GH-1 GH-13 Fixed Pattern Noise: Breakthrough?

I've made a series of tests. The scene was lit only by the LCD monitor and levels were boosted severely in post to see the difference in FPN more clearly.



What I've found is that this technique does not actually boost ISO. Quite to the contrary it rather decreases sensitivity when AE Lock button is on. In this particular case pressing AE lock button locked ISO at 400. I does help to eliminate noise patterns yet at the expense of losing shadow details and more washed out look.
 
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The +2 to +3 EV 'trick' seems to do something... It increases noise at the very least :/

With the AE Lock, if ISO limit is set to Off it will lock at ISO 400 (or so it says on the display) if there is a ISO Limit set, it will lock to that limit. I do believe that shadow detail is indeed lost, reducing the recorded DR... In practice that means that the blacks/shadows are cropped out...

I've obtained a bag of mixed results, for certain conditions it sure looks better to use the suggested settings... When I made some shots with dim light from a small window, it looked great, when I shot in a windowless room with just a dim artificial light (it should be noted that it was extreme low light), there wasn't much of a difference.

I really wonder why in certain situations I get underexposed footage in movie mode, when in the custom one it looks fine, it's on those situations where I seem to benefit from the custom setting trick most :/
 
IMO this technique is yet another, a more extravagant way to limit ISO. It's a nice find, an interesting thing to learn, another tool in your arsenal, another way to control the camera, but definitely no breakthrough, no miracles, no free lunch.
 
well I gotta say, I just hooked up emory's original settings from the first post- just to mess around real quick-....this is truly amazing stuff- not sure that the noise/fpn is completely gone but much more subdued and manageable! Plus I just love the auto iso!! I'm indoors in a relatively dimly lit room with canon fd 50mm at 2.8 plus an nd .9 filter, using blackout-powell latest hack!! REEE-DIC-U-LOUS!!!!

Can't wait to see on big screen!!

Thanks all!! this is sick!!

Z
 
zigizigi said:
IMO this technique is yet another, a more extravagant way to limit ISO. It's a nice find, an interesting thing to learn, another tool in your arsenal, another way to control the camera, but definitely no breakthrough, no miracles, no free lunch.
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+1. There's no free lunch. I'd use this trick when there is no other choice.
 
Well at least there is enough people now getting results to prove this really works, for a while there it was looking like the thread was going to die.

It's a great option to have and if Vitaliy can enable it in creative Movie Mode, even better.
 
Using an NTSC Camera (FS9Lxxxx) , GH13 hacked, in PAL mode, in PAL land this worked great until I noticed I was getting banding of a different type: from my flourescent kitchen light.

Repeating Emery & Ramboc1's instructions in P made, S mode, and M mode always locking the shutter speed to 1/50th, I got flicker, or 2 dark bands or even 3 dark band, pointing the camera directly into the light. Basically, it looks like the camera was not respecting my shutter speed and doing what it needed to do to cut down the amount of light hitting the sensor. Yes, there was much, much less FPN.

I believe my camera, despite the GH13 hack has 60i coming off the sensor, making all these varing shutter speeds a problem in a 50 Hz (PAL) country.

I checked out a GH2 in a store under FL lighting and found it was very hard to see any flicker on the monitor. I believe the cameras made for PAL land must have 50i coming off the sensor. I hope somebody confirm some of this.

Back to the GH13, using creative movie mode, 1/50th SS there is no problem at all. Only in this mode does the camera seem to respect exactly what settings are programmed. You can also see this while zooming the 14-140. In creative movie mode there will be one or 2 density changes as you zoom (anyone know how to get rid of this?). But in iA mode this is not visible. I believe the camera is using gain and perhaps SS to compensate on the fly. I know the consumer video cameras get around this using gain, while movie cameras, must use constant aperture zoom costing a small fortune.

Top line: If your camera was made for your region, then this trick should look pretty seemless for you(beware with subject movement the shutter speed may not be true) . If you are mixing a camera from another region or shooting multiple bodies with mixed regions: look out for flicker from sources iike FL lighting, CRT TVs, street lights, LED displays on stoves, clock radios, etc.

If anyone has got a tip for the zoom problem or wants to confirm my findings please post it.
 
Despite my findings I am very very happy to see how well the GH13 can do in low light and will keep the settings in my last custom preset for emergencies. Many thanks Emery & Ramboc1
 
i'm running some tests with this but struggling to understand exactly what this is doing. When I stop recording ISO shows 400 despite being on Auto ISO during recording. Does that mean its limited to ISO 400 in some way? Which obviously explains the cleaner image.

When I do the tests it does look cleanrer but my shutter goes crazily slow sometimes (lower than 1/25th) how can I set it to not go lower than 1/50th whilst in this setting or is that not possible? It seems that instead of boosting ISO above 400 it is just lowering shutter speed to something crazy like 1/4 of a sec.
 
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ok I am confused whether the ISO thats displayed through the EVF before and after recording is actually the ISO thats taking effect. As others have stated this is set to ISO400 if no limit is set in the photo menu, or 1600 is 1600 is set in the menu.

Also when setting up these settings on S mode it all makes sense, but in P mode sometimes the shutter displayed doesn't reach 1/25th as its too dark but instead of boosting the gain (which is left on auto) it seems to *display* the crazy shutter speeds I mentioned in my previous post of 1/8th 1/5th etc.

I'd like to know if both of these ISO and Shutter values displayed on the screen are accurate...
 
that's why we don't use P mode! you're letting the camera set crazy shutter speeds. for video you want to lock the shutter speed.....so use S mode, M or Creative Movie.
 
Please read my first post in this thread.

The camera is not setting "crazy shutter speeds." It will not actually go below 1/30 with these settings. If it were actually recording at, say, 1/2, you'd immediately notice. But, as I pointed out in a previous post, 1/30 is not good for SH. The bitrate drops too low, resulting in "mud." This is the case with or without these settings, with or without the hack. SH = 1/50 minimum. As I pointed out in that previous post, these settings are really only suitable for FHD.

And yes, for some reason, the camera indicates a maximum ISO of 400 (even if you do not limit ISO in the MENU -- q.v.) But it actually sets far higher ISO's in low light situations. Again, please read my posts in this thread.
 
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I did read your post. The one the said "I think" it won't record below 1/30th.

A great find regardless. Do these settings become any more or less effective using S mode instead of P just incase there is still doubt in people's minds with regards to shutter
 
tikigod19 said:
Do these settings become any more or less effective using S mode instead of P just incase there is still doubt in people's minds with regards to shutter
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Actually, in yesterday's post I was responding to averan. I guess I should have "replied with quote."

After doing some (admittedly not very scientific) tests, I can't see any real difference between P and S modes. I just prefer P because it allows you to set the aperture with LUMIX lenses.

Of course, the faster the lens, the less FPN you'll get. I find the 20mm 1.7 excellent in this regard, the 14-140mm nearly useless in low-light situations.

And for me at least, the settings work fine with manual lenses too (my venerable old Canon FDs now have a new lease on life).

Have fun experimenting!
 
I've just done some night shooting with these settings on my GH13, where the only light source was light that was reflecting off a concert stage into the crowd (for shots of the crowd, not the stage) and distant lights that were lighting a field nearby. Literally no light. In Creative Movie mode at 1600 ISO very little was visible and the noise was awful.

Using Standard film mode with contrast all the way up to further reduce noise, these settings gave me images that were almost completely absent of noise. As the camera moved you could see evidence of FPN on people's faces as they moved across the sensor, but there was almost no visible, varying noise anywhere else. Even the blacks were mostly clean. It looked like Creative Movie Mode would at 800 ISO.

Also, I was using shutter priority, and when I locked AE, it looked like the camera retained the shutter speed I chose (to maintain 180-degree shutter) and limited ISO to 1600. However, when I unlocked AE, the image got so much brighter, it was amazing. I tested shutter speeds and AE and found that using these settings with exposure unlocked and running on full manual, although you end up with a 360-degree shutter, the image is far brighter than an image shot at 1/30th and ISO 1600 would be manually. Therefore I've concluded that this method unlocks higher ISO than 1600 for video, and it even looks pretty clean.

Clearly this camera is not a 5DmkII or Sony F3 in low light, but with these settings it's performing higher than previously reported, and pretty darn well in my opinion! There was, as I said, some noise visible, but not in the blacks (thanks to the contrast heightened in the film mode) and far less noise than I've seen in Creative Movie Mode. So these settings really do help, and although not magic, they can definitely reduce the effective noise and apparently allow 3200 ISO in video.
 
Nice job, very little noise. I noticed some FPN on a few of the pans but most of the noise that was in that video was hard to see, and could just as easily be mistaken for compression artifacts.
 
CColton said:
Nice job, very little noise. I noticed some FPN on a few of the pans but most of the noise that was in that video was hard to see, and could just as easily be mistaken for compression artifacts.
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Ok and some noise also came after color grading with magic bullet looks i dont know why...

Also some shots that i didn't used in this video had way more noise than this like for example i had 2 exactly same shots: 1 dark just like in this video without noise and 1 brighter with alotta noise while setting was the same on both. So that's kinda strange too and i don't understand how with the exactly same settings you get 2 different looking shots 1 with noise and 1 without and i did not notice this in playback in gh1 screen..

Thanks for checking
 
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