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Old Sep 19, 2004, 10:58 PM   #1
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I'm a former FZ-10 owner and a new FZ-20 owner. I've played a little with TIFF files but can't see too much of a difference in quality on my monitor. Is this something I'd see more on a print? Or does it depend on what I am shooting ?

Right now the main difference is a 14MB vs. 2MB image.
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Old Sep 20, 2004, 1:30 AM   #2
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srvsd wrote:
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I've played a little with TIFF files but can't see too much of a difference in quality on my monitor.......
Right now the main difference is a 14MB vs. 2MB image.
This factor of 10 or so in size is normal for tiff vs high quality jpeg compression. Unless you are working to the very highest quality, high quality jpeg is perfectly OK. However, if you're reworking and resaving old images, make sure you always start with the original and not with an intermediate jpeg image.

You can explore this easily enough for yourself, to see if you can tell the difference. With the camera on a tripod or other firm support, photograph a detailed subject (a brick wall with foliage against it, perhaps) twice, making a tiff and a jpeg. Then compare the images alongside each other at high magnification in your computer image editor.

On all the digicams I've had, and also on filmscans fromnegatives, it's extremely difficult to tell the difference, pixel for pixel, between a high quality jpeg and a tiff, and for all normal purposes I have found the 'normal' quality jpeg from my cameras to be adequaate even for substantial enlargements.

Good luck. When in doubt try it & see!
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Old Sep 20, 2004, 10:45 PM   #3
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I think if you print out the two images (one being JPG and one being TIFF) you will probably be able to see some difference. The difference will become greater the larger the picture size. Unfortunately, the monitor is not really a great judge of picture quality. To compare photos you might want to zoom in to the photo. Or in some imaging programs (I use ACDsee to view) you can draw a box around a specific area, double click and it will zoom into that box. Then you might be able to see some differences. But if you are doing point and shoot work, JPEGs are great, and u can also take advantage of the burst mode (I never shut the burst mode off on my FZ20).
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Old Sep 27, 2004, 8:59 PM   #4
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I've compared TIFFs and high quality JPEGs, zooming right in on, say,text on the computer, and I can see practically no difference at all.

The key is what happens AFTERWARDS. If you manipulate the JPEG, it recompresseseach time multiplying the compression artifacts each time. Try it for yourself. Take a good quality shot of text,shot in JPEG.Rotate it by 5degrees, saveas a new file, then take that file, rotate it back -5 degrees, resave as a different file. Do it 3 or 4 times. You will notice that the areas surrounding the boundaries between light/dark or one color and another will show quite dramatic artefacts.

If you do this with TIFFs, it doesn't happen because there is no compression. I always CONVERT my JPEGs to TIFF before I manipulate the image, then I can change them back if required.
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Old Sep 27, 2004, 10:30 PM   #5
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dnas,

Very Good Research.

I zoomed in on both 1600x and noticed very little difference, and what you say makes perfect sense, and is a very important thing to know when working with the files.

Thank You...

bobc
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Old Sep 27, 2004, 10:36 PM   #6
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Another thing to consider is...

Pictures can be taken in jpeg fine so more pics can be stored on a SD Card. Then converted once on the computer.

We can fit more on the cards without degrading the image, as long as we convert to tiff before doing any editing.

hmmm. I like that...

bobc
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Old Sep 28, 2004, 8:13 AM   #7
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I was toldwhenretouching a photo in photoshop,always convert jpg to tiff. I don't know all the details why, but it comes from a person who makes a very good living as a pro photographer.
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Old Sep 28, 2004, 9:19 AM   #8
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Rookie wrote:
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I was toldwhenretouching a photo in photoshop,always convert jpg to tiff.
This is a good idea if you wish to save intermediate versions of the photo to disk.

However, photo editors have to have a whole uncompressed version of an image in memory in order to display it properly and allow rapid manipulation. You can makesuccessive changes, and the whole, uncompressed image as displayed will still be available. There will even be several successive versions available, as shown if you use the photo editor's 'undo' facility. This changed image exists as a bitmap in RAM or virtual memory, not as a disk file. Only when you SAVE it does it become a tiff (non-lossy)orjpeg (lossy) file.

So, if you saveyour imageto disk as a jpeg, and then reload it later, and then save it again and again to disk as a jpeg, you will risk progressive deterioration in image quality through the exacerbation of jpeg artefacts. This will be rapid if you use high degrees of jpeg compression, and slight if you use the highest quality of jpeg.

It's easy enough to try it out for yourself, by saving a succession of modified images, and comparing them on screen at high magnification. If in doubt, try it out!
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