10-15-2010, 10:08 AM
[quote name='hwyhobo' timestamp='1287131387' post='3638']
No, TC would not be just for academic exercise of comparing to another lens, but rather for practical purposes.
Well, 2xTCIII has excellent opinion for quality.
Are you saying Nikon 70-200 f/2.8 II has poor IQ?
[/quote]
To me is seems very strange to compare both lenses, they have nothing in common.
On the focus breathing, that goes gradually. The Nikon 70-200mm f2.8 VR II have an exceptional amount of breathing for its type of lens, it goes down to 135mm at MFD basically. No other lens in this class shows this, except the new Sigma with OS.
The 28-300 shows similar focus breathing to the Tamron 28-300, so again, quite a lot (but that is normal for the type of lens).
With both lenses it will be gradual. So near 200 or 300mm at infinity and then gradually less and less focal length. Photozone does not test this, it is easy for you yourself to test.
About TC's, they all do the same. They crop the center part of the image projected by the lens. So, it does not matter all that much which 2x TC you use, you will see a quite similar loss in resolution from the same lens as you crop its resolving power (or rather, you magnify its resolution-limit).
So saying that it makes more sense to compare it with an 1.4x TC is a sound suggestion. And I did not see him say the 70-200 has poor optical quality.
No, TC would not be just for academic exercise of comparing to another lens, but rather for practical purposes.
Well, 2xTCIII has excellent opinion for quality.
Are you saying Nikon 70-200 f/2.8 II has poor IQ?
[/quote]
To me is seems very strange to compare both lenses, they have nothing in common.
On the focus breathing, that goes gradually. The Nikon 70-200mm f2.8 VR II have an exceptional amount of breathing for its type of lens, it goes down to 135mm at MFD basically. No other lens in this class shows this, except the new Sigma with OS.
The 28-300 shows similar focus breathing to the Tamron 28-300, so again, quite a lot (but that is normal for the type of lens).
With both lenses it will be gradual. So near 200 or 300mm at infinity and then gradually less and less focal length. Photozone does not test this, it is easy for you yourself to test.
About TC's, they all do the same. They crop the center part of the image projected by the lens. So, it does not matter all that much which 2x TC you use, you will see a quite similar loss in resolution from the same lens as you crop its resolving power (or rather, you magnify its resolution-limit).
So saying that it makes more sense to compare it with an 1.4x TC is a sound suggestion. And I did not see him say the 70-200 has poor optical quality.