You can get the exposure to be the same between both pictures if you lock out the autoexposure so the brightness level doesn't change abruptly across the seam. You'll have to look into your camera documentation to see if your camera can do this. On mine it's a single button called 'AE lock'. It usually works best to shoot the bottom first, hit the AE lock bottom so the camera will use the same exposure settings for the crown, then take the second picture. If you do it backwards, the crown will look good (Instead of being slightly washed out/overexposed), but the bole will be black because of the much dimmer light at ground level.Larry Tucei wrote: Randy- Thanks for merging those two photos, you get a better sense of its size. Larry
Newer cameras (and even the iPhone 5!) have dedicated panorama shooting modes that do the exposure locking and stitching automatically for you in the camera.
Another issue I've run into is shooting with a wide angle lens makes a mess when you go to stitch (<35 mm). You'll get two separate regions of barrel distortion in the stitched image. So instead of one columnar tree trunk, you'll get something that looks like two fat barrels stacked on top of each other. If you're shooting multiple trunks that aren't centered on the image, you'll get two regions where the trunks bow out toward the edge of the image. I had to screw up quite a few before I figured out what I was doing, and to remember to adjust my zoom properly.