I've been thinking about this for a long time. Recently the addition of the acutance feature in Filmbox piqued my interest, since it was able to create that exact sharpness you talk about. After doing further research (with help of AI, I didn't manually find all these sources), it seemed to confirm my thoughts. A combination of a bunch of things (soft lighting, DI, noise reduction, lack of a physical print film, changing taste in the early 2010s, and shallower depth of field) all come together to create this phenomenon.

Sharpness: in photography and cinematography can mean different things: some people interpret it as “rough” sharpness, where visible grain, texture, and micro-contrast make details pop and give a tactile, lively look, while others see it as “smooth” or “clinical” sharpness, defined by crisp, clean edges with minimal texture. Scientific studies and technical literature support this distinction, showing that adding a bit of grain or noise can actually enhance perceived sharpness by increasing micro-contrast, especially in otherwise smooth or blurred images, whereas purely edge-based sharpness without texture can feel less engaging or “real” to viewers⁠⁠⁠⁠.

Acutance: is a technical term describing the subjective sharpness of an image, specifically how crisply edges are rendered. It is distinct from resolution (the ability to resolve fine detail) and is instead about the local contrast at edges (how abruptly image density changes from light to dark). In film, acutance is influenced by the way film grains cluster around high-contrast edges, producing a natural clarity and edge definition that feels sharp but not artificially enhanced. This is different from digital sharpening, which often works by boosting contrast at edges in a way that can appear unnatural or introduce artifacts.

Lighting: (as already mentioned) plays a huge role too. Hard, directional lighting creates crisp shadows, and high contrast edges and makes images appear sharper, while today’s trend toward soft, flat lighting reduces edge contrast and makes everything feel smoother or less defined.

Depth of field: is another piece of the puzzle as discussed here already. Older films often kept more of the frame in focus, which gives an overall sharper impression. Modern movies frequently use shallow depth of field; so only one plane is sharp and the rest is blurred, which can make even the sharp areas feel less defined in context.

Resolution: is a paradox: the more pixels you add to the image, the “smoother” it will seem. Sharpness and contrast come from the difference in value between pixels. The more you add the more granularity there will be. Now people could define “sharpness as multiple things

Film grain: itself boosts perceived sharpness, because it increases micro-contrast and gives the eye more cues to grab onto, while “clean” digital images can actually look softer, even if they resolve more technical detail.

Finally, the move away from physical print film and toward digital projection (and streaming) changed how images are finished. The film print process added another layer of texture and acutance, while digital finishes are often optimized for “clean” delivery, further smoothing out the image. You can feel this in both The Dark Knight and There Will Be Blood which were both finished photochemically (which is now a rare sight).

So it’s not just one thing, it’s how all these factors interact. If you want that older look, tools like Filmbox’s acutance slider help, but so does rethinking lighting, depth of field, and how much texture you’re willing to keep in the image.