Massive TC test on 70-200 2.8L IS

Started Jun 12, 2005 | Discussions thread
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Lee Jay Forum Pro • Posts: 54,890
Massive TC test on 70-200 2.8L IS

To start, I'm an engineer and research scientist for a national laboratory so, when it comes to testing and evaluation, I can't really help myself. I also did get out and shoot actual shots too (birds, planes, rabits, dogs etc.) so don't recommend that to me.

Okay, I have a new 70-200 2.8L IS. I also have 4 TCs. I have a Canon 1.4x TC II, a Kenko Pro 300 DG 1.4x, a Tamron MC4 1.4x and a Tamron MC4 2.0x. I thought I'd test these all in various ways to see what I found.

The first test compares the TCs to each other. My conclusion is that the Canon and Kenko are about the same in both contrast and sharpness with, perhaps a slight edge to the Kenko. Both handily beat the Tamron MC4 in both areas. The gap narrows as you stop down the lens:

The second test compared stacking the Canon and Kenko 1.4s to the Tamron 2x MC7. My conclusion is that the stacked combo handily beats the Tamron, though the gap closes as you stop down the lens. Also, the Tamron seems to be about a 1.86x, not a 2x:

The third test compares stacking all three 1.4s to the Canon 1.4 + Tamron 2x. The stacked combo seems to come out on top, though not by very much. Also, the less than 2x of the Tamron MC7 is apparent in this test as well:

The fourth and final test compares upresing to adding TCs. My conclusion is that adding a second 1.4 easily beats upresing a single 1.4 at all f-stops. Adding a third 1.4 does beat upresing a shot from just 2 1.4s, though the difference is so tiny, you have to really struggle to find it.

All of these were taken from 200 feet away with the system on a tripod, with remote release and MLU. The shapest of 6 shots of each system and each f-stop was used. These are all center crops. I shot these in the morning on a very clear day in hopes of minimizing heat distortion but I still ended up with a little that you can see in some of the crops. Before you ask, I did not evaluate corner sharpness as my subject matter did not allow that.

I expect lots of people would now like to tell me all that I did wrong, and that my conclusions are all wrong etc. etc. etc. so let's have it, but be nice!

Lee Jay

 Lee Jay's gear list:Lee Jay's gear list
Canon IXUS 310 HS Canon PowerShot SX50 HS Canon EOS 7D Mark II Canon EF 70-200mm F2.8L IS II USM Canon EF 8-15mm f/4L Fisheye USM +23 more
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