Possible Mud Cause - LENS CHOICE

Psynema

Psynema

Well-known member
Wanted to take the mud cause on a new angle. After watching some clips full rez on a big screen I'm starting to notice the problem is much more than nitpicking and really got to me now.

One thing I've noticed, I have two lenses

20mm 1.7
50mm 1.4 Pentax Asahi

Mud is noticeably much less on the 50mm manual lens, if any at all.

I'm noticing the 20mm 1.7 is pretty damn frequent - I shot a fairly steady shot on a gorillapod tripod of a church - the bricks had mud even though the camera was still. WTF?

Is this problem perhaps lens specific? I know the newer GH1s have less of it and I'm sure the banding colorations may contribute as it makes pixels change color, but never heard a "by the lens" theory.

Only thing I can think of is that the 20mm is lightweight so the camera is more prone to hand jitters than using a heavier manual lens leading to quick pixels changes here and there ON TOP OF the auto focus HUNTING constantly (manual focus is a pain in the butt with the 20mm and also is stiff, making for jitters).

Just an observation I just had looking over a shoot this past weekend.

You may call me nuts, I LOVE the 20mm lens and having a great DSLR/HD cam in my pocket due to it's size, but I've made a decision :( It's on ebay...I'm sad too, but the focus drives me nuts after pixel peeping, you're f'ed either way (I'm an event videographer/documentary so I can't quite lug a tripod for every shot for those that do narrative/studio stuff).

As a pain as handholding a 50mm asahi may be without OIS...I don't see mud/artifacts nearly as much.

Anyone else notice a manual vs. electronic/lightweight Panny lens mud differences or is it just me?

I'm aiming to get either 30mm 1.4 Sigma or a 18-50mm Sigma with the cash from ebay. Or I may be nuts and sell my GH1 body and get a new GH1 off amazon for $1189 (I never had the kit lens and newer bodies are supposedly better).
 
It might be that at a 50mm your dof is much more shallow so there's not as much detail to tax the encoder. Have you tried panning real fast with your 50 compared to the 20mm?
 
Isaac_Brody said:
It might be that at a 50mm your dof is much more shallow so there's not as much detail to tax the encoder. Have you tried panning real fast with your 50 compared to the 20mm?
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Maybe, but didn't notice much if any mud on the detail on the 50mm on some detail/non shallow DOF shots.

Anyone else notice this?
 
I was going to say the same thing as Isaac -- the detail is probably what's doing it. The more that's in focus, the more the encoder is taxed, and the 20mm will have more detail in focus than a 50mm would.

Plus, yeah, if you're using it in autofocus, and there's any focus hunting at all, that's definitely going to increase the potential for muddy footage. The GH1 uses a long-GoP codec so changes in one frame can affect codec efficiency throughout an entire group of frames. If focus is hunting, that could add up to a lot of changes in each group of frames, making it a lot harder on the codec.

Here's a simple test you can try: use the 20mm while you still have it, and try similar shots in autofocus and fixed-focus. If the AF shots are muddier, then you have your answer.
 
^What they said.

Also...don't sell your 20mm!! pull it down :)

Forget auto-focus! That lens has the best focus ring for manually focusing video (no joke.) It's so dampened that you can actually pull focus properly...it takes a larger turn to go from 3 feet to 6 feet, rather than 2º...it works great for video (not so great for photos but the autofocus is fast and accurate.) I've ran around with that lens on and been able to manually focus perfectly on say, each person I walked past.
 
I'd almost think it was an AF issue. The only time I have had any sort of hiccups with the codec has been in AF.

I've shot with the GH1 in an abandoned warehouse using the kit lens and the 20mm and never had any mud issues, and I wasn't shooting strictly shallow DOF of field shots. I think one time I had some aliasing/moire on some bricks, but that was about it and I wasn't gentle with my camera movements either. The codec didn't break apart on me at all during the shoot and I had the lead singer and the lead guitarist hooked into a DIY snorricam and even that didn't tax the codec. I shot everything in manual focus so that's why I think it's possibly an AF thing.

I'll only use AF to first get a quick hit on focus and then switch to manual.
 
Ben_B said:
^What they said.

Also...don't sell your 20mm!! pull it down :)

Forget auto-focus! That lens has the best focus ring for manually focusing video (no joke.) It's so dampened that you can actually pull focus properly...it takes a larger turn to go from 3 feet to 6 feet, rather than 2º...it works great for video (not so great for photos but the autofocus is fast and accurate.) I've ran around with that lens on and been able to manually focus perfectly on say, each person I walked past.
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LOL, I tried manual focus, just don't care much for it on the 20mm, I see what you mean in that you can minutely focus in a span of an inche or two in very shallow DOF, but anything beyond that requires a few turns and ruins the flow of the rack focus during recording. I'm actually much more used to standard focus rings.
 
On the weekend I was shooting an event in a park with the stock lens. That's first time I got hit by the mud issue. It's really bad. I was using AF a lot, lots of trees in the background and I was using the Multirig which doesn't give good stability with such a light camera. Not a good combination. I was just getting ready to purchase 20mm - now I am hesitant.
 
Xaveryptak said:
On the weekend I was shooting an event in a park with the stock lens. That's first time I got hit by the mud issue. It's really bad. I was using AF a lot, lots of trees in the background and I was using the Multirig which doesn't give good stability with such a light camera. Not a good combination. I was just getting ready to purchase 20mm - now I am hesitant.
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I can't possibly imagine shooting anything with the auto-focus running unrestrained on the GH1...it will never focus on what you want it to...I've never known a video camera that would. That being said, nailing focus with a half-press of the shutter release before recording will lock instantly with the 20mm...and kit lens...and 45mm Leica...and 7-14mm...auto focus works amazingly well on the GH1 with the focus assist laser beam.

But if you're trying to get the camera to do an automatic follow-focus shot, it will fail like any other video camera.

Fortunately I'm a die-hard tripod shooter for my wedding/event work, so the only time I get mud is from photographer flashes. Then again, even shooting handheld home videos, I've never seen mud in shots that I intended to keep...only when swinging the camera around between shots.

If I could have only one lens with the GH1, it would be the 20mm at #1. 45mm Leica #2, kit lens #3, 7-14mm #4. That's all I need. None of them effect mud in my videos. The way I shoot, does.
 
swyzlstyx said:
nailing focus with a half-press of the shutter release before recording will lock instantly with the 20mm...and kit lens...and 45mm Leica...and 7-14mm...auto focus works amazingly well on the GH1 with the focus assist laser beam.
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That's what I was doing.
Where I got the mud was during the speeches so subjects were stationary (and the camera was too as much as possible). That's why I was so surprised. I choose to use Multirig b/c the second part of the event involved following a march (or rather trying to be ahead of it) and I was not up to running with a tripod.


 
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