Dumb lens design question: why not design "around" stop-down improvements

[David Hughes]

I have a Olympus 38mm 6 element f2.8 enlarging lens and there is a permanent stop built into the lens. I’ve often wondered if it is actually a tweaked 38mm f1.8 lens mounted in a non focusing barrel, but have no way to confirm this suspicion.

It might just be a baffle to control stray light. They are a normal feature on refractors.


Regards, David