Originally Posted by dalemccl
I read here or in another forum that Active OIS zooms in 56% at longer optical zoom ranges (I think that was the percent mentioned - that seems awful high so I may be remembering wrong). Does this cause loss of resolution, like when you crop in post, or do you still get the full 4K resolution in the recorded file, which would allow up to 75% cropping in post and still have full 1080 resolution for rendering to regular HD?
I did the test that came up with those numbers.
Since I used a resolution chart as part of the test, I was able to see that, in terms of real resolution of the subject, there was no gain nor loss. For example, if you were zoomed in on a bird, the same amount of feather detail would be resolved whether active or standard.
You will however get a smaller FOV with active (by 56% at 4k) so that detail will be magnified and theoretically could look more fuzzy when viewed at 4k. In reality, when you're zoomed, you are a little less concerned with detail generally than when you are wide just by the nature of things and I doubt you would be able to tell by looking at the 4k image. If you look at my tele active 4k screen capture, it still looks pretty sharp even at 100%, just not quite as sharp as the Standard.
I really like Sony's implementation of variable crop based on focal length. It basically does a mild digital zoom as you go through the range and gives much better stabilization.
And if you are viewing the 4k image at 1080p, you will actually be able to see MORE detail on that theoretical bird if you are using active stab due to the higher magnification factor.
I just wished Sony did a better job on the stabilization itself...it's outclassed by most other systems I've used, including something like the OIS on the 14-140 5.6 on a m43 camera.