Hey there, this will be a storter post than normal. I got my new lens last Saturday in the mail and I didn't really get a chance to go out and test it until today. The lens is a Tamron SP 150-600mm F/5-6.3, and the main lens I've been shooting withs is a Nikon 75-300mm, so basically my zoom has doubled.
I have noticed a few differences based on my short time shooting with this new Tamron, but definitely nothing dealbreaking. There are a few differences I'll have to keep in mind while shooting with this lens though.
1. The lens is very stable, but because of the increased focal length I'll need to have an even steadier hand while free-hand shooting or stick to a tripod or monopod when I can.
2. The lens can only get down to f/6.3 in shade or f/5 in the most light I could find today. Now it might be able to get down to f/5 on better days, but since today was overcast (in fact it's storming as I'm writing this now) that was the best the lens could do.
3. The weight. With this len on my Nikon D7000 it feels like the weight has doubled from when I have the 75-300mm on it. It's not a huge deal, but I can tell for extended shooting it could cause some stress on the neck and arms.
4. The autofocus is a tad slow, but only slightly slower than my other main wildlife lens (the 75-300mm). Since the focal length is longer that's to be expected, so again no major issue there.
5. The lens mount for the tripod gets in the way of focusing, but since I don't shoot manual most of the time it's really not an issue. The lens mount also obstucts the zoom ring a bit too, but not by a whole lot and the mount can be removed so I'm not too worried about it right now. If I end up using the tripod more, which I expect I will due to the above reasons, then this small complaint will go away.
Other than those few things there's nothing I immediately noticed. It handled well for the short amount of time I used it today. I wish I could have hiked around Brazos Bend, but it's still closed due to flooding of the Brazos River and isn't expected to be back open until the 21st at the earliest.
Anyway enjoy the photos.