Day 194: Macro coupler (the macro options). Dennis got it! (194/366)
This is a small inexpensive ring that allow mounting a smaller focal lens in reverse in front of a larger focal length lens. All you need is the filter size of both lenses to get the coupler. To calculate the reproduction ratio, divide the focal length of the lens in the camera by the focal length of the reversed lens in front. Advantage: Able to use all exposure mode. Disadvantage: Not able to use aperture smaller than f/11, depending on the lens, vignetting will darken the edges. And the working distance from the lens is only 2 inches. Recommendation: Set the aperture of the reversed lens, all the way open. Set the focus on manual, so the auto focus will not get damage by the weight of the reversed lens. More about coupling rings. This guess what, is of a clear color. The blue colors inside are only reflections of the background. ( My Macro/Micro World )
Data: Canon 40D, f/11, 1.5 sec, ISO: 100, Lens: Tamron 200mm with a 28mm Canon mounted in reverse, Maginfication: 7:1, Mode: Manual, Focus: manual, Filter: none, Support: Copy stand, Remote: yes, Flash: Vivitar 283 @ 1/32 power, Process: Canon Digital Photo Professional, file: 120712EOS 40D258, Date: July 12, 2012. (Note: Exif data never show f/stops of manual focus lenses with adapters.)
Spanish: Mas abajo esta la versión en Español.