[davidmanze]

Thanks stoppingdown

     Nice review with some interesting ideas and images ......... well done!!

....... that's tempting me to put a extension tube on my Samyang 14mm F2.8 ..... and see what that can do ..... (it has very soft bokeh btw.)

What is the shortest extension tube available for F-mount?

     I think the shortest extension available is by loosening the lens mount"s screws  
  

 .......