Focus variation on Epson V700

rjschell

rjschell

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I have found that my unit is sharpest when the film holder height tabs are removed and emulsion is down. Normal recommendation is tabs in zero position and emulsion up. Has anyone else experienced this?
 
Thanks, mfogiel. However, the Better Scanning holder is variable from 2.5 to 4.5 mm. My optimal point is about 2 mm.
 
Are you sure your film was flat in the holder (not sagging) and that you were scanning using the "film with film holder" setting in the software (check each time before hitting the scan button!). With that said, there are some scanners that are really out of specification. I will soon shift production to holders for the V7xx/8xx with a base height closer to 1.5 mm. Let me know if you need one now and I can make it happen.

Doug
 
rjschell said:
I have found that my unit is sharpest when the film holder height tabs are removed and emulsion is down. Normal recommendation is tabs in zero position and emulsion up. Has anyone else experienced this?
Click to expand...

My method too. I use the stock 35mm holder with the BetterScan 35mm glass and the BetterScan 120 holder with, of course, their glass.

I messed with the height but I was best with your formula.
 
I stand by my original observation that my scanner is sharpest with film holder tabs removed and emulsion down. Film in holder was flat, and I compared results with a scan off the glass.
Doug - your idea for a thinner holder is well taken, since 2mm is optimum for my unit.
Has anyone else had similar results?
 
Been awhile since I've done it but to scan 5x7 you place the negative directly on the glass. Just looked at the manual and it says when you do this to select Film (with Film Area Guide). Can't remember if I did or not.

When I first got the scanner I spend weeks changing the tabs to try and determine the proper setting. Finally decided it really didn't matter. The taking lens must have some depth of focus > 2 mm.
 
rjschell said:
I have found that my unit is sharpest when the film holder height tabs are removed and emulsion is down. Normal recommendation is tabs in zero position and emulsion up. Has anyone else experienced this?
Click to expand...

For me, I got the sharpest scans when I raised the holders to the maximum height and adding little pieces of thin cardboard under the foots of the holder, raising it about 2mm more.

This is with the 35mm holder. The 120 holder scan best at the «0» setting, and the 4x5 holder at the «+» setting.
 
There is only one best focus point for a scanner like these scanners that utilize a fixed focus lens. If you found you needed different height settings for each film format, then your film was/is not flat within the holder.

Doug
 
xvvvz said:
There is only one best focus point for a scanner like these scanners that utilize a fixed focus lens. If you found you needed different height settings for each film format, then your film was/is not flat within the holder.

Doug
Click to expand...

Sorry Doug, that's not true.
I've personally tested various V700 units, and each had a different optimal focus distance from the glass bed, because of assembling tolerances and component variations (i.e. actual focal length of lenses).
Fortunately, your adjustable holders have always been up to task in my case (enough excursion), but I can believe some users may have been unlucky.

Fernando
 
I think he meant each scanner has an individual optimal focus point, not that everyone is the same.

I've heard mention of occasionally checking the height and focus to see that it didn't change, which would mean the focus point can actually move over time, but I've only ever adjusted my Betterscanning holders once to get the optimal focus level and its seemed fine ever since.
 
I had the same issue with my v700 : the optimal position is below the lowest calibration height permitted with standard steppers.

Regards
 
rjschell said:
I stand by my original observation that my scanner is sharpest with film holder tabs removed and emulsion down. Film in holder was flat, and I compared results with a scan off the glass.
Doug - your idea for a thinner holder is well taken, since 2mm is optimum for my unit.
Has anyone else had similar results?
Click to expand...

I would buy a slightly thinner holder as long as I don't have to rebuy the glass. It is a little confusing as Better Scan already has a thin holder and a standard holder; it now sounds like there will be one in between.

EDIT: I'm talking about the 120 holder, sorry if I misled anyone.
 
After exhaustive, and exhausting, testing on my V850 I have found the middle position, and there is more range on the V850 holders, is best on 35mm and one step down on 120. It is possible the QC has been tightened for this new run of machines, or maybe its just luck!!

Have I missed anyone addressing the OP's question of emulsion up or down?

(I'm not testing again :rolleyes:)
 
Sorry, I missed or forgot the OP's question. I only use the emulsion down when the curve is such that I have to flatten with the glass. If I'm lucky enough to not have arching negatives then I scan emulsion up. But if you have the curve arching down you have the danger for the film touching the scanner glass which will create Newton Rings.
 
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