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> A modern full-frame DSLR sensor has greater resolving power than normal medium-format film. Scanned at 5,300dpi (which seems to be the higher end offered by

> A modern full-frame DSLR sensor has greater resolving power than normal medium-format film. Scanned at 5,300dpi (which seems to be the higher end offered by negative scanning services), my medium format 6cm square negative yields a 156 megapixel image. [1] I'm not aware of any crop sensors offering comparable resolution, in fact this round-up of current cameras seems to suggest <50mpx is more likely and I'm sure some of those are "full frame". [1] https://www.pixelcalculator.com/?round=&FORM=1&DP=1&FA=&lang=en&mm1=60&mm2=60&dpi1=5300&sub1=+calculate+#a1 https://www.pixelcalculator.com/?round=&FORM=1&DP=1&FA=&lang... [2] https://www.practicalphotography.com/group-tests-articles/2016/8/24/6-best-dslr-and-csc-cameras-with-super-high-resolutions https://www.practicalphotography.com/group-tests-articles/20...

jdietrich 8y ago
I could scan a blank piece of card at 156 megapixels, but that card wouldn't contain 156 megapixels worth of information. You're scanning discrete particles of silver metal, which are effectively opaque and have a finite size. Shoot a test chart and you'll see what film is actually capable of resolving.
- bluedino 8y ago
  Is there a 'Nyquist theorem' that applies to photography?
  - e12e 8y ago
    Yes, the Nyquist theorem? https://photo.stackexchange.com/questions/10755/what-is-the-nyquist-limit-and-what-is-its-significance-to-photographers https://photo.stackexchange.com/questions/10755/what-is-the-...
  - phicoh 8y ago
    Basically, to make a film 'faster' you capture phonons from a larger area. Or the other way around, film that can resolve very fine details needs a lot of light. Film has a built-in low pass filter. Typically 'sampling' in film is random enough that you can capture very fine detail if the contrast is high enough. It behaves quite differently from digital sampling techiques. For this reason, you want to scan film at a very high resolution. But that doesn't mean that the image actually contains a huge of informaion.
yodon 8y ago
Scanning at 5300 dpi or 156 megapixels doesn't mean you have that much resolving power (I can scan a negative taken with a cheap lens at any resolution I want but that doesn't mean I magically get massive resolving power out of my crappy camera and lens). When scanning traditional film you generally want to scan at significantly above the resolving power to capture all the grain structure and other analog characteristics of the film medium. The easiest way to measure your resolving power is to print a black and white pinwheel - a large number of alternating black and white pie slices around a circle (more pie wedges is better). Pull your camera back and take a photo. Zoom into the pixels of the photo looking for the point near the center where the black and white regions stop being black and white and turn into a gray. Measure the diameter of the gray circle and use the diameter to compute the circumference (measure in pixels, then use the info about your sensor or scanner to convert from pixels to mm). Count the number of black pie slices and divide by the circumference to get your resolution. For extra fun try opening up one of your lenses to its maximum aperture and then compare the results to the same lens stopped down to f/16 or something like that - it's much easier to make a lens that performs well at a small apertures than large ones, and zoom lenses are harder to design well than fixed focal length prime lenses. To get really trippy, just look at the pinwheel with your eye, and you can use the same technique to measure the angular resolving power of your eye (using your distance from the chart to measure the diameter in angular degrees rather than in mm).
aeturnum 8y ago
Depends on the scanner! The "listed" DPI targets for scanners often aren't realized in practice. Take a look at the "image quality" section of this plustek optifilm review [0]: this one is actually very good. It's common for the "best" quality to come from scanning at 6,000+ DPI and downscaling to get ~3,000 effective DPI. In practice, it's a _lot_ of work to get more than 3,200 DPI out of a 120 negative. You can certainly do it if you wet mount and use a flextight X5 scanner [1] (list price $23,000). There's also the question of how fine the grains are in the film emulsion you're using. If you use ISO 50 film, you're likely to get more than 3,200 DPI of detail in the negative, but you don't have unlimited detail! Faster films have bigger grains - that's why they're faster! So just keep in mind that the amount of detail you can extract is a combination of the following: how much detail the lens transmits, how much detail the photographic medium records and how much detail the digitization process retains. Digital cameras are a handy hack in that the photographic medium and digitization process are one step! Film is more complex. [0] https://www.filmscanner.info/en/PlustekOpticFilm135.html https://www.filmscanner.info/en/PlustekOpticFilm135.html [1] https://www.hasselblad.com/flextight-x5/ https://www.hasselblad.com/flextight-x5/
- paulmd 8y ago
  The easiest way is to print optically rather than digitally. A midrange enlarger lens is easily capable of outperforming a high-end scanner, and high-end apo enlarger lenses are still top dog. Avoiding the quantization inherent to pixel-based formats makes it much easier to deliver resolution to paper.
  - aeturnum 8y ago
    I agree that there are good aesthetic reasons to avoid digitization all together (or even just digitize prints). Color correction with scanned negatives can be a true nightmare if you want to preserve the look you would get with a traditional print. Personally, I've always shared pictures primarily through the internet and so traditional printmaking has been less attractive.
    - paulmd 8y ago

jdietrich 8y ago

I could scan a blank piece of card at 156 megapixels, but that card wouldn't contain 156 megapixels worth of information. You're scanning discrete particles of silver metal, which are effectively opaque and have a finite size. Shoot a test chart and you'll see what film is actually capable of resolving.

bluedino 8y ago
Is there a 'Nyquist theorem' that applies to photography?
- e12e 8y ago
  Yes, the Nyquist theorem? https://photo.stackexchange.com/questions/10755/what-is-the-nyquist-limit-and-what-is-its-significance-to-photographers https://photo.stackexchange.com/questions/10755/what-is-the-...
- phicoh 8y ago
  Basically, to make a film 'faster' you capture phonons from a larger area. Or the other way around, film that can resolve very fine details needs a lot of light. Film has a built-in low pass filter. Typically 'sampling' in film is random enough that you can capture very fine detail if the contrast is high enough. It behaves quite differently from digital sampling techiques. For this reason, you want to scan film at a very high resolution. But that doesn't mean that the image actually contains a huge of informaion.

yodon 8y ago

Scanning at 5300 dpi or 156 megapixels doesn't mean you have that much resolving power (I can scan a negative taken with a cheap lens at any resolution I want but that doesn't mean I magically get massive resolving power out of my crappy camera and lens). When scanning traditional film you generally want to scan at significantly above the resolving power to capture all the grain structure and other analog characteristics of the film medium. The easiest way to measure your resolving power is to print a black and white pinwheel - a large number of alternating black and white pie slices around a circle (more pie wedges is better). Pull your camera back and take a photo. Zoom into the pixels of the photo looking for the point near the center where the black and white regions stop being black and white and turn into a gray. Measure the diameter of the gray circle and use the diameter to compute the circumference (measure in pixels, then use the info about your sensor or scanner to convert from pixels to mm). Count the number of black pie slices and divide by the circumference to get your resolution. For extra fun try opening up one of your lenses to its maximum aperture and then compare the results to the same lens stopped down to f/16 or something like that - it's much easier to make a lens that performs well at a small apertures than large ones, and zoom lenses are harder to design well than fixed focal length prime lenses. To get really trippy, just look at the pinwheel with your eye, and you can use the same technique to measure the angular resolving power of your eye (using your distance from the chart to measure the diameter in angular degrees rather than in mm).

aeturnum 8y ago

Depends on the scanner! The "listed" DPI targets for scanners often aren't realized in practice. Take a look at the "image quality" section of this plustek optifilm review [0]: this one is actually very good. It's common for the "best" quality to come from scanning at 6,000+ DPI and downscaling to get ~3,000 effective DPI. In practice, it's a _lot_ of work to get more than 3,200 DPI out of a 120 negative. You can certainly do it if you wet mount and use a flextight X5 scanner [1] (list price $23,000). There's also the question of how fine the grains are in the film emulsion you're using. If you use ISO 50 film, you're likely to get more than 3,200 DPI of detail in the negative, but you don't have unlimited detail! Faster films have bigger grains - that's why they're faster! So just keep in mind that the amount of detail you can extract is a combination of the following: how much detail the lens transmits, how much detail the photographic medium records and how much detail the digitization process retains. Digital cameras are a handy hack in that the photographic medium and digitization process are one step! Film is more complex. [0] https://www.filmscanner.info/en/PlustekOpticFilm135.html https://www.filmscanner.info/en/PlustekOpticFilm135.html [1] https://www.hasselblad.com/flextight-x5/ https://www.hasselblad.com/flextight-x5/

paulmd 8y ago
The easiest way is to print optically rather than digitally. A midrange enlarger lens is easily capable of outperforming a high-end scanner, and high-end apo enlarger lenses are still top dog. Avoiding the quantization inherent to pixel-based formats makes it much easier to deliver resolution to paper.
- aeturnum 8y ago
  I agree that there are good aesthetic reasons to avoid digitization all together (or even just digitize prints). Color correction with scanned negatives can be a true nightmare if you want to preserve the look you would get with a traditional print. Personally, I've always shared pictures primarily through the internet and so traditional printmaking has been less attractive.
  - paulmd 8y ago