Friday, August 19, 2011

MegaPixel Comparison

Commentary for MegaPixel Comparison

i recently went to A Family Reunion in Wallace, Idaho and in order to take as many pictures as possible; i set my Small Nikon Camera to 5 MegaPixels, which would allow me to take about 3000 pictures, which seemed reasonable to me.
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Unfortunately; i have never had The battery go dead on it, so i thought i would not need to take The charger with me, and discovered to my horror that after only 1,355 pictures, The battery went dead.
It’s equipped with a very expensive rechargeable battery, so i was just stuck.
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i had my iPod Touch with me, and bought The recharger for it with me, so i was able to take a few more hundred pictures at a much lower resolution.
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When i got home though, i discovered that very few of The pictures came out !
i don’t recall this happening before, even when i took a bunch of pictures at my mother’s funeral with my iPod Touch, i thought that most of them came out pretty well, and it was taking pictures at .69 Megapixels !
This was very odd.
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So i decided to do some experiments with image resolution,
And discovered that The Oldie Time ‘Film’ Images are Way Better at holding on to subtle gradations of Grey Tones than The Best ( 12 Megapixel Digital Images ! )
After scanning many of The Old Pictures from my Families Albums, i had gotten used to The idea that i could bring up very dark images, or images with very dark backgrounds, or images with seriously faded colors, and bring them back to near pristine condition !
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But my simple experiments that consisted of enlarging a small image against a sun lit background showed that whether The Image was taken with 12 or 8 or 5 MegaPixels,
The results of trying to recover it, were about The same.



In other words, The 12 Megapixel images were only marginally better than The 8 or 5 MegaPixel Images.
Further Graphing of The Results verified this.
While there is a big difference between a 1 to 2 Megapixel Image,
For The same improvement from 12 Megapixels, You’d have to jump to A 24 Megapixel Image !


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Note : The Arc Pixels in The Graph; For this =Comparison=, Refers to The Angular Size of One Pixel’s Width & Height. This would actually vary depending on The Focal Length of The Lens; But for This Graph, They are all The Same ‘Theoretical Lens Length’. The Smaller The Angular Pixel Size, The Better is The Resolution.
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Curiously; The Amount of Memory to Store These Images Remains fairly constant with a Factor of Roughly .3 of The Megapixel Volume.
That is; A 12 MegaPixel Image with Millions of Colors will be about 12 x .3 = 3.6 Megabytes.
The actual size & quality of The image is going to depend upon several factors, including The brightness of The environment & how Detailed The image is, which will factor into The .jpg Compression Algorithms.
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.jgp Compresses Images for The Best Image, Taking into Consideration that A Slightly Depreciated Image Quality is Acceptable for A Much Smaller File Size.
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.tiff Compresses Images with No Consideration for Image Depreciation, and Consequently; Have a Much Larger File Size.
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.gif is an older format for sharing images on The Earliest Generation of Computers & Very Slow Modems. When Computer modems got faster, The Better .jpg Algorithm superseded it.
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ISO originally referred to A Film’s ‘Speed’. A Greater ISO of 400 allowed The Photographer to take pictures in Darker Environments, such as Indoors, without a Flash. The Same idea is Applied to Digital Photography, with The Same Results,
Setting your Digital ISO to a higher amount will adversely effect your image quality. Something that i should have been more aware of !
The Digital ISO tells The Camera to allow for Faster Shutter Speeds in Lower Light, Sacrificing Image Quality.
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It’s best to set everything on Automatic, and if The Camera thinks that you should use The Flash, Even if you hate Flashed Images, You need to use The Flash, Or else.
Else being surprising Grainy ( Pixelated ) or Smeared Images.
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