New V750 + SF8 tests

Started Feb 16, 2012 | Discussions thread
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JJ Winkel
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New V750 + SF8 tests
Feb 16, 2012

Hi, I am back after long researches and a lot of reading .....

As I was puzzled by all your valuable comments in my previous thread ( http://forums.dpreview.com/forums/read.asp?forum=1003&message=40571447 )

I decided to study more (the i-photo V750 test particularly) and go back to the drawing board.
So I first calibrated my scanner in SF8 using the bundled IT8 target.

Then did a number of height adjustment tests and found out I was completely out of the best height, see the full size of the combo below :

The bad news as my height adjustment was wrong, is that I have to rescan all the pics done so far ....

I then discovered that I was wrong again in my understanding about how the V750 selects the "super" res lens, if I got it right now it's the choice of transparency + film holder that triggers it, not the scan resolution. One can check it by the size of the prescan window, it's smaller and the size of the film and dias holders, not the full scan glass plate area.

I made some performance tests too using 3200, 4800 and 6400 ppi res, using iSRD (the IR 2nd cleaning pass).

The bit depth has no influence on actual scan times, I think the scanner always scans at 48 bit (16) and only converts to 24 (8) at the very end of the process.

The 1st pass is always the same duration, 1'10 for a 23.5 x 35.5 mm scan area regardless of the res used. The 2nd IR pass depends on the res and takes 1'50 with 3200, 2'20 with 4800 and 6400. Of course the proc time is really longer, about 3'40 with 4800 and up to 8'45 with 6400. that's where the real difference is.

And made various crops well verified this time and decided the best compromise for me is to scan at 4800 ppi and 24 bits, with the very effective IR clean pass, and leaving all the PP to PS. No changes necessary about colours as the scanner calibration was very effective too.

But for the time being I just rescanned the very first one, here is an HDTV sized version (1920 x 1080) :
Click on the (original) button to look at the full sized pics.

And the test crops :

Now waiting again more comments .......

PS: To Pete : yes my previous helicopter crops were wrong, I think I actually made a crop of the already reduced to 4000 px file ......
--
C&C welcome if ever there's a pic of mine posted above !
JJ.

Casio Exilim EX-V7
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