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Old Feb 24, 2004, 12:14 AM   #1
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Default An Interesting Revelation about the F828.......

Some of the problems which have plagued the F828 concern edge artifacts which, upon really close examination, show a block or "clump" of four pixels which define boundaries. When prints are greatly enlarged, this tends to result in edge aliasing of some degree which detract from the very excellent images this camera is capable of producing.

Sony didn't provide much in the way of a RAW converter, but with Adobe PhotoShop 8 there are a host of supported RAW formats which allow significant improvements in the ability to convert RAW files from numerous digital cameras including the F828.

In playing with this I discovered that it's apparently the Sony jpg algorithm which produces the annoying "stairstep" aliasing. A file captured in RAW and converted by PhotoShop to a jpg doesn't have this issue and represents a substantial improvement over the Sony jpg as saved by the camera. Fortunately, Sony saves in both a jpg and RAW format when shooting RAW. This makes it very easy to compare the results without intervening variables.

Following are tiny crops enlarged 500 percent which clearly show the remarkable differences in edge smoothness and detail between RAW captures and jpg captures with the F828. Below the crop are links to a jpg converted from RAW and it's jpg as "saved" by the camera for those interested. I tried to match the color, tint, levels, etc., as closely as possible, but they are not perfect since Adobe RAW has numerous settings which can be used. But it's still quite easy to see the differences. These differences probably would not matter too much in small prints up to 8x10 or so, but if you make really large prints, shooting in RAW and converting to either TIFF or JPG will clearly result in superior detail and edge sharpness.

Hopefully, Sony will see fit to make a firmware upgrade to this camera to correct the crude jpg conversion they are using.

Best regards,


Lin



http://www.lin-evans.org/samples/raw.jpg
http://www.lin-evans.org/samples/jpg.jpg

Last edited by Lin Evans; Feb 1, 2015 at 1:33 PM.
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Old Feb 25, 2004, 8:42 PM   #2
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Agree Lin.... I have some 3ft posters that when converted from RAW to TIFF in CS they do produce a more vibrant and better overall picture.

Interestingly, quite a few of my 2ft posters have come out that great, I did'nt need to convert the files; the supplied JPG was good enough for print.
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Old Feb 25, 2004, 10:31 PM   #3
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That's very interesting, Lin. Thanks for the detective work!

Let me ask a question though. Jpg, by nature, is compressed, so is it really fair to compare a Raw/Tiff to the Sony jpg? How do you know that the edge blockiness/clumpiness seen in the jpg isn't due to the compression? I think a fairer comparison would be a RAW converted to JPG using PS to the Sony-recorded JPG.

I'm not trying to be arguementative--just trying to understand. Or maybe I completely missed the point. :-)

Thanks again for your analysis!

Update--I just reread your text, and it says that the image on the left is a jpg converted from RAW--that's exactly what I was implying, but the window is labeled ".tif" which is what had me confused---so can you confirm that the window on the left is actually a jpg? If so, then I'm on board! Thanks!
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Old Feb 26, 2004, 12:07 AM   #4
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Hi Zal,

The crops above are indeed correctly labeled and were made from the converted 16 bit tiff and the compressed jpg created simultaneously by the camera.

There are links below the crops to the full sized images, both the original jpg (jpg.jpg) as saved along with the RAW file and the jpg created when I saved the tiff converted from RAW then saved a jpg copy of this tiff (raw.jpg).

When I saved the converted tiff as a jpg in PhotoShop, there was no appreciable change in the edge pattern regardless of the level of compression used by PhotoShop.

Here'a a highly compressed jpg crop made from a compressed jpg saved in PhotoShop from the converted RAW saved as a tiff.

Even after several jpg saves and high compression levels this sample has both more resolution and much finer edge detail than the original Sony created jpg.

Best regards,

Lin

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Old Feb 26, 2004, 2:10 AM   #5
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Default Some additional information revealed....

If you look very closely at the crops, a couple additional things will be revealed.

First, look at the white square area (reflected light) on the RAW converted TIFF image side. The edges are quite clean and well defined. On the jpg side they are not well defined but wait - it looks like there is color rather than the white found in the RAW version. Does this then mean that the jpg file is actually producing a smoother gradient of transformation?

That would be one's first guess, but indeed this is not the case. The white square is an area of reflected light and indeed has little color. What is happening is that adjacent four pixel "clumps" of yellow are "bleeding" into the reflection area and actually rendering a distortion of detail.

That this is indeed the case is quite apparent if you carefully examine the black lines which delineate boundaries of these tiny glass "beads." On the converted RAW file, the black lines are continuous and well defined. On the jpg side they are broken at regular intervals. What causes this? Apparently the four pixel blocks are again "bleeding" onto adjacent detail and rendering a change or distortion once again.

These observations are difficult or impossible to see with the naked eye and in normal sized prints up to about 8x10, but when prints are made of greatly enlarged crops or when the image is interpolated for poster sized prints, the "problems" become immediately apparent.

The native jpg and tiff files rendered by the camera itself are, in my opinion, faulty. The camera is capturing correctly, but the internal firmware which converts either to tiff or jpg is introducing distortion.

Unfortunately I didn't install Sony's own RAW converter, so I can't yet speculate whether it will properly convert the files, but when the Adobe RAW converter is used to produce the final image (either an 8 or 16 bit tiff), then when that image is saved as a jpg, the borders are smooth and the detail is saved just as in the converted tiff and regardless of the degree of compression used.

Yes, jpg artifacts will be present if extreme compression is used, but the four pixel "clump" is not there and the results are superior to the native jpg or tiff files as saved by the F828.

Best regards,

Lin
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Old Feb 26, 2004, 12:17 PM   #6
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Great information, Lin. Thanks very much!
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Old Dec 18, 2004, 2:27 AM   #7
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This is ridiculous! The way you cropped this, what you claim would only be seen on a 800 foot x 600 foot photo!! You wouldn't see this on a normal print, not even on a 17 x 20 print! I can't get over how people have picked and picked on this awesome camera! Wake up and smell the coffee! What Sony has done was make the best 8MP non-slr camera out there!!!
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Old Dec 18, 2004, 5:04 PM   #8
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I agree with Sola.

The F-828continues to amaze me with its results.

Check out my F-828 images of all types of subjects and under varying conditions:

http://www.nickphoto123.smugmug.com

Regards, Nicholas






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Old Dec 19, 2004, 8:58 PM   #9
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Wow!!! I just got my F828!!! I love it!! It is amazing!!! I had no idea how excellent a camera it was until I got it!!!! I'm so happy with it and I don't see any picture problems with it at all!!! No CA, no noise, it's the best camera I've ever had in my life!!!

Sony really knows how to make cameras!!
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Old Dec 20, 2004, 4:34 AM   #10
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kski wrote:
Quote:
Wow!!! I just got my F828!!! I love it!! It is amazing!!! I had no idea how excellent a camera it was until I got it!!!! I'm so happy with it and I don't see any picture problems with it at all!!! No CA, no noise, it's the best camera I've ever had in my life!!!

Sony really knows how to make cameras!!
KSKI,

While reading your post I thought I was in the DPReview Sony Talk Forum.

I humbly suggest that you snap out of it and get back to talking photography.

The Sony F-828 has Noise, PF, and a little CF, all which can be 'eliminated' by learning how to use the camera's strong points.

Please check out my F-828 images to see my resultsin shooting the F-828 toward its strong points.

www.nickphoto123.smugmug.com

Regards, Nicholas
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