White tern taking off, Midway Atoll.

Midway Atoll and a beautiful white tern takes off from an exposed branch on a small tree.    With the 500mm telephoto focused on the bird as it perched on the branch and a bit of space around the subject in the frame,  I was able to get the tern entirely within frame even as it took off.   Fortunately I had enough depth of field and the bird took off pretty much parallel to the sensor plane so that I still had good focus.

White Tern taking flight, Midway Atoll

The problem here is that in the original frame, due to its movement, the bird was now right at the edge of the frame.  Immediately after taking the shot, I checked the cameras LCD and saw the framing issue.  What to do?

Image Compositing

With the camera and lens mounted on a tripod, and not having moved the setup after taking the first frame, I realized that there was the prospect of getting a pleasing final result via image compositing. With this in mind, I framed a second image slightly to the right of the first, allowing for some overlap, much as you would for stitching panoramics.   I was careful not to engage auto focus when taking the second shot as it would have refocused onto the background foliage.

White Tern_the original file

White Tern taking off. Original image.

The original file (except for my watermark of course) straight out of the camera.   I’m happy with focus and the wing position of the bird, but,  and this is purely subjective,  I feel the bird is a bit too close to the right edge of the frame.

The second shot, right of the original frame taken moments later.

Blank space to right of first image.

The second shot taken from the same position,  same aperture,  same focus.    A few seconds had passed between the shots and light levels changed slightly with the result that the camera, which was on aperture priority,  selected a different shutter speed.   The change in shutter speed isn’t critical but the light has changed not only in intensity but also in colour temperature,  notice that the second image is warmer than the original.

The two images brought together in Photoshop.

Two images combined

Notice the alignment of the two images.    I failed to keep the framing of the second image exactly level with the framing of the first but remember,  this was not a planned process but an exercise in problem solving having seen the original image and then deciding on a second frame.   Also the colour temperature difference becomes apparent here.

To be continued….

As I am preparing this blog post and commenting on this image it becomes apparent to me that there are actually a number of technique issues arising,  several of which are probably worthy of more detailed discussion.    From comments and emails that I’ve received I’m aware that some readers are relatively new to digital image processing and may benefit from an in depth look at the Photoshop processing of this image.    With that in mind,  I’ll set myself the task of posting a step by step explanation over the next few blog posts.       Stay tuned!   :-)   KD


← → 2 thoughts on “White tern taking off, Midway Atoll.”

Chip "Roket Man" Allen says: 21 March, 2012 at 11:27 am I ALWAYS learn something from your posts! Thanks for sharing the knowledge and the beautiful imagery, KD!

Johan says: 11 April, 2012 at 8:05 am Thanks for the comment on my blog! Wow, this is fantastic; I’ll be watching your blog.