A nice focusing target to check for front- or backfocus is useful to have.
I made this one from balsa wood, some scrap aluminium tubing and foamcore posterboard.
The depth scale is mounted at roughly 45°
PES_2018-07-18_14-21-10_25mm_ by merco_61, on Flickr
The support for the scale is made from two pieced of 25X40mm balsa
PES_2018-07-18_14-21-27_25mm_ by merco_61, on Flickr
The mounting post is glued into another piece of the same dimension balsa using cyanoacrylate adheshive. All other joints are made with aliphatic resin.
PES_2018-07-18_14-21-47_25mm_ by merco_61, on Flickr
Here are two shots that show how things are glued on the poster board.
PES_2018-07-18_14-22-19_25mm_ by merco_61, on Flickr
PES_2018-07-18_14-22-46_19mm_ by merco_61, on Flickr
This shows how the target is mounted to an umbrella head on a light stand.
PES_2018-07-18_14-24-25_42mm_ by merco_61, on Flickr
And finally a shot that shows it more or less ready to use.
PES_2018-07-18_14-24-54_34mm_ by merco_61, on Flickr
The target is an ordinary A3 printout of two black squares touching in one corner at the centre of the page. The scale has some text in 11 pt Verdana set to 60% grey.
It is possible to use some other type of focusing target if needed but this one was fast and easy to print out and worked well for the 150-600 that was my immediate need.