Laser Rangefinder for precise focusing? at DVinfo.net
DV Info Net

Go Back   DV Info Net > The Tools of DV and HD Production > Open DV Discussion
Register FAQ Today's Posts Buyer's Guides

Open DV Discussion
For topics which don't fit into any of the other categories.

Reply
 
Thread Tools Search this Thread
Old March 16th, 2007, 04:26 AM   #1
Regular Crew
 
Join Date: Jan 2007
Location: Zurich (Switzerland); Luxembourg (L)
Posts: 44
Laser Rangefinder for precise focusing?

Hello,

because of the uneasy way to get my focus right (Peaking on, zooming in + magn.) on my XH A1, I thought of buying a Laser Rangefinder (thats how Babelfish translated from german...donīt know if its the right term for the tool).
Like that you just could measure the distance very fast and set Focus afterwards....what would take far less time then otherwise.

The price for such equipment begins at approximately 100 euros.
There are some really good ones from Leica (A2) for about 170 euro, they go from 0,05m to 60m.

Has anyone already tried this, any experiences?
I donīt want to spend that much money if it doesnīt work good (iīm a student ;) ).

Thx Rolf
__________________
Canon XH A1 -> Blackmagic Design Intensity Pro
Manfrotto 701RC2 on 755BK
Rolf Seitz is offline   Reply With Quote
Old March 16th, 2007, 08:11 AM   #2
Inner Circle
 
Join Date: Feb 2006
Location: Belfast, UK
Posts: 6,143
You need good accurate focus scales on your lens if you want to use this method. You tend to only find these on cine style lens rather than ENG zoom lenses or consumer/prosumer built in lenses, which are software controlled varifocal length lenses rather than true zoom lenses. For the last two types it's more accurate focusing by eye than measuring and. unless you've got a camera assistant, a lot quicker.
Brian Drysdale is offline   Reply With Quote
Old March 16th, 2007, 10:35 AM   #3
Regular Crew
 
Join Date: Jan 2007
Location: Zurich (Switzerland); Luxembourg (L)
Posts: 44
Quote:
Originally Posted by Brian Drysdale View Post
You need good accurate focus scales on your lens if you want to use this method. You tend to only find these on cine style lens rather than ENG zoom lenses or consumer/prosumer built in lenses, which are software controlled varifocal length lenses rather than true zoom lenses. For the last two types it's more accurate focusing by eye than measuring and. unless you've got a camera assistant, a lot quicker.
But when I focus, the cam shows me the actual distance where the focus is set.
So my workflow would be...laser rangefinder, measuring the distance (about max. 5 seconds...setting focus about another 5 seconds)
__________________
Canon XH A1 -> Blackmagic Design Intensity Pro
Manfrotto 701RC2 on 755BK
Rolf Seitz is offline   Reply With Quote
Old March 16th, 2007, 10:50 AM   #4
Trustee
 
Join Date: Jun 2005
Location: Hollywood, CA
Posts: 1,675
Images: 1
XH A1? The DOF must be so deep, why would focus need to be so precise? Using peaking the focus will be as accurate as you see it on playback, no need for super-precise lasers.
__________________
BenWinter.com
Ben Winter is offline   Reply With Quote
Old March 16th, 2007, 11:29 AM   #5
Inner Circle
 
Join Date: Feb 2006
Location: Belfast, UK
Posts: 6,143
Quote:
Originally Posted by Rolf Seitz View Post
But when I focus, the cam shows me the actual distance where the focus is set.
So my workflow would be...laser rangefinder, measuring the distance (about max. 5 seconds...setting focus about another 5 seconds)
Eye focus is a lot quicker.

For focusing by tape or rangefinder you'd need to check how accurate those distance reading actually are and where on the camera they're measured from. For example cine lenses are measured from the image plane, ENG lenses from the front element.

Also what happens when your subject and or the camera moves? How are you going to adjust the focus. I know on the Z1 the focus read outs in the camera operate on an extremely compressed scale so far as the focus ring adjustment is concerned and it's easy to overshoot or miscue.
Brian Drysdale is offline   Reply With Quote
Old March 16th, 2007, 04:37 PM   #6
Regular Crew
 
Join Date: Jan 2007
Location: Zurich (Switzerland); Luxembourg (L)
Posts: 44
Ok, thanks for your answers! Thought I found something good...but it turns out to have too many downsides. Money saved....for my mattebox ;)
__________________
Canon XH A1 -> Blackmagic Design Intensity Pro
Manfrotto 701RC2 on 755BK
Rolf Seitz is offline   Reply With Quote
Old March 18th, 2007, 11:24 PM   #7
Contributor
 
Join Date: Aug 2005
Location: austin, tx
Posts: 300
laser measuring

you might look into a laser measuring tool. they sell them at most hardware stores, and they are relatively inexpensive if you're still interested in one.

http://www.stanleytools.com/default....ASER+MEASURING
__________________
Compositing is my life right now.
IMDB page: http://www.imdb.com/name/nm3596782/
Austin Meyers is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

B&H Photo Video
(866) 521-7381
New York, NY USA

Scan Computers Int. Ltd.
+44 0871-472-4747
Bolton, Lancashire UK


DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > Open DV Discussion


 



All times are GMT -6. The time now is 03:52 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2024 The Digital Video Information Network