I have some EF and RF lenses that I use with my R6, and have noticed that the RF lenses lack the focus points on the barrel, but in this case I have some quetions about the RF 15-35mm f/2.8 L: I use this lens primarily for photographing the Auroras with the AF/MF switch on MF (manual focus). Since it lacks the manual focus points on the barrel I have to focus the lens to infinite (∞) electronically though the viewfinder, something that isn't difficult to achieve, but if I power the camera off and then back on, the orange-color pointer has now moved a few degrees to the right of the infinite mark. In this case I have no idea if the lens focus has shifted too far, so I haven't had any other choice but to keep the camera turned on for long periods of time. As long as I don't turn the camera off, the focus stays put on the infinite mark. I just don't understand the reasons for Canon to not have the focus points both on the lens barrel and electronically. As it is now I have to secure the focus ring with electrical tape once I have adjusted to focus to infinite (I do the same if using EF lenses, or the Tokina lens below). If I were to use my Tokina 16-28mm f/2.8 WA lens to take photos of the Auroras, there is no way but for the focus point I choose (manually) to shift from the infinite mark as long as I use a piece of electrical tape to secure the four ring in place. When taking photos of the auroras one does not want to touch the focus ring in the dark of night, specially the one in an RF lens, simply because one has to waste a couple of seconds looking through the viewfinder to see if the focus is still set on the infinite mark. I mostly set the camera for 4-second exposures, but even so 2 seconds would mean the possible loss of a great photo. This would not happen if the lens has the four points on the barrel, since it only takes a fraction of a second to look at it.
I don't own any RF lenses. If you focus on some stars using the rear screen, and magnifying the image until the star is at it's smallest while using manual focus, and having the lens set to manual focus. Does the focus actually change if you turn the camera off and then back on again? Can you hear the lens doing anything when you power cycle the camera? And once the camera has been power cycled, if you are to take a picture of the star again, is it still in focus? Gary
i was going to say something similar, the main point being use manual focus. however, if you turn up the iso to gain light your camera should be able to autofocus on stars, then you should be able to switch to manual focus so you can drop the iso back to what you want it at, also does the mf / af switch on your lens over ride the af/mf from the camera, i only have the M50 so i don't know how the rf system handles manual / auto focus, i'd like to think if you set the lens to where you want it and then turn it to manual focus it should stay where you had it, depending on the lens i think you can set preset focal distances too, but thats specific lenses when i take star images i never use the infinity marks on lenses weither its digital or fully manual, i go by what the image looks like, i have x5 and 10x on my focus aids but if possible hooking up to a lap top will give you a much better view, not always possible but it helps alot if the little M50 can auto focus on the stars and saturn / jupiter at 1200mm i'm pretty sure the RF cameras can at lower mm
