I received the Fotasy micro four thirds extension rings yesterday and took the time today to run some tests with them. The short review is that they work. Used alone at 10mm, 16mm or together at 26mm, camera control and focus operation is perfect. The quality is acceptable for a $45 device. The flange that connects to the camera is aluminum, the flange to the lens is plastic. With large lenses on, there is some sloppiness to the fit. I would rate this product as fine for occasional use. Serious macro photographers probably will want to spring for one of the all-metal products or purchase a macro lens. Given that the Fotasy rings are light and small, there is no reason not to keep a set in your kit.
Once I had established that the extension rings worked correctly with auto focus, I tried them with my three Panasonic auto focus lenses: the 20mm f1.7, the 12-35 f2.8 and the 14-140 f4-5.8. The 20mm lens with just the 10mm extension focuses so closely that the subject has to be nearly touching the lens. I eliminated if from further tests. The 12-35 lens at 35mm works much better but even at 35mm the subject has to be close to the lens. The 14-140 at 50mm and higher works quite well, even when both extension tubes are used together. Minimum focusing distance is about 8” and a 1” subject pretty much fills the frame.
Turning on the Panasonic post focus feature will capture focus across the full available focus range. Depending upon the lens and distance, this can take up to five seconds, so a tripod would be recommended. Still, hand held shots are possible since the rendering of the post focus images aligns the individual frames anyway. I processed a few of these test shots using the technique described in the video
https://www.youtube.com/watch?v=6wFRy8VQKuQ. As you can see there are some imperfections in the focus stack created by Photoshop. These could be corrected with further work, but I did not pursue perfection with these test shots. Post focusing will try to capture everything in the frame in focus. In many cases this may be more than you actually want. It is advisable to trim the unwanted sections of the post focus video before processing the frames from it. Failure to do so, especially with images like the rulers I used for testing, creates distortion problems in the final stacked images. A small but vexing problem with the Panasonic post focusing feature is that it does not record any metadata in the resulting video file.
Using macro rings, post focus and Photoshop stacking can yield impressive close up photographs. Be forewarned that the processing and memory requirements in your post processing computer are high. Even trimmed, the focus stacks can have over one hundred images in them. In one image I processed, I examined the Photoshop scratch buffer and it was using 36 gigabytes of space to process one roughly 100 frame image! If you try this with an older or slower machine you will be frustrated with the time it takes to do this work and the machine will likely have stability issues.
Notes on the images: The ruler images were stabilized by setting the camera on a bean bag. Aperture may have been 6.3. The Christmas ornament was shot hand held. Due to lack of metadata, I can’t provide more information accurately.
