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

R2D2 wrote:

Alastair Norcross wrote:

R2D2 wrote:

Wintereater wrote:

Maybe try resetting your camera back to Factory Default (always a good starting point).

I haven't tried resetting. I was hoping that someone with similar canon cameras would test theirs out to see if the same thing happens lol.

Maybe someone else will chip in. I sold my M5 when I picked up the M6ii (no slowdowns at 3, 7, 14, or 30 FPS.).

The main reason I posted this question was to find out if the newer canon mirrorless cameras had this issue, so thank you for your input (although the M6 Mark II doesn't really interest me. Still hoping for an M5 Mark II). Have you tested out AF-Servo burst shooting with non native lenses? (EF, EF-S, third party) at all? Another user reported this issue, but only with non EF-M glass.

Hold the phones!

I just put my (adapted) 100L on the M6ii, and it did slow substantially when stopped down while in 15 FPS mode (but curiously enough not while in 7 FPS mode).

No slowdown at all when I have any EF-M lenses mounted (Canon or Sigma). I haven't tested them All though.

R2

Right, so I just tested my adapted 100L on the M6II. At F2.8 in 14fps mode it gives exactly 14fps (within 0.1 either side). When I stopped it down to F4, it slowed to 11.3fps. Not a huge slowdown (and still faster than my previous speed demon, the 7DII), but definitely there. I tested it by shooting my iPhone in stopwatch mode, so I could see exactly how many frames it shot in the time. When I tested my Sigma 16 F1.4 at F2.8, I got 14fps, so no slowdown there. What did your M6II slowdown to with the 100L? And what did you stop it down to? Pretty much the only lens I use at 14fps with my M6II is the Canon 70-200 F2.8L IS II, and, like you, I'm always shooting that wide open (that's the point of that lens), so I'm not going to notice a slowdown.

I might be able to do some more testing later today.

From what I’ve seen (literally), there are a couple of completely separate factors/causes at play here. That’s why it’s been so hard to nail down.

The first has to do with when the lens’ iris is stopped down. One has to look into the lens and observe what the iris is doing.

When the iris is (physically) stopped down from wide open, you get a slowdown in burst rate.

When this stopping down occurs, the camera has to communicate to the lens to first open back up BEFORE the exposure takes place, then it stops back down for the exposure. This opening and closing takes additional time (for the servos to operate).

This slowdown occurs no matter what focusing mode is selected (even manual), no matter which exposure mode is selected, and no matter if Exposure Simulation is selected or not.

So far from what I’ve seen, this only affects adapted lenses. It seems that the EF-M lenses (incl 3rd party) have a different method of operation/protocol.

Any additional info/testing by others would be most welcome.

Mirrorless cameras run very differently from traditional DSLRs (even under the hood). I could be out in left field on this, but I’ve always suspected one of the reasons that new RF lenses were developed (supplanting even recently-updated versions) was to provide compatibility with these new protocols. It seems that this holds true for EF-M lenses as well.

R2

ps. This is just the first cause of slowdown. There are others at work which could be looked into.

My results with the M6 and M6II make sense of the fact that the M6II doesn't seem to slow down from 7fps when stopped down. Given that it can achieve 11.3 fps stopped down at the 14fps setting, there's no need for a slowdown at the 7fps setting. And even though the slowdown in fps is similar between the M6 at 7fps and the M6II at 14fps, it seems more dramatic with the M6, because it is proportionally bigger. As I said above, even the slowed down rate of the M6II is faster than the 7DII's maximum rate (and I haven't tested my 7DII to see whether it slows down too when stopped down). It's an interesting result, but nothing to get upset about. 11.3fps is still pretty fast, and, of course, if you shoot wide open, you get the full 14fps.