RF100-500mm, Extender RF1.4, and RF Extension Tube

I tried searching (I really did!) but couldn't come up with anything.

Since the extender won't fit into the 100-500 at lower than 300mm because the front element would hit the back element of the lens, would it be possible to put an extension tube between the lens and the extender and alleviate this issue?

I have no idea if this would work physically or optically. Just a random thought that popped into my fevered brain!

A valid question, but why would you want this capability? If used at 100mm you would get 200mm and at 200mm you get 400mm. Both of those resolutions are available with the bare lens. So

Lou

Another consideration is that generally, when you place an Extension tube in the optical train, the lens will not focus at infinity, so you lose some long distance capability.

Cheers

Dennis

Speaking for myself, I prefer just leaving the extender on full-time for expediency, I wouldn't want to be faffing around trying to change in the field all the time.

I don't actually have an extender, this was more of a thought exercise. I have read a few complaints about the lens having to stay extended and not fitting in the camera bag. If I were to buy the extender I would probably only use it at the full 500mm.

I figured there would be some optical issues, or Canon might have just used a bigger body!

Canon wants RF lenses to have advantages over previous designs. The seek different kind of advantages. Smaller size is one, and then sometimes there are tradeoffs in performance. Like for the RF 70-200 mm f/2.8L IS USM, which can't use any extender at all. The EF 70-200 mm f/2.8L IS II USM can, so it's more "professional" from that point of view, but it's also of a fixed physical length. Unlike the RF counterpart, which shrinks when zoomed to shortest focal length.

greyswan wrote in post #19523289
Speaking for myself, I prefer just leaving the extender on full-time for expediency, I wouldn't want to be faffing around trying to change in the field all the time.

The problem with doing this with the RF 100-500mm in particular is that when an extender is on the lens it cannot be zoomed to less than the 300mm focal length.... i.e. at a minimum it will be a 420mm or 600mm combination, depending upon whether a 1.4X or 2X is used.

In other words, while the extender is on it the 100 to 299mm zoom range is not be usable on that lens (140-418 or 200-598, depending upon the strength of the extender).

It WILL NOT work a lot of the time to use an extension tube and the optical extender because that will cause infinity and distant focus to no longer be possible. Closer focus will still be fine. But often the point of adding a teleconverter is more "reach" for more distant subjects.

Besides, Canon doesn't yet make any extension tubes for the RF mount cameras and lenses. Although there are some 3rd party: Kenko and one or two others.

P.S. It was possible to stack the EF extenders with a 12mm extension tube between them and still focus to infinity. Below was a test I did using the Canon EF 1.4X II and EF 2X II extenders on an EF 500mm f/4L lens... an effective 1400mm combo (but on an APS-C camera, so more like 2240mm). The doe was quite a distance away so I'm confident this was close to at infinity focus. However, image quality was pretty bad. It took a bit of work in Photoshop to make the image at all usable. Even so I wouldn't print it much larger than 4x6" or 5x7". The quality just isn't there with "stacked" teleconverters. Note: the EXIF only shows 700mm... the 500mm + 1.4X. It wasn't able to record two extenders being used at once.