​The new Tamron 70-210mm f/4 telephoto zoom (Model A034) won’t break the bank to own or break your back to carry. Cost and heft aside, what really matters is performance. I used the lens with my Nikon D610 – a full-frame DSLR matched to a full-frame lens (although the lens could also be used with my DX/cropped-sensor Nikon DSLRs), photographing a variety of subjects large and small. How well did the lens perform? Let’s see. But first…
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​Why Do You Need an F/4 70-210mm Zoom?
Well, let’s imagine for the moment that you already own a variable-aperture tele zoom. What’s to be gained? We’ll put aside consideration of an f/2.8 lens, given that glass’s relatively high price and heft.
 
An f/4 lens is a workable compromise. Popularly priced variable-aperture telephoto zooms weigh in at a zoom range of 70-300mm with a corresponding variable aperture range of f/4-5.6, or, worse, f/4.5-5.6. These lenses are more than you need for that portrait session you’re shooting outdoors. Not to mention, those variable maximum apertures can be a royal pain when using a handheld meter to check exposures, especially with studio flash or manual shoe-mount flash. Knowing where you stand with your F-stops always gives you a leg up on your exposures.
 
The story doesn’t end there. Zoom out and that variable-aperture f/4-5.6 lens loses more and more light in the process. At just under 200mm, it’s at f/5, hitting f/5.3 at 200mm and f/5.6 at around 250mm. In other words, an f/4 lens is nearly a full stop faster at 200mm.
 
Photographing kids? You’ll definitely appreciate having a maximum aperture of f/4 to blur out annoying backgrounds as you zoom in, while shooting at relatively faster shutter speeds without having to crank up the ISO. But beyond that, autofocusing is faster with an f/4 lens when trying to capture a precocious toddler in an outdoor setting than with your other zoom, given that focusing sensors are designed around faster maximum apertures, for the most part. 
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​And Now for the Nitty-Gritty – Optical Performance
I’ve used this lens on things you wouldn’t normally use a 70-210, as well as the expected. I shot street candids, landscape, and even birds, bugs, and flowers. With birds and bugs there is a caveat: you keep the subject near or at the center of the frame, expecting to do some tight cropping in post. And for that reason, the lens has to be really sharp, especially toward and at the center.
 
Still, I want good performance out to the corners and edges as well. And let’s not forget that vignetting and distortion, as well as chromatic aberration (color fringing), also have to be taken into account.
 
While we can use vignetting to frame the subject on rare occasion, for the most part we’d prefer to live without it. And shooting without any pronounced distortion would be welcome as well. So, to cover my bases, I also set up some test targets, in addition to my field shooting.

​​Vignetting. I primarily tested for vignetting by shooting at a uniform area of blue sky in the afternoon (with the included petal-shaped lens shade attached). On my full-frame DSLR, with the lens set to 70mm, vignetting was readily observable at maximum aperture (f/4), diminishing as you stopped down – until you reached the magic number – 2 full stops down (the sweet spot for many lenses), where it practically vanished. (Expect performance to be even better with a cropped-sensor camera, which cuts out much of the offending vignetting from the get-go.) However, the picture was a bit different as I zoomed out. At 210mm I noticed a faint trace of vignetting even at f/8. At f/11 it was no longer a practical concern.
 
In day-to-day shooting, I focused more on my subject than on vignetting, and often found myself shooting wide open, or close to it. Vignetting was not a practical consideration – or a problem. Where necessary, I was able to address it to my complete satisfaction in Capture One using the Light Falloff slider. (I found the lens profile in Lightroom less than optimum for this correction.)

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Build
The lens certainly felt solid in my hands. All operations were smooth. If you’re fishing for more details, we should note that, despite its relatively low cost, the lens also boasts moisture-resistant seals (get it, fishing, seals?).  Beyond that, the front element features the same smudge-resistant barrier incorporated into Tamron’s costlier lenses, such as the 150-600mm G2 and 70-200 f/2.8 G2, via a fluorine coating. As I’ve pointed out in the past, I wish Tamron would add the fluorine coating to the rear element as well. Still, the front element is the one that fingers, flying insects, and the elements target first and foremost, so having this as a first line of defense, together with that moisture seal, is a welcome step.
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​This is how I ended up buying, and testing, the Tamron 150-600mm G2 lens.
 
My interest in bird photography took a decided turn earlier this year. Over the past few years, I’d been photographing deer, mostly with a Tamron 70-300mm on my Nikon D610. However, aside from the occasional waterfowl, birds were largely out of the question. Then I wrote a column for Shutterbug Magazine on the amazingly talented bird photographer Alan Murphy and I’d found the impetus I needed. 
 
Alan’s bird photography is largely reminiscent of the paintings of John James Audubon. His images have this clean, uncluttered look, with a unique depth to them. I could only hope to achieve a modicum of his success. Anyway, you really should check out Alan Murphy's bird artistry on his website.
 
Alan conducts workshops on bird photography, and I had asked him what lens focal length he recommends to workshop attendees. He answered, 600mm. Numerous factors come into play that may affect that choice (species, time of day, situation, for example), but that 600mm is normally the go-to workshop lens for many scenarios.
 
And that got me thinking. My longest focal length until recently was 300mm (in a 70-300mm zoom for my Nikons, as well as a Canon 300mm f/4 fixed-focal lens when I was shooting Canon). Not nearly enough for those birds I wanted to photograph. Even attached to my Nikon D300, that only gave me 450mm – respectable reach, but not ideal, keeping in mind that birds in the wild keep a buffer zone between you and them – and that buffer zone translates to: I need a longer lens!
 
So I explored my options, namely, the cost of a long lens, its size and weight, and how I’d primarily be using it. I usually shoot handheld with most lenses, and largely by available light, resorting to flash only occasionally. When I’d finished crunching the numbers, the choice was obvious.
 
I bought the Tamron 150-600mm G2.
 
Poor AF with fast-moving subjects on the cameras I then owned, namely the Nikon D610 and D300, also meant I needed to update to a more responsive DSLR, and one that could easily work with the maximum f/6.3 aperture on this Tamron zoom. That soon resulted in the purchase of the Nikon D500 (look for a test report on this camera soon). Attached to a DX camera - specifically the D500 (APS-C format with a cropped sensor factor of 1.5x), this lens would give me 900mm out of the gate, and 1170mm when I applied the additional in-camera 1.3x crop factor without adding any converters. That gave me considerable reach, although I’d discover that capturing flighty subjects at nearly 1200mm would prove to be largely a frustrating task.

​The Tamron 150-600mm G2: Optics
Optically the lens features low-dispersion glass to deliver crisp images, with proprietary coatings to counter flare and ghosting. Whereas both old and new versions of this lens feature moisture-resistant construction, only the new G2 can boast fluorine coating.
 
While not new in a Tamron lens, and certainly not exclusive to Tamron, fluorine coating, according to the company, makes the lens surface “easier to wipe clean and less vulnerable to the damaging effects of dirt, dust, moisture, and fingerprints.” I try desperately to avoid anything coming in contact with the surfaces of my lenses, so thankfully I didn't have to test for this feature.
 
The one question I have for Tamron is: Why fluorine-coat only the front element? Why not also the rear element? A lens can easily get smudged at either end. (A question I’ve asked before with regard to Tamron’s 15-30mm f/2.8.)
 
Tamron also improved close-focusing on this lens. The original 150-600 focused down to just over 106 inches for a 1:5 reproduction ratio. The new G2 version takes that down to under 87 inches (1:3.9), which is a considerable difference that you may not fully appreciate just from the numbers. Not a true macro lens, but very respectable – and it would prove to come in handy. I managed to capture some fairly tight shots simply by zooming all the way out to the 600mm setting and bringing the lens in as close as possible.

​Adding a Matched Converter
This Tamron lens does have the option of a matched converter. The available converters are 1.4x (TC-X14) and 2x (TC-X20). Keep in mind that adding a converter effectively slows down the lens, by one and two stops, respectively, leading to slower AF response times.
 
I held off adding the converter because I was buying the D500 primarily for its AF responsiveness and didn’t want to hamper the camera in any way. One day I might yet entertain buying the Tamron converter. But not today.
 
In combination with the 1.5x and 1.3x crop factors built into the D500, a 1.4x converter would take this lens to over 1600mm. On top of that crop factor combo, the 2x converter would effectively give me a 2340mm lens. Either would also require a bright, sunny day and birds that remained fairly stationary for less than optimum shutter speeds or which I could photograph in flight, while I panned with the camera. And don’t get me started on handholding limitations. Suffice to say, a sturdy tripod with a  gimbal head would be a practical addition to your field outfit at this point.
 
While this lens does employ Tamron’s proprietary Vibration Compensation (VC) technology, image stabilization only takes a lens so far. Although, it often comes to the fore in situations where neither a tripod nor monopod is a practical solution.

In Use: Handholding the Tamron 150-600mm G2
I own a Canon 300mm f/4 IS lens. I used to complain about handholding that lens. No more. This Tamron lens makes that one feel like a featherweight. Okay, I exaggerate. Still, the Tamron is about 2 lb. heavier, and when held for long periods, that literally begins to weigh on you.
 
I’ve taken to doing curls with a 10-lb. dumbbell to build up endurance and resistance in my left arm, the one supporting the lens – and I’m happy to say, it’s worked, though I don’t feel I’m quite there yet. Still, I’ve been able to reduce shutter speeds at maximum focal length and still achieve sharp results.
 
After all that handholding, I’d decided to make things easy for myself and bring a monopod into the picture. What a difference that made! Granted, it slows me down somewhat and now I have to be careful when moving about, unless I collapse the leg or, better yet, detach the monopod from the camera entirely – two steps guaranteed to slow me down further.

​In Use: Image Stabilization
The lens offers three VC (Vibration Compensation) image stabilization modes. Mode 1 stabilizes the image when the shutter is released, but also maintains a stable viewfinder image while the shutter button is pressed halfway, or the AF button is activated. Mode 2 is used when panning. And Mode 3 foregoes the stable viewfinder image to deliver more certain stabilization of the image (which means, you’ll have to hold really steady to keep critical areas in focus). FYI – according to the official number crunchers, Tamron’s VC will deliver 4.5 stops of optimized shutter speed performance against camera shake when set to Mode 3.
 
In practice, I largely kept the lens in Mode 1. If you have trouble holding the lens steady, your compositions and focusing may be thrown off in Mode 3. Mode 1 at least gives me a good shot at controlling both.

One thing I’ve discovered is that I do much better getting sharp shots with the lens tilted downward to some degree, rather than straight on or upward. Apparently, there’s less tension exerted on the supporting arm this way. I did manage to get a camera-shake-free picture of a flower with the lens at 600mm (= 900mm/full frame) at 1/60 second, which translates to roughly a 4-stop gain for a handheld exposure – in Mode 3. The optimum for a handheld exposure at this focal length would be 1/1000 second.
 
When I was testing the Tamron 70-300mm some years back, I was able to go 5 stops slower than the recommended shutter speed to prevent camera shake, though not consistently. I really don’t like to rely on any image stabilization technology if I can avoid it, but I will resort to it in a crunch. When shooting with the 150-600mm, especially at the longest zoom setting, I often kept to fast shutter speeds, at most stretching to one stop slower. But these settings were also based largely on the fidgetiness and movement of my subjects, which mandated fast shutter speeds to begin with.

​In Use: The Dual Role of the Tripod Mount
The lens comes with a removable tripod mount. Do not remove the tripod mount. You know what will happen if you do: you won’t find it when you need it. More to the point, I use the tripod mount as a grab handle when carrying the lens. And I’ve attached a sling strap to the mount.
 
Also, for better balance, at least with my D610 and D500 (without battery grip), I’ve used the rear screw thread on the tripod mount for this purpose. The lens's tripod mount comes with a built-in Arca-Swiss-style quick-release (QR) plate. There are two tiny screws (provided) that you should attach at the base for added security (hex wrench included). Periodically check them and tighten if required. (A little bit of clear nail polish should keep the screws in. A trick I learned from one of the nicest people in the industry, the camera repair maven, Marty Forscher.)
 
So, why do I carry the camera by the lens’s tripod mount if I’m using a sling? Whenever I use a sling, I always grab hold of the camera as I’m moving about so I can more quickly bring it to my eye. I usually grab the camera by the grip, but that’s not a prudent step with a long, heavy lens such as this. Hence my use of the tripod mount as a handle. (I strongly recommend that you steer clear of picking the rig up by the camera body, and especially in sudden, jerky movements, which may exert sufficient torque force to damage the camera.)

​In Use: Zooming and Focusing
Zooming, while smooth, is not as fast as I might like. You have to grab the lens’s zooming ring with your whole hand when zooming from one extreme to the other, and it takes several turns or one or two really good twists if you’re a contortionist. When I’m running around, I often prefer to retract the lens so it doesn’t protrude as much and bump into things. But I’ve gotten used to it. A push-pull mechanism option would have proved handy, although I’m not sure that might not play havoc with the lens’s mechanics and long-term durability.
 
For minor focal-length adjustments, by cradling the lens in the palm of your hand and then using both your thumb and index or middle finger, you can easily zoom. The way you position the tripod mount will affect how you zoom. Without it, you may find zooming goes more smoothly.
 
Manual focusing or manual focus override with AF is more to my liking, and quite smooth. I can manage that operation with a finger or two on the focusing ring.
 
Autofocus operation in and of itself is reasonably good. That is, of course, due in large measure to the D500 that I’m primarily using with this lens now. It was not nearly as good with the D610.
 
The old and new 150-600 feature Tamron’s USD (Ultrasonic Silent Drive) ring-type motor, but Tamron does claim better AF performance with this lens. How much of that is a function of the lens itself is difficult to measure, but I’ll take Tamron’s word for it that it’s improved over the previous iteration of this lens, since I can’t compare them side by side. Either way, the G2 is fast but sometimes doesn't seem fast enough with flighty subjects. But I could also be to blame for not responding as quickly as I should in these situations.