Shooting Slide Film
The more commonly shot negative films record an inverted, low-contrast image from which the final image is struck, a process designed to preserve detail in both the highlights and the shadows, and to allow for some leeway in adjusting brightness and contrast after the fact. Slide films on the other hand, offer basically no leeway. What you exposed for is what you get, and this can be tricky as slide films have very high contrast and very little latitude, with only a handful of stops separating muddy underexposure from irrecoverable, blown-out highlights. Your exposure needs to be precise, and mixed-lighting situations can be challenging. They also need a lot of light, with no current production film being faster than 100ASA. In exchange for these limitations, slide films offer gorgeously saturated colors, super-fine resolution, and the positive image needed for viewing and projection.
Current Slide Films
The following are the main currently-produced slide films. There are a few others, but these are reliable, available, look great, and can be processed with the common E6 process that most film labs offer.
Relatively accurate and naturalistic rendering of colors, while still having that saturated slide film look. Slightly more dynamic range than the Velvias. Has comparatively low reciprocity failure, so would be a good choice for long-exposure photography.
Vivid, exaggerated rendering of colors. Very limited dynamic range; highlights such as clouds tend to blow out in bright conditions. Has a magenta cast that can be beautiful but can also make skin tones quite reddish.
Vivid, exaggerated rendering of colors. Slightly more dynamic range compared to Velvia 100, noticeable mainly in overexposed highlights not blowing out as excessively. Slightly green cast.
Kodak Ektachrome E100 (new 2018 version)
I’ve only shot a handful of rolls with this one, so I may update these impressions after some more time with the film. It captures colors more naturalistically than the Velvias, but isn't quite as straightforwardly neutral as Provia; it's a little warmer, especially in the skin tones and reds/browns/tans. Notably, it seems to hold up very well when exposed at 200ASA and pushed by one stop.