In Camera Viewing of Pictures

macmac

I was reading a book by Susan McCartney and in it she wrote that viewing images by camera playback degrades them. Is this reported other places? Has anyone seen this happen to images?

ziggy53

macmac wrote:

I was reading a book by Susan McCartney and in it she wrote that viewing images by camera playback degrades them. Is this reported other places? Has anyone seen this happen to images?

No way! The only possible interaction would be if you were reviewing images while the buffer was still dumping. I have heard of minor problems occuring with some older cameras (very old digital cameras), but nothing produced in the last 7 or 8 years seems to be affected.

Seefutlung

Maybe she meant that the playback image on the camera LCD is degraded when compared to the image stored in memory.

ziggy53

Seefutlung wrote:

Maybe she meant that the playback image on the camera LCD is degraded when compared to the image stored in memory.

Good lateral thinking!

wxwax

Seefutlung wrote:

Maybe she meant that the playback image on the camera LCD is degraded when compared to the image stored in memory.

That makes sense. Good translation!

Never trust the image in the little LCD screen. If you have a histogram, use it. if your camera gives you blinkies for overexposed bits, trust them.

macmac

Quote from book: "Do be aware that each time you play back a digital image in teh camera, it may degrade the final result..."

Andy

macmac wrote:

Quote from book: "Do be aware that each time you play back a digital image in teh camera, it may degrade the final result..."

That is just dum

You may safely ignore that

jdryan3

Andy wrote:

That is just dum

You may safely ignore that

I haven't read the book, but it makes you wonder what other info is offbase.

claudermilk

...and this is a PUBLISHED book? I'd either demand a refund or at least round file that book. She obviously has no clue how digital cameras actually operate--Andy was being kind with his comments. I'd expect that kind of nonsense claim in some forums (not here, though), but not in a book.

Huh, frighteningly Amazon shows 11 books by her, though the last one is ironically appropriate considering this bit of misinformation. Out of sick curiosity, which book was it you found this in?

Seefutlung

I GET IT!!! What she 'MUST' be referring to is the JPEG compression. And that every time you open and work on a JPEG file ... the compression methodology employed will eat away at the total information. Hence degrade.

What do you guys think?

Gary

ivar

Seefutlung wrote:

I GET IT!!! What she 'MUST' be referring to is the JPEG compression. And that every time you open and work on a JPEG file ... the compression methodology employed will eat away at the total information. Hence degrade.

What do you guys think?

Gary

Maybe, but what does that have to do with in camera viewing?

Seefutlung

ivar wrote:

Maybe, but what does that have to do with in camera viewing?

Absolutely nothing ... which is why macmac is confused. The statement is just plain wrong.

This illustrates how people can make statements and claim themselves an expert in areas which they really haven't the knowledge ... and still make money. (Pretty sad state of affairs, where I, a person with very limited and purely practical computer knowledge, knew more of the subject than the author.)

Mike02

Andy wrote:

That is just dum

Agreed. Sounds like someone who doesnt really know what she's talking about.

macmac

If that is true, with regard to jpg compression, then you shouldn't open and close the files on the camera or the computer...???

I would assume raw would not suffer any degrading since they are not compressed.

macmac

I just found an interesting article on this subject.

A quote from the article: "Important warning to readers: loading and saving a JPG repeatedly will accumulate the small errors introduced, so that the image can seriously degrade. Working copies of images should be kept in a lossless format."

Here is a link to the article:

http://www.wfu.edu/~matthews/misc/jpg_vs_gif/JpgCompTest/index.html

The title of the article is "How Bad is JPG?"

ziggy53

macmac wrote:

If that is true, with regard to jpg compression, then you shouldn't open and close the files on the camera or the computer...???

I would assume raw would not suffer any degrading since they are not compressed.

Just opening and closing a JPG file does not "recompress" the image, and it is the compression and recompression that does the damage, because JPG is a "lossy" type of compression. If you open a JPG file and change it and then save it again as a JPG file, you are recompressing the image and can seriously degrade the image in the process.

Other compression algorithms are "lossless", like RLE and ZIP that can be used with TIF files. Most RAW image files "are" compressed, but they use a "lossless" compression that completely recovers all the original data.

ivar

macmac wrote:

I just found an interesting article on this subject.

A quote from the article: "Important warning to readers: loading and saving a JPG repeatedly will accumulate the small errors introduced, so that the image can seriously degrade. Working copies of images should be kept in a lossless format."

'and saving' is the important part here.

Just looking at the jpg in camera, doesn't save anything again.

macmac

This has turned into a very educational thread...Thanks! I've learn a lot about jpg...what to do and what not to do.

1. Viewing jpg image on camera is ok. It does not hurt the file.
2. Viewing jpg on computer is ok. It does not hurt the file because you are not resaving the file therefore it is not being recompressed. - which will degrade the file.
3. When making changes to an image file always use a copy so as not to recompress the original....always a good idea...work with a copy for changes.

BigAl

Jpeg degradation by repeated saving was discussed historically. Unfortunately, Shay has removed the pics he referred to.

http://www.dgrin.com/showthread.php?t=14922

I don't where that author got the notion from that viewing degrades the image, but as already mentioned it's total rubbish. The unfortunate thing is that because it is now "in a book" it is taken to be gospel.

Nikolai

macmac wrote:

Quote from book: "Do be aware that each time you play back a digital image in teh camera, it may degrade the final result..."

No way..

Thanks for the info though! (...adding the book author to the black list...)

claudermilk

BigAl wrote:

I don't where that author got the notion from that viewing degrades the image, but as already mentioned it's total rubbish. The unfortunate thing is that because it is now "in a book" it is taken to be gospel.

That's the part that is troubling. So now a lot of newbies are going to read that & take it as fact--and we are going to have to convince them the book is indeed incorrect. Worse, some of her books are published by Anherst. :nah

Makes you wonder if an editor even *read* the manuscript? I'm still curious which book this misinformation appeared in.