Then you might also be interested in articles posted at https://clarkvision.com/articles/index.html
A good reference between film and digital with a lot of studies related to resolution.
I’ve read through that several times over the years. Quite a lot of interesting stuff.
Then you might also be interested in articles posted at https://clarkvision.com/articles/index.html
A good reference between film and digital with a lot of studies related to resolution.
Seemingly you post some nice references so how about the some of your own test results to show your point indisputably? Make it available for peer review.
You can review the comparison at https://www.filmscanner.info/en/EpsonPerfectionV800Photo.html
Effectively, the V800 is equal to the V850 and achieves slightly higher res then the V700. The V800 has better holders and faster scan times too.
If a scanner has a tested MTF that drops below 50% at under 14 cyc/mm, any contrast information on the film above 50% at 14 cyc/mm or more will be steadily more lossy in its transmission to the scanner.
You are a bit wrong, your Hasselblad X1 (when scanning 4x5") has not 50% MTF at 14lp/mm, it has 50% MTF at 15.75lp/mm. It is an small error but it is 15.57 and not 14
The X1 for 4x5" resolves 1575 dpi effective, in fact it matches its yield of 6300 for 35mm, 6300/4" is just 1575. This is total contrast extintion by 31.5 cy/mm and 50% MTF at 15.75cy/mm.
The Epson V700 resolves 55lp/mm (48 in the hor axis) at extintion from 35mm to 5.9" scan witdh (with ANR or equivalent holders), with a constant yield from the fixed lens that is always covering 5.9".
Instead the X1 varies its yield from the lens distance change (zoom in/out effect), delivering 126cy/mm at extintion for 35mm, 31.5cy/mm for 4x5" and 25cy/mm at extintion for 5x7". For 5x7" the X1 has 50% MTF at 12cy/mm.
The X1 is better for 35mm, the V700 is better for LF. For MF the X1 is slightly better but this is not much noticeable, if not stitching strips.
So last night, I got to thinking about how much resolution is actually needed to scan film.
And you ran an MTF test on an X1 when?
no real need. This is already done in many image formats. The luminance information is stored in full resolution and the chroma information is stored in less resolution.
I believe you have shot right past my point.
I'm proposing a different methodology for scanning a color negative to produce an image format. What I got from the article was that the grain resolution is far higher than the color resolution, suggesting a two-pass approach to the scanning process.
But then someone will come along and win a contest with an 8 bit JPEG that a Fuji Frontier spat out at 8x12" resolution.
Many scanners can do a multi-pass, it is a feature suported by SilverFast...
But in practice this won't be much worth.
Yes... but are you sure that the Frontier isn't cooking a 16bits/ch image before delivering a 8bits/ch result that has been treated with Image Intelligence?
8 bits are enough to print, and many images are perfectly described at 8bit depth, for example a portrait in the shadow with flat illumination.
Problem of 8 bits is that it does not allow to edit well extreme highlights and deep shadows, 8 bits depth has severe limitations for some images, and no limitation for other images.
As someone who scans 7 days a week for clients I can tell you I spend NO time thinking about MTF charts.
Total contrast extintion at 6300 dpi effective at 1", which is contrast extintion at 1575 when zooming out x4 to catch 4" instead 1 with the same lens and sensor. Our tests delivered an exact inverse proportional yield to the scan width, which at all is not a surprise. Is it a surprise for you?
As someone who scans 7 days a week for clients I can tell you I spend NO time thinking about MTF charts.
So many people get lost in techno jargon. Just set a target scan size that you need to achieve, and base that probably on the largest print size you're likely to make. When you make a scan, it should be roughly as detailed as you you expect it to be, with however much grain you also expect to see depending on the film. You can tell when your scanner is not up to the task (Epson) and when you may want to even doing a slight softening (Coolscan).
Lots of people will tell you that you need to have a 360PPI file that is a 16bit TIFF and (even better) is scanned pixel by pixel in some kind of drum scanner. But then someone will come along and win a contest with an 8 bit JPEG that a Fuji Frontier spat out at 8x12" resolution.
It should look right to your eye and your standards. That's about it! Knowing the most about optics, reproduction, and printing does not equal a great body of work (See: Ctein's portfolio). It goes a long way to know enough to be dangerous and stop there.
I'm sure this will be a post full of unpopular opinions.
A slight correction... well actually a fairly big correction to what you wrote. The Nyquist limit to resolve 125 lines per mm is 6450 ppi, which is double the figure you quoted. That is a lower limit to the sampling rate required, and as a practical matter a substantially higher rate would be required.
By the way, there is a subtle and seldom appreciated point with regard to the sampling theorem. The theorem says that if the sampling rate is at least as high as the Nyquist limit then it is possible to reconstruct the original sample without error. The theorem does not say that the sampled result is, in and of itself, an accurate representation of the original signal. To reconstruct the signal actually requires interpolating the raw data with a certain interpolating function to give more points. The correct interpolation function will produce a continuous function, but to get a good representation of the original function at discrete points requires resampling the reconstructed continuous function at discrete points, and the density of sampling points for the resampled result needs to be much higher than the Nyquist sampling rate. Otherwise, signals that are close to the Nyquist limit (but within the Nyquist limit) will be severely distorted. The correct interpolating function is based on the sinc function.
making a fine print (pretty easy with the right help).
8 bits per channel, for a 24 bit image, gives you 16 million colors to work with. Perhaps not the greatest tonal range, but still-- that's a lot of options.
Many subjects have a single hue and saturation
With the Plustek 8100 scanning at resolution 7200 is reputed to give about 3600 lppm true and 7200 is a preset option in the menu ,easy to use so no point in not using it.So to make a long story into a short question, if Fuji rates their film's resolving power at 125 lp/mm, which apparently translates to 3175 ppi, what's the benefit of scanning at a higher resolution?
It's a prima facie indicator that you've never used an Imacon/ Hasselbad nor seen the preview screen in Flexcolor. 6300ppi is delivered across a 32mm width.
But then again, you must ask yourself why you and you alone think the Epson V700 is worth defending against much more expensive & higher performing scanners in the face of voluminous evidence to the contrary.
I believe you have shot right past my point.
I'm proposing a different methodology for scanning a color negative to produce an image format. What I got from the article was that the grain resolution is far higher than the color resolution, suggesting a two-pass approach to the scanning process.
I'm pretty sure you're describing a monochromatic image. If you want to say similar, I'll agree that individual subjects (within a single photo) have a similar hue and saturation, sure. But that makes the argument *for* 8 bits per channel being sufficient, not against it.
Edit: Corrected poor phrasing
I think he was smiling at me first. ;-)Claude Shannon is smiling on you from the heavens afar, knowing you have good knowledge of information theory.
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