It’s been a bit of an eye opener to try the Tamron 150-600. For years now, I’ve made do with lenses of 200mm or shorter, and added a teleconverter when I had to.
This has always had an effect on subject choice though. I’ve never really given any serious effort to bird photography, since any attempts to do so would require ninja-level stealthiness that I just haven’t got (a few weeks ago I fell ten feet down a nettled embankment trying to get close to a damselfly).
And there are some things that you just can’t approach safely with a shorter lens. Today’s gallery is one such example.
One of my local wildlife reserves is home to a family of horses. Normally, they stay well away from people, but on this particular trip, they were all grouped together on the path, and seemed stressed. One of the stallions was galloping up and down, and was asserting a boundary.
Looking closer, one of the foals appeared to have collapsed from the heat. Using the Tamron’s incredible reach, I was able to follow the action from a safe distance.
Happily, the little one regrouped after a little nudge from its mother, and all moved on after a few minutes. It was delightful to watch the foal come round, and how the others reacted to it.
The penultimate frame of the set really shows the advantage of the Tamron lens, and was taken from the same vantage point the others. The thing about this lens is that you don’t have to rack it out to get close. It breaks the all-important 400mm barrier, which seems to be the point at which serious efforts become possible. At 450mm, the results are very considerably sharper than at 600mm, and still magnify well enough to identify things when you can’t get close enough to see for yourself. Being honest, the quality of results at the more modest focal lengths would still be enough to justify the price of this lens.
Yes, it’s a slower aperture than I’m used to, and it feels it. But when limiting the focus switch to the longer reaches (15m – infinity), the focus speed seems surprisingly snappy (I can’t quantify this, but when I tried the Canon fit earlier in the year, it seemed a little more responsive than the Nikon model I’m using now). But if you aren’t shooting crepuscular subjects or spending hours in a cramped hide on wet days, I’m not sure you’ll see the need to blow an extra two grand on the next alternative.
As an entry level, or “compact” telephoto for good light, the 150-600mm is an absolute godsend.
the days zoom past 
Thanks for this post. I am looking to add this to my A7ii with LAEA3 adapter.
When you are at the zoo, is it able to make cages “disappear” like I do with my faster FD 300mm F2.8 ? I am looking for the flexibility and extra range vs my prime.
I do have the 70-200mm 2.8 but its not long enough some times.
It depends on a couple of factors. It’s certainly long enough, but sometimes it comes down to factors you can’t control, such as the design of the fence (double mesh fences are a nightmare), or the size of the enclosure. If the animal was close enough in range to you, I’d still opt for the faster lens to take out the fences, but over distance, the Tamron one will be a big help. Generally your best bet is when the animal isn’t right up against the fence, and has a greater distance between it and the back of the enclosure.
Remember that this is an F/6.3 lens, so your background effects won’t be as smooth as those from your 300mm lens.