I wanted to put another perspective to the test-charts I shot at this
I've put the original f/4.0 crops from that post below:
As you can clearly see the IQ of the lens at f/4.0 is not good esp. in the center. The circle was getting mushy and the star was showing a drop in resolution of about 1/3 compared to f/8.0. As I remarked then, the result might have been flawed due to misfocus as the corner-crop was better than the center-crop.
To do justice to the design and in reminiscence to my recent review of the Tamron 70-200/2.8 here
I decided to reshoot the test at f/4.0 with manual focussing aided by live-view.
I know that this is not showing the real-life performance of the lens as you normally use AF but I already mentioned that this lens needs a +20 AF micro-adjust on my D300 so AF with this copy of the lens is botched either
You can read from these lines that I'm still hoping somehow that there must be some well-adjusted copies of this lens out there that can show the true potential of the design. At least the production run resulted in over 6000 copies being sold. So someone might be the lucky owner of a good copy...
But now without further ado here's the reshot f/4.0 center and corner crop (at 100%). If you click on the images you can go to the full resolution version of this test-shot to see for yourself.
Don't be confused by the different crops/magnification/WB:
- the center crops are to the left, the corner-crops to the right
- the second shots have a 27% higher magnification. But the beautiful thing with Siemens-stars is that the diameter of the grey disk in the center of the star is always comparable and in this case it clearly shows that the new shots have a 25-30% smaller grey disk. This means that with a better focus the lens delivers about 33-50% more resolution. Which is perfectly in line with the real observed sharpness of this lens in that
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