Scanning Resolution Question

[Corran]

...preferring to hide behind obfuscatory nonsense about sharpening & wrongheaded application of metrological techniques to regular photography.

Right.

...not to see who knows the more, IMHO.

Your behavior belies this.

I don't know why I even bother. Since this negative was still on the scanner I did a quick test. Scanned a tiny area at 3000 DPI, less than half an inch in width, and then scanned it with the boundaries set to the max width as if it was a full sheet of 4x5. Difference is minimal. Finally I scanned the small piece at 6000 DPI and resized down to 3000, which showed a small improvement. Note that this is 35mm on a tripod with a lens at f/11 - so an actual sheet of 4x5 will show less improvement due to diffraction at typical apertures of f/22 or smaller.



To be clear, yes scanning at a higher resolution in strips is better - I've done this many times when preparing files for printing very large. In practice, the resolution achieved even at 3000 DPI and with a full 4x5 sheet is far and beyond your claimed 1350 DPI and certainly better than an Epson. There's simply no argument here. I assume some sort of software/hardware trickery that you you or I are unaware of. Let's move on.

[Pere Casals]

Nor does he care to read anything that does not agree with his bizarre assertions - from the Seybold report: "The Cézanne’s result comes very close to the figures stated in the specifications. In this case, however, the interpolated result is even better, with lines visible at 120 lp/mm - beyond the manufacturer’s claimed resolution. This is surprising, and it differs from the results with the other scanners."

aka 6000ppi of real resolution... And he's still not able to understand why a Screen or a Hasselblad or a Heidelberg Tango will produce a vastly better 2000ppi scan from 4x5 than the Epson's nominal 2400, preferring to hide behind obfuscatory nonsense about sharpening & wrongheaded application of metrological techniques to regular photography.

Please quote a bizarre assetion of those.


Hasselblad or Tango will deliver a clearly better image than a V750 if dealing with velvia deep shadows. But I don't understand what difference is there for a 1.8D BW sheet. Really I don't see the way...


If scanning 8x10 then the V750 will deliver a pretty better image than with the hassy. Note that with X5 you will need scissors for 8x10

Then a Tango 8x10 scan is (or was) for several hundred $.


About Cezanne... you'll have nice results if stitching and stitching resulted ok.


Beyond this you can like more the Cezanne results and I can like more the V850.... for the rest MTF math is MTF math, so I see no discussion there.

[Pere Casals]

claimed 1350 DPI and certainly better than an Epson. There's simply no argument here. Let's move on.

Bryan, the Cezanne sensor has 8000 pix, the scanner lens zooms to see the 4" of the negative, so you have 2000 digital samples for each inch your 4x5 negative. this is a fact. Then you have a resolving power loss from the zoom lens and from digital sampling. Seybolt says that there a 1.5 loss factor, from 8000 to 5300.

This ends in around 1325dpi, optical, if not stitching strips, or course. Then the scanner firmware/driver makes a sharpening that delivers an improved look from the 1325 peformance, but this also limits the amount of sharpening you can later do with PS.

This is technical exact information, go and find a flaw in it.

If you are happy with you Cezanne I'm also completely happy with V750 results, do you think one may need more resolving power ?

[Corran]

You were just shown that it's not quite that simple. I am done debating this with you, there is no benefit.

[interneg]

Bryan, the Cezanne sensor has 8000 pix, the scanner lens zooms to see the 4" of the negative, so you have 2000 digital samples for each inch your 4x5 negative. this is a fact. Then you have a resolving power loss from the zoom lens and from digital sampling. Seybolt says that there a 1.5 loss factor, from 8000 to 5300.

This ends in around 1325dpi, optical, if not stitching strips, or course. Then the scanner firmware/driver makes a sharpening that delivers an improved look from the 1325 peformance, but this also limits the amount of sharpening you can later do with PS.

This is technical exact information, go and find a flaw in it.

6000ppi is 120 lp/mm, 5300ppi is about 105lp/mm. That is likely to be the design specification of the optical system - ie aimed to deliver 120lp/mm, but to understate the specifications in order that, no matter the sample variation, the specs are maintained. Now, when that lens zooms to cover 4x5 at 2000ppi, it needs to resolve approx 40lp/mm. See where this is going? In other words your linear scaling is wrong because you failed to consider lens design limitations at the higher end of resolution. Indeed, given your penchant for nonsensical waffle, if such a high resolving lens was sold for other uses, you'd be drooling inane phrases to praise its resolution.

[Pere Casals]

6000ppi is 120 lp/mm, 5300ppi is about 105lp/mm. That is likely to be the design specification of the optical system - ie aimed to deliver 120lp/mm, but to understate the specifications in order that, no matter the sample variation, the specs are maintained. Now, when that lens zooms to cover 4x5 at 2000ppi, it needs to resolve approx 40lp/mm. See where this is going? In other words your linear scaling is wrong because you failed to consider lens design limitations at the higher end of resolution. Indeed, given your penchant for nonsensical waffle, if such a high resolving lens was sold for other uses, you'd be drooling inane phrases to praise its resolution.

interneg, Lets make the math accurately:

2000/25.4 * 5300 / 8000 / 2 = 26 Lp/mm

Then if you try to resolve on film 26 Lp/mm detail with a 26Lp/mm system you'll have aliases, as always with any scanner.

But, gentlemen, on film 26 Lp/mm. This can be more than enough for our output... true, but 26. Then there is the stitching way...


Note that it is impossible to retain the 2000 value through the zoom lens, a 5300/8000 (Seybold) is a fair degradation factor. This is in the same way the 6400 V850 DPI ends in 2300-2800, even a worse factor.

[Pere Casals]

You were just shown that it's not quite that simple. I am done debating this with you, there is no benefit.

Bryan, there is no benefit, true. It is impossible to make you understand why you see similar Image Quality from a D800 than from a 4x5 sheet.

After you discredited the Joe Cornish's test, the Seybold report ...and Cezanne datasheet itself, I'm also not able to go further.


I'm happy with the V850, you are happy with the Cezanne, so this is a happy world.

In the other side, I've to say that I like your photograhs, I'm not able to match that by a large margin.

[Pali K]

Apples are not oranges but some oranges are apples

I said I was done but it's hard to stay out of another entertaining debate about scanners.

Bryan, I am pretty sure your scans are from an Epson because it clearly shows more DPI than 1325

Gotta love Pere's love for Epson.

Pali

[Pere Casals]

Apples are not oranges but some oranges are apples

I said I was done but it's hard to stay out of another entertaining debate about scanners.

Bryan, I am pretty sure your scans are from an Epson because it clearly shows more DPI than 1325

Gotta love Pere's love for Epson.

Pali

Hello Pali,

I'm happy to see you joining the pixel party. Entretainment is for sure .

Still we should debate more about 11x14" wood gear !

Pali, did you remember these posts:

http://www.largeformatphotography.in...=1#post1342349

http://www.largeformatphotography.in...=1#post1342352

Have you tried to apply best sharpening to both V750 and expensive flatbeds before comparing?

IMHO different scanners may apply different in hardware sharpening, so to make justice a way is to sharpen all samples to it's optimum before comparing...

Regards.

[Corran]

Apples are not oranges but some oranges are apples

I said I was done but it's hard to stay out of another entertaining debate about scanners.

Bryan, I am pretty sure your scans are from an Epson because it clearly shows more DPI than 1325

Gotta love Pere's love for Epson.

Pali

Well don't forget your popcorn. Or perhaps it's me who needs popcorn.

I just scanned a 6x9 image from yesterday @ 4500 DPI (roughly the max it can go in one go) which is a retake of my 35mm image from in the creek on Monday. Even looking at what equates to a 15x enlargement it looks fantastic. I am tempted to print this one humongous. I probably don't have the wallspace for a 60x40. On the other hand I am closing on my house in about 3 weeks and that would be a nice addition...

Anyway, [/blog]