Gagili

Thank You for the answers. It could very esily, as You say, a problem with the contacts. I measured the resistence. It has no lasting value. All the time value varies. At no point was it a constant value. I plan to open one ring and see what and how it was done with the contacts. As well as whether there is a possibility for a firmer and more stabile connection.

First of all, I want to say hello to everyone on the forum. My first post and don't mind if the topic is in the wrong place. I looked where I could open a thread and it seems fine here. I have a problem with the Kenko Auto Extension Tube Set DG for Nikon F Mount. The camera they use is Nikon D780 with a lens Nikon AF-S 24-120mm f/4G ED VR. The problem is in the autofocus when using focus stacking. .When each of the tubes is used separately, the autofocus works. But if I use two or all three tubes, it doesn't work. I have read a lot about the possibilities of why this is so. But I don't understand one thing. If I set only the 36mm tubes, the AF works. However, if I put the 12mm and 20mm tubes together, it doesn't work. The distance from the sensor is similar. The amount of light according to the sensor is almost the same. Contrast, too. Then why doesn't it work? When they are separate, each tube works. However, it does not work in any combination with 2 or 3 tubes. I would really appreciate an answer. And don't mind the English. Because I write to the user a little of my knowledge and google translator.