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Old Jun 23, 2004, 2:28 PM   #11
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Right, but not the same exactly. Yes, you will get more dpi or ppi from a 5mp than you will from a 2mp camera.

The fact is a 5mp has more pixels than a 2mp camera- Allowing you to have more ppi or dpi when viewed or printed.

Butuntil you know what size you're printing or what monitor/resolution you're viewing the picture on- it's impossible to know the ppi or dpi. There is no inch to relate the pixel count to while stored and not seen. The ppi for a 5mp image is different if you view it at 640x480 or 1600x1200 on your monitor &actually from monitor to monitor due todot-pitch differences. The dpi is different if you take the 5mp image and print it 4x6" or 11x17". So while 5mp = more dpi or ppi - they are relative - not exactly the same thing, but of course a 5mp camera is capable of producing more than a 2mp.

I thought the question was if I stitch photos together does that increase the resolution (and ppi and dpi). I was just trying to point out that if you stitch together photos is makes more pixels in the same file (bigger x and y coordinates) and that the final pixel countis all that matters- not whether it was takenone shot taken with a 5mp camera or more shots taken 2mp camera glued together. (I mean despite the sheer difficulty in getting a good stitched photo without distortion,etc.)
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Old Jun 23, 2004, 2:48 PM   #12
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(I mean despite the sheer difficulty in getting a good stitched photo without distortion,etc.)


I don't have any problem with a simple stitch such as timotsc is referring to. I don't find my sample distorted, and you get even less if you are looking just for pixels and not the widest angle you can generate. I can grab two panos very quickly and stitching is a snap. With a little practice you can get the alignment almost perfect.

That was taken with my Oly C50. The Oly system is nice in that it flags and numbers the panoramas. You just drag them into the stitch box and select a stitch mode. The Oly panorama mode fixes the exposure with the first shot so the software doesn't have to adjust exposure – it stitches in about a second.

My little Panasonic S4 is more of a hassle because Panasonic doesn't know how to make a panorama mode. It doesn't fix the exposures so you have to use more sophisticated software. It doesn't have a manual exposure mode either. My other two cameras don't have a panorama mode but they do have manual exposure. I hold my hand over the lens and take a blank image after each series so I know where the panoramas start and end. Not really necessary for 2 shots but it gets confusing if you are doing several 360s.

I find the alignment to be a problem if you stack 4 in a box as you mentioned in your earlier post. Maybe I need to practice more, but I seldom get them exactly right. This is an example – my banister is actually straight. I got the bottom OK but the second tier gives me problems.




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Old Jun 23, 2004, 2:59 PM   #13
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Actually I was amazed at how good canon's software was (and their pano assist mode while shooting that numbers them) - I got 2 error free 4ft by 12inch panos printed up, framed and hanging on my wall my first try out- not even a tripod used. Only problem is you can only shoot left to right or up to down (by turning the camera)- doesn't go in all directions. I'm not sure if the canon software supports stacking 2 panos on top of each other or not.
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Old Jun 23, 2004, 3:10 PM   #14
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The Oly software will only stack them if you get the Pro version. Someone sent me a link to an offer I couldn't refuse or I wouldn't have bothered. There are better stitching programs like Pano Tools with the Windows GUI, and the rest of the Camedia software doesn't have anything to offer besides the stitching.
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Old Jun 23, 2004, 3:32 PM   #15
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Wow, that generated some responses.

todd651 says quality is resolution is PPI, whether in camera, on a screen or on a printer. Well, I agree that quality is resolution, but not PPI until you print. The whole thing about a 5MP cam producing a higher resolution image than a 2MP cam is right - that's what more pixels do. I think slipe's sample photo that shows the 4 stitched pics is a good example. Whether you take 4 photos with a lower res cam, zoomed in on each area, or you take the whole shot with a higher res cam (4x the MP's, for arguments sake) at a wider zoom, the end result is approximately the SAME (lets assume the lens and CCD quality are comparable). The number of pixels defining a particular leaf or rock in each pic is about the same, hence the resolution is about the same, and the size/quality of possible prints will be about the same.

All we did was zoom a lower res cam in to get a section of a larger image, which gives the same pixel coverage as the higher res cam at wider zoom. The difference in the zoom factor is what evens things out. All other things being equal, if you had two identical images, one perfectly stitched and one the whole shot fromthe higher res cam,you have the same thing. Same resolution, same image quality. Might even have trouble telling one from the other (EXIF data and such aside).

PPI will only matter when you try to print it. The bigger the print, the fewer possible PPI.

This is fun. I don't mean to be too argumentative, just bored at work, lol.

ir

P.S.: Haven't tried this with the Canon stitch software, but could you stitch the images horizontally, then rotate those stitched images and bring them back into the stitch software and stitch them horizontally again, then rotate the finished image back? I'll have to try that...

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Old Jun 23, 2004, 6:18 PM   #16
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OK, I think I see where we're going here - I got off tracka bit too.

By definition - optical "resolving power" (resolution) is the ability of an optical medium to form a distinguishable image out of closely spaced points, lines or objects. The greater the number of these objects (picture elements - "pixels") for a given sized image, the higher its resolution. Notice that pixels are device independent.

The problem arises when a given image is moved from one digital device/medium to another. The quality of the device now plays a part in the image quality. It is like listening to the finest digital recording on old hi-fi speakers that can't reproduce anything over 15,000hz. It really doesn't work.

But, the quality of the original image is still dependent on the number of pixels contained within it. The software in the camera modifies the characteristics of these pixels given whatever criteria the manufacturer and the photographer choose, that can change the overall absolute quality of the origal image.

I think what one has to do is determine on which medium the images will be viewed most often and use the camera's capabilities to produce images that will have the greatest "percieved" quality for that medium (screen, print, etc). This will also take into consideration the size of the image -enlarged to much and individual pixels are turned into unrecognizable cubes of color, reduced too much and pixels will be lost (due to the software doing the reduction) and details will be removed from the image.

Putting the four pictures together did not change the resolution of thecomponent parts and resulted in a final image of the same resolution.


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Old Jun 24, 2004, 1:55 AM   #17
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whittonj wrote:
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Actually I was amazed at how good canon's software was (and their pano assist mode while shooting that numbers them) - I got 2 error free 4ft by 12inch panos printed up, framed and hanging on my wall my first try out- not even a tripod used. Only problem is you can only shoot left to right or up to down (by turning the camera)- doesn't go in all directions. I'm not sure if the canon software supports stacking 2 panos on top of each other or not.

The newer Canon cameras (I have the Pro1) do support left to right, right to left, up to down, down to up, whatever you can throw at it. Also has a pretty neat setting where you can shoot the top two, and then two on the bottom.

I only wish the stitch assist mode would let me use all the other manual controls that the camera offers.

Vance
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Old Jun 24, 2004, 5:45 AM   #18
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timotsc wrote:
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zoom up on an object, take several pics that are stitched together and the result is a high resolution picture from a cheapish camera.
If you want see what you can do with this method, follow this link...

http://www.tawbaware.com/maxlyons/gigapixel.htm

It was discussed in the Panoramas/stitching forum here a while back.
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