Reply to thread

Message: <blockquote data-quote="lokatz" data-source="post: 642847" data-attributes="member: 43924"><p>No offense, but I do not believe this is correct.  Most zoom lenses have mechanical limitations, for instance barrels when zooming in, that keep the aperture blades from being able to use the widest position regardless of zoom length.  In other words, a Tamron 150-600mm f/5-6.3 (had one in my hands yesterday, which is why I use it as an example) will have an aperture of f/5 when focusing at 150mm and an aperture of f/6.3 when focusing at 600mm. Less light is available at the long end, and the focus gets slower.</p></blockquote><p></p>