Aperture vs out of focus-highlights

I am an amateur photographer and mainly use my Hasselblad camera for

portraits outdoors, in available light, sometimes with fill-flash.

Problem is, I don't like the pentagon-shaped out of focus-highlights for all apertures but wide open. I like the square-format but I would

prefer lenses with more aperture-blades, to give more of a circular

rendition of out of focus bright points. Are the Rollei-lenses better

in this respect or do they also produce the pentagon-shape? (I don't

ask about Bronica only because the used-market in Sweden is too small).

This is a very important issue, why do some of the MF cameras only have five aperture-blades (HASSELBLAD and MAMIYA 6)?

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As you I don�t like this pentagon shape in the out of focus highlights. So I actually sold my HASSELBALD (also for other reasons e.g. cost) and are now the very happy PENTAX 67 owner using a 200 mm for portraits, and I think this lens have eight aperture-blades.

Thank you Kim, and thanks also to James Chow who informed me by e-mail that Rollei-lenses also seem to have only 5 aperture blades.

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So, Pentax 67:s 200 mm has 8 blades, well, maybe Pentax would be the way to go... or sell the Hasselblad and buy a Contax SLR. The Zeiss-lenses of those are supposed to give very nice out of focus rendition. Not MF but quite hand-holdable. But I might get MF-

withdrawal symptoms.