How about a small spittoon for Canon 70d? Novice, novice

Absolutely.

The focusing performance of the 70D is very good, and the 50/1.8 generally has no problems with focusing.

Strictly speaking, with the same aperture, the optical performance of the small spittoon on the half-frame camera is better than that of the 50/1.4, but the poor part is the electromechanical part. Therefore, if the use is not intensive and it is not used for business requiring high reliability, this head is still very good.