Buy enough multi-item lots on eBay, and there is bound to be at least one teleconverter in the batch. Cheap teleconverters have a bad reputation—for a good reason. However, since all I have are cheap, that is what I chose to test. In this case, I used a Tamron 2x teleconverter. A Minolta Maxxum 700si was next in the queue for testing, so I popped in a roll of UltraMax.
These shots were taken the first summer after I got into photography, and I wanted to try some things I had read about. By this time, I also had a set of close-up filters and a Maxxum 100mm f2.8 macro lens. This macro lens is the sharpest AF Minolta lens in my collection, so it seemed the perfect candidate for a test run with teleconverters and close-up filters. Altogether, I used three AF lenses: 100mm f2.8 macro, 70-210mm f4 (Beercan), and 75-30mm f4.5-5.6 (Big Beercan).
Looking at these scans nearly four years later, I see they are 1/2 the pixel density I usually set when scanning at home. These lab scans are 1800 x 1200 pixels— the size of a 4 x 6 inch print. I typically scan at 3200 x 2000 pixels. Therefore, when viewing these, remember that on a regular computer screen, they will not look as good as possible. Anyway, these initial tests taught me two things. First, using a 2x teleconverter on a typical Minolta AF zoom kills the AF capability, and second, using a teleconverter costs two stops. As a result, the Beercan shots are all manually focused.
Here are the results, side by side, showing the 100mm f2.8, 70-210mm, and 75-300mm in that order. All images were taken at the maximum focal length for each lens.
Overall, the 100mm f2.8 did very well, even considering these are with low-resolution scans. Surprisingly, even the zooms did okay in some shots. No doubt, my difficulty focusing the zooms contributes to their poorer showing. At some point, I’ll likely dig out these negatives a rescan them and see the results a 3200 x 2000. It’s also obvious I shot these before learning to using -1.5 EC for red flowers.
What have I learned from this? Since these shots, I have used close-up filters to great effect. Teleconverters I have shied away from. I have also opted for better macro capability over focal length enhancement. And in that vein, I have bought bellows, reversing rings, and extension tubes to try. At some point, I will do a series of posts on my macro efforts and see how they all compare. What macro method have you chosen?