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View Full Version : Moire, ah man.



DM_rider
10-12-2011, 09:44 AM
Be cautious, this is the first serious moire I've ran into with the camera. Figured it had to happen sooner or later. I wonder if it could be tamed within the detail settings?

Download the file to really see it
http://vimeo.com/30442889
password: test

Barry_Green
10-12-2011, 10:24 AM
Yep. That's one of the first things I found on it, it has the same kind of rainbow moire that the Canons do, but only on really fine detail. The Canons show it everywhere, but on the Sony it's only on the finest details, but if you have really fine patterns or bricks or something like the fine patterns you were showing here, it can happen...

funkmusicinstitute
10-12-2011, 10:40 AM
Yeah I've encountered it w/ mine, particularly w/ screen doors and old vintage microphones. Not nearly as often however as when I shoot w/ the Canon 5D.

DM_rider
10-12-2011, 10:51 AM
Yep. That's one of the first things I found on it, it has the same kind of rainbow moire that the Canons do, but only on really fine detail. The Canons show it everywhere, but on the Sony it's only on the finest details, but if you have really fine patterns or bricks or something like the fine patterns you were showing here, it can happen...

I had forgotten about the issue, because overall, it's fairly decent with detail and I hadn't run into any serious moire yet. Surprised me more or less.

-Sandro-
10-13-2011, 05:33 AM
Well I really wouldn't expect moiré from this low MP sensor. it surprised me too. I'm curious to know if the F3 would do the same

AtticusLake
10-13-2011, 07:10 AM
Moiré happens when two repeating patterns are overlaid, and are fairly close in spacing of their elements / angular alignments. Right now I'm looking at an office chair whose back is two layers of a mesh fabric wrapped around a tubular frame, and I'm seeing moiré. (With my eyes, not a camera... :-) )

The pixel grid in your camera's sensor is a pattern; so if you shoot another pattern with similar density, you'll get moiré. As far as I know, this is a fact of life with digital cameras; but because the pattern you're shooting has to be really fine for it to happen, it's not an issue most of the time.

The problem with the still cameras (5D etc) is that they downscale a high-res image by line skipping, which introduces a third, and coarser pattern (because as I understand they don't line-skip to exactly the right number of lines). So, they have MUCH worse moiré problems. That's where the FS100 scores in having a sensor designed for video. But moiré is always a possibility, and I guess we just need to work around it. The FS100 just makes that easier.

I gotta say, though, I was surprised how much there was in DM_rider's crop patterns.

Barry_Green
10-13-2011, 12:21 PM
Well I really wouldn't expect moiré from this low MP sensor. it surprised me too. I'm curious to know if the F3 would do the same
Yes, the F3 does the same.

morgan_moore
10-13-2011, 01:10 PM
The pixel grid in your camera's sensor is a pattern; so if you shoot another pattern with similar density, you'll get moiré. As far as I know, this is a fact of life with digital cameras; but because the pattern you're shooting has to be really fine for it to happen, it's not an issue most of the time.

I thought that digicams had a filter that should blur the image to a point where the resolution of the image is just lower than the resolution of the sensor

At that point the patterns in the image should never be close to or equal to the the pattern of the sensor

So it (moiree) should not happen with a properly designed device??

Obvioulsly still/motion cameras (eg 5d2) this woud not work becuase the operate at two different resolutions

But moire should not happen in a correctly specced single purpose camera??

Barry can expand no doubt

S

Barry_Green
10-13-2011, 01:20 PM
Well, the tuning of an OLPF (optical low pass filter) is a balance of compromises. Aliasing happens when the lens passes too much sharpness to the sensor. The OLPF is there inbetween to dumb down the sharpness to a point where the sensor can properly resolve it. But how aggressive do you make the OLPF? Tune it too far down and you'll eliminate all aliasing, but probably some legitimate sharpness too. Go too weak with it, and you run the risk of getting aliasing patterns on your footage. In Alan Roberts' evaluation of the F3, he questioned whether there was an OLPF in there at all. Panasonic tuned their OLPF to eliminate all moire issues, to the point where some folks say the GH2 looks like it has "sharper" video... which then gets back to the whole question of aliasing making things look "sharper" than they actually are.

Alister Chapman found moire patterns in bricks on his F3 early on, and I found the same thing with the FS100, and now DM_Rider found it in grain patterns. Traditionally Sony has struck me as a bit more aggressive than other companies, they balanced the EX1 to get the most sensitivity, and ran too far into allowing infrared and ended up with the IR contamination issue. And it seems to me that's what they've probably done here too, they were too aggressive with their OLPF (meaning, they erred on the side of chasing maximum sharpness).

What DM_Rider's footage didn't show is the rainbow pattern that happens. Shoot some bricks from a good distance and you can get the same purple/orange type of thing happening on the FS100 & F3 that happens on the Canon DSLRs (but to a much, much milder degree, obviously). I haven't had a chance to compare an F3 against an FS100 to see if the issue happens to the same degree or not, but comparing Alister's shot against mine, they do look comparable.

Anyway, once again, it's all a balancing act, just like in a car engine -- you can tune a car for maximum power, or maximum gas mileage, but usually not both. With a single-chip sensor you can tune it for maximum resolution, or maximum fidelity of avoiding aliasing, but not both. So each company makes their choices and lives with the consequences of those choices. In the case of the F3 and FS100, it is possible to get the same kind of aliasing and rainbow moire that happens on a DSLR, but to a much less prevalent degree.

morgan_moore
10-13-2011, 01:55 PM
nicely put
S

ShawnLam
10-13-2011, 03:04 PM
I gotta say, though, I was surprised how much there was in DM_rider's crop patterns.

There is a lot more moire at reduced size but not as much at full screen.

Postmaster
10-13-2011, 03:17 PM
Finetuning the Detail settings helps a lot.

Frank

Pietro Impagliazzo
10-13-2011, 03:32 PM
Barry, I remember on another thread you said the FS100 hasn't really got a low-MP sensor, from the info you gathered it really looked like a high-MP sensor (like in a DSLR).

Is that so or I'm getting it backwards?

Barry_Green
10-13-2011, 09:41 PM
Barry, I remember on another thread you said the FS100 hasn't really got a low-MP sensor, from the info you gathered it really looked like a high-MP sensor (like in a DSLR).

Is that so or I'm getting it backwards?
That was speculation on my part, based on a few observations.

ectobuilder
10-13-2011, 11:05 PM
Have you guys compared 8-bit AVCHD 4:2:0 vs 8-bit ProRes 4:2:2 vs 10-bit S-Log 4:4:4 and see how that affects the moire?

robfilms
10-13-2011, 11:14 PM
alex-

did you spot the moire when you were shooting or only on later review?

can you recall the detail level set for that crop shot?

would lessening the detail level be the work-around?

again, thanks for making the effort and sharing your observations.

it might be worth it to repeat the obvious, "every camera is a compromise."

ymmv

be well

rob
smalltalk productions

AtticusLake
10-14-2011, 06:39 AM
Well, the tuning of an OLPF (optical low pass filter) is a balance of compromises...

Thanks for that very helpful post! I hadn't realised there were such differences in OLPF tuning between cameras.

Am I right in thinking that the OLPF on a stills camera basically does nothing for video, as it's passing everything below the camera's (much higher) stills resolution?

TimurCivan
10-14-2011, 06:52 AM
F3 will definitly do it.

Happens rarely, but it does happen. By product of being so sharp. Throw a HD soft filter to help calm the effect.

Barry_Green
10-14-2011, 10:36 AM
Am I right in thinking that the OLPF on a stills camera basically does nothing for video, as it's passing everything below the camera's (much higher) stills resolution?
Yes, that's exactly the case, and that's why a combo stills/video camera will have such aliasing problems as we see on the DSLRs. The only way to really resolve it would be to take the approach Red has taken, which is to make stills and video the exact same resolution, and that way the OLPF can be optimized for the sensor res. But when you have a case of 21 megapixel stills and 2 megapixel video... well, yeah, something's gotta give. And inherently it's got to be video performance that suffers, because what would be the point of having a 21-megapixel still camera that has a blur filter to lower the res down to 2-megapixel video?

righteous.
10-16-2011, 11:18 AM
Bummer! I was real set on an fs100 for deep, sharp focus. I knew it technically existed, but based on what I've seen and what everyone has told me, its virtually nonexistent. Maybe an EX1 is better for landscapes after all? Hmm...

moldcad
10-16-2011, 11:26 AM
Maybe an EX1 is better for landscapes after all? Hmm...

It most definitely is...

morgan_moore
10-16-2011, 12:23 PM
Personally while I get sharp images from the EX1 IMO the lens at the wide end is pretty poor, especially a little stopped down when it seems to fringe

Its very bowed making it look 'cheap' on buildings athough such distortion is less apparent in nature

IMO the EX1 chip regularly outresolves the lens

Id pick the FS100 with a good wide angle (not the kit lens) over the EX for wide images

I recently scored a nikkor 18/4 manual that puts my other wide lenses to shame, my other wide lenses are; the kit lens, Tokina 16-50, nikkor 14/2.8, the EX1 and a nkkor 20-35 to name a few

S

righteous.
10-16-2011, 01:33 PM
I'm more of a telephoto guy myself...the reason I'd ever be hesitant to go for the EX1 is because video cameras tend to have limited telephoto capabilities, and those auxiliary lens adapters are pretty crappy in my experience (yes, even Century) compared to actual lenses. Using a video camera for wide is out of the question, since I refuse to shoot something that isn't rectilinear.

morgan_moore
10-16-2011, 01:57 PM
Have you ever tried a S35 chip camera with a telephoto?

I was out playing with my 600/4 +1/.4conv today on the FS100.

The technical challenges in terms of framing without a zoom and managing the mass, rigidy, stability and focus are quite comical

The EX1 is my go to cam for longer shots than 200mm (S35) eqiv unless I was doing a very specific shot with time for a few takes

And the EX1 performs well at the long end optically

S

righteous.
10-16-2011, 04:51 PM
The technical challenges in terms of framing without a zoom and managing the mass, rigidy, stability and focus are quite comical

The EX1 is my go to cam for longer shots than 200mm (S35) eqiv unless I was doing a very specific shot with time for a few takes

And the EX1 performs well at the long end optically

S

Yes, I'm well aware of this. Good to know the EX1 holds up optically on the long end!

Dermot
10-16-2011, 07:58 PM
We have a B4 mount for our EX3, and a canon 18x7.8 zoom with a built in doubler for long lens stuff... and a Ronford F7 to hold it up... not a small & light set-up.. but yea... far far better than a coke bottle on the nose of an EX1 tho.....

d

LiamR
10-16-2011, 08:48 PM
The EX1 is my go to cam for longer shots than 200mm (S35) eqiv unless I was doing a very specific shot with time for a few takes

And the EX1 performs well at the long end optically

S

I used my FS100 with a canon fd 70-200mm f4 on it to film some surfing the other day, I was way up on the cliffs and was zoomed completely in and the images looked great (i'll get it up as soon as I can) beaches are quite possibly one of the hardest places to film anything and having the fs100 and being able to fine tune was such an advantage!

nomad-3
10-16-2011, 11:22 PM
I have seen moiré on both FS100 and F3, and they are both low-pixel count sensors. Sony is notorious for favoring detail over anti-aliasing. I'm impressed how well Panasonic is handling it with the GH2, which has a photographic sensor. I suppose they put enough computing power into that one to downscale from full-rez in realtime.

NeedCreative
10-21-2011, 01:59 PM
Same here. Rare but it happens with very fine details. Very very fine.

Illya Friedman
10-23-2011, 08:57 PM
F3 will definitly do it.

Happens rarely, but it does happen. By product of being so sharp. Throw a HD soft filter to help calm the effect.

If you are talking about one of the Schneider filters branded "HD" like Classic Soft, you would be advised to skip adding that to you F3 or FS100. That filter is optimized for sensors sizes of 2/3" or smaller. You'd be better off adding a standard Classic Soft (or other non-"HD" branded Schneider filter), which features lenslet dimples optimized for 35mm sized sensors.

Illya Friedman
10-23-2011, 09:09 PM
It most definitely is...

I disagree. The images that come from an FS100 are superior to those of than an EX1, and not by a small or insignificant amount.

1- Use a proper monitor
2- Become intimately familiar with your camera and settings
3- Test

If you can do these things it is exceptionally rare that you will run into imaging issues/aliasing issues with FS100 or F3 that are not also present on any other similar camera.

If you do the pepsi challenge of a Sony FS100 (with a decent lens) and an EX1. With the FS100 there's clearly more dynamic range, color information and apparent detail, it's not even close.

In broad general regards to aliasing, is not always created at the camera level, it can be created optically, you can see using only your eyes. You can be darn sure if your eyes can see it, your camera will to.

moldcad
10-23-2011, 11:41 PM
I disagree. The images that come from an FS100 are superior to those of than an EX1, and not by a small or insignificant amount.

1- Use a proper monitor
2- Become intimately familiar with your camera and settings
3- Test


The above 3 points are also relevant with the EX, so it doesn't change my opinion :)

With all the advantages of the FS100 picture, it's not as detailed and aliasing-free as the picture my EX1 can produce. The only obvious disadvantage of the latter is a much higher noise level.

Illya Friedman
10-25-2011, 03:38 AM
moldcad, you completely missed the main point...


With the FS100 there's clearly more dynamic range, color information and apparent detail, it's not even close.

To claim that the EX1 is making superior images, is akin to burying ones head in the ground. It makes it awful tough to see your monitor with all that sand in the way.