Why is that? Would the same apply for still images and to CDs?
(I know we're not a digi forum - but
you started it Ian

Bob H
Oh dear, I'll put the hard-hat on and slip into a bullet proof vest first.
...and type in whispered tones... with any luck nobody will notice!
When still images are saved to CD or DVD it tends to be done as a data file. In that situation the use of a CD or DVD doesn't affect the 'quality', as the CD/DVD is just a storage medium, in the same way as a 3.5" floppy or hard disc is.
Having your cine film transferred to "DVD" will create a 'video DVD' capable of playing back on a DVD player. The file format used to save the video data is MPEG2 - quite a lossy compressed format. Whilst it can be adequate for 'final delivery', if you want to carry out further editting then you are much better off having it transferred to something with less compression. If you don't have the means to handle formats such as DigiBeta/BetaSP etc, then even MiniDV is better than a DVD. MiniDV still uses a lossy compresion format, but it is less severe than that used on DVDs.
I suppose the best analogy to still photography is the recommendation not to use highly compressed JPEGs until you've finally finished editting and tweaking your photograph - use a format such as TIF for as long as possible and only compress down to a JPEG right at the end of the process. Likewise with DVDs - don't save your transferred cine film to DVD until
after you've editted and adjusted it all.
If you look closely at sequences on DVD containing a lot of moving fine detail, then you can see compression artefacts as the algorythms struggle to cope with all the high frequency information, the data rate used to generate the DVD can also have a large effect on the degradation of the image. High data rates give better quality, but can lead to problems playing back on some DVD players and PCs.
Right, did I get away with it?
To make up for it I can always discuss the joys of the 16mm clockwork K3, or the elegant Beaulieu R16 as recompense?!

...the delights of respooling 400ft recans down to 100ft daylight loads?
...my plans to adapt Arri Std mount lenses to a Russion K3 bayonet mount camera?
....all of which remains in the non-digital domain!
