Image created on September 17, 2013 at the Singapore Zoo, with Canon EOS-5D Mark III and Canon EF 500mm f/4L IS with Canon EF 2.0x Extender III. ISO 1600, f/8, 1/40s, Evaluative metering +1 EV.
After my last post and an exchange of comments with a good photographer friend, I decided to return to the Singapore Zoo and try my luck again with the Blue-eared Kingfisher but this time with a few changes in my setup
- Maximum aperture when possible and not stopping down even while using a 2x Teleconverter
- Trade the gained stop into lowering my ISO
- Use flash at -1 EV to just slightly open the shadows and get some catch eye when possible
For some this might deserve some additional information. Using a Teleconverter (with Canon a 1.4x or a 2x, Nikon has also the 1.7x) will slightly degrade the image quality produced by the lens, especially when using a 2x teleconverter. The image will will be magnified by the teleconverter factor but the amount of light as well, a Canon EF 500mm f/4L IS used with a Canon EF 2x Extender III is the equivalent of a 1000mm lens with a maximum aperture of f/8, a very long but not very fast lens. Additionally it is advised when using a teleconverter to stop down by at least one stop the lens to compensate for the degradation of image quality, so typically you’ll end up shooting at f/11.
Do that in a dark environment, like you would find in a tropical forest and you will shoot at best at ISO 3200 or even ISO 6400 with speeds not exceeding 1/100s. Not the easiest of all, especially if the subject neither large nor close the will end up being cropped, every pixel counts. Now unless the subject is moving constantly, speeds between 1/40s to 1/100s are manageable with a good long lens technique, I personally like image noise much less, even with a camera with a super low noise level at high ISO as the Canon EOS-5D Mark III.
As often in photography there is a trade-off between the optical sharpness of the setup (how sharp can a 500mm with a 2x TC get for a given aperture) and the image quality of the camera (how much sharpness is lost because of high noise level in the image). For the last post, I favoured the optical sharpness over the noise level. I ended up with decent images but I had to work quite hard to salvage some details on the bird, it is possible to remove noise efficiently from the background but the overall sharpness of the subject will suffer.
For this post I decided to decrease the noise level by shooting at one stop lower sensitivity (ISO 1600 rather than 3200), while keeping the lens at maximum aperture and using a 2x teleconverter.
I am much happier with this result as the noise level, even if really excellent on the Canon EOS-5D Mark III, is proving to penalise more the image than the more subtle decrease in image quality due to the teleconverter. Note also that I am using versions 1 of the big canon lenses (a Canon EF 300mm f/2.8L IS and a Canon EF 500mm f/4L IS both Mark I) with the version III of the teleconverters, with Mark II lenses the penalty of using a teleconverter is much lower (both in image quality and in autofocus performance) so that learning is useful: as a (breakable) rule prefer to favour lowering the ISO to preserving the image quality of a big lens when using a teleconverter.
There is a corollary to this rule: looking at the very decent results I got shooting at ISO 3200 or ISO 6400 (I did not publish the 6400 as the lower ISO where all-in-all better but 6400 was still very manageable with a bit more work in photoshop) it is clear that action shoots become really feasible in a tropical forest (provided that the subject can be found and is not hiding behind leafs, branches or bushes…). Without even going to higher sensitivity but relying on continuous shooting I was happy to get this shoot of the female Blue-eared Kingfisher cleaning her wings early in the morning.
Maybe this also require a last word about the depth of field at f/8 which is going to be smaller than f/11. In real world terms however, with a focal length of 1000mm and a subject at around 6m, the depth of field at f/8 is 1.5cm whilst it is 2cm at f/11, a difference yes but not a huge one given that the bird won’t be completely in focus in both cases, nevertheless I ran into some difficulties and the below image is a composite of two images of the female Blue-eared Kingfisher, one had the head in focus while the second had a blurred head and the back into focus. Using Photoshop I was able to combine both to increase the depth of field.
Those knowing me know that I am seldom happy and that I always strive for better, what satisfy me very much though is progress and this is exactly what I felt happened between take 1 and take 2. Of course I’ll try again at the next opportunity.