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Nikon DSLR Cameras
D5100
Explanation of image quality and image size
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<blockquote data-quote="WayneF" data-source="post: 424497" data-attributes="member: 12496"><p>For JPG images,<strong> Image Size</strong> can be selected to be Large, Medium, or Small. For the D5100, these are</p><p>Large 4928x3264 pixels (16 megapixels)</p><p>Medium 3696 x 2448 pixels (9 megapixels)</p><p>Small 2464x1632 pixels (4 megapixels - but large enough to print 5x7 inches well, unless significant cropping)</p><p></p><p><strong>Image Quality</strong> (really is JPG Quality) can be selected as Fine, Normal, or Basic.</p><p>Our RGB images are three bytes per pixel, 16 megapixels is 48 million bytes.</p><p>But these JPG settings compress the JPG file data to be much a much smaller file (JPG compression). These settings are for JPG Quality. The more compression, the smaller the file, but with less image quality. Vice versa, higher JPG quality is a larger file, and better image quality. Larger files are always better JPG quality. The maximum quality would be if no JPG compression at all.</p><p></p><p>The D5100 Ref. manual (see memory card capacity) says Large Fine file size averages around 7.1 MB, which is vastly smaller than the 48 MB (that the data actually is).</p><p>Going smaller is just asking for greater degradation.</p><p></p><p>Because, the problem is, JPG loses image quality in doing it, we don't get the same pristine image back out of the file. Normal is not "normal", it is less, not as good as Fine.</p><p>The standard advice is to NOT ruin your image with excessive JPG compression. Use Fine.</p><p>More about this at <a href="http://www.scantips.com/basics09b.html" target="_blank">What does JPG Quality Losses Mean?</a></p><p></p><p></p><p>The manual (I'm looking in the downloadable Reference Manual for D5100) says Fine, Normal, Basic compression are to 1/4, 1/8, and 1/16 original size (meaning bytes, the pixels always remain the same). Confusing to me because the typical file sizes they show are more like 1/6, 1/18, 1/36 size (of the actual 48 MB pixel data size). But these have had the dickens squeezed out of them. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /></p><p></p><p>Says Large Basic is 1.8 MB files, but Small Fine is 2 MB. Both are small files, but 7 MB is already small, and of course, Fine is Fine. Generally, we like Fine. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /></p><p></p><p>If having a smaller image file is more important than maximum image quality, then maybe smaller Image Size could be considered, but do always keep Fine Image Quality. There's no substitute for quality.</p><p></p><p>Large Fine file size is not all that large.</p></blockquote><p></p>
[QUOTE="WayneF, post: 424497, member: 12496"] For JPG images,[B] Image Size[/B] can be selected to be Large, Medium, or Small. For the D5100, these are Large 4928x3264 pixels (16 megapixels) Medium 3696 x 2448 pixels (9 megapixels) Small 2464x1632 pixels (4 megapixels - but large enough to print 5x7 inches well, unless significant cropping) [B]Image Quality[/B] (really is JPG Quality) can be selected as Fine, Normal, or Basic. Our RGB images are three bytes per pixel, 16 megapixels is 48 million bytes. But these JPG settings compress the JPG file data to be much a much smaller file (JPG compression). These settings are for JPG Quality. The more compression, the smaller the file, but with less image quality. Vice versa, higher JPG quality is a larger file, and better image quality. Larger files are always better JPG quality. The maximum quality would be if no JPG compression at all. The D5100 Ref. manual (see memory card capacity) says Large Fine file size averages around 7.1 MB, which is vastly smaller than the 48 MB (that the data actually is). Going smaller is just asking for greater degradation. Because, the problem is, JPG loses image quality in doing it, we don't get the same pristine image back out of the file. Normal is not "normal", it is less, not as good as Fine. The standard advice is to NOT ruin your image with excessive JPG compression. Use Fine. More about this at [URL="http://www.scantips.com/basics09b.html"]What does JPG Quality Losses Mean?[/URL] The manual (I'm looking in the downloadable Reference Manual for D5100) says Fine, Normal, Basic compression are to 1/4, 1/8, and 1/16 original size (meaning bytes, the pixels always remain the same). Confusing to me because the typical file sizes they show are more like 1/6, 1/18, 1/36 size (of the actual 48 MB pixel data size). But these have had the dickens squeezed out of them. :) Says Large Basic is 1.8 MB files, but Small Fine is 2 MB. Both are small files, but 7 MB is already small, and of course, Fine is Fine. Generally, we like Fine. :) If having a smaller image file is more important than maximum image quality, then maybe smaller Image Size could be considered, but do always keep Fine Image Quality. There's no substitute for quality. Large Fine file size is not all that large. [/QUOTE]
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D5100
Explanation of image quality and image size
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