Flowers are difficult subjects. The closer you get, the more shots you find, and even a shift of a few millimetres can give a completely different composition. You’ll never get the same shot twice, and you really start to think about composition, tone and colour. The fundamentals.
I used a +3 close-up dioptre to get right in with the tamron 18-270 PZD. Normally when you use an internal-focus lens, the focal length decreases the closer you focus (at minimum distance, your 270mm actually becomes a 150mm lens, but tamron are good enough to mention this in their manuals). The dioptre allows you to focus the lens nearer the middle of its range, getting greater maximum magnification for your lens, and giving the lovely, shallow depth-of-field that comes with a longer focal length.
Used under these conditions, the tamron really shines, showing remarkable resolution which belies the perceived shortcomings of a superzoom lens.
Nikon D300; Tamron 18-270mm @ 140mm; ISO 400; F/8; 1/200s. VC on.