[Hans Tucker (Hans)]

As a Winter project I have decided to see if I can make an unholy alliance of a Askar ACL200 f4 lens with a STF-8300C to create a widefield light imaging setup. Apparently the ACL200 has a Back-Focus of 55mm and the Sensor on the STF sits back 17.5mm so I am assuming that I need an adapter of around 37.5mm.

How critical is the length of the adapter?

Is it advised to go longer or shorter or exact?

Sorry in advance for the noob question.

I gather there are no off the shelf options so I will need to get Precise Parts to manufacture this adapter.