Daran wrote:
Surprisingly Dustin reports that his 400f4.5 with a TC1.4 is a hair sharper than his 600f6.3. Now I am curious whether this is due to copy variability or generally the case.
birderbill1 wrote:
Further analysis from Dustin Abbott:
Yes the plot thickens.
Shockingly the 400/4.5 with 2X is so terrible compared to the 600mm/6.3 with 1.4x. It makes no sense
How can this be? Does he have a dud 2X?
Could it be because the test chart has to be further away for an 800mm test?
We need samples with “just cropping” and no TCs on one lens
Sep 22, 2026 at 02:46 AM
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