Hi all, I'm planning on getting the sigma 100-300mm f4 used, and sticking a 1.4x tc on it. This will be used on a Nikon d7100 which has a 1.6x crop factor, and then a further 1.3x crop factor available , which would turn this set up to 'basically' a 250-800mm f5.6.
Now, would this be ok for...