Canon EF 300L f4 IS on R7/R10

BirdShooter7 wrote:

Tazz93 wrote:

TeeJay626 wrote:

Kokopelli_Rocks wrote:

I don't have an R7/R10, but I used the EF 300 f/4 IS on my R5 quite a bit until I sold the lens a few months ago. The lens worked great on the R5, no issues with the R5. I sold the lens as I decided to move to RF lenses in my kit. Plus, I have been moving away from most of my prime lenses.

I'm tending to believe there is a problem with the lens itself. Even though the lens looks like it's brand new, there has to be an electronic issue. That's the only explanation.

Not to complicate this too much, but when the R6 and R5 were introduced, there were a number of reports of cameras freezing with older lenses (most commonly 500 L f/4.0 IS). I know two people who had the issue and both sent their cameras to Canon and Canon replaced the mainboards. To date, neither of the two people I know has had a problem since.

I had the lockups with my EF 500mm f/4L IS USM, never had the main board replacement but they stopped after one of the early FW updates. No lockups at all so far with the R7 and my 500mm is now 20 years old.

That's good to hear. But are we talking about the same type of lock ups? The R5/R6 had two types of lock-ups, one required the battery be removed and was a full totally unresponsive lock up. And the other was very targeted at AF with a red AF box that wouldn't continue tracking, but the camera was otherwise responsive. On that lock up you could cycle the on/off switch or sometimes just cycle the AF/MF switch on the lens. On the second type of lock up I've only seen it on lenses older generation lenses. You could be right though, I haven't heard of those lock ups in a long time (maybe a year or more).