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Old Jan 19, 2003, 5:58 PM   #21
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Thanks, I had already found your site - liked the pic. with the artificial snow! movies without a movie cam you might say! I'm a retro 2 wheel chap myself.

PS You might be able to avoid compressing if you can get your '3' in say a 300 X 200 cutout.
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Old Jan 19, 2003, 7:42 PM   #22
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voxmagna~ From the images I already have I can pick out a bigger section 300x200 as you suggested and that should do the trick for the overall sharpness difference........

And here it is... Hope this satisfies your curiousity as it has mine...

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Old Jan 20, 2003, 11:03 AM   #23
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BigRed450... You can guess the curiosity level by the thread hit rate! Interesting pics. According to my eyes, this seems about splitting hairs!

It looks as though it's mainly JPEG artefacts that distinguish the two. Also, the contrast is lower on the 6Mpix, which is what I found and why I think some say they find the pics a bit flat. If you bring up the 6 Mpix contrast in post, I think you will find the 6Mpix even closer to the 3Mpix, since the background artefacts (they're still there!) become more prominant.

Perhaps my eyes are getting older, but I'm not seeing a stunning resolution increase with more detail - just less artefacts. Look at the 'jaggies' on diagonals. On my monitor they seem about the same in both pics. There is no sign of any texture in the backgrounds. Which is why I think lower image compression, or uncompressed at 3Mpix might have given similar results. Your cut-outs still seem well focussed, so it's not sensor res. or optics that differentiate the two pics.

Your file label said hard sharpening was used was this right for both? I hope others aren't bored by these pics - I found them fascinating. Thanks - VOX
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Old Jan 20, 2003, 5:25 PM   #24
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VOX~
You are correct, the 6MPF clip was set on hard, but the 3MPF was set to normal. The 3MP clip was also increased to match the physical size of the 6MP clip......

What is your screen resolution set at? Just curious, mine is set to 1024x768. I don't think I'm seeing what you are seeing. Contrast difference yes, but I am seeing a much cleaner image in the 6MPF. When I increase the contrast +65 on the 6MPF clip I don't see it getting more jaggy only brighter, but that is with the clip in BMP format. When I go to higher magnification (200-300X) the jaggies start to appear, but still nowhere near as bad as the 3MPF clip.

I am assuming that you downloaded the posted clip to your computer for observations, hence you are not seeing what I am seeing at magnification. At 100% both the BMP and JPG files look very close, the purpose there of course was only to show a difference between the 3MP and 6MP at normal magnification, but stepping up the magnification shows the losses from the JPG format. I will email you the BMP file if you wish.

We'll get this sorted out yet!...........
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Old Feb 11, 2003, 3:50 PM   #25
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Default Don't forget - there are TWO layers of artifacts

Interesting thread - but no-one has yet mentioned the rather important thing that makes Fuji's different from all the other digicams and its rather important.

Other digicams use CCDs with the imaging sensors arranged in a grid fashion, like a chess board. This translates directly to the grid pattern inherent in any digital image at native resolution. So in a normal digicam each pixel in the final image is a direct mapping of the oriniginal imaging sensors on the CCD array.

Fuji's use 'SuperCCDs' with the imaging sensors arranges in an octagon layout - there is NO WAY to display the native output of such a sensor as a digital image, you first have to convert it to a gridded image, bacause that what a digital image looks like.

So in a Fuji camera each and every 'pixel' in a final image has been proccessed. The nearest approximation to what the SuperCCD array looks like is to imagine a chess board turned through 45 degrees so it looks like a diamond - now imagine how you would draw that onto a grid laid over it and you get some concept of what proceesing goes on in the Fuji CCD.

So the very first series of artifacts comes from the 'pixel mixing' that has to go on to form a normal uncompressed image - and then another series of artifacts come from the lossy compression.

Now if you zoom in on a Fuji image you need to remember that you are seeing both sets of artifacts - if you try and look for sharpness at the pixel level you will never find it - there is no way to sharply represent that orignal octagon array in a normal image file.

An interesting comparison is to look at the the uncompressed 6MP TIFF file and compare it to the uncompressed TIFF file from a true 5/6MP imager (eg the Dimage) I would be VERY interested if anyone out there (Steve?) could do this.

What you will then find is that there are NO artifacts in the TIFF from a grid array CCD - but there will STILL be artifacts in the TIFF from the octagon array.

Is this a bad thing - not really. No one stares at a photograph that closely, you look at the whole picture. The eye merges all the information into a continuous image.

Try this experiment in photoshop or your editor of choice.

Create a nice white image, and then use the type tool to type a word onto the screen twice in pure black.

Render one with anti-aliasing off and one with anti-aliasing on.

Now at normal resolution the anti-aliased text looks smoother, the other text looks slightly rough and jagged.

Now zoom in and look at the pixels - the anti-aliased one is full of 'artifacts' (greyish pixels) whilst the pixels of the other are sharp and crisp.

Which one when looked at normally looked sharper - for most people its the anti-aliased text as the eye merges all the information from the pixels together and it sees it in a different way.

This comparison is exactly the some on you are doing when looking at Fuji images at the pixel level - the information from the original imaging sensor is spread over a couple of pixels. Step back and your eye links that information up, zoom in close and you see the anti-alias type effects.

If someone will host the images I can show you what I mean and maybe show you a few things to do in photoshop to show you how this works.

And no - before anyone asks I don't work for Fuji, nor do I know exactly how they are processing the image from octagon array to grid array. But I've spent a lot of time looking at satellite images and assessing resolution for my MSc, the same department researched how to make better CCDs, I'm used to procesing images to try and use the 'sub-pixel' information and I'm a keen photographer. I've owned and used Fuji 2700, then a 4700 and hopefully will have a 602 pro shortly!
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Old Feb 12, 2003, 2:35 AM   #26
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CharlieO...Thanks for your contribution, in the back of my mind I had been thinking the source image matrix isn't conventional, but how does that affect photo-editing, subsequent JPEG compression, monitor viewing and printing post processes which all output map to square arrays?

As you suggest, the structure is there in all camera modes - so comparisons have to be done with 'conventional' ccd arrays from other cameras. That explains why testing at high zoom in a photo-editor always shows indistinct pixels around edge detail, whereas you might be expecting clean defined and stepped pixels.

As far as 'is this a bad thing' the next question coming back will be what resolution gain is achieved using a Fuji octagon ccd over a conventional ccd layout. Buyers here will want to ask "Does a Fuji octagon ccd at say 3 Mpix (my 602), pixel doubled, really equate to 4 Mpix, so I will compare price and features with a 4 Mpix cam to make a purchase decision. Their first measure will be "how big can I make the Fuji print, to get similar sharpness, compared to another camera".

Sorry I can't host your pics, but I hope somebody will, as this is a very interesting topic.

PS 602's are very nice featured cameras!
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