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


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Old September 21st, 2012, 11:59 AM   #1
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you CANNOT zoom with the GH2

After weeks of runaround from Panasonic and their terrible 3rd world customer support; I finally got a definitive answer.

With any lens made for the GH2 micro 4/3rds system, Panasonic or Olympus or whomever, you cannot zoom without getting exposure flicker. That may be acceptable for still photography but totally useless for any video.
I have the 14X140 Panasonic & the 12X50 Olympus. The Pana lens flickers a fair amount and the Oly flickers a LOT during any zoom. I also have 2 Nikon lenses with manual adapter mounts and they do not flicker.

I was hoping this would not be the case, the Oly 12X50 is a pretty nice lens and the power zoom is decent. I'm not a big fan of zooms but sometimes they are appropriate & necessary. It would have been nice to make the Oly lens fill that need. Manual zooms are very difficult to do with these HDSLRs.

Looks like I'll be taking a look at other brands.
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Old September 21st, 2012, 03:38 PM   #2
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Re: you CANNOT zoom with the GH2

You could always use a slider or dolly.
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Old September 21st, 2012, 05:34 PM   #3
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Re: you CANNOT zoom with the GH2

The flicker is the result of a couple of mechanisms within the lens. So far the only manual lens that I've heard that doesn't flicker is the new 12-35 Lumix lens and you will pay for the luxury. The 45-175 power zoom Lumix doesn't flicker although the LCD does when you are not shooting. Once you start shooting the LCD is clean and well as the recording. The 14-42 power zoom however isn't the same. It shows flicker in the recordings although it depends on the scene whether it's very noticeable or not.

Supposedly the Lumix lenses with the "HD" label have been designed for video but it's clear that the Panasonic DSLR optic designers didn't put much thought into live zooms. It seems that is changing but the cost is going to be higher for us. A good zoom lens for pro HD cameras can easily cost over $5000 and they are transmitting the light to a smaller imaging surface than any DSLR style camera. The lenses we are offered are compromises between cost and practicality. A good, zoom versatile, HD resolution video lens for the GH2 would be a mediocre still lens at best.
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Old September 21st, 2012, 07:32 PM   #4
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Re: you CANNOT zoom with the GH2

The 12-35mm has a problem with the aperture "stepping" as you zoom. It is billed as a "constant aperture" lens, but I would call it a "constant NET aperture lens", the iris actually steps as the lens is zoomed to maintain a certain light level range, but you can see these steps in recorded footage. There are a number of examples on the Personal View forum regarding this lens. I don't yet own this lens (I probably will buy it anyway) but there's plenty of examples of this behavior, it's a design choice.

If you're up for a bit if DIY, there's a guy on eBay who takes used broadcast lenses, Fujinon and Canon, sometimes a Nikon, most of which are power zooms if you provide a power supply. What he sells are lenses built for 2/3" mounts that also have doubler optics... such lenses will cover the GH2's sensor without vignetting when the doubler is used, at least through most of the zoom range.

Everything will be manual, just like on the broadcast cameras these lenses were meant to go with, but you can rig up a proper variable-speed, parafocal, constant aperture power zoom.

It's too bad that 1/3" lenses can't be adapted in this way (image circle is too small) ... The Fujinon lens I have on my JVC GY-HM700 is terrific and I'd love to use it on the GH2.
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Old September 22nd, 2012, 09:22 AM   #5
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Re: you CANNOT zoom with the GH2

Yup, the same with my JVC camera lens. Wish I could use it on the GH2 as well. The more I use the GH2, the more I like it but the more I appreciate the JVC camera as well. I use the GH2 as a second camera with it frequently with great results.

And that info about the 12-35 just tilted me towards NOT getting it. GH3 body on order.
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Old September 23rd, 2012, 08:06 AM   #6
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Re: you CANNOT zoom with the GH2

Anyone know if this flickering zoom issue will be addressed in the GH3?

I will be looking to move into something more versatile. A slider is not the same as a zoom. Nice look but very limiting. Why not a Fisher 10 & 50' of track & 2 grips? Or a crane? A helicopter in my backpack would be perfect! There are times when a zoom is the right solution.
As for modifying a B4 mount...that, to me, negates the beauty of the small size/great picture quality of this camera. For many reasons, I've gone to shooting out of a backpack. So a foot long lens won't work for me.
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Old September 23rd, 2012, 10:22 AM   #7
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Re: you CANNOT zoom with the GH2

The GH2 is not a video camera, it's a still camera that takes great video under the limitations of the still camera format. An HD video camera can take barely decent stills under the limitations of the video format. I speak as someone who thrives with a live zoom lens and who started working with a camera that essentially took away my zoom habits for better or worse.

For example, I did a testimonial video for an event this summer that had 35 different people in separate locations saying something brief that had to be edited together for a banquet overseas. For this job I chose my GH2 and it performed wonderfully. The small size and the wonderful DOF gave me great results in ease of travel and quality of the projected image. However, just last week I worked as a second camera for a TV pilot and the other camera person and I didn't use use our DSLRs but our pro JVC HD cameras because of the freedom and ease of set-up they offer us. They certainly aren't light cameras but we could quickly get shots and preview them on a remote monitor where a DSLR would add lots of time fussing with lenses and monitoring issues. Plus it's a comedy and shallow DOF isn't always the best thing for humor. In couple of scenes I could quickly change the zoom from a wide to a CU when I knew that the other camera was going to be used, can't really do that with the Lumix lenses right now.
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Old September 23rd, 2012, 12:19 PM   #8
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Re: you CANNOT zoom with the GH2

ALL stills cameras, not just Panasonic, that are fitted with a non-fixed aperture lens will 'flicker' during zooming in video mode. The light passing through the lens cannot be expected to remain the same when internally the aperture is changing automatically from f/3.5 to f/5.6.

To avoid the flicker to some extent, the metering can be locked. Although the best way is to video the various framed zoomed shots, and then cut out the physical 'zooming' sections in post.

There can even be some slight 'flicker' with a fixed aperture lens, although a lot less than a non-fixed aperture lens.

Try using fixed aperture lenses, such as the superb Lumix 7-14mm f/4 (as well as the new 12-35mm f/2.8).
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Old September 23rd, 2012, 12:47 PM   #9
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Re: you CANNOT zoom with the GH2

Tony

Why the necessity of the flickering? Even in manual mode? I've worked with countless variable aperture motion picture zoom lenses in both film & video for 20+ years. You can see a very GRADUAL smooth change of exposure thru the zoom.

I'm not asking for a 'do everything' camera. but this seems like a simple thing to do. my guess is some engineer who just doesn't think a zoom is necessary vs some technical issue he wants.

I had a conversation long ago with a sony engineer, asking for shutter speeds slower than 'normal' on betacams. I had slow shutter speeds on mini DV cameras that I used on occasion for creative purposes. he explained that slow shutter speeds were "not professional" and only for amateurs. Thanks for telling me that 3/4 of the world of professional cinematography was populated with amateurs.
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Old September 23rd, 2012, 02:55 PM   #10
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Re: you CANNOT zoom with the GH2

Ed, you are talking about two different types of cameras and lenses. The lenses made for motion picture and video have smooth iris positions without click stops, and made purely for moving images. The aperture blades with precise click-stops are made for stills cameras for shooting still images, not video.

For 4/3rds cameras and DSLR cameras, the main buying market is still for photographs and not video...so you cannot expect the industry to cater for the minority (although things are changing fast in the DSLR video world).

I often do slow pan zooms with camcorder lenses, but rarely with stills cameras in video mode, although I sometimes will do a short crash zoom with my Sigma 120-300mm f/2.8 OS, and this doesn't exhibit flickering in video mode with the Canon 5D Mk II when the exposure is locked down.

I never zoom with Panasonic variable aperture lenses, such as the Lumix 14-45mm. I tend to set the zoom position and leave it locked at that setting during the actual film sequence. I also find that riding the ISO provides a smoother change for the eye than changing aperture. For example, if I am filming a scene with constantly changing light, such as with a Panasonic GF1 body inside an underwater housing in shallow water under natural sunlight, I will set the camera to "M" mode on the dial, set 1/50th shutter speed & F/8 (or any aperture depending on subject choice), and then let the camera ride the ISO. As long as the camera movements are slow and smooth, the exposure changes are subtle to the eye. The ISO setting can also be capped (in Menu settings) so that it doesn't auto-adjust into high digital noise levels.

The hybrid world of stills/video..and the myriad of lenses bayoneted on to the bodies has still a long way to go...but compared to even 5-years ago, we now have a fantastic choice.
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Old September 23rd, 2012, 03:33 PM   #11
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Re: you CANNOT zoom with the GH2

It is my understanding part of the problem has to do with the electronic communication between the native lenses and the camera. Even if you have a contant aperture lens there is still communication going on that tells the camera the focal length is changing. Even Lumix lenses at a constant F2.8 may have subtle changes in how the transfer light to the camera through the zoom range.

If you want to do a zoom with the GH2 while recording video use a 3rd party manual lens. Since they do not communicate with the camera they should not force the camera to compensate to those subtle differences.

Of course knowing what lenses will do it is not exactly easy to find as I think even some manual lenses may have issues.

The Lumix 45:175 power zoom has perfect light all the way through but then again it was designed to do it. Very few other lenses ever had the intented purpose of zooming while shooting video. They are just not built that way.

By the way my Lumix 45:200 seems to handle zooming very well even with minimal light flickering. I have been pretty happy shooting video with it while zooming by hand. Not optimal of course but it gets the job done.

I do an old Canon FD 70:210 at a constant F3.5 that seems to work very well for zooming. Well it would if it didn't weigh as much as a tank and was virtually impossible to use without a very sturdy tripod.

Since none of my current lenses show this flickering I'm not really sure what exactly others are talking about. I wouldn't think it would be that visible with faster zooms. Slow zooms are kind of a death wish with manual zooming and in my opinion will look bad regardless if it flickers or not. If you really must have slow constant steady zooms you either get the 45:175 or buy a cheap video camera.
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Old September 26th, 2012, 09:35 PM   #12
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Re: you CANNOT zoom with the GH2

I have 2 nikon mount zoom lenses with adapters for the GH2. No flickering. Seems to me pana is overengineering the lenses. When switching to manual exposure mode, it should be MANUAL.
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Old September 27th, 2012, 12:28 AM   #13
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Re: you CANNOT zoom with the GH2

Key word there. With adapters. When you use an adapter there is no electronic communication with the camera and therefore no way for the lens and camera to adjust each other. That is the tradeoff to having a camera system with such good auto control between the camera and lens. Even in manual mode with m4/3 there is still a deep level of communication going on between the lens and camera.
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Old September 28th, 2012, 08:27 PM   #14
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Re: you CANNOT zoom with the GH2

My point is that Pana is WAY overengineering this system. it works great with an adapter that disconnects all the excessive electronic controls. Pana, give me REAL manual control of EXPOSURE. You do it all the time with video cameras; pro and consumer. The camera works with manual lens adapters just fine.
Granted it needs auto exposure for the amateur market. Just not such a bizarre system that has no real manual override.
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