Double stacking Teleconverters

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SteveF

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Steve
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I was wondering if it would be possible to double up with teleconverters and if so what would the implications be??

Steve
 
It is possible, at least with some TC's, but light loss and image quality degradation mean it would rarely be worth it (better results would often be had by cropping).

But I believe some people on here have some images taken with stacked TC's so in the right circumstances it might be worth it.
 
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I've posted these shots before and they were simply a test and not something I'd use in anger.

The were shot on a 1D4 with a 70-200/2.8 MkII and a 2xII and 2xIII Extenders added....not excessively bad for a zoom when all is taken into consideration.

Native lens...at 200mm
10120_4090466564e2759fd82758.jpg


Lens + 2xII (400mm)
10120_3120199434e275a00df9ea.jpg


Lens + 2xII and 2xIII (800mm)
10120_14255534734e275a047d4c4.jpg
 
Check out my thread from 2008: Garden birding fun at f=2000mm.

There are some examples shot with stacked teleconverters. I found that I got better image quality when I used just one TC and cropped the image compared to using two TCs, but with some improvement to my technique I think I could have got a bit more IQ out of the stacked TC setup. (Part of the problem was simply that a 500mm lens with two stacked TCs is so long that I can't reach the focus ring when looking through the viewfinder! I'd need to be shooting tethered to do it properly.)
 
2000mm on an APS-C body is 0.6 degrees horizontal AoV.....the target must take some finding never mind focussing on.

Bob
 
Canon Bob said:
2000mm on an APS-C body is 0.6 degrees horizontal AoV.....the target must take some finding never mind focussing on.
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Teehee.. I used to do planetary photography. That was 7000mm on a 1/4" CCD and the object moving. Taking the photo (actually video, but that's another story) took a few minutes of the hour plus it took to setup, align and get the target on the chip. :eek:
 
Canon Bob said:
2000mm on an APS-C body is 0.6 degrees horizontal AoV.....the target must take some finding never mind focussing on.
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Not half! As I recall I didn't have a tripod with me that day, so I was lying prone on the floor with the lens on a footstool. Precision adjustments to the lens were ... difficult.

I really must have another go some day with a decent tripod and a tethered camera.

arad85 said:
Teehee.. I used to do planetary photography. That was 7000mm on a 1/4" CCD and the object moving.
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OK, you win.

At least your target was moving predictably. The only way I had a chance with the goldfinches was to focus on the feeder and wait for them to come into the frame.
 
Canon 300mm f2.8 + (2x + 1.4x TC stacked)
IMG_6377_copy_1.jpg


Was impressed with the results and handheld

Peter
 
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