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Old May 3, 2005, 10:20 AM   #11
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Ok, then I took the 3M and 5M images, blew them up to 7M size, then cropped the same area from each three pictures. Below you will find the test images. They are in no particular order.

We have 3Mpix, 5Mpix and 7Mpix. Can you guess which is which? Personally I can easily pick out the 3Mpix version, but it's darn hard to distinguish between the 5M and 7M.

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Old May 3, 2005, 10:31 AM   #12
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HeZe:

Is the order 5, 7, 3? If so, I agree the 3 MP is easy but the other two somewhat more difficult. Nevertheless, to me the middle one seemsto have the best resolution of the three?
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Old May 3, 2005, 10:43 AM   #13
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lcmb11444 wrote:
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HeZe:

Is the order 5, 7, 3? If so, I agree the 3 MP is easy but the other two somewhat more difficult. Nevertheless, to me the middle one seemsto have the best resolution of the three?
Correct-a-mundo. Middle one is 7Mpix. You can just make out a little more detail, for instance if you look at the bottom window.

Still, I think the difference should be more evident

Oh well.. maybe when the 10Mpix compacts come out, we might see more difference.
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Old May 3, 2005, 10:50 AM   #14
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I think you will notice a big difference if you were to take portraits of the same person with all three resolutions and cropped the eye or any prominant facial features. That would give you a better comparison. It is hard to tell with the choice you made from the crop. Perhaps something closer to the camera. Also, try taking a picture of a license plate from a distance. At 7MP it should be clearer than at 5MP resolution after you blow up the 5MP image to match the size of the 7. Also, is the camera set to spot focus on that area you cropped?
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Old May 3, 2005, 10:54 AM   #15
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It was center-weighted focus, with F5.6 so the best possible DOF. Pretty much as focused as you can get.
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Old May 3, 2005, 11:09 AM   #16
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I've seen this argument before.

Basically, you're taking the photos with a 7MP sensor, and the camera is then downsizing the images from the full 7 Megapixels into a lower resolution version before saving to disk.

So, you will get more detail shooting in 5MP mode from a 7MP sensor, versus shooting in 5MP mode with a 5MP sensor, if everything else about the cameras is equal.

Remember that each photosite is only sensitive to one color because of the Color Filter Array on the sensor. The algorithms must interpolate the values from multiple pixels to try and guess the color for the pixels represented in your image.

So, as a general rule, shooting in a lower resolution mode allows the camera to make better use of this process, with less detail lost from the color interpolation process when downsizing.

I saw some interesting comparisons of images from the DSC-F828 that showed a similarphenomenon (lower resolution modes producing very little discernable loss of detail compared to higher resolution modes). Again, the camera is starting out with the full resolution of the sensor.

If you compared the photos from a true 5MP sensor versus a true 7MP sensor (provided everything else about the cameras was the same), then you'd start to see a little more difference between them.

Another problem I think we're running into is that the lenses are not able to resolve the detail newer sensors are capable of. So, we'll probably see diminishing returns on trying to increase megapixel count in smaller sensored cameras.



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Old May 3, 2005, 11:53 AM   #17
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hello there.


I'm new to this forum, I just got here from googling sony dsc. but I think this is a very interesting topic.



first and foremost, I think the basic reason why difference between 3 and 5 mp is noticeable whereas between 5 and 7 it's minimal is: at 3mp, you have usually around 2k pixels wide, while at 5mp it's around 2.65k pixels wide. a 32.5% gain, dpi-wise. once you move to 7mp, which is about 3.05k pixels wide, it's a mere 15% gain. after all,one's perception of resolution is more proportional to linear gain than to area gain. if you want double resolution, you have to multiply your mps by 4, not by 2, so...



that's how I feel about it. I hope this helps.
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Old May 3, 2005, 12:10 PM   #18
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JimC wrote:
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So, you will get more detail shooting in 5MP mode from a 7MP sensor, versus shooting in 5MP mode with a 5MP sensor, if everything else about the cameras is equal.

I noticed this when I compared a 5MP image from my P200 with a native 5MP image from my F717. The P200 seemed to have better detail.


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Old May 3, 2005, 1:15 PM   #19
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OK, this is pretty amazing.. I just did another test to compare my F717 and P200. Both cameras were on a tripod, same F5.6 setting, FINE mode, 5 Megapixel. Here is the test image for reference:
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Old May 3, 2005, 1:17 PM   #20
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And, when viewing the cropped area at 100% zoom?


Interesting.. the small compact P200 kicks the F717's butt. So this would confirm what JimC just said there earlier. OK, so now I'm happy with my P200



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