rendering a section of the image to same scale


i am working on an image and want to render out a section of the image to the same scale - ie. crop the image frame

when i try to resize the output (currently 800x600) the image is resized too.

i can juggle proportions against the camera scale, but this is tedious and inaccurate.

also, i wish to change the ratio, and that seems to change the scale also.

anyone help will be much appreciated.

Thanks in advance

I upgraded to 2.42 and the crop function now works, which is a relief. any other methods i’m missing?