The Vivitar 2x teleconverter is a very small teleconverter designed to magnify images by 2x. This leads to a light fall off of 2 stops and can be a big handy cap, especially with slower lenses. The Vivitar teleconverter is very compact easily smaller then a zuiko 50mm f/1.8 at around 1.1″ without caps on. It has linkages to preserve automatic aperature control and metering. The teleconverter is composed of 4 elements in 4 groups. On the whole this telecoverter appears to be pretty good quality and is light weight and small. Something to note with teleconverters is that they preserve the minimum focusing distance of the lens, so if a 50mm lens focused down to 14 inches before, it will continue to focus down to 14 inches giving you twice the maximum maginification. With the limited amount of use I have gotten out of it, it seems supremely suited for use with a fast prime lens. I’ve used it a few times now with my 50mm f/1.4 or 50mm f/1.8 lenses to make a close focusing 100mm f/2.8 or f/3.6.
There are a pair of sample photos with the teleconverter. The first one is with a zuiko 50mm f/1.4 attached, making it an effective 100mm f/2.8 and the second photo is with a vivitar 300mm f/5.6 attached making it an effective 600mm f/11. As you can see from the first photo the quality is pretty decent, fully acceptable for use (lens is stopped down 2 stops). The second photo has somewhat low deffinition even in the smallish image, this is mirrored in the 4×6. However I don’t think this is so much a comment on the teleconverter or the 300mm f/5.6 as they both test okay on their own. I think this is more of a comment of attempting to hand hold the combination at 1/1000s shutter speed with the lens wide open (remember 600mm effective focal length and f/11, I was using iso400 film). I would expect with tripod mounting and stopping the lens down a couple of stops the image quality would be significantly better.
Overall I am impressed by such an inexpensive teleconverter.
I ended up getting the teleconverter along with an OM-2 and a Vivitar 35-105mm f/3.5 lens for $35 off Craigslist.