MiniDV tapes

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Ian Woodward
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MiniDV tapes

Post by Ian Woodward » Fri May 28, 2010 1:34 pm

I'd be interested to know approximately how many times a MiniDV tape can be recorded over before image quality in the recording is compromised.

Has there been any definitive research done on this questions?

Ian Woodward

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Stephen
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Re: MiniDV tapes

Post by Stephen » Fri May 28, 2010 11:47 pm

Hiya Ian

if I shoot something valuable I use a brand new tape once and archive it

general purpose shooting I have used tapes 3 - 4 times with no appreciable loss in quality
shooting on standard DVtape (sony premium) in HD I recently noticed a couple of drop outs on tapes used 3 - 4 times but this is not a qualified study by any means !

the price of the tape is the cheapest part of video production so I go with an ever increasing library of archived tapes!!

in the next couple of years compression algorithms will become so efficient and with the advent of nanotechnology (eg atomic holographic optical storage systems) we can achieve 100's of terabytes on 3.5" discs or small SDHC cards. there will be few DVtapes around in 3 - 5 years time!

but at the moment DVtape with 13Gb of backup storage for £1 or so is good, secure, value for money !!!!
Stephen

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It's much more important than that.

Ian Woodward
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Re: MiniDV tapes

Post by Ian Woodward » Sat May 29, 2010 1:23 pm

Thanks for that, Stephen.

What I'm doing at the moment, as part of a wildlife film, is pointing the camera at numerous manmade and natural objects in the garden and leaving the unmanned, camouflaged camera running for an hour - for example, it might be focused on the bird bath. Each hour over maybe eight hours I’ll take the current MiniDV tape out of the camera and put in another tape.

At the end of the day I download the results onto the computer. On each tape there will probably only be five scenes, averaging 10 secs each, of different species, from woodpeckers to jays. It is it is just these bits that I download. I then rewind the tapes and use them again.

Up to now I've done this about 15 times and I haven't noticed any deterioration in quality. It was because of this that I was wondering at what point I WILL notice.

As regards your point about the possibility that there might be few MiniDV tapes around in three to five years, I seem to have read countless times in the print media the point that as long as there are camcorder users worldwide with MiniDV cameras, manufacturers will continue to produce MiniDV tapes.

Am I right or wrong here?

Ian

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Dave Watterson
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Re: MiniDV tapes

Post by Dave Watterson » Sat May 29, 2010 10:51 pm

Hi Ian,
I have not found any reliable research into how often you can re-use tape. One reason for this is that so much depends on the equipment it is being used in and how it is being used.

For your purpose I suggest you re-use them until the very first sign of a drop-out or blip, then take it out of active service and assign that tape to your archive shelf.

From your description your tapes should survive many repeated runs. It helps that you run them continuously all the way through rather than stopping and starting every few seconds. Run a cleaning tape through once a week or so to keep the rollers and heads of your camcorder clean.

I asked Daphne Barbieri, the Scottish amateur film maker and winner of many wildlife film awards about this. One of her films got the nature award at the Morecambe Bay International Festival this year and is set entirely in her garden. She says:

"With regard to your query about Ian Woodward's use and re-use of mini DV tapes, I have never used any more than three times. I did like him set the camera facing a bird's nest, or similar, and leave it running for the hour. I didn't download the lot into the computer, but ran through the tape and downloaded any bits I wanted. I note where these sections are, then use the tape again, but don't tape over the pieces I want to use. I keep every tape I use and file it away in boxes, so have goodness knows how many since 2000!!"

For many years businesses backed up their computer records to tape. Normal practice was to have three or four sets of tapes, each set being recorded, then taken off site for several weeks before being brought back and re-used. They were often used hundreds of times.

As for the future ... Willy Van der Linden has reported that MiniDV tapes are vanishing from supermarket shelves in Belgium. I suspect they are still around in photographic dealers. The internet offers plenty of sources for tapes.

Tom Hardwick has pointed out that they will be manufactured for many more years to feed the demand from millions of older camcorders.

The danger point will come when no more are manufactured. There may be huge stocks available in various places, but tapes deteriorate from the moment they are made, whether they are used or not. I'd abandon tape a couple of years after the last one is manufactured. That's assuming you have not been tempted by any of the alternative storage methods before that.

By the way ... had you considered a long lead from camera to computer and recording direct onto your computer hard disk without running any tape?

- Dave

Ian Woodward
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Re: MiniDV tapes

Post by Ian Woodward » Sun May 30, 2010 8:22 am

Thanks for that very full and well-reasoned reply, Dave.

Up to now, despite the fact that the tapes have been through the camera nearly 20 times, I can detect no signs of problems.

It's very good to have Daphne's views on this topic, too.

From what I can recall of Tom Hardwick's writings on this subject, manufacturers will continue to provide miniDV tapes just as long as there is a demand for such products from the millions of camcorder users around the world whose cameras are in need of such tapes.

A thought: I wonder how many millions of miniDV-dedicated camcorders are currently in use worldwide?

Dave, you say "tapes deteriorate from the moment they are made".

And yet just a few months ago we were discussing, on another IAC forum, the supposition that, compared to DVDs and several other image-recording formats, miniDV tape was the preferred choice of experts and enthusiasts in terms of its apparently superior archival properties – and it was the preferred choice precisely because it was said (but how can it be proved?) to be more stable and therefore slower to deteriorate than other formats.

I suspect Tom will have strong views on this subject!

Ian

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Dave Watterson
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Re: MiniDV tapes

Post by Dave Watterson » Sun May 30, 2010 11:31 am

The vulnerable part of a video tape is the "binder" which holds the magnetic particles onto the base. This contains lubricants to help the tape run smoothly and they slowly dry out.

The vulnerable part of a home burned DVD is the dye layer which changes colour when the strong laser of the burner hits it. By definition it is an unstable chemistry and gradually reverts.
Note that commercial DVDs hold the signal in a different way and are not liable to the same problem.

The archive world believes home burned DVDs have a much shorter life than video tape. They also accept that technology changes every few years and a big problem can be finding equipment to play back old recordings on outdated formats. Archivists are resigned to having to copy important content every couple of years to whatever is the latest form of storage.

Dave

Michael Slowe
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Re: MiniDV tapes

Post by Michael Slowe » Sun May 30, 2010 4:52 pm

We have now migrated to the old 'chestnut', that of archiving. It is still thought that tape might currently be the best method but preferably not mini DV. If you can I would suggest getting really important stuff on to Digi Beta or at least DVCAM tape as there will be fewer drop outs and probably a higher quality tape.

Reliable hard drives (either usb or mains powered) are probably the next most popular but they can and do fail eventually so should be backed up. Soon, it is to be hoped, cards which need no working parts will become cheaper and can store media files for long periods of time. People are also now using 'gold' DVD discs for archiving media files which are marketed as being good for 100 years, nearly long enough for old guys like me.

Taking up Dave's point on burnt DVD's I suggest you copy from one to the other fairly frequently until they solve the dye deterioation problem.

Ah well, it all takes our minds off making decent films doesn't it? Never had this problem with that celluloid stuff with holes punched down the edges.

Peter Copestake
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Re: MiniDV tapes

Post by Peter Copestake » Sun May 30, 2010 5:46 pm

Never had this problem with that celluloid stuff with holes punched down the edges.
Funny you should say that, Michael. I've been copying to video/DVD a film we made in 1982.
Super 8 Kodak striped. It was given to the charity for whom it was made and they projected it with a new projector many, many times I got it back several years ago when it had been copied to video commercially and haven't looked at it since. It has worn very well, i.e. hardly at all, but is covered with blotches, on the emulsion side, several to a frame, that look brown when projected but grey under reflected light. They clean off easily with two passes of a water-plus-a drop of WU fluid-damped cloth. The emulsion doesn't appear damaged.
Obviously fungus, I thought.
BUT it has been kept in the same place as all my own films which are not infected
AND when I looked at the off-cuts which have been kept in a different house altogether they have the same defects.
SO was something done to the film when it was edited before it was cut? I think I did the edit and may have used 2.22 but then I always did and haven't had this before.
Any ideas?
Peter Copestake

Michael Slowe
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Re: MiniDV tapes

Post by Michael Slowe » Mon May 31, 2010 9:27 am

None at all Peter I'm afraid. I had most of my films, both 8mm and 16mm copied to Digi Beta and VHS some years ago so haven't had reason to look at the original film but what you say sounds like a fungus that has been giving cause for alarm to archivists. It can be cleaned off (as you demonstrated) but I believe it has to be caught early. The debate however is - where do we go from here? All the big cinema chains are now receiving their 'films' on tiny drives which they de code and project on their new super digital projectors. Think of the saving in shipping and prints! I challenge any geek to spot the difference in picture quality.

tom hardwick
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Re: MiniDV tapes

Post by tom hardwick » Mon May 31, 2010 12:01 pm

There are a lot of people out there saying that as MiniDV tape is so cheap they never re-use them, never recycle. At over 13 gigs to the £, why take the risk?

Two points.

1) The act of rewinding the tape and replaying it (otherwise why bother recording it in the first place?) is reusing the tape. The tape deck treats the tape in exactly the same way if it's recording or playing back.

2) A MiniDV tape consists of 28 components, including a 75 metre ribbon of tape, many pins, rollers, springs, guides and so on. Very many of them are tightly toleranced, high precision injection moulded parts, and assembling these 28 components is an automated process.

So when you next spend a whole pound on a matchbox size piece of such huge mechanical complexity, know that you're not paying for any inspection whatsoever - you, the final user, are the inspector.

So it is that I treat recycled tapes as being better than new. They've had any emulsion debris thrown off, had the highs burnished down by the spinning heads and they've been tested by you.

I'm a great believer in recycling tapes for this reason, and mine have been reused time and time again. My open reel tapes from the 60s still play dropout free, and my VHS tapes never showed signs of 'wear' that DVD sellers wanted us to believe was happening.

Of course I treat tapes with care. I don't load them into the camera in a dust storm. I keep the tape path spotless.

So Ian, carry on reusing your tapes. They are designed to be reused, again and again.

tom.

Ian Woodward
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Re: MiniDV tapes

Post by Ian Woodward » Mon May 31, 2010 2:19 pm

Many thanks to Michael, Peter, Stephen and Dave for informing and entertainign me with your diverse and often fulsome views on (to quote Michael) "the old chestnut...of archiving".

It has enlightened, bothered and amused me in just about equal measure.

But it is Tom who has allowed me to sleep easy at nights again with his final commented: "So Ian, carry on reusing your tapes. They are designed to be reused, again and again."

Phew...that's a relief!

Ian

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billyfromConsett
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Re: MiniDV tapes

Post by billyfromConsett » Mon May 31, 2010 7:21 pm

Tom's reasoning sounds so true and I'm sure he's spot on. But my head still tells me to use new tapes for new movies, and not trust or reuse the old tapes. Maybe old habits die hard.

Having said that, I also record with a CF card when I film, and leave the tape for archive often without playing it.

tom hardwick
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Re: MiniDV tapes

Post by tom hardwick » Tue Jun 01, 2010 7:49 am

I should perhaps add that like Ian, my MiniDV tapes are run in the camera for long periods at a time (church services, wedding speeches and so on). In this mode the tape is under very little strain, it just ambles along, whistling in the wind.

If you're in the habit of constantly stopping and starting your camcorder, rewinding and reviewing, pausing, fast forwarding and the like - well, that sure introduces more stresses and strains onto the delicate, mighty thin and vulnerable tape.

Some cameras have what I call 'kind' tape deck mechanisms, whereby the tape is gently accelerated away from rest and decelerated when stop is pushed. These mechanisms avoid setting up stresses in tape. Then there's maintenance - if your camcorder has had a fair bit of use the tape tension settings on the feed and take up spools can change, and need to be checked and reset. It's not a DIY job. If this is not done tape can be 'squidged' as it's pulled reel to reel, and this can crinkle the edge and give you dropouts.

Tape has done us proud and I'm in awe that something so cheap can record and hold onto such staggering image quality. But its days are numbered, and all the above is deleted at a stroke by the switch to flash memory (card) recording.

tom.

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Dave Watterson
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Re: MiniDV tapes

Post by Dave Watterson » Tue Jun 01, 2010 9:52 am

Hmmm. How many times do you expect your flash memory to be re-used without failure?
I do not have figures, but certainly so far as flash memory "discs" for normal computer use is concerned: they are quick, they are costly and they have a limited useable life. The way the recordings are made actually reduces the efficienct of the memory chip.
-Dave

Geoff Addis
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Re: MiniDV tapes

Post by Geoff Addis » Tue Jun 01, 2010 11:41 am

I cannot say how the longevity of DVDs compare with that of CDs, but I have recordable CD's that go back at least 22 years and still play perfectly. I also have some professional Ampex tape of similar age that, although having been used for one master recording, shows signs of deterioration. Both have been kept in a humidity controlled environment and out of direct sunlight. So my money is on DVDs!

Geoff

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