GH2 GH2s ETC MODE

F

flinty

Veteran
Hi most people on vaious sites who own the GH2 praise its ETC function,they say that although when in ETC mode the picture in the viewfinder/lcd will look grainy and low resolution even when focused but as soon as recording starts the picture sharpens up and is virtualy as good as with ETC off.My GH2 is not like this when recording using in ETC mode with any lens the picture has far more noise and of lower resolution than filming with it off.
Is it possible that my GH2 has a faulty etc mode,or am i seeing what others dont.:(
 
i wouldn't say yours is faulty, unless there is a serious amount of noise and sharpness/resolution loss.
Basically, ETC... your only using about half the normal image sensor plate to capture video. Still its full HD, but since your using very specific "image receptors" noise and sharpness issues start to creep in.
Im sure someone else with more technical knowledge can chime in on what exactly is happening.
Bottom line, in ETC mode, you will notice some loss of quality and especially more noise when your shooting lowlight.
But with plenty of light, ETC preforms relatively well.
 
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daihard said:
i wouldn't say yours is faulty, unless there is a serious amount of noise and sharpness/resolution loss.
Basically, ETC... your only using about half the normal image sensor plate to capture video. Still its full HD, but since your using very specific "image receptors" noise and sharpness issues start to creep in.
Im sure someone else with more technical knowledge can chime in on what exactly is happening.
Bottom line, in ETC mode, you will notice some loss of quality and especially more noise when your shooting lowlight.
But with plenty of light, ETC preforms relatively well.[/QUO

Thanks for the reply,one thing of note on wider lenses it is better than long lenses where i find ETC of little use.
Click to expand...
 
Its using a smaller area on the actual image plate, thats why you can use C-mount lenses thanks to ETC.
Also, that means when you use standard 35mm lens your using the "sweet" spot of most lenses... the center is usually the most sharp and vignetting free area.
Probably the reason why Zooms aren't as sharp is just because there is more glass and possibly more distortion as light passes through to the smaller image area.
Frankly, the only time id consider ETC is with Prime lenses. I carry a 35mm f2 Nikon, which translates to about a 60mm on my GH2, then with ETC ive got about 120mm.
 
Someone said that the increase in noise in ETC mode is close to the 2.6x multiplier that it magnifies the lens. So ISO 160 would be closer to 400, 400 would be about 1000, 1000 about 2500, etc. In good lighting, shouldn't be too much of an issue, but unless you have a fast lens (C-mounts are available down to F/1.0), the noise will kill low light shots.
 
It is my understanding the footage looks noisier because you are using a 1 to 1 pixel area of the sensor. Remember these cameras have sensors with much higher resolution then full HD video. Normal shooting uses the full sensor and the camera scales this down to 1920x1080 before it records it to the card. ETC mode only uses the 1920x1080 pixel area in the center on the sensor. The sensor isn't so much noisier in ETC mode then it is in normal mode. What is happening is that you are seeing a more raw image of what the sensor is actually doing. This is pretty much exactly what is going through the sensor. Normal wide however masks some of the noise by scaling down the image to 1920x1080. Take any noisy photograph in Photoshop and scale it down to a smaller size and it will look cleaner. That is pretty much what is happening here. The noise just gets hidden better due to the scaling of normal mode. This will also in effect make the image look sharper due to the softer native pixels getting scaled down. Normal mode isn't any sharper it just looks sharper because the large sample area gets scaled down.

ETC mode is more like what a regular video camera does. They typically will have native resolution 1920x1080 sensors and record a 1 to 1 pixel ratio of that sensor. So ETC mode basically looks like a 1/2" single CMOS video camera or something like that. I still think they look better then most 1/2" video cameras if a single chip 1/2" actually existed out there but that is basically the concept here. A single chip camera with a bayer pattern will always be softer at 1920x1080 when 1920x1080 samples are used because of the interpretation of the bayer pattern colors.

The way around this is of course make sure you don't have to bump up the ISO as much and filter the video in normal mode so it doesn't look sharper.
 
I agree with what everyone else has said. It works in 1080p @ 30 FPS mode for wider lenses. It really isn't great for longer lenses or with 720p @ 60 FPS mode.

The video below was shot mostly in 1080p @ 30 FPS and some in 720p @ 60 FPS with ETC on. I used the 25mm F1.4 and the 45mm F1.8. I tried to use the 14-140mm natively and it just underexposed in this very dark climbing gym so it was use the primes without IS and with ETC or nothing. It is not great but it is better than nothing.

The 35-100mm F2.8 cannot get here fast enough. That lens is ideal for this type of handheld filming.

http://www.youtube.com/watch?v=PJ6o-oHaFMc


 
I do most of my shooting in ETC mode, 720/60p since I shoot wildlife/birds. My main lens is the Panasonic 100-300, and ETC up to about iso 640 is fine, but anything higher hasn't been pretty. Older lenses don't handle ETC well, the loss of contrast and sharpness can be too much.

To my knowledge, there's no scaling involved in normal HD uncropped mode, but keep in mind that any Bayer sensor will always involve some algorithm to de-bayer the image which involves a calculation based on the surrounding pixels, so there probably is some benefit to exposure by not cropping, but I don't see anything more than 1 stop or so.
 
I also have found ETC noisy and not great for indoor shooting (interviews), but somewhat better outdoors. I try to avoid it whenever possible, but there's one scenario when I need it: Sometimes when I'm using the 20mm/f1.7 indoors because I need a low-light lens, I need to be closer to the subject than I can physically be (for whatever reason--whether it's an interview, or I'm filming someone working or doing something else physical that I have to stay back from). Then I turn on ETC. But only reluctantly...

That said, I DID get some good results with a 200mm Nikon prime lens from the '70s (I believe) and ETC. I had such a long effective focal length that I was able to get a close-up of a distant breakwater viewed from a hill in a seaside town. However, with that set-up, the faintest hint of wind was shaking the camera too much on its tripod, and I also had heat waves and atmospheric distortion causing problems. That said, I was able to pull some usable shots out of the footage and they'll be in the final project.
 
Interesting replys,i rarely film in low light but even outdoors in good light there is no way i would film mostly in ETC mode,i also own a Pana FZ150 which has a 1.3 x i zoom this is lossless to my eyes unlike ETC which admittedly is double the extension on the fitted lens,as i have said on wider lenses the degradation is not as bad as using a lens like my 45-200mm,i always try and keep the iso as low as possible.Also i film in 25P [pal]mode mostly .
 
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