At 2,990 Php, this is my most expensive purchase from cd-r king to date.
Granted, there are cheaper alternatives out there with non-electronic extension tubes costing 400-800 Php. Although there are no differences in terms of image quality when using non-electronic extension tubes, manually adjusting the aperture of an electronic lens is time-consuming and it leaves the sensor exposed more often.
Thus, I went with the electronic version not for the autofocus (manual focus is best for macro anyway) but for the convenience of easy aperture adjustment.
Extension tubes, a 50mm f/1.8, and a reversing ring.
Unlike teleconverters, extension tubes are essentially hollow tubes. Considering that there are no fancy motors or glass elements involved, one may wonder how manufacturers could charge absurd prices for these chunks of metal and plastic.
Despite that, extension tubes are still worthwhile investments for SLR owners interested in macro photography since extension tubes could be used with any lens already in the photographer's arsenal. Combined with a reversing ring and the cheap but venerable 50mm f/1.8, it's possible to obtain high magnification without breaking the bank.
50mm f/1.8 lens
50mm f/1.8 lens with reversing ring
50mm f/1.8 lens with extension tubes (13mm + 21mm + 31mm)
50mm f/1.8 lens with reversing ring and extension tubes (13mm + 21mm + 31mm)