While it's absolutely true that cheap triplets, specifically built as low cost alternatives, don't stand big enlargments as much as a Planar or Xenotar (and also the best Tessars), there are very good triplets which are very desiderable lenses even by today's standards.
Of course none of them was ever fitted to a Rolleiflex, but i have read of other alternatives in this thread, so i guess that i'm not going totally off topic.
There are medium format folding or reflex cameras with very good triplets, like a Meyer Trioplan, and with some luck you could even find one with the best of the breed, a coated TTH Cooke lens.
A nice Rolleflex with Planar would come cheaper though, as i jave just seen a coated f/2.8 5" Cooke triplet being sold for about 1400 USD on Ebay!
The fact that some of those lenses are still used to shoot 35mm footage for big budget movies speaks volumes about their quality...
I love some triplets for their flexibility (optical "signature" wide open is different from when the lens is stopped down).
Whatever... optical quality has more to do with tight mechanical tolerances, the use of computers to optimize old projects, and the introduction of better coatings, than with the type of optical layout.
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