Playing with Teleconverters
During my last trip to the Kruger National Park, and while enduring a long period of grey overcast conditions, I decided to see how far I could push my equipment. The mission was to stack my Canon 1.4x and 2x teleconverters and see the resultant images. I’d have to say that I was pleasantly surprised by what I saw. I learnt a lot thanks to the patient and accommodating subject, a Bateleur Eagle.
Canon 1d MkIV
Canon 500mm f4 IS
1.4x and 2x teleconverters
Eventual Focal Length
Lens focal length: 500mm
Canon 1d crop factor:650mm
1.4x teleconverter: 910mm
2.0x teleconverter: 1820mm
Setup, Focus performance and Settings
You’ll notice when trying this, that the 1.4x teleconverter has to be attached to the camera body first, then the 2x teleconverter before attaching it all to the lens. It cannot be done the other way as around because they won’t connect. I’ve heard the great bird photographer, Arthur Morris, talk about using extension tubes to connect the 2x converter first but don’t fully understand the benefit of swapping the two around.
With this setup, you’ll notice that only the central focus point lights up and although Autofocus still works on that point, it is amazingly slow. As you press the shutter button halfway down to achieve autofocus, It searches for a second or two before acquiring focus. So, action photography is out of the question then. I did minimise the ranging somewhat by setting the distance focusing setting on the side of the lens barrel from (4.5m – ∞) to (10m – ∞)
As you can see from the EXIF data of the above photo, it only shows the focal length at 1000mm and f/8 (which is the same if you only have a 2x converter on). For the photo, I rested the lens barrel on a beanbag on the window frame of the car and turned the image stabiliser off. This help to minimise the camera shake.
Results and Lessons Learnt
If I zoom by100% of the image, it’s a little soft, but then at a shutter speed of 1/60sec, I would expect it. I’m happy with this picture because I didn’t want to up the ISO to 800 or more. I could easily have done that and accepted some additional noise, but I wanted to stay below 400. I will try this again on a front-lit subject and compare the difference in the sharpness. Now just to find some sun!
I’m very keen to try this with my Canon 1Dx and the new range of mkIII teleconverters. I’m told they’re much sharper than the mkI that was used. The 1Dx is also far superior in low light that the 1Dmk4 that I had, so I’d be happy to push that ISO limit a lot.
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