parfocal zoom at DVinfo.net

Go Back   DV Info Net > Sony XAVC / XDCAM / NXCAM / AVCHD / HDV / DV Camera Systems > Sony Digital Cinema Camera Systems > Sony NXCAM NEX-FS700 CineAlta

Sony NXCAM NEX-FS700 CineAlta
4K EXMOR sensor with SDI, slow-motion recording.


Reply
 
Thread Tools Search this Thread
Old May 15th, 2014, 07:46 AM   #1
Regular Crew
 
Join Date: Dec 2008
Location: Montreal, Quebec, Canada
Posts: 91
parfocal zoom

According to this video interview below, the Sony FE 70-200mm f/4.0 G is parfocal.
Is this true? Does anyone know more details?
NAB Interview: Sony's Juan Martinez on the NEX-FS700R and Latest E-Mount Lenses - Streaming Media Producer

I'd be willing to lose 1 stop in exchange for parfocal... but description in the B&H listing doesn't mention parfocal.
Sony FE 70-200mm f/4.0 G OSS Lens SEL70200G B&H Photo Video

Bill Kerrigan,
Montreal Quebec Canada
Director of Photography
Bill Kerrigan is offline   Reply With Quote
Old July 25th, 2014, 09:35 AM   #2
Regular Crew
 
Join Date: Sep 2008
Location: Port Coquitlam, BC
Posts: 28
Re: parfocal zoom

Hey Bill,
I have never seen a manufacturer list a lens as being parfocal, which is unfortunate as this is such an important consideration for videographers.

I did test the FE 70-200mm f/4 G at NAB 2014 just before I shot the interview with Juan and I can confirm that it is a parfocal lens. The FE 24-70 f/4 is parfocal as well.

Regards,
Shawn
Shawn Lam is offline   Reply With Quote
Old November 23rd, 2014, 08:48 PM   #3
Regular Crew
 
Join Date: Mar 2013
Location: New Orleans, La
Posts: 39
Re: parfocal zoom

Sony describes the Sony FE PZ 28-135mm f/4 G OSS Lens as:

"Maintains plane of focus while zooming and maintains field of view while focusing (important for video)."

Funny, but for most of my shooting career I never knew there were zooms that are NOT parfocal. All I ever operated were broadcast tv zooms. I didn't realize how few still photographers focus manually, so it never occurred to me that the still shooters would be using zooms that require re-focusing with each change of focal length.

The Sony marketing for that same lens says "Angle of view variations while focusing (breathing) and axial displacement while zooming have been reduced ". Any idea what "axial displacement" means in terms of photography? The Google isn't of much help.
J. David Pope is offline   Reply With Quote
Old November 24th, 2014, 10:20 PM   #4
New Boot
 
Join Date: May 2014
Location: Toronto
Posts: 16
Re: parfocal zoom

Quote:
Originally Posted by J. David Pope View Post
Sony describes the Sony FE PZ 28-135mm f/4 G OSS Lens as:

"Maintains plane of focus while zooming and maintains field of view while focusing (important for video)."

Funny, but for most of my shooting career I never knew there were zooms that are NOT parfocal. All I ever operated were broadcast tv zooms. I didn't realize how few still photographers focus manually, so it never occurred to me that the still shooters would be using zooms that require re-focusing with each change of focal length.

The Sony marketing for that same lens says "Angle of view variations while focusing (breathing) and axial displacement while zooming have been reduced ". Any idea what "axial displacement" means in terms of photography? The Google isn't of much help.
I found this (Buy - Arri / Zeiss UltraPrime T1.9 / 135mm PL mount prime lens with IMPERIAL scale (K2.52133.0)) which may be relevant:

"Iris and Focusing Rings without axial displacement
The rigid construction creates the prerequisite for an important advantage: the position of the gears for focus and iris does not move axially during focusing. External motor units thereby work more simply and with considerably increased reliability. Also, lens changing becomes much easier, faster and safer. "
Chris Andrikakis 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 Digital Cinema Camera Systems > Sony NXCAM NEX-FS700 CineAlta

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 01:37 PM.


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