Thursday, November 27, 2008


I mentioned Panorama Paul who uses a technique for vertical panoramas.

The idea is to get the effect of a wide angle shot with a lot of detail in the foreground and in the background by stitching a few photographs that have been focused on different parts of the scene together.  He also does not shy away from mixing the exposure to bring together images that are exposed differently for the foreground and the background.

Paul has written an excellent tutorial for this as well and while I have been very satisfied with the way Photoshop handles stitching, I can see the usefulness of this technique for a combination of closeup and distance work - especially if the light does not allow you to use very small apertures.

I used the technique on an outing to the Ipswich nature reserve on Wed where I wanted to combine two landscape photographs into what would result as a portrait image of the river which is starting to freeze.  I left the camera on auto-focus and also on aperture priority to get the best exposure for each scene.

The two tricky bits are aligning manually and getting the variable exposure to look natural.  Paul pays attention to where the stitching is likely to occur when he composes the shot.  To be honest I was not really thinking of this when I did and was probably lucky that I didn't run out of space in the photograph when I did the stitching.

I am quite happy with the result.  

In photoshop, once I aligned the images with one set to about 50% opacity, I pushed the opacity back up and selectively erased with a very fuzzy brush to blend the two images.  I then added a overlay layer with 50% gray and use the brush and the white and black to selectively lighten and darken the ice and river so that they blended continuously.  Paul suggests a bit of a vignette to enhance the sense of depth and I applied this very lightly because I don't really like obvious vignetting.


I have been using Photoshop Elements as my main photo editing package.  It does a great job for the price and I suspect will be adequate for me for some time (until I realize how much working in 8bits is hurting my post-processing).

One thing that has astonished me is how well it handles panoramas.  I had previously taken a few (perhaps 3) photographs in landscape mode and used photoshop to stitch them, but more recently I tried to take 2 or three layers of pictures of a scene and left photoshop to figure out how to stitch them.  The main reason for going this route is that I wanted to get a scene that had the aspect ratio of a regular scene but covered around 180 degrees.  My camera's standard lens is a 18-55mm so with the lens on 18mm you can cover a fair amount of ground

To be clear, there are limits to how well this works.  For starters, I have been careful to
  •  maintain a top to bottom, left to right sequence and shoot each photograph in portrait mode
  • set the exposure to a constant value - in brightly back lit scenes this can be tricky, but if you choose an average exposure for the scene you can use the inherent exposure flexibility in raw to selectively brighten or darken to get the correct effect
  • focus on somewhere about a third into the scene and go for a small aperture so that you don't get variable focus in the scene
Admittedly, the computer takes considerable time to churn through a scene that is around 20 photographs in size and the psd file that results is huge (hundreds of megabytes).

Once the photograph is stitched, photoshop gives you multiple layers with each component that it has broken down for the stitching.  I usually use Merge Layers and quickly resize it to roughly what an ordinary photograph would be so that I can deal with a more or less normal file size.

Of course if you have taken the sky and something very close to your feet as the vertical range, there is considerable distortion - but I am happy to live with that for the added bonus of including the entire scene.

By way of example, here is a scene shot with my regular 18mm.  The scene is from the eastern head in Knysna, South Africa - a spectacular opening into the sea that is apparently quite a feat to navigate into when the weather is bad.

The scene was shot with a polarizing filter which accounts for the graduated blue in the sky.

I also took 17 (and I see now that these were in landscape mode) separate photographs of the scene which I then stitched together.  I didn't adjust the polarizing filter so the darker sky is still relative to the position of the sun with an apparently even graduation as the camera was moved from left to right.

The distortion is most obvious in the bottom part of the photograph.  I was pointing the camera almost directly down and the notch inward is not accurate - the inlet runs more or less straight from the sea to the town - but in my opinion this rounding effect is perfectly acceptable for the additional drama that is captured in the scene.

I have been following Panorama Paul's stream on flickr for some time now - he has an interesting technique for vertical panoramas which he began as a result of his disappointment with automatic stitching and with the fact that you can't blend two photographs where the is variable focus between the foreground and the background.  More on this and a link to Paul's tutorial later.

Wednesday, November 26, 2008

Birds for Africa

I have always regretted having had a film camera in South Africa and not taking photographs of wildlife.

Living in New England has made me appreciative of the diversity of wildlife that we enjoyed in South Africa and it was quite striking to 
go back and see how many different birds there were.

I was reminded in the resort that we stayed at that I have never seen a Knysna Loerie up close. You would hear them in the forest in Knysna byut never see them. Up in Limpopo there is a Grey Loerie that is a somewhat duller version of the Knysna Loerie. 
Its common name there is the "Go away bird" because its cry sounds like it is telling you to go away.

When we drove down to Cape Town we stayed with friends in Knysna who said that the Loeries were regular visitors to their garden.  It was great wake up and see a pair in their garden on our first morning there. Although the image is not sharp, I prefer this one because it shows the bird's striking red wings as it flies away.

Been away a long time

Child minding
Originally uploaded by bowtoo

We took eight years to get it together, but finally managed to get to go back to South Africa for a holiday last month.

Wow - what a whirlwind of emotion and nostalgia. Of course, seeing my family again was fantastic - we were able to reconnect after so many years of relying on only phone calls to keep in touch and my sister was inspired to arrange a the first weekend at a warm spring resort in the North East. The resort is called Die Oog - which means "The eye"
and had a swimming pool that was the temperature of bath water.

The resort also had a camp adjacent to it with wild game that for the most part were pretty used to people. The Nyala - a long-haired buck in particular let me get really close. The Blesbok were shyer but I managed to get a photograph of them that was pretty decent.

My favourite photograph of this weekend was one taken with back light  of a group of monkeys. They seem to take turns looking after the young and one of them had a baby but was being bugged by another who kept on trying to take the baby away. They paused for a moment and I
took this shot.