Great Grey Owl (Strix nebulosa, Chouette Lapone, GGOW) ©Christopher Dodds Sony Alpha a9 Mirrorless Camera & Sony FE 400 f/2.8 GM OSS ISO 1,250, F2.8 @ 1/5,000s Manual Exposure mode. Join me for my winter owl workshops this January/February to learn More CLICK HERE.
Sony FE 400 f/2.8 GM OSS Mini Review
I am just back from a cross Canada road trip that took just over six weeks and covered more than 17,500km. I was honoured to stop and present at various camera stores across the country, then ended the trip with presentations at ProFusion (Canada's largest camera show); all sponsored by Sony of Canada. Thank you Sony. I got to meet so many great photographers along the way; it was a blast!
I have received a lot of email asking about my thoughts on the new Sony FE 400 f/2.8 GM OSS lens; if I had one, and if I thought it was worth the price tag. Yes, I do own one and YES, it is worth the price! When paired with the Sony Alpha a9 Mirrorless Camera, the Sony FE 400 f/2.8 GM OSS is the fastest, most reactive with the most accurate auto focus lens that I have ever used. It is light and very well balanced (there was a lot of engineering involved to carefully design the lens with most of it's optics toward the back to make it really easy to hand-hold; a real win for birds-in-flight photographers). Add the Sony 2X Tele-extender, and you end up with a prime killing 800mm f/5.6 that is sharper and more capable than the Canon or Nikon prime lenses that I have used.
Sony took a huge step when thy developed the hybrid AF system that the Sony a9 uses; they have leapt forward with the XD Linear focus. There is no camera and lens that can focus as fast!
From the Sony website: "The XD Linear Motors have been newly developed to deliver higher thrust and efficiency than conventional types in order to make the most of the rapidly evolving speed performance of current and future camera bodies. Linear motor design and component layout have been thoroughly revised to achieve significantly higher thrust. Two of these new motors are used in the SEL400F28GM, achieving up to a 5x improvement* in moving-subject tracking performance. This means that the full speed performance of advanced camera bodies can be applied to capturing perfect images of the most dynamic sports or wildlife subjects. The XD Linear motors are further supported by new algorithms developed specifically for them, notably improving the motors’ response to control signals and minimizing lag and instability that can occur when driving a large aperture focus lens group for quiet, low-vibration operation. "
In summary, XD Linear focus is so much faster than the conventional rotational focus because it quickly and efficiently "thrusts" forward and backward to achieve tack sharp focus. Since conventional lens elements rotate like a nut on a bolt, they have to travel about five times further (think how little a nut moves in relation to how many times it must be turned). There is a limit as to how fast a lens (or lens group) can safely move in a rotational manner.