On the question of the need for 25p, I'm curious - is the problem of syncing to lamp flicker for mains-driven lamps no longer relevant?

I was under the impression using 24p in a scene with 50Hz-driven-fluros, for example, (white balance issues aside) would produce some rather undesirable effects... and if we're going the GH2 route, I presume we're not all in situations with a large lighting budget. Yes, I'm aware of the 1/50th shutter trick, but that's a bit constrictive, particularly if you want a faster shutter / wider aperture combo for bokeh (I'm old school ;o) don't really like the term 'bokeh', but I'll admit it covers an aspect of DOF effects that didn't have its own name before).

There's been plenty of comments that 25p is irrelevant because you can speed up 24p, which is well and good as long as you stay outdoors, but surely being unable to shoot under lights is an important limitation for any kind of video or movie work - unless someone is suggesting that shooting in the dark is just fine.

If the GH2 or the PTool hack has fixed this issue somehow, please let me know - it would be awesome (if unexpected) news...

That's the issue I face with using my GH2 with my 2 XHA1 camcorders hence run my GH2 at 1080i

@zigizigi +1

Aside from attempting to mix 24 and 25 footage, I am finding that the GH2 drifts out of sync in 1080 50i (much more than my Canons) so don't know what's going on there - but that caused me a lot of work the other day to mend a bunch of clips (60+) in a shoot which was being mimed to playback.

Unfortunately I'd removed the audio from the timeline GH2 clips having done what I thought was an initial sync and then cut the clips up - so I had to match them up again one by one by syncing up the original takes and then matching my edited video clips to that (too much work already done to just start again). Won't make that mistake again - I'll keep all the audio with the gh2 clips but mute it all - so I have a sync reference to return to should I need it. Not something I've worried about for years with my XHA1s and other SD camcorders I have, which hold sync perfectly. I've now got pluraleyes, so am ready for my next shoot, but the GH2 shouldn't be drifting that much.

That's without dealing with 24p!

Of course I could ditch my Canons but they're great for lots of usability reasons (and have 25mbps cbr).

Not cries but just should point out (and rant) that 25p is used in a lot of countries...and sometimes ESSENTIAL for work.
I currently conform from 24p and on occasion I get out of sync trouble. 50i is frankly shit on the gh2....soon as everyone abandons interlace format the better.

So its so unreasonable to hope with the hack that 25p is a possibility? Seems it isnt taken very seriously but for some of us it is.
Every bit as important as 4.2.2 mjpeg and hdmi output.

wah wah wah ;-)

I think the simple question that has not been answered...will we get 25p from the hack?
When we get the answer to this then we can all shut up ;-)

+1 wah, wah, wah. You've started me off now!

@evero correct. 25p is vital for me working in London and the lack of it if the only reason I have not dived in and purchased one. I work 99% in post so am no expert in actual shooting so have one question...Am I right in thinking if 25p is achieved on this camera then you could shoot under our 50Hz lights at any shutter setting of our choosing?

edit: @madact answered the question. But I wouldn't think 25p would solve all those problems? Would more of the shutter settings be compatible with 50Hz lighting when using 25p vs 24p?

Moving all conforming discussion here...

@_gl @mrbill Please give me a scenario, other than maybe B-cam, where conformed 24p is insufficient, now that we've established it is widespread in industry and produces indistinguishable results.

Time stretching and pitch correcting in Premiere is as easy as speeding up by 4.2% and checking the preserve audio pitch box.

@Donnie88 @madact You'd get the same problems with lighting and shutter speed at any other frame rate, nothing to do with conforming. The shutter is still open for the same amount of time for each frame.

@evero If you're thinking of the 180 shutter rule, the difference between 1/48th and 1/50th shutter speeds is indistinguishable.

Not saying that 25p/50p isn't needed on the GH2, but this is a perfectly usable workaround.

@Ptchaw I have just illustrated in my post above how the 24p to 25p workflow is insufficient with music videos.

@ptchaw For many of us, using the GH2 as B cam is very likely. I use it with AF100, but in the future also in other multicam settings with various PAL cameras (with the 30 min (pal) timelimit gone, it's very usable for this).
Time stretching and pitch correcting huge projects will add even more rendering time, and believe me, I struggle enough with time and power consuming timeline issues as it is.
In some projects you have the time, in some you don't.

@Ptchaw "You'd get the same problems with lighting and shutter speed at any other frame rate, nothing to do with conforming. The shutter is still open for the same amount of time for each frame."

Not quite sure what you mean by this? I agree that it has nothing to do with framerate conforming, but the comments about "any other frame rate" and "open for the same amount of time" don't seem to make sense. I'm not sure you're disagreeing, but I'll give the lecture for the benefit of all ;o)

The problem is that if you have 50Hz mains, the light output from incandescents and particularly fluros has a ripple at 100Hz, though some have an asymmetric response (or in one case I saw, a bridge-type dimmer circuit with one side burnt out :oS) which gives a waveform that repeats at 50Hz. If you run a fast shutter speed and the frame rate is not 25 or 50 fps, you hit that ripple at a different point each frame, and hence get a different amount of illumination on the scene each frame, hence the flicker. If you set your shutter speed to *exactly* 1/25, 1/50, or if you're really lucky (depending on the specifics of the lighting) 1/100 of a second, you get *exactly* a full cycle of the ripple in each frame, which averages out to no flicker. Any other shutter speed, and the whole thing strobes at either 2 or 4 Hz, depending (once again) on the specifics of the lighting.

However... and this is why it matters: if your shutter fires 25 (or 50) times a second, you can use any shutter speed you like, because it will always 'open' at the same point in the ripple and 'close' at the same point in the ripple.

So the general rule is, if you're shooting under domestic / low budget lights with detectable ripple, you match your *shutter* frame rate (i.e. the rate at which images are physically taken at the business end of the camera) to whatever frequency is running the lights. Or get limited to a couple of set (and relatively slow) shutter speeds... which can suck, esp. if you want a bit of control over motion blur.

Note: A lot of stage lighting and big-*** quartz floods don't really suffer from this as the thermal mass of the filament takes the ripple out pretty well, and DC or HF LED arrays have no issues at all, but any domestic globe, fluro, or mains-drive HID lamp will do it.

@madact You are right, though there are a couple of things I'd like to add:

You can't quite use any shutter speed you'd like due to rolling shutter; on high shutter speeds the time the top of the image was captured will be earlier that the time at the bottom of the image, so the brightness will vary across the frame.

You are limited to a shutter speed of 1/50th at 24p (and very slow shutter speeds) for lighting, though there isn't really a reason for not using 1/50th at 24p.