in other posts. Please also read the Camcorder Forum sticky.
-Which gives the best picture quality out of the three (in the same price category)? MiniDV tape.
-Which is the best in terms of storage capacity (time of recording)and also in terms of costs of storage? If a single long duration recording is required, HDD. If up to 1 hour segments are acceptable - but limited by only the number of tapes you carry with you (hundreds?) and power... it takes about 8 seconds to take out the full tape, insert the new one and start recording again - miniDV tape. Costs of storage comparison could be debatable since hard drive costs are coming down so much - but most people wouldn't fill the HDD on the camcorder and go get a new camcorder... so it depends on what your definition of storage is. If I only store 5 hours of video, that is 5 tapes for a miniDV machine - and potentially fills the hard drive on a HDD machine... then what? Did I bring a computer with available hard drive space to transfer the video (13 gig per hour)? For the next five hours I need a place to dump the HDD camcorder's video - but I have 5 more tapes at ~US$2.50 each I can store that - presuming there is a power outlet or I have extra capacity batteries charged and ready to go. Yes, I have been on shoots that were 14 hour days... and filled 12 tapes... it is not a regular thing, but it has happened more than once.
-Is there a loss of quality when copying from DV tape to DVD or to HDD? It depends what format video is used to store on that media. If your video editing application allows you to choose a "Full Quality" format, then no, there is essentially no loss of video quality. DV = Digital Video - so it is a digital-digital transfer. The zeroes and ones stay the same. (This is NOT analog.) HDD and DVD based camcorders are also digital - but NOT DV. The compress a LOT. The "lots of compression" results in degraded video - the hard drive camcorders really aren't THAT bad - but DVD based are worst video quality (especially if you import to a computer for editing or transfer to another media) of the three media. Memory card camcorders (like the Sony CX7 are just now coming out - too bad it used AVCHD to compress hidef video - otherwise, it might be a nice camcorder - they will be in the realm of HDD video quality).
-Should one go for the DV model out of the three, if in the same price range it gives more spcs (and not fear phasing out of the tape) There is no reason to fear tape phase out. MiniDV tape is a digital format that is more acceptable as an archive mechanism than HDD or optical media. That it is cheap and continues to provide the best available quality and the pros continue to use it adds to its continued availability.
- Out of Sony DCR-HC38/E , DCR-DVD608/E, DCR-SR42/E - Which one is more preferable if picture quality is the consideration and not storage capacity? The one which uses miniDV tape (DCR-HC38.)
You will notice that I don't talk about DVD camcorders much - I believe they should be removed from the market. Finalize or not? Scratch the disc? Video recovery challenge. 20 minutes recording time per disc - or 40 minutes if double sided and you need to manually flip the disc - so not enough recourding time. Ripping the DVD to get to the video is the only way to edit, and the resulting quality degradation on top of the poor original quality due to the compression - well, it is icky. I no longer do "favors" for friends asking me to edit their DVD-based camcorder footage. If you are not planning to edit this footage, this might be the method you want - but I've read too many post here about DVDs with video on them turning into coasters.