Today I had some time over and thought I would try an old 20mm extender. I bought this years ago on Ebay, sadly it was the wrong one. I had a Canon back then but now I switched to Nikon so now it fits. I had forgot about it and found it just a while ago.
An extender shifts the focus so that come closer to your subject. Perfect for Macro photography with other words. You do lose a bit of light with an extender but with today's excellent cameras that is no problem. I can easily go to ISO 1600 and get usable photos with my d810. You will not get full on macro but I think it was enough. There are some problems with getting to close too. Like camera shake, extremely short depth of field and a lot of post processing. So this was a good middle way to go.
I used my Zeiss 135mm with the 20mm extender. This turned to work perfectly. The Zeiss is manual focus but that dose't matter, the auto focus would have to slow any way. So I just set the lens on closest focus and moved the camera back and forth to get in focus. A god tip is to take a lot of pictures since most of them are going to be blurry. Don't be to harsh it is more or less the first time I try Macro photography but I think the spider and butterfly shot turned out fantastic. Enjoy!