Size of Image Files

Hello

I've been reading on the internet a lot of information from pro photographers and on various sites that talk about file sizes of around 60 megabyte for digital images. Can someone tell me how it is possible to take a picture with a file size this large? I thought that cameras made around 1mb per megapixel when shooting in RAW but I am obviously incorrect here.

Would be good if someone could explain this as its got me puzzled.

Cheers
TOny

My camera is 14.2mp which is pretty big but each raw file is biggest 12mb. Perhaps its these full frame digital camera jobs?? I think they are 14bit files as well which would increase the data file size.

Just a guess!

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Denny Boy

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I think a Phase One P45+ digital back makes that sort of file size, 39MP rings a bell but I could be wrong there?
Also files easily get that big with a few adjustment layers bit of sharpening etc. if saved as a .psd. I think TIFF's can be quite big too.

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Copied from Phase One site:-

P 45+
Imaging technology
CCD: Full frame CCD
Lens Factor: 1.1
Resolution: 39 mega pixels
Active pixels: 7216 x 5412 pixels
CCD size effective: 49.1 x 36.8 mm
Pixel size: 6.8 x 6.8 micron
Image ratio: 4:3
Microlens on CCD: No
Antiblooming: 10 f-stops
Dynamic range: 12 f-stops


Storage files
Phase Ones IIQ RAW file format speeds up the image capture and file transfer. Increases the storage capacity by turning the full 16 bit image data into a compact RAW file format. The default IIQ RAW-large format is completely lossless.
llQ small: 27 MB
llQ large: 44MB

Phase One - Digital Backs - Digital RAW Software - Capture One

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If you submit images to picture libraries they often need to be the size you mention, because they are often blown up to a larger size - they could be used for advert boards etc. They therefore need to be high res and large size.

If files are 16bit that nearly doubles the size over 8bit. Layers in a file will greatly increase the size. PSD files always seem to take up more space than TIFFs. Files from a Canon Mk1d, or something like it will be larger, due to the high pixel rate of the camera. It's easy to make a file bigger, just change the size and user interpolation.

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Rob
Thanks I am starting to understand it a bit better now, however please could you expand a bit more on how to make a file bigger, just by changing the size and user interpolation. Also, does this make the resultant image any better.

Interpolation is basically a means of making something larger and filling in the resultant 'spaces', in the case of a photo with similar surrounding pixels. That's why the file size gets bigger - more data. The image won't really be any better printed at the original size because the human eye, and printers work at an optimum resolution. It's more of an issue when you blow up an image to a larger physical size. If I have an image 3000x2000 pixels and it prints fine at A4, if I print it at A3 it has to cover twice the physical area with the same number of pixels. The pixels therefore start to look degraded. By interpolating I make the physical size larger and it fills in the gaps with relevant pixels, so I could end up with say 6000x4000 - and it would print OK.


Have a look at this,

http://www.ephotozine.com/article/In...-images-bigger

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hmmm...eavesdropping here...I think I'm learning a little bit by listening in...thanks guys

i thought interpolation was a police force that worked in different countries. Fay if it involves maths i am going deaf not eavesdropping........

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Denny Boy

"Logic gets you from A to B, its your dreams that take you anywhere"

http://www.flickr.com/photos/dennyboy

Picture of me if you are curious!

thanks for helpful hints as just learning myself have found a free image file converter that allows me to up load large files by reducing the picture size to 600x600 so as to upload to some websites as this is all they will accept to save server space but when viewed still have file size