One of the implications of moving from film capture to digital capture is that images tend to have a different “depth” or “presence”. This is probably because of the way light scatters through layers of emulsion as opposed to the way it hits a cold, hard, digital sensor.
I’m not referring to sensor crop, or any other lens aspect-based change. Rather, this is more about why digital images look “flatter” or resolve distance/light differently than their analogue equivalents. This article is more about lens design, but has little nuggets of information that apply in a this context:
The emulsion layer that holds the light sensitive silver halide grains has a certain thickness and contains up to twenty layers of grains, any one of which can be struck by photons and therefore is part of the latent image. Light rays that strike the surface of the emulsion layer at an oblique angle will travel through the depth of the gelatine layer and will be stopped by some grains in the lower layers. So the angle of incidence is no problem at all. Ideally the film plane should be plane, but film is never flat at the film gate and will bulge. But the depth of the emulsion layer and the depth of field tolerance will offset this state of affairs and optical designers can use this characteristic to compensate the problem of the curvature of field…
…The main characteristics [of a] sensor are the fact that the sensor is flat (plane), constructed as a discrete matrix of pixels and not transparent (has no depth). The flatness of the sensor is bad for the curved nature of the image created by the lens. The opaque nature of the sensor cells implies that the oblique angle of incidence of the light rays striking the sensor surface must be limited. Otherwise only a few photons will be captured. [link]
So to paraphrase: film scatters the light in a gooey, flawed (but nice), analogue sort of way, whereas a sensor is a bit more “clinical”… yes, wild, over-simplification…
An interesting footnote is the Foveon X3 sensor, which is built more like film - red, green and blue all layered on top of each other (other sensors are usually one layer, arranged like a checkerboard). Sigma markets a series of cameras which use this sensor. Supposedly, it gives a more “film-like” look, as well as less noise and a higher dynamic range than other sensors. I can’t tell, from what I have seen online.
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Another difference might be that SH grains vary in size, with every frame a different pattern, giving that soft gooey organic feel. There are some sensors that have mixed pixel sizes, but the eye is always going to resolve the digital noise out and leave the “blocky” fixed array. As Digital gets higher in res and lower in grain the difference just gets larger. Analogous to the problem with CG delivery ala FF,
These problems will only be exacerbated when Digital content is delivered Digitally also. Even now digital goes to film and when projected has film bulge and registration weave aberrations, to soften the “look”. When its all Digital, images are going to look very clinical.