I've one on loan from canon and only really snapped a few shots with it and so far it has impressed me.

Checking out TDP it seems to murder the 17-40L at f4, and kick my sigma 50 into touch too.

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=100&Camera=453&Sample=0&FLI=5&API=0&LensComp=810&CameraComp=453&SampleComp=0&FLIComp=0&APIComp=2

I probably cant justify it as just a nice little prime, even though it is, but it seems to me it would make a great pano lens, so long as your past the vignetting, parallax issues should be minimal too?

Should be good for pano purposes. Personally for me, I really like using alt. MF lenses for panos with their hard infinity stop (useful during night). Zeiss 50 1.7 and Takumar 50 1.4 are good candidates for even cheaper than the 40STM

I've done some stitching with it, its pretty good. (excellent for its price actually) Better/sharper than any of the Canon 50's I've tried, or the 45mm tse. But does not have the wow look of the 35L or 24L.

Only bad thing I can say about it, is it can be more tricky to manually nail the focus using live view, due to the tiny crappy focus ring. But it gets the job done.

Frank

This is 6 shots stitched with the 40mm.

That is gorgeous. I'm getting mine this week off Adorama soon. Will be my walk around lens on the street. Very discreet and light weight Will pair nicely with 5D2.

This is 6 shots stitched with the 40mm.

Beautiful. Great little lens in capable hands, that's for sure...

Thanks mpr, I'm probably not getting the 24L as I have the 24tsemkII , the 35L is gorgeous but I cant see it really, too chunky.

Looks like the 40 is quite capable though!

Yep; I did quite a bit this summer on a trip to Europe.

Here's the one I was happiest with; you can see a much larger version at my blog here:


linky

The distortion would be a big downer in a non-photoshop world. Barring that, though, I've been really happy with it for stitches.

Wow, cool stitches MPR and Fast.

Thanks! Computer didn't like me at the end, but so it goes

I have done a couple and it works very well.

This one is from 10-12 vertical images on a 650D http://www.flickr.com/photos/pixelpixcomau/7990089988/in/photostream/

I dont think I bothered to offset the camera to optical center in this one either?

Here are a couple I did a few days ago, testing my lens after it got back from Canon. Mine was out of whack, and required three trips to Canon to get sorted out. Now it seems quite stellar.

I cross posted these a few days ago.

This hand held pano is shot at f/8 and completely avoids issues of vignetting and focus error -- shot in Av with AF in eight vertical frames. Shot on 1D2 APS-H frame, so f/ 5.6 would have been fine too for avoiding vignetting.