Pocketable Canon lens query.

[David Morison]

I use my Canon 7DII solely for birding/wildlife and for the very infrequent occasion I wish to snap an insect, flower or scene I carry my Olympus E-M1. Carrying two systems is a bit of a fag so I am investigating buying a small/light zoom lens that I can carry in a pocket for occasional use on the 7DII. A friend has got the 18-55mm STM kit lens and I have had a quick go with that and been surprised at the quality of image producing some decent close-ups, even though it seems a bit "plasticky". Another option is the much more expensive and larger/heavier 15-85mm which gives quite a bit extra range although to be honest I don't really need this. Interestingly Photozone give the 18-55 a better score IQ wise so if I'm not bothered about build quality, as it will not get much use, then is this the better lens to buy?

I'd be interested in folks experiences and opinions of both lenses, which should I go for?

Many Thanks

David