« on: February 24, 2014, 03:04:23 AM »
http://www.ephotozine.com/article/tamron-sp-150-600mm-f-5-6-3-di-vc-usd-lens-review-23866How good do you think the IS is at 600mm? It doesn't seem like 4 stops to me.
how do you calculate that it is not 4 stops?
you shoot handheld with and without VC and look how many stops you need to see no blur from your tremors?
or you just say you should be able to handhold it at ~1/30s. @600mm.
It is claimed in this review that 50% of his shots at 1/40 s are sharp. Most of mine are blurred at that speed.
Sharpness at such speeds is entirely subjective. Given the kind of use cases this lens will most likely be used for (birds, wildlife and other action with cropped sensor cameras), at 1/40s, your likely going to get considerable blur, even if you have steady hands. Your subjects will be moving, and even a small amount of movement (ESPECIALLY for birds) at anything under about 1/800s results in blur.
I used to try to keep my shutter speed slower with the 7D to keep noise levels lower (and avoid having to go over ISO 1600), however for passerines, they are so jittery and constantly on the move that anything under about 1/800s (and in the case of the really small, super hyper birds like chickadees or bushtits and the like, even shutter speeds of 1/1250s and slower) results in subject blur. This was even the case with the EF 600mm f/4 II on a heavy duty tripod and gimbal (GT3532LS + Jobu Pro 2).
The only time your going to get stable 1/40s shots hand-held is if there is no motion in the scene. I had the luck of getting a 1/6s handheld shot ONCE in my entire time photographing:
Night Heron at Night
Canon EOS 7D + EF 600mm f/4 L II
1/6s @ f/4 ISO 3200
The only reason I was able to get the shot is because the bird was literally motionless for the entire time it took me to uncap the lens, stabilize myself so that I was motionless, configure the right camera settings, and take the shot. This was about a half hour or so after sunset, during the last minutes of civil twilight/first minutes of astronomical twilight. It was truly "night". Unless you intend to go around photographing night herons at night, I don't expect many nature photographers who get the Tammy 150-600 will be getting many sharp handheld shots at such low shutter speeds.