greg, could you kill the lights please?
I need him to kill the lights to get an accurate metering.
I am still in Program mode and the camera is saying--let's turn the light on here--
13 seconds at f/2.8. Now I have already said I need deep depth of field; f/2.8 is
not going to cut it.
So I'm going to switch over to Aperture Priority mode, which I know is two
clicks from program on my Mode dial.
Notice that I didn't need to look at the camera.
It's good, because it's dark out here. I can't see the camera.
This is what I mean about you need to be able to work your controls
without looking at them.
I am going to dial my aperture up to f/8 and when I meter now, it says 30
seconds and it's flashing.
Now in this case that means, that it's saying, I've gone to 30 seconds and it's
still not exposed right.
So your image is going to be underexposed.
So the camera cannot do an exposure longer than 30 seconds on its own.
So I know that f/8 is too small an aperture at ISO 800,
so I'm going to bump my ISO to 1600 and see what happens.
And now when I meter, 30 seconds is still flashing.
So f/8 is really causing some trouble.
That means that I need to do an exposure longer than 30 seconds.
How do I do that if the camera won't let me dial in a shutter speed longer than 30 seconds?
Well, I have a mode here on my Mode dial called Bulb.
As long as I hold the shutter button down in Bulb mode, the shutter will stay open.
So I can hold it down for longer than 30 seconds and get the long exposure that I need.
The problem is handling the camera, pressing the shutter button and having to
hold it here, as it gets colder and I'm shivering and all that kind of stuff--
Greg, you can turn the lights back on--
having to hold the shutter button, that's going to really run the risk of
vibrating the camera. So I have hooked up a remote control.
This remote control allows me to press the shutter button and lock it, so it
will take care of holding down the shutter button for me.
Notice, too, that I don't have the remote control dangling from the camera.
I wrapped it around the camera and around my tripod here, because if it's
dangling from the camera and a wind comes up, that could blow it and that
could vibrate the camera.
So we have got the remote control all locked down.
So I have a way of pressing the shutter button without handling the camera, and
holding it down without handling the camera.
Now I need to know how long to hold it down for.
I could sit here and try and calculate this myself, but it's much easier to let
the camera do that for me.
Greg, lights please!
What I'm doing is I am switching the camera to Manual mode.
Now I know that I told you that I need to be in Bulb mode, and I will, but
for the time being I am going to use Manual mode to calculate the exposure that I need.
So I have said I want it at f/8, and f/8 at 30 seconds at ISO 1600 without the lights on,
Manual mode is now telling me that I am one stop underexposed.
So that's information I can use.
That's valuable intelligence there.
If at 1600 I'm one stop underexposed, I could go to ISO 3200 and have a correct exposure.
But I'd rather not shoot at ISO 3200; I'm little worried about noise.
I want to go back to ISO 800.
So at ISO 800--that's one stop down from where I'm at right now--I would be two
stops underexposed, at 30 seconds.
So, I am going to first dial my ISO down to 800 and when I do that, Manual mode,
the meter is now showing me that I am two stops underexposed at 30 seconds. Great!
So if I am two stops underexposed at 30 seconds, at one minute, I would only be
one stop underexposed.
At two minutes, I would be well exposed. That's the exposure that I need.
At f/8 I need to be at two minutes.
So, I'm now going to switch to Bulb mode and set my Aperture to f/8.
In Bulb mode I have control of aperture, but I do not have control of shutter speed.
I have my phone here now which has a stopwatch application on it.
I know I need a two-minute exposure.
I am going to reset my stopwatch.
Take my remote control here. I'm in Mirror Lockup mode still, so I am going to
press the Shutter button to raise the mirror.
Now when I press it again, the shutter will open, and I will lock it while I
start the timer, and so now I can let this go for two minutes.
Now I've got two minutes to kill.
So, I can go look for another shot.
I can enjoy the light on the water, or I can suggest that maybe we just go to a
cross dissolve and imply that time is passing.
Okay, we have got about 45 seconds left.
While we're waiting, I want to discuss one other matter here.
With this long exposure I'm going to have star trails.
There's no way around it.
In the last movie, I gave you a formula for calculating the longest exposure
you could use to prevent star trails, and at my current focal length I'm way beyond it.
However, as you saw earlier, I have framed this shot to be very wide.
And at short focal lengths you're not going to get really bright stars anyway.
Also, the moon is up and it's really washing out the sky, and on this shot I am
pointed a little more into the moon, so that's going to compromise my ability to
see very much in the way of stars, and there are some low clouds and a lot of
mist on the horizon.
So I don't think that I am going to get lot of stars in this image anyway.
And that's two minutes, so I'm going to close the shutter, and it comes up, and
there is my shot, and it looks quite reasonably exposed.
I managed to pull this off at f/8 at a reasonable ISO and yes, I can see there
is some slight motion in the stars but they still look fairly pointy.
Greg, you can hit the lights again. Thank you!
They still look pretty good.
So, I'm taking the shots pretty good.
I would probably go ahead and bracket it one stop in the other direction to get
rid of the star trails, if I decided I wanted pinpoints of light, and I would do
that by raising my ISO to 1600 and cutting my exposure time down to one minute.
I would still have a little bit of trailyness on the stars, but it would not be
as long as it is here.
Obviously, if I wanted to go for star trails, I would lower my ISO and possibly
even close down my aperture to give me a really, really long exposure.
But the way that I would calculate that again is by going into Manual mode and
letting the meter tell me how off my exposure is at a given ISO, and then I can
work backwards from there simply by doubling either my shutter speed, aperture
or ISO, to figure out a good exposure.
So, again, it's all a balancing act in any kind of shooting, but especially in low
【更多lynda教程字幕，尽在www.iacrobat.com】 light, but you should have all the tools that you need right here on your camera
to calculate exposures on the fly when you get into a situation like this.