Sorry, but the confusion here is that you’re confused about the relevant concepts. Focal length is an intrinsic property of a lens, independent of the sensor behind it.
So what you are suggesting is not make a 100-400 APS-C specific lens, you make actually make a 65-280mm lens and sell that as '100-400 equivalent'. You seem to be confusing magnification and field of view: in magnification terms, a 280mm lens is a 280mm lens not a 400mm lens nd people buy these lenses for magnificaiton, not field of view.
Manufacturers tend to do that: eg Sony RX10 Mkiv
It was far from clear that you were talking equivalency, but what I said still holds for telephoto lenses. You can scale a 320mm FF lens to 200mm and call it a "320mm equivalent APS-c lens" if you like, but the fact remains that it won't be much if any smaller than a 200 mm ff lens if it has any significant speed. There is also another aspect of equivalency that you are missing. An APS-c sensor (Canon) only has about 0.4x the area of a FF sensor, so if you want true equivalency, then that 200mm lens needs to be about 1.3 stops faster than the 320 mm FF for the same IQ and DOF as the FF. This is essentially what speed boosters do. They take all the light from that 320mm FF lens and put in in a smaller image circle and one stop faster for approximate APS-c equivalency. In the end, you still have exactly the same lens you had before with slightly different exit optics. Here you have a bigger lens feeding a smaller sensor (just the opposite of the teleconverter example I gave before). However, even if you optimize the 200mm lens for APS-c, it will still have the same objective diameter as the 320mm FF if it is truly equivalent. To paraphrase neuroanatomist, physics is a stone cold bitch.
My standard flight option is:
I believe it happens at high frame rate in low contrast situation. Here's Duade Paton's experience .
Choose airlines that don't weigh cabin luggage - I use BA and Easyjet locally and avoid Ryanair. I did take a vest on a trip to Borneo as the Malaysian airways weigh for the local leg. Mind you, apart from the weight advantage, BA now give Ryanair service at BA prices.My standard flight option is:
Scott eVest for bodies, batteries, chargers and smaller lenses etc = ~7-10kgs
Backpack with RF100-500 and PC = ~7kgs.
Repack backpack after checkin/security
Did it recently from Oz to JP/UK/FR/DK/NO/SW/SG but didn't take my underwater gear that trip. Fortunately, I have no issues to carry the weight.
Wife hates the vest but c'est la vie
My favorite is when they weigh your checked bags and they're too heavy, so they ask you to move something into your cabin luggage, as if the weight and balance of the aircraft are now unaffected by it.
Maybe they’d rather you schlep the extra weight than those who’s job it is to move your heavy bags on and off the plane.
The R7 is a bit fiddly on AF. I think part of the issue is that it just doesn't focus very fast compared to a pro body. I've used both a Tamron 150-600mm with the EF to RF adapter and an RF100-500mm on my R7 and they are abominably slow focusing compared to using the same Tamron on my 5D MkIV. The Tamron on the 5D is one of the fastest focusing combinations I own. If I put that same lens on the R7 it's frustratingly slow.
Maybe. The way things are going in the industry, I wouldn't be surprised to see carryon bags get weighed and fees assessed in the near future.
