i did not FUCKING realize that there was a split diopter shot in DEEP SPACE NINE, fully NINETEEN YEARS after 1975, the last year anyone could get away with a split diopter shot. you will begin posting your favorite / most jarring split diopter shots at this time
the split diopter is one of the nuttiest concepts in cinema history. it describes a lens that has two different focus distances, with a split down the middle. and you think "well how do you cover up the split" and the answer 90% of the time is "you don't."
split diopter shots are simply two separate half-width pictures, married at the center with a big, ugly blur where the halves meet. it looks like shit. it's absolutely arresting. you can't not notice it and you can't not wonder "what the fuck is that."
i don't know when they were invented, but IME they showed up a lot in the 60s and 70s and then mostly disappeared. there are better and worse ways to use them, and you'd think a lot of effort would have gone into making sure they got used in the better ways, but it did not. precious few movies bothered to hide the split.
look at the last shot above, from All The President's Men. i absolutely sussed out that this was a split diopter when I first saw it, but I can imagine that many people didn't, because they hid the blur in a part of the image that had relatively little interesting detail, and was mostly occupied by a column. this is the best case scenario. most other movies are the worst case.
they were used heavily in Star Trek The Motion Picture for some reason, and in fact the shot i attached isn't even the worst one, but it's always the one I think of.
like, I think I see what the director had in mind. he wanted what is usually called a "deep focus" shot, where the iris is closed to a nearly shut position, like f/32 or smaller, so you have sharp focus all the way from a couple feet in front of the camera to infinity. But they either built the set too small to move the camera back far enough, or they couldn't get enough light to use an aperture that small, so he went with this approach, and it just... doesn't work.
I don't have a copy of the movie handy to reference, but I believe the character in the background - if they're even a named character? i think they might be a nobody? - doesn't do anything in the scene. He's just there, while Kirk is acting. had this been a conventional deep focus shot, it would make sense; Star Trek is full of shots where the commander is right up in the camera, but you can still see other characters or even extras milling around in the back. it's perfectly reasonable.
but since the DP used this absurd split diopter approach, it WRECKS the scene. the huge blurry mess in the middle SCREAMS at you that something special has been done to this image, and since Kirk is the obvious focus, your brain assumes that you're supposed to be looking at this other guy. so your eye just gets dragged over to this random dude in the background like a MAGNET. you're just latched right onto him, and he does NOTHING.
split diopters are horrible. they're the sort of bad idea that a six year old could easily recognize, and their awfulness cannot be mitigated. even in the best cases, they simply don't look good, because there is something deeply uncanny about them.
the closeup subject is always uncomfortably close. like, check out the second example image here. it's always like this, a near-macro shot where you can see the subject's pores. nobody would ever compose a normal deep focus shot like this even if they could, and even in the cases where the DP successfully hides the split, you can feel that something's wrong.
but again, the latest thing I'd ever SEEN one in was made in the mid 80s. i had NO idea there was a split diopter shot in DS9, but I can name two probable reasons:
first, Paramount in this era - and star trek in particular - had a phenomenon called Paramount Film School, in which actors (et al) could spend their downtime working other roles. Jonathan Frakes is probably most well known for this - he hired on as an actor on ST:TNG, then did every other job successively for years until he was qualified to direct. He spent countless hours in the editing bay, working with the director, DP, etc. and ultimately became one of the most prolific directors in the whole franchise.
I believe he's still directing episodes of SNW and Picard, but he's not the only person to come up through the ranks on Star Trek. So it's entirely possible that this split shot was the work of a neophyte who was trying the DP or director position for the first time. I could check that on Memory Alpha, I suppose.
Second, there are a couple known cases where ST directors got told they could have more photography budget for a given episode, and just had to figure out how to spend it. You can see this in one of the TNG season 3 eps, I think, which just inexplicably contains a number of bizarrely overwrought steadicam shots near the beginning, which are not only mismatched to the style of the rest of the series and season, but to the rest of the episode itself.
The steadi just doesn't work for bridge scenes, not only because the Enterprise bridge is very tough to shoot in 360 degrees (due to the need to introduce lighting gear, etc.), but also because the nature of bridge scenes involves a lot of back-and-forth cross shots that are incompatible with a steadicam approach. Sure enough, the steadi shot cuts out after the first reaction shot. It just doesn't work - but someone wanted to spend the money somewhere.
I suspect this was a similar situation: They were given breathing room, so they tried an experiment, since they had an extra $8000 or whatever to burn on a reshoot if it didn't work out. After I post this I'll go check Memory Alpha and see if there's any commentary about it.
Anyway, I love split diopter shots in that "oh my god everyone look, ANOTHER DP made an inexplicable decision" way. Now that I've explained them, you will see them everywhere. They are the only reason to watch ST: The Motion Picture, so I suggest you go torrent it right now.
