Resolution Comparison: Digital Sensors vs Film

Quick summary: a 35mm slide (Velvia/Provia) provides roughly 12 to 22 MP of useful detail in practice. A 24 MP Full Frame sensor often exceeds it; a 45 MP sensor (Z7 II/Z8/Z9) mainly oversamples the grain and provides greater processing latitude, without revealing much more subject information.

Are you digitizing your archives and finding your images look “soft” at 100%? That is normal: a modern sensor can see beyond the amount of useful information actually contained in 35mm film. Below, I explain the principles involved (MTF, lp/mm), my real-world tests and a gentle “de-graining” method to optimize the final rendering.

For more information about processing black-and-white negatives in Lightroom using a Full Frame camera, see this complementary guide: Digitizing black-and-white negatives with a camera + Lightroom.

For a complete comparison of the different scanning methods (flatbed scanner, dedicated film scanner, camera + macro lens), see: Scanning film photographs: comparison of the different methods.

Contents

• Resolution comparison
• A personal context
• Equipment and equivalents
• Technical basics: lp/mm & MTF
• How many useful megapixels for Velvia / Provia?
• Nikon Z sensors: 24 MP vs 45 MP
• Why scan at 45 MP?
• Why scans can look soft
• Gentle de-graining: a practical method
• What about medium format?
• Comparison summary
• Practical recommendations
• FAQ: digital sensors vs film resolution

Resolution comparison

How much useful detail can a properly exposed, sharp 35mm slide (Velvia/Provia) actually record compared with modern Full Frame sensors?

A personal context

While digitizing my Formula 1 slides from the 1990s, the result is revealing: at 100%, the grain is sharp, yet the image itself can appear soft. There are several reasons for this.

First, two digitization methods should be distinguished:

• Flatbed scanning: the rendering may appear slightly “milky” or less contrasty. The CCD sensor and diffuse lighting can reduce micro-contrast.
• Camera reproduction with a mirrorless camera: the result often looks punchier, sharper and more contrasty. This is due to:
  • modern lenses, which are highly corrected and can produce a clinical but very precise rendering;
  • and certain camera settings: disable automatic sharpening, desaturate the Picture Control, work in 14-bit RAW, use a low ISO setting (64/100) and neutral continuous lighting (5000–5600K, high CRI).

In all cases, a modern sensor may exceed the usable resolution of the film: subject detail stops increasing; only the grain becomes more visible.

Equipment tested & scope (specific examples + equivalents)

Why provide these details? To ground the comparison in real-world experience while extending the conclusions beyond the equipment used.

• Cameras used: Nikon Z8 (45 MP) and Z5 (24 MP).
• Digitization: camera reproduction using a JJC slide-copying attachment; Nikkor Z 50mm f/1.8 S and Nikkor MC 50mm f/2.8 lenses.
• Transparency films (E-6): Fujifilm Velvia 50 (ISO 50) and Provia 100F (ISO 100), with results comparable to other fine-grain transparency films when their characteristics and shooting conditions are similar.

Resolution equivalents (comparable results):

• ≈ 24–26 MP Full Frame: Nikon Z5/Z6, Canon R6/R8, Sony A7 III/A7c…
• ≈ 45–50 MP Full Frame: Nikon Z7 II/Z8/Z9, Canon R5, Sony A1… (with a tendency to oversample the grain if capture or processing pushes micro-contrast too far).

These conclusions broadly apply to Full Frame cameras around 24, 36, 45 MP and beyond, regardless of brand. When digitizing with a DSLR, use mirror lock-up or Live View/EFCS, a 2–10 second self-timer or remote release, and a stable tripod to eliminate micro-vibrations.

The comparison concerns useful resolution — the ability to reproduce fine subject detail and contrast — rather than pixel count alone. For digitization methods (flatbed scanner, dedicated film scanner, camera reproduction), see my detailed film scanning comparison.

Technical basics: lp/mm & MTF explained simply

What does “useful resolution” mean in photography? To go beyond pixel counts, we use concepts such as MTF, which describe how well a system reproduces detail and contrast.

lp/mm (line pairs per millimeter) measures how fine a pattern a medium can resolve: the higher the number, the tighter the alternating light and dark lines that can still be distinguished.

MTF (Modulation Transfer Function) measures the ability of a system (film + lens + digitization, or sensor + lens) to transmit the contrast of increasingly fine patterns. The closer the MTF is to 1, the better contrast is preserved; as it approaches 0, fine detail becomes progressively harder to distinguish.

• MTF10 (≈ resolution limit): the pattern can still be distinguished, but with very little contrast.
• MTF50 (≈ perceived sharpness): the spatial frequency at which contrast has fallen by half; this is more closely related to the “sharpness” we perceive visually.

In practice: to judge overall sharpness, MTF50 is particularly useful; for extreme fine detail, MTF10 is more relevant. This helps explain why a 45 MP Full Frame sensor can look sharper than a Velvia or Provia slide: its MTF remains higher at fine spatial frequencies, while film contrast falls progressively because of grain and light diffusion within the emulsion.

In simple terms: film may still “resolve” extremely fine patterns near its limit, but with very low contrast. A digital sensor uses discrete pixels but can preserve stronger contrast up to its own sampling limit. This is one reason why a 24 MP digital file can appear sharper than a slide scanned at a very high resolution.

Important: a film’s resolving power also depends on the contrast of the test target used to measure it. The figures published by manufacturers can therefore vary considerably depending on test conditions. Fujifilm, for example, specifies 60 lines/mm for Provia 100F with a low-contrast 1.6:1 target, but 140 lines/mm with a very high-contrast 1000:1 target. For Velvia 50, the corresponding values are 80 and 160 lines/mm.

The values used below to estimate useful detail deliberately refer to the low-contrast measurements. They are more representative of a photograph containing tonal subtleties than of an extreme black-and-white laboratory test target.

How many useful megapixels for Velvia / Provia?

To obtain an order of magnitude that can be compared with a digital file, I use Fujifilm’s resolving-power figures measured with a low-contrast 1.6:1 target. The conversion assumes digital sampling of at least two pixels per line pair and therefore should not be interpreted as an exact equivalence between film and a digital sensor.

• Provia 100F: 60 lp/mm at 1.6:1 → 4320×2880 px ≈ 12.4 MP
• Velvia 50: 80 lp/mm at 1.6:1 → 5760×3840 px ≈ 22 MP

In practice, a properly exposed, sharp and carefully digitized 35mm slide therefore generally provides around 12 to 22 MP of useful detail. The much higher values measured with very high-contrast targets represent a laboratory resolution limit and should not be converted directly into the “useful megapixels” of an ordinary photograph.

With medium format, the larger film area greatly increases the potential amount of detail. Applying the same 60 and 80 lp/mm values strictly to the approximate film dimensions gives the following theoretical orders of magnitude:

• 6x4.5 medium format: around 33 MP at 60 lp/mm and 59 MP at 80 lp/mm.
• 6x7 medium format: around 56 MP at 60 lp/mm and 100 MP at 80 lp/mm.

These figures represent a theoretical sampling potential, not a guaranteed amount of subject detail in every photograph. In practice, the taking lens, aperture, focusing accuracy, camera stability, processing and the quality of the digitization usually reduce the amount of detail that can actually be extracted.

Nikon Z sensors: 24 MP vs 45 MP

• Z5/Z6 (24 MP): 6000×4000 px (~4230 dpi across 36×24). Generally above a well-scanned 35mm slide in usable detail.
• Z7 II/Z8/Z9 (45.7 MP): 8256×5504 px (~5830 dpi). Often oversamples the slide: more processing latitude, but not necessarily more subject information.

Why scan at 45 MP?

If a slide contains only around 12–22 MP of useful detail, why digitize it with a Z7 II, Z8 or Z9 at 45 MP?

• For fine local retouching: range masks, correction of small elements, etc.
• For long-term archiving: digitize once, process several times.
• For large-format printing: even if the grain is oversampled, a richer file can provide cleaner interpolation for printing.
• To smooth grain through controlled downsampling: reducing the file later to 24–30 MP can produce a very clean result.

In short: oversampling provides greater workflow flexibility and processing latitude.

Why scans can look “soft”

• The film does not contain additional subject information: higher resolution increasingly records the grain rather than more image detail.
• Flatbed scanners do not always reach their advertised optical resolution in practice.
• Viewing the file at 100% may correspond to examining the equivalent of a very large wall print (120×180cm or more), which makes this softness much more obvious.

For capture and lighting methods (JJC slide copier, camera + macro lens), see the detailed digitization comparison already published.

Gentle de-graining: a practical method

Context: digitization with a Nikon Z8 using a 50mm f/1.8 S + extension tubes or MC 50mm f/2.8 in a JJC slide copier produces very contrasty grain. The goal is to soften it without losing subject detail.

1. At capture: ISO 64/100, 14-bit RAW, electronic shutter, diffuse LED lighting (CRI ≥95) at 5000–5600K, and perfect parallel alignment. Avoid adding local contrast (Clarity/Texture) on import.
2. In Lightroom / ACR (starting point):
   • Sharpening: Amount 10–20, Radius 0.8–1.0, Detail 0–10, Masking 60–90 (hold Alt/Option to restrict sharpening mainly to subject edges).
   • Noise Reduction: Luminance 5–15 (low), Detail 30–50; Color 5–10.
   • Optional: Texture −5 to −10 on flat areas, using a Luminance Range mask to preserve subject edges.
3. In Photoshop:
   • Duplicate the layer → Filter > Noise > Dust & Scratches, Radius 2–3 px, Threshold 2–5 → use a layer mask to target skies and flat areas.
   • Alternative micro-smoothing: layer in Luminosity mode + Gaussian Blur 0.3–0.5 px → paint through a mask over the grainiest areas.
   • A slight downsample to around 5000–6000 px wide for a slide can reduce the prominence of the grain without sacrificing useful subject detail.

Important: Lightroom’s AI noise reduction is designed primarily for digital sensor noise. Film grain is part of the actual image structure, so a controlled, localized softening approach is generally preferable.

What about medium format?

Moving to medium format is often imagined as an automatically decisive improvement in image quality. The reality is more nuanced:

• A 24 MP Full Frame digital sensor already generally exceeds a well-scanned 24x36 slide in useful subject detail.
• A 45 MP digital sensor is in roughly the same range as the theoretical potential of fine-grain 6x4.5 film measured at low contrast. Depending on the film, lens, shooting technique and digitization method, either may preserve more usable detail.
• 6x7 film has a higher theoretical potential because of its much larger surface area: around 56 to 100 MP in the extrapolation above. That potential is not automatically present in every photograph.

Why? Because these values assume very favorable conditions: high-quality lenses, excellent stability, precise focusing, an appropriate aperture, rigorous processing and digitization capable of extracting the information present in the film.

A poorly exploited 6x7 negative may therefore contain less usable detail than a good high-resolution 24x36 digital image, while a technically excellent 6x7 photograph may clearly exceed the capabilities of a 45 MP sensor.

Also worth reading: resolution is not the only factor that differentiates formats. To understand how medium format, Full Frame, APS-C and smaller sensors change framing and depth of field, see my focal length and aperture equivalence calculator according to sensor size.

If you are not a professional working in advertising, beauty, still life or another field requiring extreme resolution, do not allow yourself to be overly influenced by some YouTube recommendations.

Today, a used Nikon Z7 II or D850 (around €1,800) already provides considerable resolution and can produce large fine-art prints fully suitable for gallery presentation. Moving to film or digital medium format therefore does not, by itself, guarantee a visible improvement for every use.

Comparison summary

• Velvia / Provia 35mm: around 12–22 MP of useful detail when using low-contrast resolving-power measurements.
• 24 MP Full Frame: generally exceeds a well-scanned 35mm slide in usable detail.
• 45 MP Full Frame: often oversamples 35mm film; useful for fine retouching, archiving and subsequent downsampling.
• 6x4.5 film: theoretical potential of around 33–59 MP using a resolving power of 60 to 80 lp/mm at low contrast.
• 6x7 film: theoretical potential of around 56–100 MP under the same assumptions, although the amount actually usable depends heavily on the entire capture and digitization chain.

Practical recommendations

• Digitization: Full Frame camera + macro lens, even lighting, perfectly flat film.
• Workflow: work in batches, keep RAW + XMP files, and document your settings.
• Prints: up to 40×60cm, a clean 24 MP file is generally sufficient; for larger prints, aim for high-quality oversampling and gentle de-graining.

FAQ: digital sensors vs film resolution

How many “useful megapixels” can a 35mm slide really contain?

In practice, a good 24x36 Velvia or Provia slide provides around 12 to 22 MP of usable detail when the comparison is based on resolving-power figures measured at low contrast. Beyond that, additional resolution increasingly records grain texture and the optical limitations of the system rather than a clear increase in subject information.

Why do manufacturers sometimes quote much higher resolution figures for film?

Resolving power depends strongly on the contrast of the test target. Fujifilm, for example, specifies 60 lines/mm for Provia 100F at low contrast, but 140 lines/mm at very high contrast. These extreme figures indicate that a highly contrasted pattern can still be separated, but they do not directly correspond to the amount of useful detail in an ordinary photograph.

Why does a film image look “soft” at 100% on a modern screen?

Because 100% viewing often corresponds to examining the equivalent of a very large print. A modern high-resolution, high-contrast digital capture reveals grain, micro-diffusion and the fall in contrast at high spatial frequencies. Film can resolve fine detail, but with lower contrast near its limit, producing a less “clinical” perception of sharpness.

Can a flatbed scanner make a slide look less sharp than camera reproduction?

Yes, frequently. Flatbed scanners can produce a softer result because of lower micro-contrast, more diffuse illumination and an effective optical resolution that may be lower than the advertised figure. Camera reproduction with a modern lens and controlled lighting often produces a punchier file, without creating additional subject information if the slide has already reached its useful resolution limit.

If 24 MP is enough, what is the point of digitizing at 45 MP?

A 45 MP capture mainly improves workflow flexibility: more latitude for local corrections, additional archival margin, and the option of reducing the file later to 24–30 MP for a cleaner result. The most visible benefit often lies in processing flexibility and final-file cleanliness rather than in a dramatic increase in subject detail.

Why is film grain more visible with a high-resolution sensor?

A higher-resolution sensor oversamples the structure of the film. If sharpening, local contrast or texture are pushed too far, the grain becomes very prominent and can interfere with the subject. Gentle localized de-graining and strongly masked sharpening help preserve useful detail while reducing the visual prominence of the grain.

What simple settings can improve the rendering without altering the character of the film?

A good starting point is to avoid tools that aggressively break up the grain, such as excessive noise reduction or strong Clarity/Texture adjustments. Instead, use low sharpening with strong masking, supplemented by targeted softening of flat areas. A slight resize to an output resolution appropriate for the intended use, whether screen or print, often produces a more natural result.

About the author

Sebastien Desnoulez is a professional photographer based in Paris, specializing in architectural, landscape and travel photography. Trained in photography during the mid-1980s, he covered Formula 1 races and produced photographic reports around the world before devoting himself to demanding fine-art photography combining composition, light and emotion. He also shares his technical experience through practical articles for photography enthusiasts, drawing on a strong visual culture developed through both film and digital photography.

All the photographs displayed on this website are copyright protected © Sebastien Desnoulez. No use is permitted without the author’s written authorization.
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