Don, the depth of focus clearly does depend on ones standard. I plotted the resolution as a function of distance from the platen for my V750 pro a couple of months back and put the plot in a previous thread. I added a copy above (I hope). Note some astigmatism with the scan direction but there is more DOF at the 10 to 12 um range than I would have expected. Of course this is only relevant for my machine but I suspect that most recent 750s' are quite similar.
Nate Potter, Austin TX.
My Epson 4990 sure doesn't have it. Maybe your Epson does? I didn't think any Epsons came with it out of the box but I could be wrong.Originally Posted by sully75
My 4990 doesn't have ANR glass either. I have gotten plenty of Newton's rings.
Sorry...didn't mean the scanner glass. The holder glass. I believe the holder glass on the dry mount better scanning holder is anti-newton. I'm not sure about the wet mount.
You do not seem to understand what I said. I see it has been explained better.
Thanks Nathan, that's why I use the Better Scanning adjustable film holders.
Don, the depth of focus clearly does depend on ones standard. I plotted the resolution as a function of distance from the platen for my V750 pro a couple of months back and put the plot in a previous thread. I added a copy above (I hope). Note some astigmatism with the scan direction but there is more DOF at the 10 to 12 um range than I would have expected. Of course this is only relevant for my machine but I suspect that most recent 750s' are quite similar.
Nate Potter, Austin TX.
Don
I'm not sure I understand. Nathan makes clear there is an area of about 0.5 mm where focus changes very little. What that has to do with BetterScanning holders escapes me.
Maybe I'm just being picky but:
1) I like my film to be as plano parallel as possible. BS holders provide that capability better than Epson OEM holders. You used the word 'almost' which rivals the word 'reasonable' for vagueness, but in the context of your post I don't agree that almost is okay or acceptable.
2) I do not like cropping my film which the OEM holders do. I attempt to compose to the very edge of the film. I like seeing the rebate in my scans. So for me OEM holders are inferior in two major ways.
3) There aren't any OEM holders larger than 4x5. So for 5x7 we have to use the wet film holder (either dry or wet). Over the years I've determined that purchasing the BS option gives me a productivity boost (compared to The Epson solution.)
4) For portfolio work I drum scan, even so I like getting maximum quality from Epson flat bed scans.
Don Bryant
Last edited by D. Bryant; 21-Sep-2010 at 04:41. Reason: Double Signature
You miss the point completely. Hi ho.
I think he meant that with Epson holders and supplied spacers you might or might not be at the 0.5mm sweet spot. If not, you're SOL, or have to use your DIY spacers. With BS holder you have more room to adjust and more precision, so you are sure to be able to reach the sweet spot.
Or perhaps I missed the point(s) as well
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