The best thing about BLOW UP is the Yardbirds. I love seeing the youthful Jimmy Page and Jeff Beck and I love their music. The rest of it, not so much. Yeah, Val Lewton used wind earlier and better. At least things happen when the wind is blowing in a Val Lewton movie rather than in BLOW UP.
Especially when they smash the guitar much as Jimi Hendrix and the Who a year later.
Blow Up and L'Avventura are two films that you generally don't like the first time you see them because you are expecting a straight forward mystery story with a satisfying ending and... surprise!
Yet both are highly entertaining when you watch them a second or third time because you finally "get the point". Everyday people are easily distracted in life and they lose out, particularly when it comes to carnal pursuits (either sex or collecting stupid propellers from antique shops). There is lots of whoopee going on in both movies, which is why a missing lady is never found in the sea and a corpse disappears in a park.
I love it that a photographer (David Hemmings) first tries to scam a lady (Vanessa Redgrave) because he took incriminating pictures of her having an "affair" in the park. Blackmail is part of his profession. Then, after blowing them up, he sees a man with a gun in the bushes and initially thinks he saved a man's life by interrupting the rendezvous. Only he didn't. There is a body that shows up in the other images. Then he returns to the park and finds a corpse. Only this time he forgets his camera! This guy was literally "glued" to his camera during the first half of the movie!
Note that he "made love" to a model with his camera early on. Later he "makes love" with two naked sex kittens without his camera. It is afterwards that he forgets his camera when he returns to the park and finds the corpse! He is camera-less the rest of the movie.
Adding to the fun, Vanessa's character re-appears as a phantom later and may quite possibly be involved in the murder as an accomplice... at least we suspect this, but aren't sure. (Echoes of Vertigo, another movie nobody feels neutral about here.) Neither is he. In addition, he isn't getting help from his friends because they are too busy enjoying whoopee or getting high on pot. Even the model he used a camera to "make love to" earlier is occupied in Paris... only not geographic Paris. Just "far out" Paris in her brain.
I love the mime performers. So much symbolism there. They appear at the start just as we see Hemming's character intermingle as a scruffy factory worker before "transforming" into a high class photographer in his fancy set of wheels. Right away, you don't know what is real and what is just a mirage. The mimes re-appear at the end after he gets his camera but can no longer find the corpse. Thus, they play tennis with invisible balls... which seems down right silly until you realize this photographer forgot his camera when he needed it. So it makes perfect sense that he plays tennis with them with no tennis balls. Might as well enjoy your self like the Yardbirds performing with a broken guitar (a remnant of which winds up in a street and ignored by the people as trash).