Lens extender or another lens?

[Thiophilos]

Remembering that the general handholding rule is 1/focal length for the slowest practical; ....

It's amazing how resilient our rules of photography are. The 1/FL rule was used way back before we had 5 stops of image stabilization.

 

[Overread36]

It's amazing how resilient our rules of photography are. The 1/FL rule was used way back before we had 5 stops of image stabilization.

Yep, but its still a good rule of thumb to go by, esp if you don't know what camera and lens the person has or if they are using an older lens. Even on a newer body that has built in stabilization it might not work as well with an older lens than with a modern one due to quirks in design and communication between lens and body.

So the old rules are still good guidelines to work from in a very general sense. At the very least they establish a baseline to work from.