GH2 Dynamic Range?

V

VidE

Active member
As a videographer new to the DSLR game, I'm trying to figure out how to do things with the GH2 that I do with my FX-1. And yes, I know that the GH2 is fundamentally a different sort of beast. I thought the GH2 would have a greater dynamic range than my Sony FX-1 HDV camcorder. It probably does but I'm not sure how to realize it yet.

Shooting a theatrical show with the GH2/14-42mm kit lens-as a 'set & forget' setup. Manual Movie mode locked down on a wide angle.The shutter at 60, (shooting 60i to match w/FX-1) and the iso at 800. It did really well on some scenes but blew out highlights on others while still leaving areas of the frame dark. (Theatrical Lighting = FUN...Not!).

With my FX-1, I can set it to "Spot", which basically brings the exposure down a bit to compensate for bright spots without bringing the overall exposure down too much. On the GH2 I tried using the 'iDynamic' function but that doesn't seem to help. And I'm not sure that even if the iris can be left on auto where there is any way to tell the iris to start closing once you hit 100 ire.
I read a post that says 'Cinema Mode' helps flatten the dynamic range, but right now I'm not sure that's enough and if I set the iris to expose for the highlights, the whole frame gets too dark.

FX-1-Shot-sm.jpgGH2Shot-sm.jpg
(FX-1 on the Left-the GH2 on the Right.

The FX-1 has a 'flatter' tonality and even using color correction on the GH2 footage, I couldn't retrieve the colors of the girls dresses. I've since tried shooting with the irs down from f3.5 to f5. The dresses look great but the midtones get real dark and the darks are way too noisy to try and retrieve any detail with CC.

Any ideas on how to not blow out highlights and still get decent darks?
 
Hmm, I compared my Gh2 with my HVR-Z7 and they are pretty much the same in dynamic range.
I use Smooth and every option @ -2
The GH2 performs much better than my EOS 60D which really crushes dark midtones.

BUT (Big but) I would never use my GH2 for this kind of work. I often film ballet and I usually need to adjust the iris about ~300 times while a performance and I zoom a lot. That´s a job for a casual prosumer camcorder!
 
m4/3 just doesn't have the same dynamic range. Watch video clips of the GH2 and you'll see more blown whites a bit more. Luckily the noise is good so you can underexpose a bit and fix in post later, but it is something of an issue that I've noticed more and more. I don't have a 60D, but my 5D2 at ISO 3200 has more dynamic range than a Gh2 at ISO 800. DXO backs this up as well as from what I've seen.

People think that just because you have X amount data rates and X amount of noise that you are set. Dynamic range suffers and is a big factor for some. I hate clipping, so there are some circumstances when I would want to avoid the GH2 or any m4/3 system. This becomes more of an issue when you need to bump up the ISO. Clean images isn't everything with higher ISOs.
 
Question: are you using the Record Highlight function? This is a sort of Zebra functionality. I recommend not using Idynamic or anything auto. Set your onboard LCD so that it stays at a fixed brightness at all times. Use Record Highlight (on) Try setting your profile to Smooth, and dialing from there. Not what you want to hear - but you might be shooting with too Deep of a lens stop on the 14-42 and idynamic is overcompensating and messing everything up... for that kind of work you need a fixed 2.8 zoom lens..or the olympus 35-100 if you feel like dropping mad cash. Seriously though - a third party fixed aperture zoom will do you good. It's hilarious to hear people criticize the dynamic range of the cam - you get a LOT of dynamic range in this cam. I'll do some tests with charts later to prove this.
 
Oh one more thing - you should really try putting your shutter at 1/125 or 1/100 for a 60i shot. Give it a try and let me know if that helps.
 
FelixGER- I tried to fit the GH2 into 3 slots; inexpensive Video B Camera for theater work - video camera w/DOF options not so available with my FX-1 - decent still camera. I can see where the GH2 might not work in slot 1, as an untended B camera for long form theater work.

skulpt- I've tried exposing a bit lower and fixing in post but the blacks do seem noisy. You know a post technique I don't? (For video).

Two questions: 1) How does exposure compensation function, what does it change? In Manual Movie mode, with iris at f3.5, shutter at 60 and iso at 800, what does exposure compensation use to change the picture?
2) Can I set the iris to auto while leaving shutter and iso fixed?
 
Dan, I replied before I saw your post. I do shoot manual, but I have to leave the GH2 alone, using the FX-1 for medium shots and close-ups. I'm loathe to switch cameras, i.e. set the FX-1 on lockdown wide and use the GH2 for the close-ups simply because the FX-1 handles so much better. I just read about the Record Highlight function, loks good although it doesn't help much when the camera is untended....

For this particular venue at 14mm I'm almost full wide. And it's going to be awhile before I can find another lens. My shooting situation seems to be really hitting the camera's weaknesses. I'm not bummed by the camera and I had a hunch the dynamic range is nice. I will try taking out the iDynamic and seeing if that will help.

Am curious as to the remark about shooting at 100/120 shutter speed. To underexpose I could adjust the shutter speed up but I'm curious as to what benefit that gives me other than cleaner movement.
 
I find the contrast of the kit lenses to be a bit overwhelming in some lighting situations. Specifically for this kind of bright light/light-colored clothing scene, maybe you could try a contrast lowering filter, i.e. a black promist, or use an older manual lens - they usually have milder contrast that can give images a more filmic dynamic range.
 
Isn't the exposure different in the two images?

Just look at the ground. Dark grey on left, light grey on right.

Not sure you can judge DR by this.
 
htinla - great idea. For some reason I had completely forgot about using filters.

Pietro - the two images were never meant as a definitive test of either camera's abilities. These images came from a real shoot -not a comparison test. I went back and test-shot another performance and found that if I set the exposure of the GH2's down to where the dresses weren't over-exposed the rest of the frame went considerably darker. And there is a scene later on that is lit very dark and I'm afraid that I'll lose it altogether if I underexpose. All you folks with more DSLR experience might have solutions to my predicament of inexperience coupled with pushing the camera into a situation it wasn't designed to deal with.

Normally, I would use two FX-1's, leave one on +3 gain in auto iris and Spot mode on lockdown wide and then workthe close-ups with the other one. The owner of the other FX-1 is using his on gigs and so I had to get another B-Cam for this gig and it had to be cheap. I probably should have gotten a cheaper AVHDC camcorder but I couldn't resist getting a DSLR for what it might add to my toolset on other, non-theatrical gigs.

I'm learning so much in a short time thanks to you folks about this new tool so please take no offense if i seem to complain about its seeming 'shortcomings'. For instance, the FX-1 came with a 12x zoom that goes down to f1.8 and can hold to a single f stop through 80%+ of its travel. We videographers have been blessed with many benefits that we take for granted that do not come automatically in the DSLR realm. OTOH, shooting a 4k still of my granddaughter at Xmas is somehting the FX-1 cannot do, different tools doing different things.

But I do have this current issue of what seems to be too much contrast and hence blown highlights in this particular shoot. And in two days I have to shoot 2 more performances for real.
 
stonebat said:
Wouldn't the super ultra contrast filter make the aliasing worse?
Click to expand...
<br />
Though the name implies otherwise the ultra contrast filter lowers contrast, that would make aliasing less, not that the GH2 has problems with aliasing compared to other VDSLRS to begin with.
 
VideE,

I have a solution that should solve your problem. there is a function on the GH2 which is much like the "Spot" mode on your other camera.
On the GH2, go to the "Motion Picture Menu". First, set "Exposure Mode" to "P" instead of "M". This will function like a "Full Auto" exposure. On page 2 of the same "Motion Picture" menu, go to "Metering Mode, and make sure it's set to "Center-Weighted", which is the icon that looks like this: (*). Lastly, set your ISO to "AUTO". Normally, I'd never recommend this as a setup for filmmaking, but for recording a play, it's necessary, especially if you have to "set it and forget it" as you say. Lighting cues for stage can go from near pitch black to super-bright. That's more than any camera's dynamic range can handle without changing the aperture or ISO. Setting the exposure mode to "P" makes the camera automatically adjust the aperture for proper exposure, and it should handle the white dresses just fine. Auto ISO helps in the same way. For even more control, I'd set the Film Mode to "Smooth" and dial the Contrast down to minus 2. This will give you the flattest image the GH2 can provide. Seriously, try this, and it should solve your problem.
 
dvBrother-The GH2 image pulled from from the previous posts was with just such settings. Except for the center-weighted which might help with the dresses being over-exposed. That might help, so thanks. The big problem is that for darker scenes (and there is one really dark scene), it really cranks up the iso to really ugly, noisiness. And there is no iso limit in Movie Mode. (Damn!). For this particular show I may have to shoot two shows in two different styles and hope. If I can get the contrast filter I might give that a try as well. Thanks.
 
The problem with any video is the higher the ISO, the lower the dynamic range. If you could shoot with a brighter lens and drop the ISO a bit, that could help at least a touch. The filter is an interesting option. Another option is looking for a lower contrast lens. Actually older Zuiko OM lenses are known for being less contrasty and great for tonal range. If you're setting things up as set up and forget, the fact that they're manual focus would be no big deal. Beyond the settings you're using though and the other stuff mentioned, you're a bit stuck with the dynamic range of the m4/3 sensor. I don't know how people do weddings consistently without blowing out the dress or underexposing the shot.
 
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