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Old Apr 18, 2004, 11:32 AM   #21
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If so, why do we lose sharpness at 6mp and then get it back at 3mp ?
Because, when you downsample an image, it averages/bins data from surrounding pixels to create a single pixel. The 6MP image contains less image data per density then the 3MP image. Numerically, the 6MP image contains 7-8 percent more linear(one dimension) resolution then the 3MP image, when measured. However, the 6MP linear dimension is approximately 50 percent larger then the 3MP image. Therfore the density of data is lower, even though the 6MP file ultimately contains more data in absolute terms. You do not gain sharpness, really, when you downsample. It is only if you do not take actual full file dimensions into account, that this is true. Looking at image 100 percent on-screen, of course the dowsampled verison will look sharper at 3MP rather then 6MP. Downsample to 640x480 and it will look even sharper. It will not contain more data, or even the same data. YOu will drasitly reduce the amoiunt of data in that case.

-Chris
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Old Apr 18, 2004, 12:59 PM   #22
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You don't need too use 6MP. 3MP is usually fine. 6MP is just a little better, in resolution.

-Chris
Chris, you've been so patient with me as I try to understand this. Thank you first and foremost.

Since the 6mp file isn't as sharp as the 3 mp file when printed as an 8"x10", when would I benefit using the 6mp file for printing photos? Would it be for larger photos over 8"x10"?
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Old Apr 18, 2004, 4:09 PM   #23
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Chris, you've been so patient with me as I try to understand this. Thank you first and foremost.

Since the 6mp file isn't as sharp as the 3 mp file when printed as an 8"x10", when would I benefit using the 6mp file for printing photos? Would it be for larger photos over 8"x10
Well, just remember that sharpness is not nescarrily a representatio of detail. The 6MP is best when you want to maintain maximum detail.

Let me show a simulation, and what I believe you are seeing....



I cropped part of an image at 100 percent(I don't remember who posted this image, i just using this as an example do to it's statistical content in this crop). I then downsampled the image by 33 percent linearly, bicubic, to simulate what the S602 is doing. I then upsampled both images to the same size, which was larger then the original largest file, using nearest neigbor interpolation. This is going to simulate what you see at 8x10 print on a standard hi resolution photo printer.

Left size is the original crop, upsampled. Right side is the downsampled, then upsampled to the same size as left side. Both used nearest nieghbor inerpolation, simulating what a printer will be doing when you print. I want you to notice specifically single lines like the cross, horizontal line of roof and the thick up/down border above the cross on the steeple. The right side has at first glance, easier to notice edges on these features. The edge accutance was raised due to an artifact of the nearest neighbor interpolation. SInce a greater degree of this was required to make the smaller image the same size as the otehr image that was bigger in the first place, this is a good guage of difference for your reference. Look at the left image. Their is ultimately more detail in the bricks. THis is a simple example of what I am talking about when trying to judge detail vs. sharpness. They are not the same thing, nesecarrily. THis is the same thing that will basicly happen if you let your printer interpolate the images, and then comparing 3MP vs 6MP. However, this example is a magnified view. When the images are printed the issues here are at smaller scale. It is easier to mistake sharpness for 'detail' considering the smaller scale. Just trying to illustrate what is happening.

I tend to write my posts in a hurry, so please ask me to clarify anything that is not clear.

-Chris
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Old Apr 18, 2004, 6:29 PM   #24
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Originally Posted by WmAx
Well, just remember that sharpness is not nescarrily a representatio of detail. The 6MP is best when you want to maintain maximum detail.

Let me show a simulation, and what I believe you are seeing....

...

...THis is the same thing that will basicly happen if you let your printer interpolate the images, and then comparing 3MP vs 6MP.
-Chris
Chris,

Again, thanks for explaining all of this to me. It has made me look at this from a difference angle (no pun intended!).

Is this situation just pertinent to the Fuji diagonal sensor?

P.S. Is there a way to prevent the printer from interpolating an image or is this something that has to happen due to the nature of the image?
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Old Apr 18, 2004, 11:00 PM   #25
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Is this situation just pertinent to the Fuji diagonal sensor?
No. This is true on any camera, if you use a downsampled resoluton mode vs. the highest resolution mode. The unique thing to the Fuji SCCD sensor is that is has fuzzier looking files at 100 percent at highest resolution; but this does not carry over to prints because the printe rhas to interpolate the images anyways. The Fuji prints just require less interpolation at printer level.

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P.S. Is there a way to prevent the printer from interpolating an image or is this something that has to happen due to the nature of the image?
Yes, you can prevent the printer driver software from interpolating. Here aer the options:

(1) Upsample to the printers native input resolution(found in printer's documentation) in your imaging program before printing. THis will be slow and tedius, however.

(2) Use an automatic upsampling printer program. Qimage is an example that allows you to choose from many different types of interpolation to allow you to find the one you like best, and bypass the printer driver's crude interpolation. Qimage will then automaticly interpolate/upsample instead of your print driver doing the job.

http://www.ddisoftware.com/qimage/

-Chris
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Old Apr 19, 2004, 9:32 AM   #26
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Chris,

Thanks for all the help and information. I wish the magazine that I subscribe to explained things like this the way you have!

Jerry
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Old Apr 20, 2004, 5:56 AM   #27
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I tried out the suggestions posted before. I used PSP8 to reside the images to 11" wide (and let PSP decide how tall) and to 300 dpi. I then blew them both up to 100% and examined them. The 6 mp one was ver very slightly better - it does contain more information but not much more.

I then downloaded a load of different images from the reviews pages and looked at them (all of the house with the signs in front). I applied the same techniques. I compared the S20 Pro, the 602, the 7000 and the Minalta A2.

All were much the same - but the A2 seemed to be that little bit clearer. I was using 6mp on the 7000 (I downloaded the wrong image) and will redo it all again tonight.
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Old Apr 20, 2004, 9:37 AM   #28
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Just remember to make sure FOV is within 3 percent or so on images you compare between cameras. Also, you must consider lighting differences if these shots were taken at different times. I think Jeff over at dcresource.com did some shots under controlled conditions(samve FOV, same lighting) of some of the 8MP cameras to compare them? Maybe you should check.

-Chris
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Old May 12, 2004, 8:53 AM   #29
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I always use a photo editing software resize the picture before print. Using a good resizing algorithm like bicubic and resize your picture to 200 ~300 dpi and the print out size you want like (8"x11") before send it to your printer will generate much sharper image print out. Send them directly to your printer usually generates very soft images because printer drivers do a very poor job of resizing. The larger your picture is, to softer you image you get. Most of the free tools from Microsoft (even include its PictureIt! package) are very poor in print out.

And remember, specifically to S7000 as this topic relates to, 6MP and lowe resolution does not give you any control of JPeg compression. And they are agressively compressed! 6MP file from S7000 is around 1.5MB file size. Even my 3MP Sony generates 1.8MB file size!

I believe what most reviewers said is that photos from 12MP mode in S7000 is much noisy than 6MP which makes sense because 6MP in S7000 is downsized from 12MP. The downsizing averages out some of the noise. But you can do that easily with any Photo Editing software.
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Old Jun 9, 2004, 8:42 AM   #30
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WmAx wrote:
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KGB wrote:
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OOPS my friend,


"Raw (Photoshop)
--------------------------------------------------
****You can save the image in an interleaved or noninterleaved format. If you choose interleaved, the color values (red, green, and blue, for example) are stored sequentially. Your choice depends on requirements of the application that will open the file. ****"
However, my meaning was different. As with many things, 'interleave' can have many different applications, depending on the specific context. In my example, this was meant to apply stricly to the physical configuration of source sensor. IN your example, interleaving is applied to the order of stored bytes, not to the physical format of the sampling device(SCCD). The extent of direct manipulation with the non-traditional 'interleaved' graphic format from teh SCCD sensors ends with the RAW conversion. You then have a standard format, represented and manipulated in editing in a physically non-interleaved format. Their is no editor that allows modifiocation or display in native 45 degree format that I am aware of, since all image display and printing devices print in a square(0 degree) format.

-Chris

You're from Vulcan, right? :roll: You've used up the big words of the day, so take a nap... I'm sure the newbies who are still trying to understand all of this are having fits now. LOL
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