G9 photos: corners softer than center

All the photos taken with my Canon G9 have the same problem: the corners are A LOT softer than center, you could say the corners are out of focus.
You can notice it only at ISO 80 or 100.
I didn't have that problem with the G5.

The same problem can be noticed also in the DPReview test image http://a.img-dpreview.com/reviews/canong9/samples/resolution/canong9_resF5.JPG

... but they didn't noticed it ... :-(

Do you have the same problem?

Take a look at this:



Now a 100% crop of the center:



And a 100% crop of the right corner:

To a point, this is surely the case with most, if not all cameras (or their lenses). It's like noise... you may not see it, at least not in the best low-light performing cameras and with lower ISOs... but it's always there; it's just a question of degrees.

I find the G9 to be quite a decent performer, corner-to-corner. It may not be tack-sharp all around the frame, but it's definitely better than others. The defining factor seems to be the amount of optical zoom... the more of it, the least sharp you can expect the corners to be (and the more chromatic aberration and barrel distortion it'll have, unless the imaging processor takes care of that, as is usually the case with Panasonic cameras). Look at comparable samples from the Canon SX100 IS or the S5 IS: you'll probably see more of it all.

Imaging Resource's analysis and samples of the G9 show pretty much the same degree of corner sharpness, if not in all the photos (I've been unable to determine if it changes with the aperture setting or not).

http://www.imaging-resource.com/PRODS/G9/G9A7.HTM

I experience the same disappointment with my G9. One of the reasons I bought the camera over a smaller one is so i would have good edge to edge sharpness.
At f2.8 it is not nearly as sharp as my little s410, but does improve at f4.0.

This is unfortunate because for lower light f2.8 is essential. The a640 I had previously performed much better in regard to edge sharpness.
It seems to me the focal distance my have something to do with it as well.

Here the issue is previously discussed
http://forums.dpreview.com/forums/read.asp?forum=1010&message=26465262

Thanks for your reply.

Today I'm going to do some test using different Depth of Field values.
Have you checked my photos in my second post ?

Daniele

Full photo at F2.8



Crop 100% F2.8, center



Crop 100% F2.8, right side



Crop 100% F5.6, right side



I'd say F5.6 is better than F2.8.

Koosla said:

To a point, this is surely the case with most, if not all cameras (or
their lenses).

Click to expand...

I would agree with this (BTW: I am not a G9 owner, but interested

literally all lenses, whether for cameras, telescopes, microscopes, hand loupes, binoculars etc are softer at the edge than at the center.

Generally speaking, all other things being equal; the higher the price of the optics, the less the width of the band of deterioration of image quality at the edge, and less distorting it is.

You will find extensive discussions on this in binocular forums. A cleaner edge is highly prized, and some will pay highly for it.

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Trying to live inside the circle of minimum confusion. Also trying to not respond to impolite posts.
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In your tests (distant subjects, widest angle zoom, largest aperture) please include manual focus at infinity.

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Gordon
http://hornerbuck.com
http://lightdescription.blogspot.com