[Kguru]

Have just received the Tamron 90mm Macro from qdoan. Amazingly sharp lens. The front glass sits 2 inches deep into the barrel which makes me curious. It comes with a separate hood so that part isn't really there as built-in hood, Tamron could have made the barrel 2 inches shorter without affecting the optics design. Thanks for any explanation why it's made that way.

[Nesster]

Focus all the way down to max macro. The lens gets much much longer. I'm guessing here, the extra barrel length has to store somewhere: the deep front section. Having that extra length in a single piece makes the lens more stable and solid when at full macro extension.

[Wheatfield]

Focus all the way down to max macro. The lens gets much much longer. I'm guessing here, the extra barrel length has to store somewhere: the deep front section. Having that extra length in a single piece makes the lens more stable and solid when at full macro extension.

You are 100% correct.