Flawed, but I liked it
Okay. First the negatives. The Lens is a very simple series with simple storytelling. You're not going to see any twists. You'll find yourself thinking, "Oh. a closeup of the guy with the tattoo. I wonder if he did it," The setup for the first episode made me think there was going to be a story arc through the series, but then they wrapped it up in the last few minutes and I'm left thinking, "oh, they're gonna really make it that simple?" If this were a UK drama, I'd probably be giving it 2 or 3 out of 10. It's also a bit hard to relate too much our main character. He seems too much like a student who's only in the Police because his dad got him the job - which IS essentially what happens. Okay to watch at first, but when he's messed up for the hundredth time you start to wonder why anyone would even want him around.
But I found myself watching the whole series of The Lens. The fact that it was a Czech drama made it interesting. If you took away the modern phones and cars, and it was in English, I would swear I was watching a drama series from the early 90s: People smoking inside public buildings, the style of the clothes and the buildings, the feel - Everything. Does modern-day Prague feel and look like 90's Britain? You'll have to ask someone who's been there whether this is all a stylistic choice or reality. I found I had to remind myself several times that this is set in present-day Prague and it's not 20 years old.
I found myself watching for just the general weird cultural differences. Episode 1 involves a scene where father and son go to a pub and get drunk IN THEIR POLICE UNIFORM and fall in their home legless - Something that would get them the sack from any UK police force probably from the inception of the idea of having a police force. Then contrast that with later scenes where the Czech police seem highly professional and working at a high standard.