Serious artifact

A

Alpha Beta Omega

Veteran
I took a bunch of photos last week of my family and when going thrue them in Lightroom I got this ugly artefact. The shirt has a pattern that the GH1 couldn't handle. It was shoot in RAW.

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I think it's more of a feature. It looks awesome! It's probably just the pattern of the shirt, and possibly your sharpening settings.
 
That "maze" pattern is typically due to incorrect processing of the RAW file by the post software. It is certainly not limited to the GH1.

Cheers,
 
Too much detail and sharpness, I have seen this in the DPReview resolution chart as the lines converge into very very fine detail. The GH1 has a low strength AA filter. Add a bit of anti-aliasing and it should disappear.
 
methinks a moiré pattern
link

EDIT: if its a still there is a really easy fix in photoshop. grab a soft brush, change brush mode to color, eyedrop the shirt to get color value, brush away and texture stays intact
 
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Same result when using Silkypix. The distorted pattern is still there. The tip about painting away the distortion works fine, but isn't this a bug/artefact in the camera?
 
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I'd be really interested in seeing the raw file. Can you post the raw file? If you don't have a place to host it, try http://www.yousendit.com . If that's what I think it is, I have a fix that can completely eliminate it!

Mike
 
editman said:
Here's the raw file
Click to expand...

Thanks. Surprisingly, that looks like typical moire to me. I didn't expect it to be that bad. :( Looks like the AA filter on the GH1 is way too weak. That gets the reviewers bragging about how well the GH1 does on a "per-pixel" level, rendering sharper images than the competition... but at the same time it leads to this ugly mess in rare cases where the frequency of patterns aligns perfectly with the photosites on the sensor.

Mike
 
I've shoot 10 000 pictures with the D90 and no moire or other strange stuff. And only about a couple of hundreds with the GH1. Disappointing!

This one form the GH1 was in a series of six images shoot with the self timer. And they all have this artefact.
 
editman said:
I've shoot 10 000 pictures with the D90 and no moire or other strange stuff. And only about a couple of hundreds with the GH1. Disappointing!

This one form the GH1 was in a series of six images shoot with the self timer. And they all have this artefact.
Click to expand...

Did you shoot in JPEG + RAW? I wonder what the JPEG from the camera looks like. Those don't seem to suffer from the problem. Also, if you rip the 1920 x 1440 JPEG out of the raw, that doesn't show the problem either. Here is the JPEG that is embedded inside the raw photo: untouched except for cropping.

Mike
 

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editman said:
I only shoot RAW. So there's something wrong with the RAW or is the RAW file revealing things the JPEG are hiding?
Click to expand...

I think the latter. It looks like Panasonic used a weak AA filter and just compensates for that in software like they compensate for the severe barrel distortion of the 14-140 lens in software. Unfortunately none of the raw software does the auto-correction of moire like they do barrel distortion. For now, until the raw software catches up with the GH1 "technology", I'd shoot raw+jpeg. That way you can easily salvage photos like this while at the same time enjoying the other benefits of raw.

Mike
 
Panasonic isn't necessarily using a "weak AA filter", they're having to straddle the line between stills and video. Do they tune the AA filter for 1080p video? If so, it'll make the 12-megapixel stills unnecessarily soft! Do they tune the AA filter for the still camera needs? If so, then it'll be "weak" for the video.

They had to make a choice, and seeing as the GH1 is primarily a stills camera, they optimized the AA filter for stills (I'm assuming here, as I haven't talked to them, but I can't fathom why they would have done otherwise). So yes, that means that the AA filter is not strong enough to eliminate aliasing in 1080p video.

But it wasn't necessarily a "mistake", it was a tradeoff that happens when you've got 12-megapixel stills and 2-megapixel video; you can't have both without some sort of compromise.
 
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