Polarizers and Stitching

[Peter McLennan]

I'm thinking about a 67mm pola for my Nikon 16-85.  Even full wide, this lens produces good stitching source images.  If I use a polarizer am I likely to run into problems with stitching resulting from dramatic sky darkening across the frame?  I usually stitch with PSCS3 Photomerge.

[Ken Bennett]

Yes, at the widest settings in particular.

Using a fixed 24mm lens (on a full frame camera, which is the equivalent of your 16mm) I sometimes get wildly variable darkening over the width of the sky. It can look okay in a single image, sometimes. But I would hate to have to stitch a panoramic with a polarizer.

The polarizer effect is variable and depends on a lot of things, but you'll want to experiment before using it. That's not to say you shouldn't have one for this lens -- it's very useful for single images.

[francois]

You'll need to be carefull if you want to use a polarizer on your camera for stitching. Even if the uneven darkening of the sky is not obvious on a single frame, it can become a major problem in the final image.

See the attached pano. I shot it with a polarizer and one can see the nasty effect it has on the sky. I forgot that I still had the polarizer on my camera (   ) . It was a quick 20 seconds, hand-held 5 or 6 photos pano... and I was already late!

Photoshop had absolutely no problem for stitching.

[fike]

You can do it if you have plenty of overlap between frames that will give you the room to blend from the deeper blue towards the lighter sky.  

I have generally had better luck doing it with other tools besides CS3, but it looks like someone here has been successful with that too.