It is not difficult to make such a standard head, because its optical structure is not complicated and there are not many lenses.

The domestic lens is doing very well now. As for defocusing, this is not a high probability event. If it happens occasionally, you can adjust it. Don't worry too much. There are also shooting technical problems, such as how to make good use of it, using a suitable lens and a large aperture head. Generally, it will not run out of focus at close range, and the probability of running out of focus at a slightly longer distance will be greater. Pay attention when shooting.

I don't know what you will shoot when you buy this head. If you take female tickets, mainly portraits, you don't often take quick snapshots. And the price is not high, it is not bad to buy a trainer.