Camera Focusing (Need help!)

shockimpulse

shockimpulse

First off, I have a Canon XL1 s and I must say I'm quite a noob. I mean, I try to study film on my own but its times like these when I need help from this site because my school doesn't offer help with film.

So I have two main problems/inquiries that revolve around camera focus.

1. My canon XL1 s does the strangest thing. I was on vacation this weekend, just testing out the ol' cam. I tried turning the dial to get the depth of field going, and to focus on my father. So, the objects in front of the camera turned blurry and he was the only thing focused. All good. But then, it automatically went back into making everything focused. It seems whenever I use manual focus to try and blur out everything or focus on depth of field, it works, then when i stop turning the dial, it goes back into making everything sharp.

2. Go to this video: http://www.youtube.com/watch?v=arpLaUZeL6k

Skip to :34 seconds. Notice how the main character is so sharp and defined while the background is all blurry. I have a canon xl1 and i've been trying to do it with the manual focus but it just doesn't seem to quite get it. any tips or help?

I posted that question on Yahoo Answers and I got this answer:

"Essentially, you need to take a shorter exposure with a wider apreture. This narrows the Depth of Field, keeping only a small part of what is in your lens to be in focus.

And THEN, manually focus only on what you want to be kept sharp."

So, I don't understand what the person means by "take a shorter exposure with a wider apreture". Yeah, I'm a noob. So if anyone can help with one or both of my problems, that'd be great. And if anybody knows a site or a video or anything that can help me study and understand manual focusing and depth of field, referrences would be nice!
 
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How to go from person to person in one scene?

I was watching a TV show and I remembered something that I always wanted to know. Let's say two people are talking and the camera is behind one of the persons, but we can still see both people.

Let's say the person far from the camera is person "A" and the closest is "B". So let's say "A" is talking. then "B" and almost everything else but "A" will blur. Then when "A" is done talking, "A" will blur and "B" will unblur and "B" will start talking.

Is this depth of field or some other technique? If it is, how do you do it properly? I'm fairly new so details would be appreciated!
 
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shockimpulse said:
I was watching a TV show and I remembered something that I always wanted to know. Let's say two people are talking and the camera is behind one of the persons, but we can still see both people.

Let's say the person far from the camera is person "A" and the closest is "B". So let's say "A" is talking. then "B" and almost everything else but "A" will blur. Then when "A" is done talking, "A" will blur and "B" will unblur and "B" will start talking.

Is this depth of field or some other technique? If it is, how do you do it properly? I'm fairly new so details would be appreciated!
Click to expand...

It's called a 'rack-focus'...or 'pull-focus.' You are pulling focus from one point to another. Set your focus on one person and if you're using a special lens with an adapter remember your focus point....then focus on the next person and set your number. Then either the DP. camera operator, or the second camera operator (whatever he's called) can hit those focus marks/numbers when needed.

If you don't have adapters and lenses, you can do it more easily by rehearsing a few times.

If you are not using lenses and you want to get that depth of field effect (DOF), you'll have to place the camera farther away and zoom in to the subjects...

Have fun playing around.


ps. Don't OVERUSE the rack-focus...it's annoying. The audience should hardly notice. Don't show off with it. :)
 
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M1chae1 said:
It's called a 'rack-focus'...or 'pull-focus.' You are pulling focus from one point to another. Set your focus on one person and if you're using a special lens with an adapter remember your focus point....then focus on the next person and set your number. Then either the DP. camera operator, or the second camera operator (whatever he's called) can hit those focus marks/numbers when needed.

If you don't have adapters and lenses, you can do it more easily by rehearsing a few times.

If you are not using lenses and you want to get that depth of field effect (DOF), you'll have to place the camera farther away and zoom in to the subjects...

Have fun playing around.


ps. Don't OVERUSE the rack-focus...it's annoying. The audience should hardly notice. Don't show off with it. :)
Click to expand...

What's this about numbers? Sorry, I'm really new to all of this and I'm just trying to learn. And no I don't have any adapter or different lenses.
 
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shockimpulse said:
What's this about numbers? Sorry, I'm really new to all of this and I'm just trying to learn. And no I don't have any adapter or different lenses.
Click to expand...

Lenses have numbers on them...that way you know which number corresponds to which focus point.

If you're not using lenses then your DOF will be much less apparent. Most standard DV cams have infinite focus (maybe I'm wording that improperly), so in general all of your subjects will be in focus. So if you want that really shallow DOF look...you'll have to bring the camera farther back from your subjects and zoom in...this should allow you to focus on one of the people and if the other person is far enough behind the other person they will be out of focus. Then just rack to the next person when your ready. It's much harder to achieve with a stock DV lens.

Maybe a DP here can help you out more effectively. Anyone?
 
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You are right that most consumer cameras are set at infinity for focus.

Infinity = Everything is sharp.

When you have have lenses attached, you can focus from a certian point up to infinity.

If your working with a consumer camera, there's no need to worry about this effect.
 
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That stock lens SUCKS!

There, I said it.

You can't rack focus with that lens. Okay, not
exactly true. Take your camera far away from
the subject and zoom in. You can do a bit of a
rack focus that way.

You need a much better lens to do what you want.
Fortunately you have that option with the XL1.
 
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If only I had the money to get an XL2... also, I have a question. So I tried the rack-focus and it worked, but after i stopped turning the dial, everything turned sharp again. Like, INSTANTLY. Is there a way I can stop this? I have a Canon XL1s
 
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Hrmm, well what lens do you suggest directorik? If you're thinking about price, you can just suggest a lens that's a reasonable price, and then you can suggest the best one, regardless of the price.

And Michael, is the effect in the video I linked, Rack-focusing? The guy seems to be walking forward and he's so clear and defined while the entire background is blurry.

And can anyone explain to me clearly what this means?

"Essentially, you need to take a shorter exposure with a wider apreture. This narrows the Depth of Field, keeping only a small part of what is in your lens to be in focus.

And THEN, manually focus only on what you want to be kept sharp."

I don't quite understand what it means by "take a shorter exposure with a wider apreture."
 
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Im not sure what exposure has to do with DOF.

Exposure is how much light is let in.

The apreture is what is in focus at a certian length. A wider apreture would make more things in focus.

So I don't understand that statement.


Rack focusing is:

[Camera]<~~O~~//O//~~~~~

~=blur, /=in focus, O=person

So racking is going from Diagram 1 to Diagram 2:

1[CAM]< ~~O~~//O//~~~~

2[CAM]< ///O///~~O~~~~~

you switch your focus from one person/object to another.
 
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So I tried the rack-focus and it worked, but after i stopped turning the dial, everything turned sharp again. Like, INSTANTLY. Is there a way I can stop this? I have a Canon XL1s
 
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shockimpulse said:
So I tried the rack-focus and it worked, but after i stopped turning the dial, everything turned sharp again. Like, INSTANTLY. Is there a way I can stop this? I have a Canon XL1s
Click to expand...

The stock lens on that camera SUCKS!

Oh wait. I think I already said that.

A fairly nice prosumer camera that was expensive in
its day made by a company known for its excellent
lenses and the put a crappy lens on it.

shockimpulse, you want to rack focus, you have to
use a different lens.
 
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turn off your auto focus (AF on the left side of the lens)... you'll have to practice ALOT with the XL1s as there are no numbers to hit with the focus (the only real problem I have with the XL1/s ... can be done though)... know that on that lens, the faster you turn the focus ring, the faster it will focus (not in a 1 to 1 fashion unfortunately).
 
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knightly said:
turn off your auto focus (AF on the left side of the lens)... you'll have to practice ALOT with the XL1s as there are no numbers to hit with the focus (the only real problem I have with the XL1/s ... can be done though)... know that on that lens, the faster you turn the focus ring, the faster it will focus (not in a 1 to 1 fashion unfortunately).
Click to expand...

Hrm the switch is to the ride on the M but it's still being weird. and it keeps focusing back into focus. and the rack focusing is being an ass.i try to focus on one object/person but i dont have enough time to adjust it right cus it keeps going back into making everything sharp
 
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