No Open Iris In Wide-Photo? at DVinfo.net

Go Back   DV Info Net > Sony XAVC / XDCAM / NXCAM / AVCHD / HDV / DV Camera Systems > Sony HDV and DV Camera Systems > Sony VX2100 / PD170 / PDX10 Companion

Sony VX2100 / PD170 / PDX10 Companion
Topics also include Sony's TRV950, VX2000, PD150 & DSR250 family.


Reply
 
Thread Tools Search this Thread
Old April 21st, 2007, 06:44 PM   #1
Major Player
 
Join Date: Mar 2004
Location: Cape Town, South Africa
Posts: 276
No Open Iris In Wide-Photo?

I was shooting a band today, one shot was in telephoto with the iris open and a gain of 3db. When I moved to widephoto, I noticed the iris automatically went down to F2, but the 3db was still displayed. However, in widephoto, I could manually open the iris again. The adjustments were on manual, autolock in the middle position.

I understand that this isn't a defect, but what is the principle behind closing the lens during a wideshot? Is it to deepen the depth of field?
Aviv Hallale is offline   Reply With Quote
Old April 21st, 2007, 10:20 PM   #2
Inner Circle
 
Join Date: Dec 2003
Location: PERTH. W.A. AUSTRALIA.
Posts: 4,356
This is a normal optical characteristic of some zoom lenses. Other zoom lenses are designed to perform with the same aperture value through the whole zoom range.
Bob Hart is offline   Reply With Quote
Old May 14th, 2007, 04:12 AM   #3
Inner Circle
 
Join Date: Mar 2003
Location: Billericay, England UK
Posts: 4,711
It sounds to me Aviv that your shots at full telephoto were under-exposed by half a stop. You were shooting wide open (f/2.4) at +3dB of gain up? Then you pulled back to wide-angle and the camera chose f/2 at the same gain setting?

That would suggest to me that it wanted f/2 in the first place, and your zoom isn't that fast at the 72 mm end. It's nothing at all to do with D of F and all to do with the fact that the max aperture of your zoom varies from f/1.6 to f/2.4 depending on what focal length you're shooting at. All perfectly normal.

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...

Professional Video
(800) 833-4801
Portland, OR

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

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

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 > Sony XAVC / XDCAM / NXCAM / AVCHD / HDV / DV Camera Systems > Sony HDV and DV Camera Systems > Sony VX2100 / PD170 / PDX10 Companion

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 11:01 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network