 Dana F. Greenwood Sr |
Why not the full 5 megapixels? I have a 5.25 megapixel digital camera. I have taken many pictures. I always run it on the highest settings to get the best photo. My question is, when I check the pictures file size I am lucky if it is 2.50 megs. Shouldn't the file be 5 megs on all of the super high resolution settings? I can save .Jpg, .Tif or anything else and it is just not 5 megs. The camera saves as a .Jpg file if this helps. Thanks
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Tom Kwan |
Take the picture with RAW and save as TIF after adjustment at 300 p/in, you will get a file as big as 20MP. I don't know what camera you are using, most DC don't have RAW, all DSLR can take RAW.
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Dana F. Greenwood Sr |
I am using the Gateway dc-t50 camera. There is no raw. But I guess what I am asking is why doesn't the camera use all 5 megapixels? I can resize photos in a program I have and get 187mg files. The pix are at 100 to 300 p/in right out of the camera. Is the file size do to compression of the jgep? Thanks.
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Jon Close |
The DC-T50 saves files only as JPEGs. JPEG incorporates a data compression routine, so the file size will vary, but will always be less than 5 MB. Per a review at http://www.steves-digicams.com/2004_reviews/t50_pg2.html, the average file size at Fine setting is about 2.3-2.4 MB.
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doug Nelson |
I have butted my head against this issue as well. JPEG compression is mandatory; we don't get the whole 5 megapixels. I think it is deceptive and irresponsible to claim a megapixel size that the customer will never see. Mine was a gift, and my kind relatives saw only the "5 Megapixels" in huge garish letters on the box. Our only way out is a higher line point'n shoot, or a digital SLR. I don't buy the second time from companies with deceptive marketing practices. These JPEG-only cameras are fine for snapshots that do not have to be printed large. I keep mine for non-serious fooling around.
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Jon Close |
Gateway is being no more deceptive than any other digi-cam maker. The pixel capture of the digital sensor (5mp) is a separate issue from the file format and file size. It still gives better performance and larger prints than 3 mp camera, even though both may save only JPEGs.
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Dave Cross |
Hi Dana. Everybody who has replied so far is correct, I'll try to pull all the answers together in a way that we all should understand. OK, your camera sensor has 2560 x 1920 pixels, or 4915200 individual pixels, about '5 megapixels'. Each pixel will use a minimum of 24 bits to represent its colour (8 bits each or red, green and blue). 24 bits is 3 eight-bit bytes, so you image will use 14,745,600 bytes (14.4 megabytes)straight off the sensor. This is a LOT of data. An uncompressed TIFF file would be roughly this size. Luckily we have the wonders of data compression to help us. There are two types of compression, lossless and lossy. Lossless compression (eg .zip) squeezes the data without losing any information. Let's say we have a string of 250 pixels that are the same colour. Rather than coding each pixel as 3 bytes we can say 'there are 250 pixels this colour' considerably reducing the amount of data space. This would be the amount of space that RAW would consume. If our string of 250 pixels has even one pixel that is a different colour half way along, lossless compression will need to show two shorter strings of one colour and a single pixel of the other. Now, the human eye will probably not notice this different pixel amongst all the others, so we could ignore it and stick to our original 250 pixels all the same colour. This is the basis of 'lossy' compression (eg JPEG), it throws away data that the eye 'won't notice'. The result is files that are very much smaller than the raw data. These small files are gained at the expense of losing some of the image data. This is why your files are much smaller than you might expect from the 5 meg sensor. I hope this (highly simplified) explanation is of help. Cheers DC
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