M4/3 & Sony A7R Lens' Focal Length Extension

[cellotone]

Hi, while using cine lenses on mirrorless camera, there's vignette problem can be shown on the conners of the picture. Here are settings to extend the lenses' focal lengths, also could effectively eliminate vignettes:

On Panasonic GH:
https://www.newsshooter.com/2017/03/28/gh5-extra-tele-conversion/

On Sony A7R:
https://www.diyphotography.net/heres-sony-mirrorless-cameras-allow-double-lens-focal-length-without-losing-quality/

These said the extension setting won't losing image quality. Any experience?

I haven't found whether there is a same function on Olympus M4/3 yet.

The first picture shot at 1X, second shot at extended 1.2X, a 50mm C lens on Sony A7R APS-C:

[kymarto]

Of course you lose quality--in the sense that some pixels have to be doubled in order to expand the image. The camera makes a decision on which pixels to doubled so that you don't get the obvious aliasing artifacts that you get when you blow up an image directly, but you will not have any more detail than you would by leaving the function off and cropping the image. At most the images, at high magnifications would not appear as pixellated, but they will appear slightly softer instead. The only real advantage is that you will not have to "crop the image in your head" as you compose in camera. The disadvantage is that you can only do this with jpgs. This feature is basically for cinematographers, who don't have an easy option for cropping videos.

[cellotone]

@kymarto Glade to know it. Thank you for the info!