As I have already pointed out in my Sigma 1.4x teleconverter review, none of the Nikon teleconverters mount on Sigma lenses. It turns out that teleconverters are brand-specific – Nikon teleconverters are designed to only work well with Nikkor lenses, while Sigma teleconverters are designed to only work well with Sigma lenses. So if you were thinking of buying a Sigma 2x teleconverter to be used for a Nikon telephoto or super-telephoto lens – forget it. Even though the teleconverter will physically mount on any Nikon telephoto lens that can take teleconverters and might perform well optically, it will still cause all kinds of lens communication and autofocus issues. For example, when I mounted the teleconverter on the Nikon 300mm f/2.8G VR II lens, it confused my camera into thinking that the maximum aperture of the lens was still at f/2.8 (the correct max aperture is f/5.6 instead, since 2x teleconverters lose two full stops of light). I also lost the ability to autofocus – the teleconverter caused the Nikon 300mm lens to go to an AF loop. In short, only use this teleconverter with Sigma lenses! Accepts both 1.4x and 2.0x EX Teleconverters to produce 420mm F4 and 600mm F5.6 Autofocus ultra telephoto optics. Big, fast glass is a serious investment for any photographer and for those who specialize in nature photography, it's no different. Depending on the size of the subject, a 300-millimeter telephoto lens is considered by most knowledgeable wildlife photographers to be the absolute minimum practical focal length for fieldwork. Most prime (single focal length) telephoto lenses can accept and work well with teleconverters to extend their reach, but at the expense of shutter speed due to the smaller effective aperture when a teleconverter is employed. Just as 300 millimeters is considered the minimum focal length for serious wildlife photography, so is an aperture of 5.6. While a 300 f/4 lens with a matched 2X teleconverter will yield a 600mm focal length with acceptable image quality, the effective aperture of f/8 makes the viewfinder dark, shutter speeds long and autofocus in most camera systems slow or inoperative. Sports and Wildlife photographers would love this lens. The best thing is, I did not care about the weight after a while. It was fun to shoot with. Please Support The Phoblographer The drop-in 46mm filter holder in the rear part of the lens barrel can be rotated to facilitate the use of a polarizing filter.

APO 300mm F2.8 EX DG HSM / EX DG - SIGMA Corporation

The Sigma 120-300mm ƒ/2.8 DG OS HSM Sports lens is the first telephoto lens produced by Sigma as part of their Sports ("S") series lenses under their new Global Vision strategy. Serving as a replacement for the previous model, the Sigma 120-300mm ƒ/2.8 EX DG OS HSM APO, the new lens features redesigned mechanics and exterior construction. It's also heavier than the previous model, weighing in at around 8 lbs. with the hood and tripod foot attached, compared to the 6.5 lbs. of the old version. It's also slightly larger in length and width. In summary, good results on average, but you don't see big gains through stopping down. As well, the Sigma magic doesn't seem to come through on this sample of the lens; there isn't an aperture setting which provides extraordinary sharpness. When you add a 1.4X converter it will still produce sharp images but will reveal more chromatic aberration (in some situations) with a Sigma converter than the Canon prime with a Canon converter. However the chromatic aberration can be managed with software. These were all taken stopped down a good deal, unlike most all the shots taken during my Tanzania outing which were mostly taken at or near wide open.On a Crop sensor, this lens is effectively a 450mm lens. That’s a nice focal length to be able to work with. The Sigma 300mm f2.8 made my Nikon D90 feel really small. It felt decent on a crop sensor but I preferred it on the full frame for the balance. Portraits Taken by Scott Wyden D800 f5.6, 1/80, ISO 100 Similar to AF performance, lens sharpness, contrast and color rendition will depend on the lens the teleconverter is coupled with. When I used the teleconverter on the Sigma 120-300mm f/2.8 Sport, contrast decreased a little, similar to what you would see with the TC-20E III. Sharpness was certainly impacted, especially at the widest aperture of f/5.6. Stopping down to f/8 improves things a bit, as illustrated in MTF charts below. I wrote a few PM responses to a couple of people who asked for my thoughts about the Sigma 300mm f/2.8. Here's a re-work of them with some additions. Basically, you can create a custom profile with different autofocus speed settings (speed vs accuracy priority), optical stabilization and focus limiter. For example, you could set the first Custom switch for fast autofocus, no optical stabilization and focus limiter set to 10m to infinity for photographing fast action at very fast shutter speeds, while the second switch can be programmed for more accurate autofocus, OS and a full range of focusing for other situations. This is great and something very unique to Sigma – neither Nikon, nor Canon allow this much customization on their lines of lenses.

Sigma 300mm f2.8 EX - The Phoblographer Sigma 300mm f2.8 EX - The Phoblographer

With a magnification ratio of just 0.13x and a close-focusing distance of 2.5 meters (over 8 feet), macro users should look elsewhere.

Not all is bad though. The all-metal lens barrel is surely impressive, making it feel like you are shooting a pro lens. There are a number of useful switches on the side of the lens for additional tweaking. Aside from the typical autofocus / manual focus switch, there is a very useful focus limiter switch that allows going from full rotation to 10m-∞, and from close focus to 10m for macro shots, which is great (the 120-300mm f/2.8 EX DG HSM did not have one). There is a separate switch for setting two different optical stabilization modes like OS 1 and OS 2 (more on image stabilization below). This lens is sharp depending on the subject distance. I found it is not that sharp when the subject was over 150 feet away. For a telephoto lens I did not like working with subjects at a great distance. Color Rendering and Color Fringing How well (or poorly) it works w/ the Sigma converters is largely a matter of users' expectations. IMO the IQ w/ the 1.4x is still close to excellent; significantly better than cropping the image done w/o the converter, and with the benefit of better magnification in close-ups. With the 2x there is a greater loss of IQ, but combo is still usable and still yields better IQ than cropping the 300mm image; the biggest loss IMO is in contrast. Of course a 600mm combination is very vulnerable to subject motion, so high shutter speeds are called for in many situations, but that would be the same issue with almost any very long lens or combination. I personally did not like the Canon 300 IS for birding either. The Canon 300 II changed all that. It is the first lens I am happy with. For birding. A great all around-er that takes T.C.'s fairly good and AF excels with pro body's.