Is it normal for the burst rate to slow down when you stop down the aperture?

Bear in mind that generally higher ISO shots have larger file sizes, which may influence burst rate. So, stopping down will increase ISO (either on Auto or manually, assuming you adjusted the exposure to suit the slower aperture), which will generally increase file size.

I controlled for ISO by keeping it low during my tests and still had slowdown immediately after shutting down, irregardless of what the exposure was like in the end. I even changed the JPEG size to the smallest possible to eliminate any issue with file size

I cannot explain why it would speed back up at f9 though ?

After testing more, the slowdown at each aperture varies for some reason. The one thing that remains consistent though is that it slows down from max any time I stop down (even half a stop), and it never slows at max aperture (which isn't very bright to begin with with my lenses).

Do you have continuous AF (different to servo AF) turned on ? That may be trying to focus between shots even if on One Shot ?

There are only autofocus modes on the M5, One-shot and Servo AF. One shot should not be focusing between shots in burst mode and yet it slows, though not as dramatically (only losing maybe 1-2fps).

It could be a 3rd party lens peculiarity ? Since your 15-45mm behaves differently, it may be a combination of things (like continuous AF + lens "issues" + file size).

Colin

I don't think it's a third party lens issue. While it does behave slightly differently with canon's own lens, it still happens :/

Thanks for your input.