A couple of days ago I received my 2.0x TC - I had already tried it briefly in the field, but I was really curious to see how it performs in a precise test, in comparison with bare lens, 1.4x TC, and stacked TCs.
The results are even better than whay I expected: even wide open at f/8, it is perfectly usable, and it has clearly more detail than the sharpest 600+1.4x photo. Af f/11 it is fantastic
With stacked TCs it is possible to extract a little more detail, but it is necessary to stop down to f/16 and to use a rock solid support.
If you are interested, I added the full test to the Canon 600 f/4 IS Review. (scroll down the page to "Performance with Teleconverters (Studio Test)")
". . . even wide open at f/8, it is perfectly usable, and it has clearly more detail than the sharpest 600+1.4x photo."
This will be news, I suspect, to every optical designer on the planet. The 2X in your test showed more detail because the image was at a higher magnification. Wouldn't the true test of the 2X TC be to move the camera back such that the image size was the same as with the 1.4? Then you'd be doing a head-to-head test of the teleconverters. I do not for a moment believe the 1.4 is sharper than the 2X.
Hi Cliff,
the purpose of the test was *not* to do an head-to-head test of the teleconverters - I already know that the photos taken with the 1.4x are sharper than the ones taken with the 2x. This is quite obvious
What I really wanted to see is if the TC actually adds detail to the image, or if it gives just a more magnified image, without any more detail. In other words, I wanted to see if it was really useful to use TCs, or if you get the same results up-resizing the image with PS.
In conclusion, the results are:
1.4x TC : the TC actually adds detail at every aperture
2.0x TC : the TC actually adds detail at every aperture, even though at f/8 you gain a little less detail than at f/11
1.4x + 2.0x : the stacked TCs do not add detail (the up-resized image has more detail) at every aperture, with the exception of f/16, that gives slightly more detail than the upresized photo.
One more thing to clarify the previous statements: the 1.4x gives sharper images but - at the same distance camera-subject - the 2x gives more detail, even though the images are softer...with softer I mean exactly "less sharp" not "less detailed"...after reading a couple of time your post, I think that we are saying the same thing, but we gave a different meaning to the term "sharper" ;-)
If you compare the crop 840 f/5.6 with 1200 f/8, the 1200 f/8 is *softer* (in terms of absolute sharpness), but it has more detail (because the gain in magnification is higher than the loss in optical quality).
Discussion
4 repliesThe results are even better than whay I expected: even wide open at f/8, it is perfectly usable, and it has clearly more detail than the sharpest 600+1.4x photo. Af f/11 it is fantastic
With stacked TCs it is possible to extract a little more detail, but it is necessary to stop down to f/16 and to use a rock solid support.
If you are interested, I added the full test to the Canon 600 f/4 IS Review. (scroll down the page to "Performance with Teleconverters (Studio Test)")
This will be news, I suspect, to every optical designer on the planet. The 2X in your test showed more detail because the image was at a higher magnification. Wouldn't the true test of the 2X TC be to move the camera back such that the image size was the same as with the 1.4? Then you'd be doing a head-to-head test of the teleconverters. I do not for a moment believe the 1.4 is sharper than the 2X.
the purpose of the test was *not* to do an head-to-head test of the teleconverters - I already know that the photos taken with the 1.4x are sharper than the ones taken with the 2x. This is quite obvious
What I really wanted to see is if the TC actually adds detail to the image, or if it gives just a more magnified image, without any more detail. In other words, I wanted to see if it was really useful to use TCs, or if you get the same results up-resizing the image with PS.
In conclusion, the results are:
1.4x TC : the TC actually adds detail at every aperture
2.0x TC : the TC actually adds detail at every aperture, even though at f/8 you gain a little less detail than at f/11
1.4x + 2.0x : the stacked TCs do not add detail (the up-resized image has more detail) at every aperture, with the exception of f/16, that gives slightly more detail than the upresized photo.
If you compare the crop 840 f/5.6 with 1200 f/8, the 1200 f/8 is *softer* (in terms of absolute sharpness), but it has more detail (because the gain in magnification is higher than the loss in optical quality).