Tz7/Zs3 color blotches in pictures

The following images are all taken from imaging resources

http://www.imaging-resource.com/PRODS/ZS3/FULLRES/ZS3hSLI0080.HTM

You can see color blotches in the images of the Tz7/Zs3 as in the following:





The following is image from the 12mp Canon SD940. It doesn't have any color
blotches. The Zs3 image may be sharper but color blotches are not acceptable:





The following is image from the new 18mp Canon DSLR 550D:





Are the color blotches in the Zs3 images a result of chromatic aberrations or
is it chroma noise or others?? It spoils the sharp pictures of the Zs3.

btw.. they were all taken using the base iso (lowest iso)... so how come the Zs3
has yellow blotches in the image??

To get the better "out of the camera" jpeg Panasonic does a fair amount of sharpening etc. It isn't going to blow up to 300% as well as the far less processed pictures of the Canons. At 100% it looks better than the SD Canon but obviously less so than the DSLR shot. I have the camera, you really can't go up to a 300% blow up (which would be a staggering 10,999 pixels across).
Regards,
Kurt
--
For some random samples:
http://www.pbase.com/khoss/
http://www.pbase.com/susanshaw
http://www.susanandkurt.blogspot.com
http://www.slshaw.info

can sharpening cause color blotches in the image? Maybe it's cause by
chroma noise or even chromatic aberrations?

Imagine those lines inside those letters are window grills.. blowing it up
to 300% is useful to see the most details if one is examining for details.

On any of the small sensor cameras, once you are over 100% (and most of the time far less) the artifacts from various processing not only will obscure detail but frequently distort it so it looks like something else. It's a crapshoot varying from picture to picture. If you need that kind of detail stick with an APS-C or larger sensor with today's technology.
Regards,
Kurt
--
For some random samples:
http://www.pbase.com/khoss/
http://www.pbase.com/susanshaw
http://www.susanandkurt.blogspot.com
http://www.slshaw.info

freddiev said:

Are the color blotches in the Zs3 images a result of chromatic aberrations or
is it chroma noise or others?? It spoils the sharp pictures of the Zs3.

Click to expand...

Perhaps it is moiré. That is, a kind of interference pattern between regular lines or dots in the original subject, and the pixels on the sensor.

If so, it's nothing to worry about. This can happen with any camera, but will vary depending on sensor resolution, lens focal length etc.

Regards,
Peter

You have joined the fourm/dpreview yesterday (6th April 2010) and starting with a negative comment on panasonic forum comparing panasonic and canon.

You should buy canon and I would buy panasonic and NOBODY is going to blown out 300% in everyday life photos unless you;re a gem merchant or textile merchant

I am happy with SIMPLE_NORMAL STANDARD Photos

keep it simple

enjoy

minzaw

freddiev said:

btw.. they were all taken using the base iso (lowest iso)... so how come the Zs3
has yellow blotches in the image??

Click to expand...

--
http://www.dpreview.com/galleries/598254917/photos/13
5580/p1180522

These examples are from a different camera, to show the effect of moiré.

First, a perfectly ordinary shot. The thing to notice is the vertical iron railings around the church.



Larger version: http://www.pbase.com/peter_k/image/123389242/original.jpg

Next, a distant shot of the same church, the railings are now barely visible, but are located beneath the chestnut tree.



And now a full-size crop from that same image:



Above, the iron railings appear as bands of yellow and grey.

This is the only time I've seen this problem occur in several years of shooting with the camera (Pentax K100D). It is dependent on matching the scale of repeating lines in the subject with the sensor pixels. This can occur with any digital camera at the limits of resolution.

In order to avoid it completely, one could shoot with film instead of digital, then the random placement of grains in the film will not clash with the subject.

Regards,
Peter

Kudos, Peter - you've nailed it with complete accuracy.
--
djotai

My gallery : http://www.flickr.com/photos/djotai/
My tutorial on how to compare image quality between cameras :
http://forums.dpreview.com/forums/read.asp?forum=1033&message=23887837
My tutorial explaining the issue of noise and CCD overpopulation(small sensors):
http://forums.dpreview.com/forums/read.asp?forum=1033&message=23947755

Yes, the TZ7, along with a host of other Lumixs, suffer from this yellow blotching. It's easily spotted in just about any expanse of darker blue sky, even at base iso, on a shot from a Lumix produced in the past 2 years or so. They also have this odd grain showing up at low iso. Mind you, other cameras have other issues. Pick your poison. I find the Lumix blue sky blotches to be relatively easy to remove in PP without destroying detail. I haven't tried removing it on other backgrounds.

Edit: I just tried removing the yellow blotching on a textured image with Neat Image. That didn't turn out well at all.

My TZ3 and FX33 didn't have this blotching at all, so I assume it's related to newer Venus Engine processing.

Shouldn't one be bothered by the yellow blotches? Didn't the Zs3 owners
noticed them in their shots?? What kind of background or images do they
usually appear?? How about in anything with uniform color or edge
divisions? It appears in the text.. why won't it appear elsewhere? How do
you predict where it would appear?

freddiev said:

Shouldn't one be bothered by the yellow blotches? Didn't the Zs3 owners
noticed them in their shots?? What kind of background or images do they
usually appear?? How about in anything with uniform color or edge
divisions? It appears in the text.. why won't it appear elsewhere? How do
you predict where it would appear?

Click to expand...

It's an interference pattern between two grids. One grid is the sensor itself, the other is some part of the subject containing regularly spaced lines.

http://en.wikipedia.org/wiki/Moir%C3%A9_pattern The article has some useful illustrations and animations showing typical behaviour.

First off, I really don't think we are talking about moiré. Moiré in a clear blue sky would be unusual. It's chroma noise.

At up to maybe about 200 ISO and fit-to screen you won't see the blotches unless you look for it. I doubt most TZ7 owners ever notice it.

It bothers me, personally, though. As I said, it is apparent even at base ISO in any blue sky. It is not just in text or textures.

Trensamiro might have an efficient way of dealing with it.

freddiev said:

Shouldn't one be bothered by the yellow blotches? Didn't the Zs3 owners
noticed them in their shots?? What kind of background or images do they
usually appear?? How about in anything with uniform color or edge
divisions? It appears in the text.. why won't it appear elsewhere? How do
you predict where it would appear?

Click to expand...

it would enhance the discussion if the original post mentioned the ISO settings of the pictures.

In practice, the ZS3 does not create strange colour patterns in pictures, unless it's in dark-ish shadows or in low-light at ISO 400 and higher.

Since i have never seen that beer label directly, i cannot know how it's printed. Sometimes, printing uses a matrix of coloured dots. Then, digitizing a picture would create a "moiré" pattern.

I suggest to bring a SD card in a shop and try the various cameras and ZS3 there.

jf_tea said:

Since i have never seen that beer label directly, i cannot know how it's printed. Sometimes, printing uses a matrix of coloured dots. Then, digitizing a picture would create a "moiré" pattern.

Click to expand...

Apparently it is printed using solid ink, rather than dots, at least in the area under consideration. However, in order to represent a shade of grey, the letters are filled with horizontal lines:



Full size image available here: http://blogs.houstonpress.com/eating/2010/02/tasting_beer_samuel_smiths_lag.php

It's a tough subject for a digital camera. The example which I've posted shows coloured bands (red and blue) which I think arise from the same cause.

The root of the problem is that digital cameras, with the notable exception of those using the Sigma Foveon sensor, do not collect full colour information at each pixel. Instead an array of red, green and blue sensitive detectors are used. This data is then processed in order to derive (in effect take a reasonable guess) at the colour of each pixel, based upon its neighbours. When a pattern such as this set of horizontal lines is encountered, the image processing software (inside the camera) is unable to reach a correct result.

The problem is worst when the lines happen to fall on the sensor at the exact spacing of the rows of pixels. If the camera has a much lower resolution, the area will simply appear grey, at a higher resolution, the individual lines are properly displayed, but at intervening resolutions, problems will occur.

As I have said previously, this is a general problem affecting digital cameras, and is not specifically a problem for the ZS3.

Regards,
Peter

.

Indeed, I was musing to myself this morning that the higher resolution 14MP sensors that everybody is bucketing may in fact have finer noise, and finer moire, and, after noise processing, therefor actually look better than the sensors with fewer pixels.We shall see...

But I do wish people would stop comparing images made with the cameras on fully automatic. I have never been satisfied with any of my cameras on fully automatic...
.