GH2 Video Shutter Speed, Wonky Footage, 1080p 24fps / 720p 60fps etc.

B

bvalentine

Member
Hi...

I understand the fundamentals of photography and such (aperture, shutter relation and what-not). But I just seem to be dealing with the same run-around issues when it comes to video. Keep in mind I mainly shoot ENG/documentary style, very seldom do I have a controlled studio environment. And although I enjoy the beauty of slr video, I'm not trying to make 'films'.

The rule I've been following for video: "Shutter speed should be double your fps."
-Cinema Movie Mode 1080p 24fps, set shutter to 50 and adjust aperture accordingly.
-Manual Movie Mode 720p 60fps, set shutter to 120-ish and adjust aperture accordingly.

Right?

1080p 24fps issues:
-Indoors not many problems. Everything looks great, especially with some fast glass. It doesn't like movement (slight stutter), but I try not to move anyway.
-Outdoors. Almost unusable. With that shutter on 50 man, lots of stutter. And I have to use an ND filter. I don't know if my filters were cheap, but they sure do booger things up (gray, dirty color cast).

720p 60fps:
Everything I've ever read about the GH2 says "only use this when you plan to slo-mo it later". And I remember how cold 60fps looks on proper video cameras, so I haven't really experimented with it until lately. The other day I shot outdoors in 720p Manual Movie Mode 60fps.... and was pleased as punch. With that 120-ish shutter I didn't have to use a ND filter. AND any movement was smooth as silk. I can run & gun with this setting! Plus, with slr glass all of that coldness I remembered with 60fps seemed to vanish.

So I thought "screw this, I'm sticking with 720p! Most all of my stuff ends up on the web or getting converted down anyway. Why are all of these people anti-720p? Ohh yeah... they're making 'films'."
-Then I went inside and.... crap. Not enough light even with the 25mm f1.4 wide open. Not with that 120shutter. And... all that indoor beauty of an slr seemed to disappear.

So, if you'd be so kind... what am I not getting? There must be something, or perhaps a lot of somethings I'm not doing right.

Thank You for not being mean in advance!
 
Last edited:
bvalentine said:
I was a bit bummed that nobody responded.....
Click to expand...

Perhaps because the issue has been discussed so many times in multiple threads. I know the search function here is far from perfect but your questions have all been addressed here.

In short, the old film camera requirements only apply if you like the look, but are certainly not necessary. I prefer a 40 shutter speed, going down to 30 if I have to for light issues. And a poor ND filter will definitely impact your image in a bad way.
 
Your're not doing anything wrong. Higher shutter means darker image. So, because you like 720p (on a higher shutter...which makes things darker) and not 24p (on the standard 50...which keeps things brighter) and want that buttery smooth slow motion then those primes will have to be really opened up when indoors or you better have more light at your disposal.
 
Yes typically the 180degree rule is only really a rule for 24p and even then it isn't written in stone that you have to use it. For normal video which is typically 60p or 60i you wNt to use a shutter of 1/60th. Just the way it is and how video cameras that shot 60i have done it for years. The only time you want to use 1/120th with 60p is if you want to slow it down.

If you do a search on this forum you will find lots of huge debates about shutter speed. In fact there was just a conversation about it again recently. That may be why few have responded.

Be careful what you trust on the Internet as well. In this biz most people are very opinionated and there is a lot of mis information out there on the subject of shutter speed.

Basically it comes down to look and nothing more. Yeah it is true that you can't really have a shutter speed faster than your framerate without looking funky. For example you can't really have 1/30th with 60p without basically loosing frames. If this is ok with you then yes it works but like I said creates a funky look. In theory 24p can use 1/24th but since the framerate is so low it creates a very smeared look. 60p and 60i using a shutter at 1/60th doesn't smear as much because there are more frames in between.

Personally I shoot 24p at 1/40th since it works well with lights in the US and helps the motion a bit more without looking too smeary. This also has a similar look to the shutter speed used for the Hobbit which was 1/72nd and not 1/96th with the 48p they shot. You will find a few of us on here who now use 1/40th on digital cameras.
 
What about 30p at 1/60th as a compromise? A bit smoother in terms of motion than 24p but still using a shutter ratio similar to 24p. It also stays at 1080p and may be a good in between area for you. Now in the broadcast world 30p is a bastard format but if most of your delivery is the web then shooting 60p is kind of a waste anyway since all web video formats can only do up to 30p.
 
I have to ask, what kind of ND filter were you using, and how many stops of light did it cut? In my part of the world, on a sunny day, I need at least a 3-stop ND filter to use my lenses outdoors at 1/50th shutter speed. And that's setting my ISO down to 200 on the GH3. Going from 1/50th to 1/120th is just over a one stop difference, so I'm curious how switching to this shutter speed eliminated the need for using an ND outdoors. Either it's an overcast day or you're stopped down to f22! :-)
 
The reason for the 120th shutter speed applies to 60p is for slow motion, in order to get smooth slomo, you want to boost your shutter speed to 120 or even higher if possible, but if you like the way 60p looks, handles motion, there's no reason you couldn't lower the shutter speed to get exposure. It really doesn't effect the image as much as when you lower the speed by half.
 
Thank you for the responses and I am sorry if these questions have been asked before. I searched and could not find anything that fit my particular predicament. These comments helped!
 
My guess is that your variable ND filter is partly responsible for your displeasure with the outdoor image. Reflections and color casts can really muddy up the image, like you said.
Thomas Smet is right about 30p. I think all web formats (Youtube, Vimeo, etc.) cut the frame rate of 60p material to 30p. If you shoot 30p at 1/120th outdoors an at 1/60th indoors, you may get the look you like in terms of motion. And at half the frame rate of 60p, each frame should contain more data and therefore exhibit superior quality than 60p, especially in scenes with lots of motion.
 
bvalentine said:
Promaster 52mm Variable ND
Click to expand...

Most of the low cost variable ND filters will degrade the image a fair bit. If money is tight, then you might want to look at buying a Tiffen ND filter set that won't degrade your image...

Tiffen 52mm Digital Neutral Density Filter Kit : $42

Otherwise you might consider investing in one of the new Genustech Eclipse variable ND filters...

Eclipse ND Fader 52mm : $113

Genustech Eclipse Fader ND filter Sets New Standard

Genustech Eclipse Variable ND Fader Review
 
You must log in or register to reply here.
Back
Top