Epson v700 or v750

[beichh4046]

I currently have a Microtek i900. I like the no glass feature. However, I'm having problems with it now with streaks going down my scans. I've tried cleaning and even contacted the company. I would be looking at $175-300 in repairs is what I was told. I'm betting on $300 and with the age and use of the unit I could very well have more problems down the road.

So, I've been thinking about just buying a new scanner. I've read many of the threads discussing the 700 and 750. I keep going back and forth after reading the posts.

I don't plan on doing wet mounting as I read it could be kind of messy if you don't know what you are doing.

I currently use the Silverfast AI 6 that came with the Microtek. I don't do any sharpening or color correcting with Silverfast. I only use it to set my white and black points. Everything else is done in Photoshop.

I mainly scan 2.25 x 2.75, 4x5, and 8x10s. Very seldom 35 mm.

With that said it seems the v700 is what I need. Am I missing anything? Want to make sure I'm not missing anything.

[sully75]

You should check out some wet-mounting videos. I don't think it's that big a deal. Never done it but it's not particularly intimidating after watching some youtubes...

[Leigh]

Epson has a feature comparison of the two scanners on their website.

I got the V750 due to the enhanced optics in high-res mode. It has two lenses, a separate one for high res.

- Leigh

[chuck94022]

Epson has a feature comparison of the two scanners on their website.

I got the V750 due to the enhanced optics in high-res mode. It has two lenses, a separate one for high res.

- Leigh

I too have the v750, for the optics, not for the wet mount capable holder. I would not use that one, for two reasons: 1) you have to mount on top of yet another piece of glass, so the scanner has to peer through two pieces of glass to get to your film; 2) the standard holders with the Epson do not allow the height to be fine tuned to the precise plane of sharpest focus.

I recommend the v750 (for the better optics), and purchase after market film holders from www.betterscanning.com. I have their wet/dry mounting station, which allows you to mount the film *under* the mounting station glass. Their holders also allow precise height adjustment, so your scan will be as precise as is possible. (I have no relationship with that company, by the way, I'm just a happy customer).

Regarding wet versus dry mounting, I think you will see small differences, not large. Wet is more work, and you may feel it is a waste of time for the small improvement. But that's a judgement call for you to make yourself.

[Tony Evans]

The 700 and 750 both have the same enhanced optics. Both are greatly improved with the BSH, mainly due to being able to finely adjust the focus height. With the ANR, also great for convenient wet scanning.

[Jim Becia]

You might check Epson's Clearance shop as both the 700 and 750 show up there every once in a while. I picked up a 750 (refurbished) a month or so ago at a pretty good price. It was $548 and free shipping. Jim

[Leigh]

The 700 and 750 both have the same enhanced optics.
The V750 has two lenses, one for the high-definition scanning mode. The V700 has only one lens.

That's one of the major differences between the two products. Says so right on the Epson website.

- Leigh

[beichh4046]

Thanks for all the replies.

I thought about the 750 and the high res mode. But, unless I'm remembering wrong, I'm capped on the size that I could use with it. Also, I have to ask myself, What am I going to need scanned at such a resolution to justify the price increase?

Now, if I could get one refurbished for roughly the same price then it becomes a no brainer.

[Tony Evans]

The V700 has the same dual lens set-up as the V750. The differences between them are the mounting system and the included software.
The V750 PRO has the same dual lens system, with improved coatings on the lenses and mirror, called "enhanced optics". Reviews I have read claim no noticable resolution improvement due to the coatings.

[chuck94022]

The V700 has the same dual lens set-up as the V750. The differences between them are the mounting system and the included software.
The V750 PRO has the same dual lens system, with improved coatings on the lenses and mirror, called "enhanced optics". Reviews I have read claim no noticable resolution improvement due to the coatings.

I do not believe Epson distinguishes between what you are calling v750 and v750-M Pro anymore. Your note implies there are three choices, as far as I know (and I bought one not long ago) there are only two - the 700 and the 750-M Pro. So you have a choice of a system without the "enhanced optics" (mirror and lens coating improvements) or not.

Regarding the quality difference: I am disappointed in the evaluations done by otherwise quite thorough reviewers. All appear to use the OEM holders, which are well known not to hold the film either flat or in the sharpest plane of focus. Unless you are very very lucky, you will need to shim your holders to get them to the perfect height. And still the film won't be acceptably flat (the plane of sharpest focus is very thin). As far as I know none of the mainstream reviewers have done this, so all their review results are suspect. (Additionally, the OEM wet mounting station requires that you mount the film *above* the mounting station glass, which adds to the already refracting glass on the scanner base.)

When I replaced my OEM film holders with the betterscanning.com mounting station, and I followed the directions to properly adjust the holder into the plane of sharpest focus, I saw an immediate and marked improvement in scans, even with just dry mounting under the mounting station glass. I have done experimental wet mounts but so far have not done sufficient testing to make a true judgement for myself on whether it is worth it (I don't have access to Kami or equivalent in my overseas location at the moment).

For large format scans, you may not care at all whether you can do a 1200 ppi or 3200 ppi scan. Most anything above 1200 will create more data than you need for 4x5 or above anyway. But still it's good to get the best quality you can right from the start.

[Tony Evans]

Chuck,

Thank you. Was not aware Epson no longer sells the V750 although used ones do come up for sale on this site and others occassionally. Agree with your comments on the BSH. On my V700, noticable provements in "apparent visual sharpness" as observed on my monitor with a finely scratched negative, came about in two steps.
1. Getting a BSH (my optimum height 3.75 mm, higher than the Epson max of 3.5 mm), then later,
2. Moving to Wet Scanning. Seems to also improve micro-contrast.
I acknowledge that these conclusions have not been verified in print tests.

[Ed Richards]

Just looked at the Better Scanning dry mounting system - you have to tape the film to the glass. I am usually pretty nervous about getting crap on my negatives. They recommend 3M magic tape, but even that will leave some residue. How do you clean the filter afterwards?

[photobymike]

The V750 has two lenses, one for the high-definition scanning mode. The V700 has only one lens.

That's one of the major differences between the two products. Says so right on the Epson website.

- Leigh

Thats why i picked the v750.... i get great scans at 12800 although large file size.... most of the time 6400

The v750 has coated optics also.... supposedly sharper at hi rez scans... B&H still shows the V750 in stock... just checked

[chuck94022]

Just looked at the Better Scanning dry mounting system - you have to tape the film to the glass. I am usually pretty nervous about getting crap on my negatives. They recommend 3M magic tape, but even that will leave some residue. How do you clean the filter afterwards?

Taping is not a big deal. You just put a little of the tape on the edge of the film, outside the image area. If you wet mount, depending on the fluid you use, you might just tape the outer mylar, not the negative itself.

In either case, my experience is that when you pull off the tape (I use some random Chinese clear tape, sorta like 3M magic tape) it comes off cleanly. Sometimes a tiny bit of glue stays behind, but it just rubs right off. In the worst case, there's always Edwal.

Dry mounting with tape is slower than using a holder, but it is far more precise in terms of control of flatness. While it might be slightly slower than using a holder, it isn't by much once you get the hang of it. I will say that the 4x5 OEM holders are the best holders of the OEM set. If not for the height issues, I'd be pretty happy with them because they are quick. But the smaller format holders are a royal pain. It is not easy at all to get a film with any curl to lay down well in those holders. It is much, much easier to just tape them down on flat newton glass.

With wet mounting, depending on the fluid system you use, you might not tape the negative at all. You might instead just tape the mylar. I think you probably need to tape with Kami, because the chemical dries so fast at the edges. But there are a couple of other fluids that probably will work better in this regard (I've not yet tried them). Check out Prazio fluid, it sounds interesting. Also, check this link for a discussion of alternatives to commercial fluids: http://www.photo-i.co.uk/BB/viewtopic.php?f=34&t=1873 .

Since I'm in China, I'm trying plain old lighter fluid and some generic mineral spirits. My biggest problem is getting solvent resistant tape (regular tapes get gummy when they touch these petroleum distillates. Also, I'm having a difficult time getting quality mylar or cellophane for the outside of the wet mount "sandwich". Thus, I'm mostly dry mounting with infrequent wet mount experiments when I have time.

[chuck94022]

One more thing: I do use the OEM 4x5 holders for "proof" scans. Lots of times I finish developing a sheet and I just want to do a quick scan to play with how I'll conduct post on it later. For that, a quick scan with the OEM holder is fine, I don't worry about the lesser sharpness, because at that point I'm making larger decisions about how I'll manipulate the image.

When I understand whether I like the shot and how I'll finish it, then I'll commit to a high quality scan with my best effort at cleaning, dusting, and mounting.

I've even done this step by photographing the negative on my light table using a Nikon D200, with its kit 18-200 lens fully zoomed. For proofing, whatever is quick is all I need.

[Tony Evans]

Leigh & photobymike,

Read my and chuck's posts. I can't believe this continuous posting of erroneous information.

[photobymike]

Leigh & photobymike,

Read my and chuck's posts. I can't believe this continuous posting of erroneous information.

Q:
What are the hardware differences between the Perfection V700 Photo and the Perfection V750 Pro scanners?
A:
The Perfection V750 Pro features an enhanced optical system (High Pass Optics). By using anti-reflective coatings on the CCD lens and a high reflection mirror (extra coating), the Perfection V750 Pro delivers better image quality and scans faster. The Perfection V750 Pro also offers a fluid mount accessory that allows photographers to perform wet scans on a flatbed scanner, which is especially valuable for enhanced scratch removal and grain reduction from black-and-white film.

The link below is Epson support website

http://www.epson.com/cgi-bin/Store/support/supDetail.jsp?BV_UseBVCookie=yes&infoType=FAQ&oid=66134&prodoid=63056500&foid=154463&cat=30989&subcat=30992

ok the truth strait from the manufacture.... i have had both and i can say with proof there is a difference in the scans they make..... well worth the extra shekels for the v750. It scans faster and at higher resolution ...the quality is noticeably improved on the higher resolution scans. Have several TBs of scanned film and scan almost every night... scanning now as i type ... i have 80 images i have to get done tonight and get them burned onto datadvd for customers...... I been on the phone several times with Epson for customer support, discussing the differences between both scanners.... The lenses are different..... they are coated and the v750 was built on a different factory... according to the Epson guy i talked to..... there are actually many differences between the two scanners including electronics.... been using Epson scanners since 2004 or 5 .... I have had a total of 6 of them.... sold one here on LF....

[photobymike]

The way to really make your V750 scan well is
1. clean glass front and back when you get new.
2. evenly torque glass back on the scanner... about 15 inch pounds evenly on all four sides....
3. dont move your scanner after you tighten glass on....
4. Betterscanniing.com!!!
5. dont let your cat sleep on the lid (cat hair allover)

I had a Nikon 8000 and a Konica Minolta scanner ... i like my Epson better ... never used the wet option....

[chuck94022]

I did a full set of tests today trying wet and dry mounting using the betterscanning holder. I also compared to the OEM holder. I do not have high quality wet mounting supplies in China, so I'm testing using the closest equivalent to Kami that exists here: lighter fluid. According to the MSDS for Kami, it appears to be a well cleaned lighter fluid. I'm using Zippo, the only stuff I can find here. It evaporates as fast as Kami, and left the slide very clean. So except for the fact that static could set my whole office on fire, it's not bad. :p

More importantly, I don't have the best quality mylar to cover the wet mount. I will need to keep searching here in Beijing. It is bound to exist somewhere.

With those constraints, I found that the difference between wet and dry mounting is very subtle. For all practical purposes, I think dry mounting on the betterscanner mounting station is good enough. I do think there are very small improvements with wet mounting, but they are very hard to see.

The difference between the OEM holder and the betterscanning holder is much more apparent.

I was going to upload the scan results, but for some reason the image uploader doesn't work. I'll post them somewhere and provide a link in a follow up note next time I am online.

[chuck94022]

Just looked at the Better Scanning dry mounting system - you have to tape the film to the glass. I am usually pretty nervous about getting crap on my negatives. They recommend 3M magic tape, but even that will leave some residue. How do you clean the filter afterwards?

Ed, I just got some Magic Tape here (some stuff is hard to find in China). Magic Tape leaves nothing on the negative. It came off very clean, no residue at all.

[thomas ciulei]

i got the 700 and quickly exchanged that for the 750.
the 700 had great problems with newton rings especially visible on 4x5.
also the bundled software of the 750 is a big upgrade compared to the 700 (no multiple scanning, very primitive dust removal).

overall a good scanner, the software silverscan is NOT optimized for multicore processors and somewhat buggy, and i was never able to install IT-8 target with EZ colour on Mac 8-core.

[chuck94022]

I was unable to get the EZ Color or the Silverscan software to work on my Mac. I just use Vuescan.


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I am here: http://maps.google.com/maps?ll=40.023054,116.505169

[chuck94022]

Here are a few of the images from today's test scan. The first is a full scan at 1200 dpi, but I had to reduce it for this website. This image was orginally taken to test tilt, but it is a reasonable one to work with for mounting practice.

71947

There is an area of sharp focus along a strip of the pillow on the sofa in the background. The remaining scans focus on that.

The first one is a detail scan at 2400 dpi of the wet mounted slide. There is no visible difference between this one and the dry mounted one on the same betterscanning holder.
(Click the image for the full size image.)

71948

The second one is the same detail area from the OEM holder.

71949

Finally, this is a scan at 100 dpi, which should show how large the portion of the negative is that is being scanned (assuming you are viewing on a 100dpi monitor):

71950


It is really hard to tell from this post the difference in the images, but on my monitor, looking at them in Photoshop, the differences are significant. Also, scans at higher dpi (I've scanned the test up to 6400dpi) show clear differences in sharpness between the OEM and betterscanning mounts. But there doesn't seem to be any difference between wet and dry mounting.

[Ken Lee]

The 3M tapes (like Magic Tape) are acid-free.

[Tony Evans]

Photobymike,

I am referring to the erroneous statement (originally made by Leigh) that the V700 has only one lens while the V750 has two. Claiming that the V700 does not have the dual optical system is misinformation to readers. In fact they both have two and are used in exactly the same way. I have already mentioned the upgraded Holder & Software of the V750. The V750 "enhanced optics" BS refers to lens & mirror coatings, which as far as I can gather, only Epson claims is an improvement. I can find no independent reference or test confirming this.

[Tony Evans]

Chuck,

Re: Mylar. I have ton's. PM me and I will send you some.

[lbenac]

It is really hard to tell from this post the difference in the images, but on my monitor, looking at them in Photoshop, the differences are significant. Also, scans at higher dpi (I've scanned the test up to 6400dpi) show clear differences in sharpness between the OEM and betterscanning mounts. But there doesn't seem to be any difference between wet and dry mounting.

I have to say that for me it is impossible to see the difference between the two images. The second one is more contrasty. Depending on what software and setup you used for scanning there might have been sharpening already added to your scan.
From my part I have found that my V700 was the sharpest at the default lower position of the 4x5 holder so I was not really tempted to buy the BS holder.
I do have a BS holder with antiN glass for MF but as I have a Nikon 8000 I never really use it.

Cheers,

Luc

[photobymike]

Photobymike,

I am referring to the erroneous statement (originally made by Leigh) that the V700 has only one lens while the V750 has two. Claiming that the V700 does not have the dual optical system is misinformation to readers. In fact they both have two and are used in exactly the same way. I have already mentioned the upgraded Holder & Software of the V750. The V750 "enhanced optics" BS refers to lens & mirror coatings, which as far as I can gather, only Epson claims is an improvement. I can find no independent reference or test confirming this.

I cannot find a test that shows the difference either.... i just have my personal experience and feelings.... of many years of scanning... am still looking for the logical proof .But i do know that the v750 scans faster...and that is a big plus for me because of the production work i do........thanks

[Greg Y]

......maybe this scanner discussion should be in the digital hardware sub-forum? :confused:

[venchka]

Do either, or both, of the Epson scanners come with Epson Scan?

Wayne

[chuck94022]

I have to say that for me it is impossible to see the difference between the two images. The second one is more contrasty. Depending on what software and setup you used for scanning there might have been sharpening already added to your scan.
From my part I have found that my V700 was the sharpest at the default lower position of the 4x5 holder so I was not really tempted to buy the BS holder.
I do have a BS holder with antiN glass for MF but as I have a Nikon 8000 I never really use it.

Cheers,

Luc

Luc, yes you are right it is hard to see here. Maybe impossible. It is readily apparent in photoshop viewing the .dng files, but these images are .jpeg conversions. I disabled sharpening in the scanner and did no adjustments other than invert to make the image positive. I also don't know what the image upload process does here on this forum.

Suffice to say if one does this at home it will be easier to evaluate.

Glad you were fortunate enough to have a well adjusted scanner! I was not. I had to raise the holder significantly to get the scans sharp.

I think the bottom line for large format film is that even out of the box with OEM holders, the v700 is good enough for 4x5 and above. The scan ppi requirement is so low one just doesn't stress the capability of the scanner. It is only if you will also scan smaller formats (as I do regularly) that you will really appreciate the improvements of the 750 and the betterscanning holders.


---
I am here: http://maps.google.com/maps?ll=40.029159,116.510979

[Marc B.]

Leigh & photobymike,

Read my and chuck's posts. I can't believe this continuous posting of erroneous information.


Ditto. Agree with Tony; tired of erroneous info being repeatedly spread by mis-informed individuals.

Both the v700 & v750 have dual lenses. IIRC, that is what the 'V' stands for, (variable, or choice of lens).

[Marc B.]

Do either, or both, of the Epson scanners come with Epson Scan?


Wayne,
Yes. Both the v700 & v750 include 'Epson Scan' in the bundled software package.

See page 9:
http://www.bhphotovideo.com/lit_files/377.pdf

[venchka]

Thanks Marc. I actually went to the Epson page and confirmed that. As for the "V" prefix, Epson uses it for all of their flatbed film scanners.
Is it possible to force the higher quality lens to be used for 4x5 or larger film sizes? Or does it happen at a certain dpi setting? I generally scan B&W at 1600 dpi. Will that setting enable the "good" lens?

Thanks!

Wayne

[Marc B.]

Wayne,
I haven't been able to do that. However, I currently have my v750 in a state of dis-assembly.
I am attempting to convert my v750 into a glassless scanner.
I sourced another piece of glass for the bed, and am working with a stained glass artist.

Her skills (and glass grinding/cutting equipment) will enable me/her to cut a hole in the glass
exactly where, (and only where), the film holder places the 4 X 5 film. I purchased enough glass
to make another bed glass where I will cutout a space for side-by-side MF holders,
but again will use this mainly for 4 X 5: Two passes, then stitch in post processing.
This will enable use of the High-Res lens for 4 X 5.
Fingers and...toes, crossed.<grin>

Cutting the hole in the glass is akin to cutting a hole in a new kitchen counter top to receive a sink.
The scanner still needs glass around the perimeter to hold the film holders, and read the register marks
on the film holder, so 4 X 5 is probably about the largest the cutout will be. Maybe 5 X 6. I don't shoot 5 X 7.

Will be using the wet mount ANR(?) glass in the film holder, but will wet mount the film on
the bottom of the holder glass, emulsion side down (facing the lenses).

Hoping to have this up and running, with trials, by mid summer.

Marc

[buggz]

Please keep us updated, I'd like to know how this goes.
Thanks!


Wayne,
I haven't been able to do that. However, I currently have my v750 in a state of dis-assembly.
I am attempting to convert my v750 into a glassless scanner.
I sourced another piece of glass for the bed, and am working with a stained glass artist.

Her skills (and glass grinding/cutting equipment) will enable me/her to cut a hole in the glass
exactly where, (and only where), the film holder places the 4 X 5 film. I purchased enough glass
to make another bed glass where I will cutout a space for side-by-side MF holders,
but again will use this mainly for 4 X 5: Two passes, then stitch in post processing.
This will enable use of the High-Res lens for 4 X 5.
Fingers and...toes, crossed.<grin>

Cutting the hole in the glass is akin to cutting a hole in a new kitchen counter top to receive a sink.
The scanner still needs glass around the perimeter to hold the film holders,
so 4 X 5 is probably about the largest the cutout will be. Maybe 5 X 6. I don't shoot 5 X 7.

Will be using the wet mount ANR(?) glass in the film holder, but will wet mount the film on
the bottom of the holder glass, emulsion side down (facing the lenses).

Hoping to have this up and running, with trials, by mid summer.

Marc

[lbenac]

Wayne,
Her skills (and glass grinding/cutting equipment) will enable me/her to cut a hole in the glass
exactly where, (and only where), the film holder places the 4 X 5 film. I purchased enough glass
to make another bed glass where I will cutout a space for side-by-side MF holders,
but again will use this mainly for 4 X 5: Two passes, then stitch in post processing.
This will enable use of the High-Res lens for 4 X 5.
Marc

Hello Marc,

This sounds very interesting. A few questions/remakrs:
1) Would the lenses be in some way be optimized for the light going through the original glass?
2) Why cut the glass which sound complicated if the only purpose of the remaining glass is to support the holder and register the holder. Would a simple clear plastic cut to size be easier?
3) My undertsanding is that the use of the better lens is controlled by the software/driver i.e. if you select scanning with a holder it will use the better lens
I will definitly follow your project :-)

Cheers,

Luc

[Marc B.]

I thought about Lexan, Plexiglass, even Corian, but was worried about reaction to Kami (lighter) fluid.
Even though 'plastics' may work, I now have the ability to cut and dress the edges of the glass.
This will make for a more professional mod, and I want the heft (mass) that the glass will provide.

Do you put your left shoe on first, or your right shoe?
Either way works, just so long as the shoes match, and you get each shoe on the correct foot.<grin>

Marc

[Old-N-Feeble]

I mentioned removing the flatbed glass a couple years ago and everyone called me crazy. :D

[Marc B.]

O-N-F,
I'm sure some of the usual suspects will do the same here, (flame/burn the idea).

There are probably a dozen different ways to work this mod, and everybody will have different opinions.
When it's all said and done, it may just be a big waste of time; little or no benefit at all.
If so, I'll just put the original bed glass back on the scanner, returning it to factory normal.

So far, I've got the glass cut into three pieces to fit the Epson's bed frame, (with all four edges polished) and
I'm only out about $25. I enjoy DIY projects. Some results work...some don't, but it's fun.

Some folks may have flamed your idea of removing the glass, thinking you wouldn't be able to support
a film holder, or hadn't explained how you were going to support the film/holder.
Who knows? And, in many ways...who cares what others think or say? Just do it!

Marc

[Laurent L]

Hi !

I don't know what happens with Epson but since July 2013, the V750 pro is sold with silverfast SE 8 plus (here in europe) therefore since I decided to buy this so-called scanner for Xmas, I wonder why I should pay an extra 20 bucks just to get a caoted lens (which hasn't been proved better) and a anti newton glass.

Entering 2014 what should I buy ? isn't a V700 with a betterscanning a better choice than a bare V750 ?

Please help...

[Shootar401]

I have a V700 and it's a great scanner. I think the only difference between the V700 and V750 was a different film guide, but I'm not 100% sure.

I would get a V700 and a Better Scanning holder http://www.betterscanning.com/scanning/models/vseries.html

FYI I don't have the Better Scanning film holder, but it's on my list

[Laurent L]

Thanks Shootar

V700 and V750 are the same scanners, the only difference lays with the coated lens and anti newton glass for the most expensive, here in Europe the price gap between V700 and V750 is 200 dollars, IOW the price for a betterscanning system...

I have to make up my mind quickly, the french taxes are increasing in January.

[sanking]

Thanks Shootar

V700 and V750 are the same scanners, the only difference lays with the coated lens and anti newton glass for the most expensive, here in Europe the price gap between V700 and V750 is 200 dollars, IOW the price for a betterscanning system...

I have to make up my mind quickly, the french taxes are increasing in January.

I have used both of them, the V700 and the V750. There is not $200 difference in value IMO. I might pay $25 more for a V750, but certainly not $200 more.

Putting aside software bundles, the only difference between the V700 and V750 is that the V750 has an anti-reflection optical coating applied to the CCD glass. The lenses of both models are coated the same way and are identical.

Buy the V700 and get on with your new year. I hate to think how much more taxes will increase in France!!

Sandy

[Laurent L]

Thanks Sandy

I'm tired of wasting my time looking for informations about V700 V750, I should be in my darkroom processing my sheets instead ! That's why I will follow your advice et get myself a V700.

I will be able to enjoy my C41 and E6 4x5 and to share them here and there...

Mmmm I think 2014 is gonna be a good year

Best regards from France

Laurent

[Sanders]

We use a V750 and scan 35's, 6 x 6 and large format, using present holders and recommendations of Epsom. Perhaps Chuck can share the critical focus plane with us and what we need to do to get the perfect scan. Perhaps this should then be passed onto Epsom who will no doubt alert the media to the findings.

[Nathan Potter]

I've posted focus data and resolution data previously here but will summarize what I've found for my V750 PRO again since there has been a very high level of interest.

For best focus using the 4X5 Epson carrier (high res lens arrangement) the focus is known to vary from machine to machine but seems to fall within the 3 to 4 mm above the surface of the platen.
I've measured a depth of focus of about 2 mm at a resolution at 12 µm centered about 3 mm above the surface of the platen. Perhaps you can get a 1 mm depth of focus at about 9 µm. But most importantly that figure does not specify a contrast at that resolution, which is important when looking for a smooth gradient in tone at that high resolution. For my measurements shown in the plot below I used a Toppan repeating USAF type resolution target sloped on the V750 platen such that the patterns run in and out of focus by a micrometer measured amount.

http://farm5.staticflickr.com/4147/4989733373_1d5cc658b1_z.jpg (http://www.flickr.com/photos/argiolus/4989733373/)
V750RESjpg (http://www.flickr.com/photos/argiolus/4989733373/) by hypolimnas (http://www.flickr.com/people/argiolus/), on Flickr

You can draw your own conclusions from the plot but the general form of the DOF vs Resolution will be similar for all like Epson machines with the same lens design.

A following post below shows the V750 PRO resolution and contrast at the point of best focus for my machine.

Nate Potter, Austin TX.

[Nathan Potter]

Following is a resolution and contrast at that resolution plot for the Epson V750 PRO at the point of best focus for my machine (about 3 mm above the platen). Note the scan was done at 2400 DPI setting. I could only find a slight gain by scanning at higher DPI but did not take the time to quantify it.

Note the most important results. If you want 2500 DPI results you'll have to accept an abysmally low contrast of a few percent resulting in a severe compression of tones at that high resolution.
Really acceptable tonal ranges can be obtained at contrasts around 50% but the DPI drops to 1500 or so. Plot reproduced below.

http://farm7.staticflickr.com/6171/6154033421_f5c72e4169_z.jpg (http://www.flickr.com/photos/argiolus/6154033421/)
EPSONcont-web-1 (http://www.flickr.com/photos/argiolus/6154033421/) by hypolimnas (http://www.flickr.com/people/argiolus/), on Flickr

Again, draw your own conclusions.

Nate Potter, Austin TX.

[Heroique]

For best focus using the 4X5 Epson carrier (high res lens arrangement) the focus is known to vary from machine to machine but seems to fall within the 3 to 4 mm above the surface of the platen.

I've always been curious if the ideal height for the low res lens (for scanning 8x10) is actually above the platen, too.

It's supposed to focus on the platen, of course, but I suspect there's some variability among scanners w/ the low res lens, too.

For comparison, the ideal height for my 4990 (w/ its single, fixed-focus lens) is 2mm above the platen.

[Doug Fisher]

>>Perhaps Chuck can share the critical focus plane with us<<

As others have mentioned, this can vary for each scanner unit shipped so you have to test for the specific scanner that you own. I know people who have tested and said 2.5 mm was best. Others have said over 3 mm. It really varies.

Doug