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Old Dec 21, 2005, 9:23 AM   #1
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Do you lose any image quality when you transfer pics from the memo card to a CD rom?

Can anyone reccomend a good book on diggys for a newbie? Or, should i just learn my owner's manual well? I bought a FZ-5 last week.
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Old Dec 21, 2005, 9:47 AM   #2
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Copying a picture to CD will not cause any loss of quality it is an identical bit for bit copy on the CD.

If you use JPG you will lose quality when you open, edit and save a picture.
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Old Dec 21, 2005, 9:58 AM   #3
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Nagasaki wrote:
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Copying a picture to CD will not cause any loss of quality it is an identical bit for bit copy on the CD.
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****ok. that it good to know. thanks
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If you use JPG you will lose quality when you open, edit and save a picture.
Interesting. A noticable amount of quality? Should i shot in something else if i want to be able to open, edit and save? What format would you reccomend? A good quality format that doesn't lose quality when being edited.

Bummer. I didn't know that you lose quality when editting

That kind of defeats the purpose of editing doesn't it? Again, how much quality is lost?
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Old Dec 21, 2005, 11:57 AM   #4
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dwelsh7 wrote:
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Should i shot in something else if i want to be able to open, edit and save?* What format would you reccomend?* A good quality format that doesn't lose quality when being edited.
Most important rule is to not use JPEG inside editing/processing.

It's lossy compression and everytime when you save picture again some data is lost, so if you edit picture using JPEG you can loose lot of smaller details, especially if you don't use smallest compression settings. Same way you should always use best output of camera. (because you can't get lost details back if that photo ends up being your best shot)
It could be said to be similar like photocopying from previous copy or taking analog copies like with VHS or C-cassette, quality decreases gradually because every new copy is little different than previous.
(but in digital world you can make infinite generations of copies from original because every new copy is completely identical, that's unless data is converted to other format between copies)

So while doing editing you should use lossless format and use JPEG only after you have done editing.
And when needing differently edited photo (like for different purpose) it's always better to start from original/as little edited copy as possible.


For complex editing 16 bit accuracy per color channel would be better because it won't cause so much "rounding errors" every time when data is manipulated... It's just that 24bit per pixel/8 bits per color channel gives only 256 brightness value for single color. (65536 for 16bits)
It's like in mathematics where you have to use bigger accuracy inside calculations and do rounding only for result, if you do rough rounding in every phase of calculation difference can become considerable in last phases. (for comparison while graphic cards output 24 bit image they use 64, even 128 bit internal accuracy)
But for light editing 8 bits per color would be enough. (and 16bits per color channel is available only in more expensive programs)

Similarly if you do lot of editing you should always use RAW format in camera which means camera doesn't do any processing and just saves information captured by sensor which always enables best results. (consider lossy compressions and all extra data conversions as analog copying)
Depending on quality of in-camera conversion and processing difference can be big in accuracy and amount of details when compared to good conversion. (compare three pics in here)


Your camera doesn't include RAW, only already processed and uncompressed/very big TIFF.
But in-camera conversion appears to be quite good.
Considering best JPEG setting makes 2MB sized files (average) and "resolution" is five megapixels there should be only very minimal loss of data/details compared to TIFF so unless you specifically need uncompressed images I would prefer JPEG.
And then save it in lossless format when you need to edit it.


Also some (propably all better) editing programs support thing called adjustment layers or something like that, which means that you can do things like color, brightness and contrast corrections etc. to separate layers while original picture stays untouched all the time until layers are combined. (if you later in editing notice that some adjustment doesn't work/make result worser you can just delete approriate layer) For this to work inside editing you have to use format which supports multiple layers, like proprietary formats of programs.
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Old Dec 21, 2005, 12:04 PM   #5
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I would recommend TIF files while editing. Once you have the final image you can save it as JPG using the highest quality setting and you shouldn't notice a difference. If practical I would use the TIF setting in camera particulary if it creates 16 bit files. I use 16 bit while making initial adjustments to levels in PhotoShop and then convert to 8 bit. It does all depend on how much post processing you do.
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Old Dec 21, 2005, 12:21 PM   #6
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Nagasaki wrote:
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If practical I would use the TIF setting in camera particulary if it creates 16 bit files.
No hope for that:

2 560 * 1 920 * 3 = 14.745.600
So those are 8 bits per color channel TIFFs
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Old Dec 21, 2005, 3:14 PM   #7
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It is not possible to "use JPG inside editing/processing". When you open the image it is decompressed and the image is processed and edited exactly the same way as if the image had been a TIF. Say you were to open a JPG and save it as a TIF, then close the image onscreen and open the TIF. The image onscreen from opening the TIF would be exactly the same image and would be treated in exactly the same way in processing as the original you closed.

The only difference is in what format you save the image in after processing. If the images come from your camera as JPG, then that is as good as it gets. You might as well start your editing by opening the JPG in your editor and working with it. Changing it to another format first makes no difference and wastes your time. I like to "Save as" a PSD early on to make sure the original JPG isn't accidentally altered. That JPG is your digital negative and shouldn't be altered IMO. Some people work on a layer to protect the original, but I prefer the "Save as" method.

Someone commented that the SHQ JPG images from his camera were so good that he could resave them 20 times in Photoshop at best quality JPG and not start picking up artifacts. I thought perhaps he had just hit the Save button 20 times – you can hit the save button a hundred times and only end up with one JPG compression in the saved image. So I downloaded a SHQ JPG from his camera and tried it in Photoshop. I made a mark on the image and did a "Save as" and changed the file name so I would have the original to compare. I closed out the image and opened the recompressed one, made a second mark, closed the image and reopened the saved one. When I had 20 marks indicating 20 saves at quality 12, I compared it with the original. There wasn't a lot of difference that I could see even blown up. You don't take much of a hit with a quality 12 JPG save from Photoshop.

I don't find TIF to be a practical mode from cameras. Your files would be 14.4Mb each and you would lose your burst ability – which is very good with that camera. The cycle times between shots goes up enough that you miss a lot of shots except in static situations. The JPG compression isn't bad in the FZ5.

I work with my raw images in 16 bit. I'm not getting the full advantage as the processor in the camera is only 12 bit, but there is enough advantage for me to use 16 bit. But I don't convert 8 bit images to 16 bit to work on them. You can use up a Gig of RAM in a big hurry working in 16 bit on a full sized image from a 7 or 8 Mp camera. And even before the computer goes to full slow motion by writing to virtual memory, everything goes a lot slower in 16 bit. I've tried it and can't see any difference in the finished image when starting with 8 bit and converting to 16.



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Old Dec 21, 2005, 5:04 PM   #8
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Ouch. You guys are hurting my newbee head! Can you 'dumb' it down a little?

So, my FZ-5 saves images as JPEGs. And, if i edit these with software i lose some quality - is that right? Do i lose much quality?

If i edit them in the camera - then no quality is lost?




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Old Dec 21, 2005, 7:52 PM   #9
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Save your original exactly as they come from your camera with no changes whatsoever. Those are your digital negatives, don't mess with them. As you learn more about editing, you will realize that you can do better than your first attempts. If you still have the orginals, that is not a problem.

Save your originals and don't worry much about what you do after that. Pay attention and learn - you will figure it out.


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Old Dec 21, 2005, 8:49 PM   #10
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dwelsh7 wrote:
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Ouch. You guys are hurting my newbee head! Can you 'dumb' it down a little?

So, my FZ-5 saves images as JPEGs. And, if i edit these with software i lose some quality - is that right? Do i lose much quality?

If i edit them in the camera - then no quality is lost?



If you open your image in an editor you lose no quality. Most things you do in the editor lose no quality.

If you save an image after editing it in a loseless format like TIFF, PNG or PSD you lose no quality.

If you save after editing as a JPG you lose quality recompressing the image. How much quality you lose depends on how much you compress the image. You lose very little quality saving at best quality JPG (lowest compression).

You should shoot at "Fine" quality and not "Standard", and at 2560x1920.

Any editing you can do in the camera like cropping and rotating the image can also be done in a good image editor without degrading the image. I'm not sure whether the camera will do those loseless or not.

Resizing both in the camera and in an image editor lose a little quality. But the loss of quality is very small.


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