On paper this scene should not work. A floodlit white stone bridge sits against a sky with no light in it at all, the water throws back a dozen point sources at different colour temperatures, and the whole thing has to be held still by hand because you are standing on a floating pontoon with people moving past your shoulder. Start with why the tripod is not the answer here. The banks along this stretch are narrow, busy well past midnight, and the good vantage points are all working infrastructure: vaporetto stops, taxi pontoons, delivery moorings.

The seafront promenade is one of the few street environments that reliably delivers subjects moving in a predictable direction at a predictable pace. People walk the length of it, they walk slowly, and they walk away from you as often as toward you. That last part is usually treated as a wasted frame. It isn’t. A long lens does most of the work here. At 85mm or 100mm on a crop body you are effectively shooting at 135mm or 160mm, which stacks the promenade into a shallow ribbon and pulls the distant benches, café lights and background walkers into a soft wash directly behind the subject.

Most gallery photos fail for the same reason. The photographer points the camera at the art, gets a flat rectangle of someone else’s work, and goes home with a bad reproduction of a good painting. The room is the more interesting picture. Walls, spacing, wall text, and one person deciding where to stand. This frame works because the subject is turned away from the big canvas and reading the panel instead.

There’s a window of maybe twenty minutes where a street like this works. The sky still holds blue. The sodium lamps are already on. Ten minutes later the sky goes black and you’re just shooting lamps against nothing. I got this one somewhere in the middle of that window, standing on the tram tracks at the bottom of Jaffa Road with the Holy Trinity domes sitting at the far end of the street like a full stop.

The stall had everything a photographer thinks they want. Whole crabs on crushed ice, whelks in their shells, three grades of oyster, lemon wedges cut that morning, parsley banked up like hedging. I shot the counter twice, wide, both frames from standing height. Both were mush. Too much of everything and no reason for the eye to stop anywhere. Then I bought one oyster, the vendor handed it over in a paper tray, and the picture was already made.

Everybody photographs this square. There is probably no square in Europe with a worse ratio of photos taken to photos worth keeping. I stood there anyway, with the sun sitting somewhere behind the Týn towers, and shot into it. The light was wrong. That’s the whole thing. Late afternoon, sun behind the church, every façade on that side of the square dropped into shadow while the sky stayed loud. The camera hated it.

A leopard walking straight down the middle of a dirt track, head low, eyes locked on the lens. It is the frame everyone wants and the one most people blow, because the animal is doing the one thing telephoto gear handles worst: closing distance along the axis of the lens while the light is flat and the vehicle is still rolling. Focal length is a distance problem, not a prestige problem The reflex is to buy the longest lens available.