problem with aperture value when i zoom ? at DVinfo.net
DV Info Net

Go Back   DV Info Net > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon EOS Crop Sensor for HD

Canon EOS Crop Sensor for HD
APS-C sensor cameras including the 80D, 70D, 7D Mk. II, 7D, EOS M and Rebel models for HD video recording.

Reply
 
Thread Tools Search this Thread
Old December 4th, 2009, 10:48 AM   #1
New Boot
 
Join Date: Aug 2005
Posts: 24
problem with aperture value when i zoom ?

Hi! In video mode When I zoom with my 15-85mm the aperture value changes automatically (exposition ?) ... how to avoid it or disable this function !
Because of that i can' t zoom and make video without light changing !

Thanks !
Daniel
Dan Lim is offline   Reply With Quote
Old December 4th, 2009, 10:56 AM   #2
Major Player
 
Join Date: Sep 2009
Location: Bakersfield, CA
Posts: 232
Daniel,

The 15-85mm is a variable aperture lens. As you zoom it HAS to adjust the aperture accordingly due to the design of the lens. The way around this is to purchase a fixed aperture lens (it will say something like "f2.8" rather than "f3.5-5.6").
Craig Coston is offline   Reply With Quote
Old December 4th, 2009, 11:04 AM   #3
Inner Circle
 
Join Date: Mar 2003
Location: Billericay, England UK
Posts: 4,711
Dan - the aperture value only changes automatically if you're shooting at full wide and max aperture. Try it the other way around - shoot at full tele and max aperture - then zoom to full wide - you'll see that the aperture doesn't change.

Craig's right, you need to buy a fixed aperture zoom lens (usually a lot dearer than the vari-aperture lens you've got)

tom.
Tom Hardwick is offline   Reply With Quote
Old December 4th, 2009, 12:35 PM   #4
Regular Crew
 
Join Date: Jun 2008
Location: New Orleans, LA
Posts: 57
Weeell... You don't NEED to...
Jesse Haycraft is offline   Reply With Quote
Old December 4th, 2009, 01:02 PM   #5
Inner Circle
 
Join Date: Mar 2003
Location: Billericay, England UK
Posts: 4,711
he needs to if he wants to (quote) 'make video without light changing'.
Tom Hardwick is offline   Reply With Quote
Old December 4th, 2009, 01:49 PM   #6
New Boot
 
Join Date: Aug 2005
Posts: 24
I understand now !
I must to purchase a fixed aperture lens : maybe the 50mm f1.4 or 1.8 !
Thanks a lot for all of yours !

Daniel
Dan Lim is offline   Reply With Quote
Old December 4th, 2009, 01:51 PM   #7
Inner Circle
 
Join Date: Mar 2003
Location: Billericay, England UK
Posts: 4,711
Well you'll find it difficult to find a fixed aperture lens, but I know what you mean.

No - you want a constant maximum aperture zoom. Yours is probably 15 - 85 mm f/2.8 to f/5.6, something like that. What you want (what we all want) is a 15 - 85 mm lens that has a maximum aperture of f/2.8 throughout the zoom range.

tom.
Tom Hardwick 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 > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon EOS Crop Sensor for HD

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



All times are GMT -6. The time now is 07:16 AM.


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