Tamron AF 2x Teleconverter

Normally i hook up this tele on my 80-200 F2.8 lens to snip on street or basic bird photography. It provide a low cost alternative to go up to 400mm (equiv to 600mm on a 1.5 crop factor Dynax 7D) without the need to purchase expensive 400mm. Image appear slightly softer but acceptable for print up to 6R. The quality is so far as good although some chromatic abbreration on the edge of the photo.

Low cost Good alternative to double the zoom length provided you have a fast base lens.

Chromatic Abbreration at edge.

Never did

This 2x teleconverter and the Quantaray sold by Ritz camera look suspiciously similar. Although Quantary is usually made by Sigma, I suspect they did something different here. The Quantaray is much cheaper (only $80), and as far as I can tell, optically identical when comparing pictures side by side. I used this TC with a Sigma 28-300 macro lens (which is a surprisingly good lens - sharp even at 300mm). With the TC, I had an effective 52-600 lens. To my surprise, sharpness was fairly good at 600mm in the center of the photos, especially if I stopped down the main lens slightly. But toward the edges there was chromatic aberration that degraded the photo quality. There was an overall loss of contrast with this TC compared to without it. This TC works OK, but you should get the Quantaray version, which seems to have identical lens elements, but is 1/2 the price.

Not awful.

More expensive than identical Quantaray. Minor chromatic aberration at edges.

Quantaray 2x TC