Ah sorry yes, that would make more sense! I am having a look at a few other close up filter lenses, currently using a 52mm filter size but I know you can get 88mm filter lenses so if this works I could perhaps look at getting a larger close up filter lens with the same dioptre giving me a lower f number.
Currently with the 52mm size it would be: 166/52=f3.2
With an 88mm filter it would be: 166/88=f1.9
I will look into attempting to mount/free lens the setup already onto a digital camera and see what the image quality is like on it.
I might still look into getting a single element lens or a cemented doublet lens commercially and mount it, but I will see how this performs first as the imperfections have a certain feel to them.
Here is an example of some free lensing I did with the +10 lens (there was a gap between the camera body and lens which is why everything shines lol