Features of a universal Filmscanner and why the Epson 700/800 has or has not.

[Bernard_L]

Hi Joshua,
Hi Berhard,
We know that the 4800/6400 dpi optical resolution is sampled. The Epson technical specs say, the scan unit consists of 2x3 (RGB) scanlines with each of 20400 pixel. The second linetriple has an offset of 1/2 pixel to the first triple and with this "optical sampling" the 4800 dpi (groundglass) and 6400 dpi (filmholder) resolution is reached.
But even with only one scanline-triple without oversampling there is a resolution of 2400 and 3200 dpi (half of oversampled). Why dont we get it, for me 3200 dpi net output would be enough. Is it the inferior "high quality" lens or what else?

regards
Rainer

As you guessed, it has to do with the lens. I am unable to say if the lens is "inferior". But the performance of the system is going to be limited by, separately, the optical resolution of the lens, and the sampling of the sensor.

there is a resolution of 2400 and 3200 dpi (half of oversampled). Why dont we get it,

Oversampling is not just moving the sensor in steps of half the pixel spacing (or offsetting the second row by 1/2pixel). The native pixel size may already be oversampling (i.e. be smaller than necessary) with respect to the true optical resolution; meaning the focal spot size from a point source, before discussing any sensor or pixels. From the V700 specs:

Optical Resolution: Epson Dual Lens System, 4,800 dpi and 6,400 dpi

In my book, that is NOT optical resolution. Just CCD pixel density. Optical resolution is a property of the lens.

And, on second thoughts, that V700 lens is (IMHO) not that bad. Quoting again from Epson:

Effective Pixels: 40,800x56,160 (4,800 dpi), 37,760x62,336 (6,400dpi)

Take the hi-res case 37,760x62,336. Decrease linear resolution by a factor of 4, to 1600dpi "only". Giving 9440x15584, i.e. 154 megapixels. When digicams started to push above 24 Mpx, it was said that Canon, Nikon, etc, would have to re-design their lenses to match the increased sensor resolution. What about 154 Mpx!!? And without distortion.

Some high-end flatbed scanners have addressed that issue --high pixel density and large scanning area; can't have both-- by scanning parts of the object (negative, prnt...) and splicing the pieces digitally. Same thing for some folks who scan their film with a digicam.

[Kiwi7475]

I really don’t expect Epson to produce a new higher capability scanner any time soon, and if they did, the price point would not likely be around 2k just based on how much new engineering would be required, the declining market for such higher capability, and current pricing of existing models (including the 12000xl series besides the V series).

The V700 came out in 2006, and the V800 and V850 in 2014, representing relatively minor evolutions over a period of 16 years.

IMO, a higher capability scanner would require a lot of new development in the optical/mechanical front, and is just not something that we have seen coming from Epson for many years.

That’s just my opinion, I do hope I’m wrong. I’d be first in line to buy it.

[Alan Klein]

I think a universal scanner is about as practical as a universal camera.
We need something quick and high quality (a step up from the Epsons, maybe coolscan quality) for scanning rolls of small and medium format film.
Then an upgraded Epson for medium and sheet films. If it must be universal, then a motor feed carrier for the Epson.

The Epsons could be improved by less plastic. A sheet metal construction would reduce static electricity greatly (and thus dust). I manage by keeping the scanner in a dust free darkroom, something most people can't do.

I don't have any problem with the resolution of the Epson for large format film. It would be nice to have more resolution AND speed for smaller film.

It would be nice to have a brighter light source either for more depth of field of focus, or more dynamic range in overly dense negatives.

When I got my V850, I calibrated the height of the various film holders. I was surprised by how important that was. You could really see the difference from one height setting to the next.

[Alan Klein]

It's nowhere near precise enough in construction - and the way it tries to squeeze resolution from the 1/2 pixel overlapping sensors & interpolating them together (not very well) will deliver a misleadingly high resolution (from an ultra high contrast chart) at very poor MTF. So, the 2200-2400ppi across the sensor is really only about 2x1200ppi + questionable interpolation. High MTF is critical to good scan results - and that overall transfer function is sensitive to both mechanical and optical components/ precision.



If it was built to much higher standards and used leadscrew rather than belt drive systems - and an optical path that is designed for high MTF over absolute resolution, then it might be a potentially good machine. The available length of linear scan sensors is why most of the high end flatbeds resorted to XY scanning & stitching.

Could a better machine be built? Unquestionably, yes. Could it be built for less than USD 10,000 selling price, I don't know - maybe if you could sell a lot of them & leverage newer manufacturing techniques. If it could deliver 1500ppi across the bed & 3-4000ppi down a narrower strip (6000ppi could probably be done, if the thing was well enough designed) at USB 3 speed, then it's potentially very good. Better yet if it automatically complies with how colour neg is supposed to be 'seen' by the paper and how colour transparency is supposed to be viewed (easily done with appropriate RGB LED and engineering). Autofocus and reliable focus calibration should not be difficult to implement either - if it's designed to quality, not price.

When you select higher dpi like 6000 over let';s say 2400, the speed has to slow down even if a new machine can reach that resolution. How long would it take to scan and 4x5 at 6000? WOuld it be worth the time spent?

[Alan Klein]

6400 dpi is not optical resolution; just marketing. That is obtained with high sampling (small steps) but because the optical resolution is 2200-2400, at 6400 successive samples are essentially repeats of the same data. In techspeak that is called oversampling.

Leaving marketing aside, the 2400dpi figure is obtained by scanning a resolution chart (there are other means, but let's keep it simple) and looking for the last (finest) patch with discernible lines. At that point, the contrast is almost zero. So even the technically correct figure of 2200-2400dpi does not match very well the perceived resolution. In techspeak one says that the modulation transfer function (MTF) drops to zero at the limit of resolution.

One way to improve the perceived resolution is sharpening (in techspeak MTF restoration). Meaning boost the response at the spatial frequencies below the resolution limit, where the contrast has dropped but not fallen to zero. Best done with unsharp masking (USM). Two parameters must be chosen properly: radius and amount. If done properly, a significant improvement in perceived shaprness is obtained. If overdone, it can be ugly: an image that "hurts the eyes", and, in extreme cases, bright rims around dark areas, and vice versa.

I do all sharpening in post.

[Alan Klein]

I really don’t expect Epson to produce a new higher capability scanner any time soon, and if they did, the price point would not likely be around 2k just based on how much new engineering would be required, the declining market for such higher capability, and current pricing of existing models (including the 12000xl series besides the V series).

The V700 came out in 2006, and the V800 and V850 in 2014, representing relatively minor evolutions over a period of 16 years.

IMO, a higher capability scanner would require a lot of new development in the optical/mechanical front, and is just not something that we have seen coming from Epson for many years.

That’s just my opinion, I do hope I’m wrong. I’d be first in line to buy it.

A better lens that automatically focuses on the film would be a huge leap in quality. Maybe a stronger lamp and better amplifier (more modern). CHangin lenses, amplifiers, and lamps won't change the basic structure. So it should be able to be done on the cheap. After all, the technology has advanced in 8 years.

Also, a film holder with less static doesn't attract so much dust.

They don't have to start from scratch. They could leave the rest of the machine the same.

[Kiwi7475]

A better lens that automatically focuses on the film would be a huge leap in quality. Maybe a stronger lamp and better amplifier (more modern). CHangin lenses, amplifiers, and lamps won't change the basic structure. So it should be able to be done on the cheap. After all, the technology has advanced in 8 years.

Also, a film holder with less static doesn't attract so much dust.

They don't have to start from scratch. They could leave the rest of the machine the same.

Alan, they have autofocus on the Expression series starting with the 10000xl back when it came out in 2004 (!!) what does that tell you about whether they will implement it in a V860 or V900 or whatever new model? Zero chance IMO. They haven’t done it in 18 years and they already had that technology ready to go!

Like the V line, the expression series has not seen more that minimal evolution in interfaces and lamps to LEDs since their inception.

[jp]

Like the V line, the expression series has not seen more that minimal evolution in interfaces and lamps to LEDs since their inception.

Part of my business is being a distributor of a niche of Japanese electronics. That includes having repair parts for 0-20 year old electronics equipment.

I would be confident in guessing that the change to LED in the Epson scanners is because the cold cathode fluorescent lamps (or it's corresponding power supply) probably became discontinued at some point, and some other minor parts have disappeared from production requiring some minor interface updates.

If a 2004 scanner had autofocus, surely the parts for that have disappeared or evolved into something totally different by 2022.

[Kiwi7475]

Part of my business is being a distributor of a niche of Japanese electronics. That includes having repair parts for 0-20 year old electronics equipment.

I would be confident in guessing that the change to LED in the Epson scanners is because the cold cathode fluorescent lamps (or it's corresponding power supply) probably became discontinued at some point, and some other minor parts have disappeared from production requiring some minor interface updates.

If a 2004 scanner had autofocus, surely the parts for that have disappeared or evolved into something totally different by 2022.

I don’t think so. The autofocus capability continued in the 11000xl and then with the 12000xl (which are all the minor evolutions of the 10000xl), which came out in 2017. You can still buy the 12000xl today, it is not out of production.

[Alan Klein]

Alan, they have autofocus on the Expression series starting with the 10000xl back when it came out in 2004 (!!) what does that tell you about whether they will implement it in a V860 or V900 or whatever new model? Zero chance IMO. They haven’t done it in 18 years and they already had that technology ready to go!

Like the V line, the expression series has not seen more that minimal evolution in interfaces and lamps to LEDs since their inception.

The fact that I received a request to review the V850 from Epson is interesting that they're interested in my comments. Something's up.