Canon 70-200mm f4L IS first light

[dugnsuz (Doug)]

As promised...
Single sub, 5mins exposure, iso1600, 200mm @ f4.
100% crop of edges and centre performance.
Cheers
Doug

[bojan]

Doug,
Thanks.. this looks pretty good. Apart from only slightly emphasised coma and lateral CA at upper-right corner (could be cropped out, or corrected with software - PtLens or DPP would do it nicely- and they might disappear with another 1/2 stop down), the lens performs very good.
This behaviour in UR corner (coma? ) could also be due to a camera (or lens) flange, not being strictly parallel to a sensor plane... or is it the artefact of IS? This could be determined by playing with a focus a bit.
But, all in all, a great lens for astro photography..

Now I remember we had a similar discussion on one of the Canon zoom lenses here on forum earlier, couple of years ago.. The interesting thing was it outperformed its prime counterpart, which was a total surprise.
I wonder if it was about this one .

[dugnsuz (Doug)]

Originally Posted by bojan

Now I remember we had a similar discussion on one of the Canon zoom lenses here on forum earlier, couple of years ago.. The interesting thing was it outperformed its prime counterpart, which was a total surprise.
I wonder if it was about this one .

It may have been regarding the non-IS version which I owned at that time.
The MTF graphs of the 70-200 f4L IS has it very much in prime territory at 135mm and above.
http://www.photozone.de/canon-eos/19...review?start=1
Only let down by a slight increase in CA compared to prime equivalent FLs as shown on the above test image.
Doug