The longest zoom lens, which I still have after all these years, has been the Tamron 200-500mm f/5-6.3 which wasn't very fast as in the auto focus being screw driven and it also had a tendency to zoom in and then out before auto focus would lock. Fortunately the new Tamron 150-600mm is driven by an Ultrasonic Silent Drive (USD) auto focus motor so should provide quick and precise focusing. One thing missing from the Sony version of this lens is the Vibration Control function as Sony camera bodies have built in image stabilisation. The lens is designed for both full-frame and APS-C image sensors and on a 1.5x crop crop of an APS-C sensor the 35mm equivalent focal length equals 225-900mm except that the focal length of the actual lens isn't 600mm, it's 582mm(873mm). As with my motorbike which is sold as a 250cc machine, the engine capacity is actually 248cc with the number rounded up.
Ordered at the start of January 2014 when the CanNikon fit became available, I was hoping the Sony fit would soon follow so I could use it over the summer air show season. It eventually arrived the first week of September 2014, the day before the Shuttleworth Collection Air Show at Old Warden, so I've only used it in action at that and the Duxford air show. The following is a quick first impressions review until I can use the lens more thoroughly next year.
PART 1 - First Impressions. (September 2014)
Shuttleworth Air Show ~ 7th September 2014
Duxford Air Show ~ 8th & 14th September 2014
This is a big and heavy and very long when extended in use lens. Closed without the hood attached it's 10.5 inches(270mm) and fully extended with the hood on it's 17 inches(430mm) then you add on the camera. I used it attached to a Sony Alpha A77II/24.3mp Digital SLT camera which itself has a bit of weight to it and balanced out the lens a bit. I hand held the camera and lens combination and as with my Sony 70-400mm G SSM lens, I had the tripod mount resting in the palm of my left hand and used my thumb and index finger to adjust the zoom ring. By the end of the Shuttleworth Air Show I had a sore hand from supporting the extra weight of the lens and by the time I got home on my motorbike I could hardly release the grip on the handle bar and had to massage my hand to get the fingers moving again. I now use the tripod mount as a handle to carry the lens. For the rest of the week and the Duxford Air Show, I had the zoom ring resting on the palm of my left hand with my fingers gripping around it.
Unfortunately you can not rotate the zoom ring from 150mm to 600mm in one go. Well you can but you end up doing contortions and standing awkwardly with your elbow pointing sky wards. With paning I quickly found that with the lens at 600mm I could comfortably rotate the zoom back to around 300mm when the aircraft got closer and then zoom out to 600mm again. At Shuttleworth and Duxford you are reasonably close to the flying action and really didn't get the zoom to 600mm that often. Auto Focus is very fast and quiet on the lens but one thing I do miss is a focus lock button on the lens barrel. There is a lock on the lens to stop it creeping if you point it downwards though.
GETTING TO GRIPS WITH IT.
I use the camera in manual mode as much as possible, setting the shutter speed around the 1/400 second mark to give propellors a bit of blur and for hand holding is probably a bit on the low side with the lens at 600mm. Aperture varied from about f7.1 to f11 depending on the light available and the ISO left on AUTO and Metering Mode on Centre Weighted Average. I've found in the past that if you use just shutter or aperture priority and let the camera work out the other settings, it can tend to get them wrong and hence under/over exposed images.
The Shuttleworth Air Show was held in bright sunshine and I had no problem's with the image quality which is bright and vibrant and coming out very sharp, even at 600mm at slow shutter speeds. A week later at Duxford and it was cloudy and overcast. At times I was using the camera aperture at f6.3 and as with my Tamron 200-500mm lens, the 150-600mm did struggle a bit with grey aeroplanes against grey clouds. As with most lens with a maximum aperature of f5, they work better in bright light like sunshine. Several times it lost focus lock, something I didn't get with the Sony 70-400mm G SSM which starts at f4. When that started to happen, usually at the 600mm end, then I just pulled back on the zoom a bit and focus was re-established with the super fast 79-point phase-detection AF system in the Sony A77II.
Although the specifications for the lens say that there are three 'Low Dispersion' elements to correct chromatic aberrations, or color fringing around high contrast edges, this still occasionally occured in some of my photos not that I noticed it at Shuttleworth but more at Duxford where the sun is generally in front of the aircraft and I had the aperature open wide. I did manage to control it by adjusting camera settings. Vignetting, or the darkening of the corners of the image when compared to the center, did occur from time to time. Nothing that can not be corrected in image processing software and Tamron have thoughtfully provided a lik and product key, included with the lens paperwork, to download a copy of SILKYPIX Developer Studio 4.0 which can be used for the vignetting/chromatic aberrations corrections amongst other things.