That explains it. I see more artifacts now that I look closer. Good job on an early focus stacking attempt though
. You may have done just as well to stop down some and go for one shot. At the typical web sizes, you can go pretty high before diffraction gets to be an issue. If you were stacking for the sake of trying it, that's cool too
.
If this were alongside photos of a similar quality that were less generic (and I don't mean that as a bad thing) that showed off the different parts you have for sale, it would be more convincing that you took the photos (I'm talking from the context of someone viewing your ad, I certainly believe this is yours
). Especially if you have detail shots showing off any flaws.
From the selling standpoint, it may also have been better to have this on white so it stands out more. As a buyer of a used item, I'm more interested in seeing the thing I'm about to purchase clearly than having my interest piqued with a little mystery like a typical magazine ad.