I hope this comparison between ND grad filters (and colour casts) done by AP is of interest:

link

Tiffen did best, with most of the others showing some sort of colour cast.

And from the thread title I was thinking you'd been to the Crich Tramway Museum, Kris! Should have known it would be somewhere a bit more interesting. What a find these old relics are. I hope they'll be saved from completely rotting away although it's great to see the hand of time on them.

I think most of the films i've seen recently have been 3d. To the point where i've initially been disappointed by 2d ones. Not sure how big 3d photography will be though. A lot of the tricks of photography rely on how it flattens things into a 2d image.

Point taken, but the OP talked about taking pictures while he happened to be taking a tube journey, rather than arranging an extended photo shoot.

Therefore I think he should just do it - being considerate, but open about it when he's taking a few pictures. I think furtiveness will make people more uncomfortable - and why should he feel he has to be furtive, presuming he's not one of those evildoers!

Worst that can happen is he'll be asked to stop, unless he decides to start quoting back the European Convention on Human Rights etc Lol

Let's not normalise asking permission for things which ought to be reasonable things to do. We're far too ready to comply with petty little rules in the uk. Look at the guy in Strathclyde who asked permission to take pictures in the park, only for some lazy risk averse jobsworth to tell him he couldn't.

(As Alan Partridge would deploringly say 'this country...')

Well, I like Giant's Chainsaw!

Just do it, but be considerate to others, and humble if you are queried by a member of staff. I suspect that a lot of the confrontations we hear about are partly due to the attitude of the photographer. But the worst possible thing you could do is ask permission. You think Japanese tourists write for permission? No, because you are a visitor to London, and it's perfectly normal to want to take pictures wherever you go.

The 18-55 definitely does not make the most of the k7 sensor (not tried the 50-200). Very useful for wet weather conditions though, and it's probably good enough most of the time to be honest. My first copy was very soft on one side, and needed exchanging.

Slow worm Matt. It's actually a lizard

It's probably a 100% crop, possibly from the edge of the frame, in which case many zooms and older primes will sometimes show a similar amount of purple fringing, especially wide open. The kit lens certainly will.