GH4 manual exposure issue at

Go Back   DV Info Net > Panasonic P2HD / AVCCAM / AVCHD / DV Camera Systems > Panasonic LUMIX G / GF / GH / GX Series

Panasonic LUMIX G / GF / GH / GX Series
4K and AVCHD on a Micro Four Thirds system camera with interchangeable lenses.

Thread Tools Search this Thread
Old October 7th, 2014, 01:24 AM   #1
Join Date: Jun 2014
Location: Los Angeles
Posts: 2
GH4 manual exposure issue

I use a GH4 with a Sigma 24-70 f/2.8 lens and MFT to EF adopter that does not have iris control. I set the aperture of a lens on a Canon 7D and put it on the GH4, and even though GH4 is roughly on the same exposure setting with the 7D (f/22, shutter 1/50, ISO 200 - in Los Angeles daylight), the image gets way overexposed.

The only way I can get the right exposure is to switch to one of the auto exposure settings, which raises the shutter speed and is not ideal for video recording.

Does anyone know what the issue is? Is it possible that somehow the aperture size changes while I switch the lens between 7D and GH4? Thanks in advance!
Hideto Shimizu is offline   Reply With Quote
Old October 7th, 2014, 05:04 AM   #2
Join Date: Oct 2009
Location: York, England
Posts: 1,323
Re: GH4 manual exposure issue

DSLRs don't actually set the aperture until it takes the shot, so merely selecting an aperture on the 7D doesn't actually set it until the shot is fired and then it also opens back up again immediately after the shot too.

With this in mind, can you actually see the aperture blades in the closed position while transferring the lens to the GH4 or does the lens appear to be open (as I would expect) ?
Qualified UAV Pilot with CAA PFAW
Aerial Photo / Aerial Video | Corporate Video Production
Dave Partington is offline   Reply With Quote
Old October 12th, 2014, 11:44 PM   #3
Join Date: Nov 2006
Location: San Angelo Texas
Posts: 1,514
Re: GH4 manual exposure issue

When setting the aperture on a Canon EOS body to transfer the lens to a MFT body, the DOF Prevue button must be pressed in and held while the lens unlock button is depressed and the lens twisted off the Canon body.

If the DOF Prevue button is not held in while the lens is "unlocked" and twisted at least 1/4 inch, the lens diaphragm will simply open back up and remain wide open.

With the old Canon T1i there was no provision for manual settings in video mode, so to manually set the aperture (at some setting other than wide open) we had to set the aperture in Manual mode then use the "unlock and twist" method above while holding the DOF Prevue button in.

The 7D, T2i, and subsequent models solved the problem with full manual in video mode.
Bruce Foreman is offline   Reply

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

(800) 223-2500
New York, NY

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

Texas Media Systems
(512) 440-1400
Austin, TX

Precision Camera
(800) 677-1023
Austin, TX

(800) 323-2325
Mineola, NY

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 > Panasonic P2HD / AVCCAM / AVCHD / DV Camera Systems > Panasonic LUMIX G / GF / GH / GX Series

Thread Tools Search this Thread
Search this Thread:

Advanced Search



All times are GMT -6. The time now is 08:13 PM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2018 The Digital Video Information Network