For the record, slide film has a smaller dynamic range than negative film.
However, it still held at least as much "data" as did negative film.
Therefore, there was much more detail in the image coming from a slide, but exposure latitude was not as forgiving. Blown highlights, and lost shadows were more likely with slide film. Overexposure in particular is much less of a problem with negative film, because there was a lot of headroom with negative film. Not so with slide film.
The way this compares to digital images is as follows:
Approximately the brightest 1/2 of the image data (i.e., the right side of the histogram) represents one stop. Therefore, the most image detail is in this area. Subtle variations between brightness are easily discernable.
The darkest 1/2 of the image data is divided up as if it was another image, like this:
* the brightest 1/2 of the remaining 1/2 of the image data (i.e., the upper half of the bottom half of the histogram) contains another stop of brightness data. There is slightly less detail, since not as much data is used to represent one stop of light.
The remaining quarter of the image data is divided up again, recursively:
* the brightest 1/2 of the remaining 1/4 of the image data contains another stop of brightness. There is significantly less detail, etc.
Let's assume that your image data is stored as 16 bits per pixel, and the primary part of your image is exposed at EV 16.
Then the top 8 bits contain a detailed view of the brightest one stop of the image from EV 16.0 to 16.9.
The next 4 bits contain a moderately detailed view of the next brightest stop of the image from EV 15.0 to 15.9.
The next 2 bits contain a poorly detailed view of the next brightest stop of the image from EV 14.0 to 14.9.
The final 1 bit contains a very low detail view of the darkest stop of the image from EV 13.0 to 13.9.
This is how it works, simplified, with "linear gamma."
All modern cameras use non-linear gamma systems to expand the dynamic range of linear gamma from the maximum of four stops to many more stops of dynamic range.
But the principle is the same.
If you want to get the most detail from your images, then the major area of your image's histogram should be towards the right.
Try taking a photo of a subject with little dynamic range, like a a square foot in the middle of a field of green grass. If the image is underexposed, the histogram will make a narrow band towards the left side. The size of the band represents the detail recorded from the grass.
If the image is properly exposed, the band will be a little bit larger showing that more detail is being recorded in the upper area of the histogram which is more detailed because more bits are used to record each stop of light.