You're likely right. Actually lenses that run from 6-12mm in diameter are in the range of most ecomomical. Using a longer fl 12mm diameter lens wont increase the cost of production. I have a 532nm Nova Lasers after the warranty expired I swapped the original 6mm diameter lens with a longer focal length 12mm lens. I chose that diameter because through experimentation found that it would not clip the beam within the amount of space I had. Like the op I have this laser. I'm toying with the idea of putting a new lens in.My thought the reasons why are; most people want to see that skinny, high power density, bright beam coming out of the aperture. Also, larger diameter collimation lenses cost more. As you well know, stating for the newbies, the smaller the collimation lens, the greater the divergence.
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