Image quality concerns... Am I doing something wrong?

Fluke

Fluke

Active member
So, I've had the GH1 for a few days now and I've been having a lot of fun with it but I've been having a little trouble...

I keep noticing colour fuzziness in the pictures and it doesn't handle indoor light as well as I thought it might. I don't know if this is something I am doing wrong, or if it's a fault with the camera or whether this is totally normal low-ish light behaviour and I just had too high expectations.

Here's some screen grabs from me flailing the camera about in my bedroom...

Look at Alec Baldwin's suit, the weird look of the wallet and the rough gradient on the glasses case.

Test1.jpg


Lots of fuzziness. Particularly on the edge of the bookshelf.

Test2.jpg


Wall looks terrible.

Test3.jpg


It was recorded using 720 50p, at 400 ISO, 1/50 shutter on Nostalgic setting with everything at 0.

The room is lit by a single 240V 100W ceilng light fixture.

I imported the footage into iMovie09 at full size. There was no adjustments done to the picture. Exported at full size.

I would have thought the GH1 would hold up better than this in pretty normal indoor lighting.

This could be iMovie09's fault, too, or at least a problem with how I'm using it. The footage seems to fall apart very quickly with even the slightest adjustments.

As I said in my previous thread, I am very new to this whole video thing so there's probably may things I'm overlooking and have done wrong, but if anyone could comment on what I'm seeing, I would be most grateful.

Here's a link to download the .mov file.

http://www.mediafire.com/?zwromx3aiqz
 
Ive had the camera for a month or so and i do notice the same stuff as you do.
Try shooting at something color red and you will be appalled. The ghosting on some of the red colors is horrible....
 
I can imagine... Me and red have never been best of friends. There's a live music venue that I sometimes take photos at that has almost exclusively red lighting. I rarely come away with anything more than "passable".
 
Yeah, it's really impressive. I was surprised how well they cut together, which makes me more confused about why my "test" looks so awful. I mean, I know they were shot in entirely different situations and environments, with entirely different gear and vastly more experienced people, but the above images look so awful that I wouldn't believe it was the same camera as in the shootout. Especially after everything I read about how well the GH1 copes with low light situations.
 
could it be something as simple as shooting above your stock lens capabilities. It is quite a slow lens so shooting stuff in doors and low light will look terrible as your pics suggest. I have read that stills are clearer than video in low light which also suggests its codec issues?

you gotta remember with that test they aren't using stock lenses but quality fast lenses i would guess judging by behind he scene shots.
 
I don't know about the setting but the quality of light looks terrible to begin with.
 
yslee said:
I don't know about the setting but the quality of light looks terrible to begin with.
Click to expand...

That's the thing. It's pretty standard indoor lighting. It's not a dank, dimly lit room. It's far from ideal as far as filming goes but I wouldn't really call it particularly low light.

I'm not so concerned with the way it's exposing the image. It's dark, but that's okay. It's the way that the codec (?) just can't seem to process flat surfaces and gradients. I mean, if the light looked the way it does in the screen caps I posted but the areas of solid colour were smoother, I'd be over the moon. It's just the way flat surfaces are pixellated that has me cringing.

Even the DVD cover and wallet, positioned directly under the light source, look pixellated.

MR Fanny said:
could it be something as simple as shooting above your stock lens capabilities. It is quite a slow lens so shooting stuff in doors and low light will look terrible as your pics suggest. I have read that stills are clearer than video in low light which also suggests its codec issues?
Click to expand...

Would a faster lens help with with this pixellation issue? (Is macroblocking the right word?)

And, yeah, a photo of the same situation with equivalent settings looks much clearer.
 
I shot some stuff indoor during the day with light coming in through only one medium-sized window and it looked better than what you're showing here. Kit lens even.

I also shot a bunch of stuff inside a very dimly lit bar and aside from the streaks (a known "issue" with the GH1) it looked better than what you're showing. Granted that was with a Zeiss f/1.4 lens.

You could have underexposed. Maybe you need to adjust the aperture, ISO, and/or shutter speed. If you used the kit lens, what was your zoom at? Were you wide and at f/4 or were you zoomed in and at f/5.8? That could make a big difference. Try different film modes and see if you notice a difference, and even adjust the settings of those film modes. Lower your contrast, lower saturation, increase sharpness (according to Barry Green in another thread).
 
Yeah you're filming with a slow lens, in a room lit by a single light bulb, at the extremes (IMO) of useable ISO for video.

When shooting indoors with the kit lens I throw up at least a kilowatt of light from whatever sources are available, and open all the windows I can...lol. I really don't like to shoot above ISO 100 or 200 if I can avoid it, and higher than ISO 400 is a self-imposed production NO in an environment where I can control the lighting..like, you know, my room.

The kit sucks low light long story short. Get some fast primes. And maybe some lights? Don't know what kind of shooting you're doing but with a camera with a sensor like the GH1's, a few 500 watt worklamps go a looooooooong way (and they are DIRT CHEAP compared to a real lightning kit which I assume you have no access to.)
 
If enough of the shot is well exposed, the darker bits seem to not go noisy in my experience so far. Something to do with contrast and with the proportion of the shot that's adequately illuminated.

I may well be shouted down but I'd also try the full auto idiot mode and see what you get. Then the GH1 is doing its best to show what it's capable of. If it's still no good, well, maybe you are expecting too much. If it's better, then think through what the GH1 auto settings may have been (shame you can't tell) and try to replicate with manual settings, modified to suit your needs.
 
Make sure it doesn't do shutter lower than 1/60 or 1/50 720p/60/50. Look I think what it comes down to is that this is a camera for making films..you wouldn't expect other cameras to perform low light miracles so why this one...all cameras need light. Just because you're used to cranking ISO and increasing shutter speed for still photos doesn't mean it will work for video...your high ISO which normally could hide in your big fat high res photos leads to many problems when pumped through to AVCHD, and of course you can't shoot slow shutter in most situations.
 
super low light, ugly low detail scenes, F4, and underexposed... guess what you get??

I've found that Barry is right.... If you want to shoot super low light with the gh1 you have to SLIGHTLY OVEREXPOSE (around +1/2 to +1) and then beat it back in post. To do that in lighting situations like your showing here... F4 is probably not going to work. At least get an F2.8 strapped on. Add some detail and interest vola your audience won't notice a thing.
 
That kind of blockiness present on a subtle gradient is usually more of a codec thing, isn't it? When the codec decides that certain regions are close enough in colour to combine them into one macroblock. It's called 'banding' sometimes.
 
Ben_B said:
I really don't like to shoot above ISO 100 or 200 if I can avoid it, and higher than ISO 400 is a self-imposed production NO in an environment where I can control the lighting
Click to expand...


Ben,
Excuse the inexperience, but what advantage does shooting at lower ISO's do?

And if you do shoot at lower ISO's (like 100 or 200) will this work in low light situations?
 
Lower ISO = less noise, but you'll need to make sure there's adequte light.

Fluke:

Typical room light is usually crap. Pardon if I generalise a bit, but don't most American homes tend to use tungsten lighting? While having a high CRI, the extreme shift in colour temperature means the camera is pumping even more gain to the other colour channels in order to try to make it look less warm.

On top of that, there's at least 2 stops of underexposure in the last two images. There just isn't enough detail for the codec to figure what's going on, hence the weird colour blocks. Lit the room properly and they'll go away.

As an example, my room is lit with 10 fluoroscent 6000k tubes with 80 CRI rating and I still need to use ISO 800 at f/2 to get a steady shutter speed of 1/60. What do you think about the amount of gain the camera has to use when the kit lens is 2 stops or more slower?
 
Excuse the inexperience, but what advantage does shooting at lower ISO's do?
Click to expand...
Typically people here want to shoot with narrow depth of field (using wide aperture) and low shutter speed, so unless the iso is low, in many situations you'll end up with an overexposed movie. To help counter that in bright light, people use neutral density (ND) filters.
 
Thanks for all the replies!

upshot said:
To do that in lighting situations like your showing here... F4 is probably not going to work. At least get an F2.8 strapped on. Add some detail and interest vola your audience won't notice a thing.
Click to expand...

Yeah, I think I was jumping to conclusions with an unfair test using a slow lens. I'll look at getting some faster glass.

AndrewGentle said:
That kind of blockiness present on a subtle gradient is usually more of a codec thing, isn't it? When the codec decides that certain regions are close enough in colour to combine them into one macroblock. It's called 'banding' sometimes.
Click to expand...

Ohh. So *this* is banding. I assumed banding was lots of veritcal or horizontal lines, not a pixellation issue. I should have read the huge banding thread then...

yslee said:
On top of that, there's at least 2 stops of underexposure in the last two images. There just isn't enough detail for the codec to figure what's going on, hence the weird colour blocks. Lit the room properly and they'll go away.
Click to expand...

I see your point. Tungsten = not ideal. Low light tungsten = dear god no. Heh. I think I need to readjust my position on what low light is. I think I was being too hopeful.

Ben_B said:
Just because you're used to cranking ISO and increasing shutter speed for still photos doesn't mean it will work for video...your high ISO which normally could hide in your big fat high res photos leads to many problems when pumped through to AVCHD, and of course you can't shoot slow shutter in most situations.
Click to expand...

Seems I have a lot to relearn and let go of past habits.

Ozpeter said:
I may well be shouted down but I'd also try the full auto idiot mode and see what you get. Then the GH1 is doing its best to show what it's capable of. If it's still no good, well, maybe you are expecting too much. If it's better, then think through what the GH1 auto settings may have been (shame you can't tell) and try to replicate with manual settings, modified to suit your needs.
Click to expand...

I took your advice and shot the same scene with idiot-proof mode and it got rid of a lot of the macroblocking. I was surprised. It did leave a lot of noise in it's place though, as I assume it had to crank the ISO and gain, but I guess this somewhat proves that, so long as the scene isn't underexposed, macroblocking isn't such an issue. I'm interested to try some shots with nicely exposed subject on a dark background and see if the pixellation rears its ugly head again.

I guess a bit of me is still a little disappointed that the codec can't handle smooth gradients as well as I hoped. I think I assumed that underexposed images would be, well... underexposed but still smooth. I had too high expectations of the codec, I think.

But, so long as I'm not running around with a faulty camera, I can live with that. Hey, at least I've got one, right?

Thanks for all the help.




Edit: Interestingly enough, I went back to watch this video I found on Vimeo a while back...

http://vimeo.com/5515095

That was the video that pretty much sold me on the GH1 in terms of low light performance. I was stunned. Couldn't believe how good it looked. But, watching it now, I'm picking out bits of banding and macroblocking that I didn't notice before. Not heaps, mind, but I didn't even really notice it the first time.

I've become a pixel-peeper! Ack! The illusion has been shattered... I feel dirty.

If, with faster lenses, I can shoot footage of that quality in low light, I'll be a very happy lad, indeed. Must stop worrying so much about technical stuff and start filming.
 
Last edited:
You must log in or register to reply here.
Back
Top