# SQ1, SQ2, HQ, SHQ, TIFF image resolution differences



## PC person

My camera is pretty old, it's an Olympus C765UZ camera.
http://www.olympusamerica.com/files/oima_cckb/c765-refman.pdf

I'm just wondering. As well as resolution it has different modes for different pictures. For example, on page 98 on the manual, I can take either an HQ, or SHQ picture, both at 2288x1712 resolution, but why is one a bigger file size than the other, if they are both the same resolution? What else is taking up more space? I hope these modes are generic and not specific to my camera, so someone knows what the difference is. It says compression, but what's different about high compression vs low? If you could have the same quality images, but more of them at the same resolution, wouldn't you want to choose the one which gives you the same amount as the same res?


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## zuluclayman

Welcome to Photographer's Corner

The resolution refers only to the pixel sizes (2288x1712 etc) - this tells you how many pixels are in the image.

The quality standard (SQ1, SQ2, HQ, SHQ etc) refers to the compression that is applieded to the image in camera - when your camera takes an image it then employs whichever compression algorithm you have chosen to compress it as a jpeg file - jpeg is a lossy format, something is getting thrown out when the image is converted to a jpeg.

Compression doesn't throw out pixels it throws out some of the information contained in each pixel, typically it will cut down the colour depth among other things. If you take the same image on each setting then download them to your computer and compare them you will find less gradual toning as colours merge, colours are often slightly out, edges are not as clearly defined etc.

The TIFF setting is as close as you will get to a lossless version of the image - the only setting that truly keeps all the image information is RAW but your camera doesn't output RAW files so TIFF is as close as you will get to having all the information that reached the sensor.

As you go up in quality (lower amount of compression) you also go up in file size - you can easily see this by switching modes and seeing how many images you can take at that mode.

Cameras have this feature for a number of reasons:

* enabling you to take more photos - if you are going somewhere where you may not be able to download the images and quality is not the major concern switch the camera to high compression (low quality) - you'll get many more images on your card or internal memory.
* if the images are to be emailed or put up on the net where there may be file size limits you can use the higher compression (lower quality) settings 
* print quality will be affected by quality/compresion settings - if you want big prints make sure you have low compression (high quality) for best prints

The reverse of these points above also applies :grin:

hope this helps


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