This will be my second moan in succession. It must be a sign of old age. I have become a grumpy old man.
I sold my Lumix 100-300mm lens several months ago in anticipation of buying the new 100-400 as soon as they became available on the second hand market. It always amazes me how quickly you can buy used camera gear. The first one used one appeared on Amazon a few weeks ago for £700, but was an obvious scam and I did not proceed, but it made me notice how much they had dropped in price. I could now get a new one from France for £1007. I placed my order and it arrived a few days later.
As well as the extra pulling power of a 100-400mm lens (equal to a 200 to 800mm on a full chipped camera) I was looking forward to it having a foot mounted on the lens so the lens can be attached to the tripod and not the camera. This means the lens can be swivelled from the horizontal to vertical mode, unlike the 100-300 which had no foot mount. I was immediately disappointed to see that the lens will only swivel 90 degrees. So unless you start off with the tripod dead level you can’t get to the vertical mode and if your horizon is not level you can swivel in one direction only. Why would they do that? It must take extra engineering in the design to incorporate the stops, preventing a full turn. Any other lens I have used with a foot mount turns 360 degrees and it is necessary. Every time you pick up and move the tripod you have to stop and make sure it is dead level. Not convenient at all when stalking a bird. It always makes me think people who make camera gear are not photographers.