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jpeg compression
I recently bought a Canon G9 and took a trip to Utah. The G9 can run through a lot of memory cards in a hurry. In order to get by for a 10 day trip, I used a fine jpeg compression and still used up for 4 x 2 gig cards..

After my trip, I did a little experimentation on jpeg compression and compared the fine and superfine settings to raw files converted to jpeg. When I zoom on the images, I can see almost no difference. Even at the pixel level the pictures images look nearly identical. This makes no sense since the superfine file is about 2x larger than the fine and the jpeg converted raw file is another 2x larger. I even zoomed, cropped and printed the images and could see no difference. What am I doing wrong?thanks..

Comments (13)

Jrkliny wrote:.

...I did a little experimentation on jpeg compression andcompared the fine and superfine settings to raw files converted tojpeg. When I zoom on the images, I can see almost no difference.Even at the pixel level the pictures images look nearly identical.This makes no sense since the superfine file is about 2x larger thanthe fine and the jpeg converted raw file is another 2x larger. Ieven zoomed, cropped and printed the images and could see nodifference. What am I doing wrong?.

Nothing! You are one of the lucky people born w/o superb taste. .

You just can't see the differences. I suggest you not complain or ask what to look for to tell the difference..

Charlie DavisNikon 5700 & Sony R1HomePage: http://www.1derful.infoBridge Blog: http://www.here-ugo.com/BridgeBlog/..

Comment #1

Thanks for the reply even if it was just a tad condensending..

I looked for a difference pixel by pixel and was amazed to see almost identical pixels. I don't think that has anything to do with taste...

Comment #2

Jrkliny wrote:.

When I zoom on the images, I can see almost no difference.[snip]What am I doing wrong?.

What you are doing wrong is pointing out that the Emperor is starkers. .

For all of the hoo-hah about the evils of JPEG compression, the levels of compression generally used in modern digital cameras just don't produce *visible* effects. The highest quality levels are there for the people who demand the very best even if there is no perceptible difference..

The digital revolution in photography has brought in a lot of people who evaluate photos with a calculator rather than with a critical eye. They see digital photos as capturing data rather than capturing an image. Which I'm pretty sure is a legitimate philosophy even if it's not mine. The "digital photos are data" people demand superfine quality settings for JPEGs. We "digital photos are images" people can generally ignore the superfine quality settings...

Comment #3

You might be interested in this; which I posted a while back..

Http://forums.dpreview.com/...forums/read.asp?forum=1036&message=23677257..

Comment #4

Jrkliny wrote:.

Thanks for the reply even if it was just a tad condensending..

Go back and note the winky face...that means I was joking..

I looked for a difference pixel by pixel and was amazed to see almostidentical pixels. I don't think that has anything to do with taste..

If you look in places where there are obvious details to compare, they will be as you described. Look in the places where almost no details exist, like the sky..

Charlie DavisNikon 5700 & Sony R1HomePage: http://www.1derful.infoBridge Blog: http://www.here-ugo.com/BridgeBlog/..

Comment #5

GaryDeM wrote:.

You might be interested in this; which I posted a while back..

Http://forums.dpreview.com/...forums/read.asp?forum=1036&message=23677257.

The OP was asking about fine vs super-fine JPEG. RAW vs JPEG is a completely different issue. First, it depends on the skill of the person doing the RAW conversion. Most cameras DON'T apply sharpening, color saturation, WB, etc settings when saving the RAW file. It's up to the operator to adjust these. A RAW file that doesn't have sharpening applied will look less attractive than a JPEG file that has been sharpened in camera (unless the camera over-sharpens)..

Your two pictures were obviously taken hand-held, not on a tripod. Not only did you rotate slightly, you moved laterally. When I tried to compare the two pix and got the foregrounds to overlap, the background was off registration. No way to really compare them! It's much better to take the RAW and JPEG simultaneously (some cameras can do that)..

Your two pix were so tiny that even major differences were hidden. They were each only 0.427 MP! How do you expect anyone to detect anything significant in a picture that small? Next time, try cropping to create what is called a "100% crop" of the two pix, showing the pixels from the camera, not resized by your photo editor..

Charlie DavisNikon 5700 & Sony R1HomePage: http://www.1derful.infoBridge Blog: http://www.here-ugo.com/BridgeBlog/..

Comment #6

Jrkliny wrote:.

After my trip, I did a little experimentation on jpeg compression andcompared the fine and superfine settings to raw files converted tojpeg. When I zoom on the images, I can see almost no difference.Even at the pixel level the pictures images look nearly identical..

I've done the same process (with different cameras) and been able to ascertain tiny differences in detail in areas just off focus and shadows etc. where compression is more likely to take place. High detail areas probably look the same, the compromise on discarded data probably takes place in more subtle areas..

I've always had the feeling that I should shoot images at the highest possible size and quality level - seeing no point in throwing potential data and capacity to crop or heavily manipulate away. But for most practical purposes, the difference is a very subtle one and if memory were a factor, on a long trip or day out etc., I would happily drop quality before losing images or feeling restricted in what I could take..

I habitually work at the highest settings for everything, because there's no reason not to, but in reality, for most cases, especially on my compact cameras (I shoot RAW with my DSLR) it probably doesn't make any practical difference. Better to have images in the camera than lose potential killer shots due to memory shortage. I'd reduce size and quality as a card approached full rather than not have any capacity..

I read a lesson from Patrick Lichfield - the English Royal Photographer - who said that he always left one or two frames unexposed at the end of every film as some of his best shots were at the end of a shoot where he'd started to pack away and where everyone had relaxed and started smiling more naturally, so he'd snatch a last shot with his remaining frame in the camera. It's something I've done ever since, I NEVER fill a memory card, I always leave 4 or 5 potential frames on each one - and there have been several occasions where I was glad of it and used them, after I thought I was done taking photos - most especially in my live music work. I can think of 3 significant shots just off-hand where exactly that happened..

So many photos, so little time.http://www.peekaboo.me.uk - general portfolio & tutorialshttp://www.boo-photos.co.uk - live music portfoliohttp://imageevent.com/boophotos/ - most recent images.

Please do not amend and re-post my images unless specifically requested or given permission to do so...

Comment #7

"After my trip, I did a little experimentation on jpeg compression and compared the fine and superfine settings to raw files converted to jpeg. ".

The quote is from the op's statement. what is the 7th and 8th words second line? what are you reading, if you did...

Comment #8

Mostly I agree with the above comments. There is an issue, though, where higher quality, lower compression is desireable. If you are going to do significant post processing, then higher quality will be of benifit. Higher compressions do create more artifacts and such that can cause problems during post processing. Many post processing steps can amplify artifacts and noise even though such things may not be very visible in the original..

I would recommend using the highest quality to preserve the ability to to good post processing if required. If you don't, then you may have lost some potential quality that you can not get back during post processing.Leonhttp://homepage.mac.com/leonwittwer/landscapes.htm..

Comment #9

I went back to my images again and spent quite a bit of time comparing. I could see no differences in the foreground objects. The background is foliage. With a high zoom I could see subtle differences in the background. The jpeg image converted from raw was very slightly better. Some of the twigs and leaves in the background were more distinct and had better color.

It took me a lot of viewing. Next I tried to compare the fine and superfine compressed images. I forgot which I shot first. After a considerable amount of review, I guessed wrong..

I still think I will restrict my use of raw. For an extended trip, the 15 meg file size is a problem..

Thanks for the input...

Comment #10

Your experience seems the same as that of an FZ50 user a few months ago. You might be interested in the discussion/followup in that thread:.

Http://forums.dpreview.com/...forums/read.asp?forum=1033&message=22666671.

Note: the FZ50's "standard" compression is about the same as the G9's "fine" setting, with both right around 11:1 compression..

Comment #11

GaryDeM wrote:.

"After my trip, I did a little experimentation on jpeg compressionand compared the fine and superfine settings to raw files convertedto jpeg. ".

The quote is from the op's statement. what is the 7th and 8th wordssecond line? what are you reading, if you did..

Sorry, my bad. I DID read it, just didn't remember what I read..

Charlie DavisNikon 5700 & Sony R1HomePage: http://www.1derful.infoBridge Blog: http://www.here-ugo.com/BridgeBlog/..

Comment #12

Jrkliny wrote:.

[...] The jpeg image converted from raw wasvery slightly better. Some of the twigs and leaves in the backgroundwere more distinct and had better color..

I suspect that you're perhaps confusing the benefit of RAW. It's not necessarily a fair test (for what you're discussing) to judge an 'as shot' JPEG derived from a RAW original with a JPEG saved by the camera - they should largely, without any intervention, be the same - the differences may well just be down to the software used and another application would almost certainly give a subtly different result - I know all my RAW developers give slightly different results on the same file..

The significant RAW advantage is in the stage between the camera recording it and you saving the result of the development as an image, to a JPEG. If you don't change anything in that process, you're not gaining anything from RAW that will be obvious just by looking at the result..

The big advantage comes in the actual process of converting a RAW image to a JPEG (or whatever image format you choose) where you're using the greater computing power of your desktop machine, your personal judgments and choices and the ability to manipulate the image data in a way that would be detrimental when done to a JPEG..

Perhaps you'd see a greater difference if you were to take an image that wasn't taken quite right, adjust it until it was right visually - in the RAW development process in one copy and to an in-camera JPEG with another, then look at how that change changed the pixels (and you'd have to then save it again too). That's where RAW offers it's advantage - the more you change, the greater the advantage..

Same with the difference between the compression levels. With a correct and un-manipulated image the differences will be very subtle if it is used 'as shot'. The finer setting will offer greatest advantage when you start doing a lot to the image - cropping, printing very large, heavily post processing etc. If you're taking a memory card to a photo shop to get out of camera reprints done, then the subtlety of advantage won't be evident in anything other than large prints, if at all..

It's really a case of horses for courses - if you think you might want to work further on an image, use the best compression, if you know it's a tricky shoot in difficult conditions or an unrepeatable shot, use RAW. For most general purposes, a lower quality setting will probably be perfectly adequate for most uses..

So many photos, so little time.http://www.peekaboo.me.uk - general portfolio & tutorialshttp://www.boo-photos.co.uk - live music portfoliohttp://imageevent.com/boophotos/ - most recent images.

Please do not amend and re-post my images unless specifically requested or given permission to do so...

Comment #13

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This question was taken from a support group/message board and re-posted here so others can learn from it.

 

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