No Exposure Comp w GH2 with Legacy Lens

[Kevin Janisch]

Stumped on this one. I have a Super-Multi-Coated Takumar on an unhacked GH2. In movie creative mode HBR I get the +3 and -3 exposure compensation when aperature priority is the exposure mode. I can adjust this while recording by turning the thumb wheel. When I select Shutter priority as the exposure mode which is what I Prefer than I can no longer adjust the exposure setting. The thumb wheel adjusts the shutter but when I Press it to adjust the exposure it just zooms in for focussing. Am I missing something?

[Kevin Janisch]

Anyone? The manual states this functionality is available in this mode. Anybody able to use exposure compensation while in Shutter-Priority mode with a non-four-thirds lens?

[Bruce Foreman]

You should be in full manual mode for what you want to do. Being able to set exposure compensation seems to be available in Aperture Priority but not Shutter Priority, even with a "native" Micro Four Thirds lens mounted.

But in Manual exposure mode you can at least directly address shutter or aperture and still get the -3 - +3 meter readout as a guide. If you need one and a third stops under as a compensation factor simply adjust shutter, aperture, or ISO until the readout shows you have it.

Be sure you have "CONSTANT PREVUE" and "EXPO.METER" set to "ON". These are found in the "CUSTOM" menu on page 4 (be sure the dial on top is set to "Motion Picture". The "CONSTANT PREVUE" insures the EVF and LCD images change as you make exposure changes so you can "eyeball" exposure effect.

[Bruce Foreman]

This is an article I wrote late last year. I'm waiting to see what differences may appear in GH3 to see if I need to make any changes before submission. You may use keep this for your personal reference but please do not distribute without my permission.

Please respect my copyright.

GH2 Manual Exposure Control In Video Mode


© 2012 Bruce Foreman

A few things need to be configured in the menus first. Taking them one at a time:

1. Setting Manual Exposure in Movie Mode. Set the mode dial on top of the GH2 to “Motion Picture” (the icon that looks like a movie camera and an “M” beside it. Press the “Set” button on the back of the camera and you get a “Creative Movie” menu that allows you to select from 4 choices (3 if firmware is still ver. 1.0). I select “High Bit Rate”, many others will select "24p Cinema”.

Go to next menu down, “Motion Picture” (Movie Camera icon). Scroll down to Movie Camera with “M” icon, EXPOSURE MODE. 4 choices, PASM, select M for “Manual”. This exposure mode choice applies ONLY to “Motion Picture” mode when that is selected with the mode dial on top.

Next menu, CUSTOM, “C with wrench”.

HISTOGRAM – Set to ON if you understand how to read a histogram. This is NOT an exposure meter but can be a useful guide when properly interpreted.

CONSTANT PREVUE – Set to ON. This allows LCD and viewfinder to actually show exposure by being darker with underexposure and lighter with overexposure, making it easier to “judge” exposure in conjunction with the exposure metering display at the bottom of the screen. If this is left to OFF the LCD and viewfinder will pretty much always display an image that looks like the exposure is correct even when under or over exposed.

EXPO.METER – Set to ON. This enables exposure meter display at the bottom of the screen.

Movie (icon) BUTTON – Set to ON. This is the red button on top of the camera. You can also start Motion Picture recording with a full press of the shutter button (in Motion Picture mode ONLY). A half press of the shutter button will attempt AUTOFOCUS depending on how you have FOCUS mode switches set.

TOUCH SCREEN – I recommend ON

TOUCH Q.MENU - I recommend ON also

TOUCH SHUTTER – I set to OFF, I don't want the camera to focus and shoot a still if I accidentally touch the LCD.

SHOOT W/O LENS – Set to ON if you plan on using adapted lenses.


Those are the important ones for manual exposure control in video mode. Several of the other configuration options can be personal choices but I do recommend Highlight Warnings, Focus Priority, Direct Focus Area, and PreAF all be set to OFF. They shouldn't affect manual exposure control but you can have “too much” going on.

Now on to HOW.

SHUTTER SPEED:

Depending on the power line frequency in your area this should be set so that it is likely “in synch” to head off “banding” or “flickering” problems if artificial lighting is either used or included in the scene. In most PAL regions this will likely be 50Hz, In most NTSC areas power line frequency will be 60Hz, shutter speed should be some close multiple of this. I'm in an NTSC area so I set mine at 1/60th of a second. Those in most PAL regions should start at 1/50th.

Both shutter speeds are close enough to the 1/48th second that used to be the result of a rotating disk shutter in early film motion picture cameras so that the degree of “motion blur” we've become used to is similar.

Faster shutter speeds to “freeze” motion/action in each frame may be used but as you get much above 1/125th to 1/250th second motion may “strobe” or get “stuttery”. So far at 1/60th second I've had no problems, any blur which occurs with rapid movement looks natural to me.

APERTURE:

Set this for the desired “depth of field” or “zone of acceptable focus” effect desired. Smaller aperture for deep zone of focus, wider for more selective focus or “shallow” zone of focus, or a medium aperture for somewhere in the middle. A word of warning here, the extreme “shallow” selective focus that can be done with some “faster” lenses is being very much overdone. So I suggest you do some research on “depth of field” and look at a lot of examples so you can apply these techniques more judiciously.

ISO: Set this to a value appropriate to the ambient lighting conditions. Outdoors in daylight start at 160. Indoors or outdoors at night somewhere in the range of 400 – 1600. With the original firmware the high ISO limit in “motion picture” mode is 3200, with the various firmware modifications (hacks) that upper limit can be expanded to 12,800.

Before you get too excited over this possibility, you are likely to be quite disappointed in the image quality at 12,800 due to digital “noise” (I haven't tried anything like Neat Video for noise removal so I have no idea how well it would work here). While I might be able to “live with” the results at ISO 6400 I try to stay at ISO 3200 or lower.

Generally ISO can be adjusted up or down some to “tune” exposure until you get the “zero” or “+/-” +0 reading on the exposure meter readout at the bottom of the screen. If you're not locked into a specific aperture for a specifically desired “depth of field” effect you can also “tune” exposure with aperture adjustment.

So at this point you have complete manual control over shutter, aperture, and ISO. Each independent of the others and an exposure meter readout at the bottom of the screen.

OTHER EXPOSURE CONSIDERATIONS

Shooting video outdoors can present some exposure problems, you may find yourself having to set the aperture an minimum or near minimum aperture even at ISO 160. This can result in quite a bit deeper zone of focus than you would like and very small apertures subject the image to an effect known as “diffraction”. The image forming light rays instead of following a strictly straight path begin to “diffuse” some. This can result in a general softness, slight loss of inherent contrast, and an image that can seem to lack edge detail and sharpness.

The way to counteract this is through the use of ND filters. I found that a .9ND (3 stop reduction) just barely got me down into the f11 to f8 range of apertures on a bright day in the West Texas sun. So I used 46-52mm and 37-52mm stepup rings with my existing 52mm .6ND and .9ND filters (2 stop and 3 stop reduction respectively) for the Lumix 14mm and 20mm “pancakes” and also with the Olympus Zuiko 45mm (37mm filter thread). “Stacking” those two filters for a 5 stop reduction caused a slight magenta color shift and definite vignetting with the 14mm lens, so I ordered a 1.2ND (4 stop reduction) to get away from those problems.

Then I discovered variable ND filters. B&H photo in NYC sells a Polaroid variable ND filter at $34.99 in smaller sizes (37 to 52mm). I ordered two sizes, 46mm and 52mm. The first size fits the 14mm, 20mm, and the Panasonic Leica DG Summilux 25mm f1.4; the 52mm fits the 14-42mm “kit” lens directly as well as the smaller lenses with stepup rings.

So now when you have shutter, aperture, and ISO set you can very conveniently “dial in” exposure by adjusting the variable ND filter (with the outer ring) until the meter readout indicates “zero”.

There are a few possible “downsides” to using the variable ND. A few reviewers mention problems or “unwanted” effects when using these at their darkest settings. Some report no problems, I don't use the darkest settings so I haven't seen any “unwanted” effects, but I usually stay away from “extremes”. There are also reports on the forums of increased incidence of internal reflections. The variable or “fader” ND filter is two pieces of “glass” which adds 4 potentially reflective surfaces. So far I like the way these things work but I'm keeping the conventional ND filters handy.

And the front filter thread size is different from the rear thread that mounts to the lens. On the 46mm size the front thread is actually 49mm (the rear side of the filter threads in perfectly to the 46mm thread on the lens) so if you wish to use a hood you need one in 49mm size. I had some 49-52mm step up rings so I can use a 52mm rubber hood in conjunction with the 46mm variable ND filter (with the 20mm that needs to be a wide angle hood or it will vignette, no hood should be used with the 14mm).

The 52mm Polaroid variable ND has a larger front thread also. I haven't figured out what it is yet but I suspect it will turn out to be 55mm (I don't have a “real” camera store here where I can go see what fits so I'll probably have to order to find out.)

Final note on filters, DO NOT even try “cheap” ND filters. You risk running into color shifts, so I advise nothing cheaper than TIFFEN brand (I read that Shane Hurlbut likes TIFFEN).

To Touchscreen (Or Not)

I've never been much of a fan of “touchscreen” operation but the implementation in the GH2 is about the slickest I've ever seen in a camera. Anything that might need to be changed in the way of settings while you're working can be accessed either by the Quick Menu (Q.Menu) or directly by the buttons on the camera. Your choice. When working out in bright daylight you likely won't really be using the LCD (hard to see it in really bright light) so the Touchscreen function won't be that available. Using the EVF (electronic viewfinder) you'll be using the camera controls instead. But in lighting conditions where you can use the LCD you may be amazed at what you can access and change almost “on the fly”.

One very handy function I like is the Touch focus and the main reason I recommend this be set to ON is that you can actually do a “rack focus” with this. Simply focus on the first object you wish to be focused on and when ready, touch the second object. The camera will then move focus to that second object. There is slight delay between the time you “touch” and the time the camera refocuses so a couple or three “rehearsals” would be a good idea. You do need to have TOUCH SHUTTER set to OFF or the camera will also take a still picture at the same time.


Lenses

Most other brand lenses including a lot of “legacy” Nikon, Pentax Takumar, Minolta, Canon FD and other known brand “glass” can be fairly easily adapted to the m4/3rds mount, and this is the way many go for optics for the GH2. My choice was to remain within the system of lenses made for m4/3rds so that I could work with all of the camera body features. So the optics I've assembled over the last year includes the Lumix 14mm f2.5 and 20mm f1.7 “pancakes”, the Olympus Zuiko 45mm f1.8, the Pan/Leica DG Summilux 25mm f1.4, the Lumix 45-200mm f4-f5.6, and with the second body came the Lumix 14-42mm “kit” lens.

I'm not putting down in any way those who shop for and adapt other lenses, but for me the advantages of lenses that “communicate” with the body and make available all features of the GH2 body make working “motion picture” with this camera go smoother. Some of the optics made for this system are incredibly compact and this is very much appreciated with me often being a “one person” crew, less weight to “lug around” and setup.

My latest lens acquisition, the Pan/Leica DG Summilux 25mm f1.4, is an incredible performer. Outstanding in low light environments, excellent sharpness and detail stopped down a bit and still compact enough on the GH2 body.

Handy Accessories

The use of lens hoods whenever possible is always a good idea, but careful attention needs to be paid to hood shape and depth. The 14mm may be best used with no hood, this lens is wide enough that vignetting can be a serious problem. The 20mm is best used with a bit of a wide angle hood, this lens is what I call “wide normal” in that the field of view is slightly wider than “normal” but not quite wide enough to be a wide angle lens. The 25mm and longer can take deeper hoods. I recommend you shop B&H for their “collapsible” rubber lens hoods, they are often inexpensive and can form a rubber “bumper” around the front of the lens.

Of course the primary reason for a lens hood is to keep stray light off the front element, preventing excessive internal reflections. The deeper a hood is, the more effective it will be but be sure to test it at smaller apertures, shooting some still images to insure it is not causing any vignetting you don't see looking through the camera.

Another thing that can cause internal reflections is an unnecessary filter. I used to keep a high quality multilayer coated UV filter on all my Canon EOS lenses and never ran into a problem. So as I began to acquire Lumix and Olympus lenses for the Olympus Pen E-P3 and GH2 cameras, I also ordered Hoya HMC UV filters to keep on them for protection. Turned out I started seeing spots in the images that were twice as annoying as shooting with no filter. So I no longer put any filter on any of the lenses for the GH2 unless one is needed for a very specific reason.

Remote shutter devices: I looked for a wireless remote for my Canons that would let me start video from in front of the camera. No dice, the video function was a separate button and no remotes seemed to allow what I needed. But the GH2 is a different story altogether. Even though it has a dedicated motion picture start and stop button (the little red one), when you have Motion Picture mode selected with the mode dial on top you can start/stop recording with either the red button OR the shutter release. And since using the shutter release also initiates autofocus depending on how you have the focus configured, it is possible to do this with a wireless remote. I ordered the Rainbow Imaging wireless remote on amazon.com and IT WORKS.

A “half press” on the shutter button does autofocus (just like in still photo modes) and the full press from there starts the recording. This is useful for a one person operation where that one person also has to step out in front of the camera and “demonstrate” or do something.

Your “rig”: The temptation is to “deck out” your camera with a shoulder mount rig that then lets you “hang” lights, monitor, audio recorder, mic, rails, large mattebox, and other “things”. You can easily run the bill up to 4 figures. But when you do this you also negate one of the advantages of the GH2. It's compact size. Some kind of shoulder mount or stabilizer will often be very necessary, the one I use is simple, lightweight, and made to take nothing but the camera. Check out Spiderbrace, they have just developed a design specifically for DSLRs. Less than $100 delivered to your door in the U.S.

I've used an older version for a couple of years now (with DSLRs) but will be ordering the new design soon.



© 2012 Bruce Foreman

[Kevin Janisch]

Thank you Bruce. I do indeed use full manual but looking to create a preset for something that's a little quicker in constant changing lighting conditions. I appreciate the info but am still puzzled at why I cannot use the exposure compensation in Shutter exposure mode even though it states you can in the manual. I'm wondering if the camera adjusts the shutter when shooting in Aperature Priority when adjusting the exposure compensation.

[Adrian Frearson]

Kevin, I think you might be misunderstanding how shutter priority works ( or doesn't ) with legacy lenses? As there is no way for the camera to control the aperture of the lens you're using, it is more or less impossible to dial in any exposure compensation. The camera can adjust ISO on the fly on certain settings though.

Best bet is to do as Bruce says and shoot full manual, or to shoot aperture priority and adjust exposure using the ring on the lens. If your lens is a preset type, then this is ideal for adjusting aperture on the fly, whilst filming.

[Kevin Janisch]

Originally Posted by Adrian Frearson

Kevin, I think you might be misunderstanding how shutter priority works ( or doesn't ) with legacy lenses? As there is no way for the camera to control the aperture of the lens you're using, it is more or less impossible to dial in any exposure compensation. The camera can adjust ISO on the fly on certain settings though.

Best bet is to do as Bruce says and shoot full manual, or to shoot aperture priority and adjust exposure using the ring on the lens. If your lens is a preset type, then this is ideal for adjusting aperture on the fly, whilst filming.

Then why does Exposure Compensation not work with native four-thirds lenses In Shutter-Priority as Bruce stated? I was thinking the expo-comp in Shutter-Priority would adjust the iso if the iris was fully open/closed
or if a native four-thirds lens was not detected. You can adjust expo-comp while recording but not ISO settings. I am mostly referrIng to low light situations where my lens is already fully open and I want have small increments of exposure adjustments while maintaining my shutter speed of 60. Changing my aperature is too abrupt. Auto ISO does a great job in that it Is more gradual and natural. All of this is of course for those situations where I don't have time to go full manual and don't want to miss the shot.

[Adrian Frearson]

Now I'm a little confused. Shutter Priority does work as advertised with native lenses no ( auto ISO can be set )? Sorry, I don't have a GH2 in front of me so can't double check, but at least that's what I recall. With non native lenses, which you are using, then you should stick to manual or aperture priority ( manual if you want to stick to 1/60 ).

Either find a fast aperture lens that has a stepless aperture ( so your changes aren't abrupt ), or set ISO on camera using button and wheel.

[Kevin Janisch]

Me too! I don't have the kit lens handy so I'm going to have to check it out when I get a chance which was my original question to begin with.

[Bruce Foreman]

Originally Posted by Adrian Frearson

Now I'm a little confused. Shutter Priority does work as advertised with native lenses no ( auto ISO can be set )?

Shutter Priority does work, but in Shutter Priority exposure mode exposure compensation doesn't, even with native M4/3rds optics.

@Kevin - In a low light situation you really wouldn't want your ISO auto adjusting. You'll likely have your lens wide open, probably want the shutter to stay at 1/60th (1/50th for PAL), and your ISO set to a specific value perhaps for "noise" control. The "unhacked" GH2 has an upper ISO limit of 3200 in "motion picture" mode, applying most of the firmware "patches" will "unlock" that upper limit and allow selection of ISO values up to 12,800 (which will in all likelyhood look extremely crappy.

I'll go 6400 if I have to but if I want to limit noise to what 3200 will have (in underexposed areas) then I want to be able to set it at 3200 and not have it "auto adjusting" at all.

[Kevin Janisch]

Originally Posted by Bruce Foreman

Shutter Priority does work, but in Shutter Priority exposure mode exposure compensation doesn't, even with native M4/3rds optics.

Just tested out the Panny 14-140 kit lens and Exposure Compensation definitely works in Shutter-Priority in Creative Movie Mode.

@Adrian: In a dark room in Shutter-Priority mode in Creative Movie mode when the camera has the iris wide open with Auto-ISO on, I am able to compensate the exposure to +3 which is "brightening" up the image but it is noisy. This can be done while recording. Conclusion: the GH2 is adjusting the ISO when the iris is at its limit which is what I suspected originally.

Now here is where it gets really interesting. Auto-ISO allows the image to be "brighter" with +3 exposure compensation than setting the ISO to 3200. This is visible in the recording and I tried this with both ISO limit on and off at 3200. This is an un-hacked GH2. So the GH2 is doing something else to the image. Any thoughts?

So, Exposure Compensation works in Shutter-Priority in Creative Movie Mode with Panasonic four-thirds lenses but not with legacy lenses. Perhaps a hack could allow legacy lenses to have exposure compensation via changing the ISO in Shutter-Priority mode as it does with native lenses?

[Adrian Frearson]

Glad you got it to work with a kit lens. Thought I was going slightly mad for a minute or 2!

I'm guessing the reason it's brightening up when you're using Auto ISO, is it really is pushing the ISO past the supposed set limits. I think all the G cameras do this little trick, hacked or not.

Personally, I would avoid shooting anything but manual, even in fast changing light and try to search for lenses that will allow you to change aperture smoothly ( and are reasonably fast ). Depends what focal length you need, as to how much this will cost you.