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02-22-2012, 12:21 PM   #1
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Picture resolution with my K5

The highest resolution I can get in a JPEG picture taken with my K5 is 10.5 M despite the fact that the recorded pixels is set to 16 in JPEG and quality is set to the highest level. Can someone pls tell me what I'm missing here?
Thanks, Bill

02-22-2012, 12:37 PM   #2
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What exactly do you mean by resolution? Do you mean file size?

JPEGs are compressed images, so you won't generally get a 16M file even if that's now many pixels there are. And that's a good thing

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02-22-2012, 12:40 PM   #3
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That sounds normal for a high-quality jpg. The K-5 jpgs are better than the Leica M9 (18 MP Full frame) that run around 6 MB files in "best" mode. The K-5s are good enough I normally leave it in jpg mode, while on the Leica I need to use RAW (DNG).
Jpeg, by nature, compresses the photo information, and loses some potential quality. For best possible results shoot in DNG mode, which requires post-processing software to optimize to jpg images.
02-22-2012, 01:04 PM   #4
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QuoteOriginally posted by Boydmaine Quote
The highest resolution I can get in a JPEG picture taken with my K5 is 10.5 M despite the fact that the recorded pixels is set to 16 in JPEG and quality is set to the highest level. Can someone pls tell me what I'm missing here?
Thanks, Bill
Try this:

Shoot a RAW image with your K-5. The file size will be around 20 megabytes.

Now, develop that image (can be done in the camera) as a TIFF file and you will get a file size around 48 megabytes.

Now develop the same RAW image (can also be done in camera) as a JPEG and you will get a file size less than about 10 megabytes.

That's the difference between uncomressed (TIFF) and compressed (JPEG) image files.

Somewhat crudely speaking: You have 16 million pixels that each has to carry 3 bytes of information (red, green, blue colour levels) in the uncomressed image. RAW is a so-called lossless compression while JPEG is a so-called lossy compression.


Last edited by Stone G.; 02-22-2012 at 01:15 PM.
02-22-2012, 03:35 PM   #5
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QuoteOriginally posted by Boydmaine Quote
The highest resolution I can get in a JPEG picture taken with my K5 is 10.5 M
According to page 356 'Main Specifications' of the K-5 Manual. 16MP JPG's shot on the K-5 should be 4928x3264 pixels in size.

Open one of your images in any image browser and tell us the size (in pixels) of the image. If it is indeed 4928x3264 pixels, everything is OK.

If not, make sure your camera is set to something like P mode (not a User setting), then reset your camera to defaults (p335 of the K-5 Manual) and reset the Custom settings to default values (p-336 of the manual).

By default (p328 of the manual) the JPG settings for the K-5 are 16MP, 3 star quality, 4928x3264 resolution. Take a shot, view it to see what size image you got, and see if that works.
02-24-2012, 07:26 AM   #6
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Thanks to all who replied. My pictures are indeed 4928x3264 pixels in size, so I'm happy. What I don't understand is that sometimes my pictures are 11.2MB in size and sometimes they are 10.3MB, yet both are 4928x3264. Obviously some are compressed more than others, but why?

Thank You again.

Bill
02-24-2012, 07:38 AM   #7
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jpeg compression is complicated... it doesn't do the same thing to each image...
02-24-2012, 07:39 AM   #8
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.jpg files from a camera will vary quite a bit in file size, depending on their content, even at the same "quality" setting. For example, an all-black image will have different file size than an all-white image, and ISO settings seems to make a huge difference in file size.

02-24-2012, 07:44 AM   #9
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QuoteOriginally posted by Boydmaine Quote
Thanks to all who replied. My pictures are indeed 4928x3264 pixels in size, so I'm happy. What I don't understand is that sometimes my pictures are 11.2MB in size and sometimes they are 10.3MB, yet both are 4928x3264. Obviously some are compressed more than others, but why?

Thank You again.

Bill
That is the very crux of compression: Pixels with the same or almost same colours and intensities are grouped during compression such that only one piece of information needs be stored together with information on the position of the pixels. When you decompress your image file (i.e.: When you open it) pixels and colurs will be re-arranged to show the original picture. BUT inevitably with a loss in information. For example: Almost - but not exactly - same colours will be assigned just one colour. How much information you loose depends upon the degree of compression.

And thus, if you have large areas of almost same colour and intensity, your compressed files will be smaller in size than if you have images that are very varied in contents. It is simply a question of how much "information" there is in your image.
02-24-2012, 10:37 AM   #10
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Great information to have. Thanks
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