Visible crew/equipment: At the beginning when Sarah, John, Cameron and Derek are driving past the dead cows, the shadow of a camera can be seen on the inside of the passenger door that Sarah is sitting in.
Episode #1.4 - S1-E4
Visible crew/equipment: When Lee is being interrogated, at one point (after the detective says "Are you crazy?") the detective walks towards the large two-way mirror and you can see a clear reflection of a cameraman in the lower part of the mirror. (00:27:31)
Dark Spirit - S1-E9
Visible crew/equipment: In the parking garage, Catherine's car captures a reflection of both the camera crew and the studio lighting panels. (00:26:00)
Visible crew/equipment: As the energy being moves down the city sidewalk, we see its shadow on the concrete. Right beside that, however, we can also see the distinctly-shaped shadow of the camera. (00:35:00)
Double Cross - S3-E2
Visible crew/equipment: When the Professor returns from the vortex and punches the guard, in the guard's glasses is the reflection a crew man holding a boom in his hands. Look closely in the right lens. (00:39:05)
Visible crew/equipment: At the dance club when Caleb Mathias holds Emma, Brennan comes to the rescue with a few swift airborne kicks. During one particularly high kick, the lines attached to Brennan are in perfect view above him.
Visible crew/equipment: In the scene where they get in Eddie's new car watch Raven get into the car, her left foot kicks a some sort of power outlet on the ground with a lot of plugs in it. Judging from the direction of the cords they seem to go to the camera or other equipment. They wouldn't have put a power outlet there for set decoration.
Visible crew/equipment: In Episode 8, "Cabin in the Woods": When Daedalus finds Archon on the floor of the mansion, he picks him up and helps him into a chair. The camera follows their movement upwards when they are rising from the floor, and there is a boom mic that comes into view, at the top of the screen.
El traje del tío Jacinto - S2-E16
Visible crew/equipment: In the credits, there's a unknown person hiding behind Don Ramón (Raymond).
A Single Piece Was Lost - S1-E10
Visible crew/equipment: When the Gruenaks attack the Scientist a puppeteer is visible to the right of one of the Gruenaks, just before it grabs the bird cage and throws it onto the Scientist's head. (00:28:18)
Visible crew/equipment: During the final battle between Duncan and Luther, you can see a crew member holding a boom microphone pole standing on the stack of hay bales in one of the shots. (00:44:10)
Chapter Twenty-Eight: Sabrina Is Legend - S3-E8
Visible crew/equipment: During the strobe lighting at the very end of series three, with Faustus Blackwood seemingly releasing something evil, it is noticed that during the flashes, it is leaving after effects, showing the shape of the equipment that make the strobe lighting. (00:58:00 - 01:00:00)
Visible crew/equipment: When Arthur goes to Dragoon to ask for help, when Dragoon runs out of the hut to turn back into Merlin, on the left hand side of the screen you can see a camera crew in modern clothes. [Fixed in Netflix version]. (00:23:00)
Suggested correction: I don't see any crew. I'm watching it on Netflix. Perhaps they fixed or perhaps they edited it out after realizing the mistake. But they aren't there anymore.
Even if Netflix corrected the mistake doesn't mean the mistake is now invalid if the mistake existed in the original BBC One airing. Netflix is known to change or edit programs they stream (such as replacing soundtrack songs).
Visible crew/equipment: During George's funeral, the camera swings around to follow the employee from Happy Time (the guy who George gives files, minus the red ones, to) and as he crosses the room to the other side, you see a crew member holding a boom mic, who looks over a little startled and moves back out of view.
Visible crew/equipment: When Nicky wakes up after falling asleep at the kitchen table, you can see the mike in the mirror behind her.
The Town Where No One Got Off - S1-E4
Visible crew/equipment: The overhead boom mic dips into the scene as the old man is speaking.
The Losers - S1-E4
Visible crew/equipment: When Lodgepoole is telling Marshall about how the Bureau of Lost caused the Great Depression, someone's arm becomes visible in the upper left corner of the screen. (00:12:51)
Visible crew/equipment: When Baby tries to walk, and he falls over, as he falls you can see the black sleeve covering the puppeteer's arm.
Gortimer vs. The Mobile of Misfortune - S1-E3
Visible crew/equipment: When Stanley is riding the kart in the race, the shadow of the camera equipment is briefly visible bottom right, just before the kart starts to fall apart.