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

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.

Interesting findings you guys! Hopefully things get resolved in the next round of Canon's mirrorless (or maybe the RP and R have fixed this already?)

Makes sense to me.

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.

Hi Guys,

I have the M3, M6 and M6 MkII. I also noticed the slow down. My reasoning is the following:

Every mirrorless camera (from Canon) will try to attempt auto focus wide open, because they get a cleaner image and the framerate, they can achieve, is higher.

When you actually take a shot, the camera has to adjust the aperture to your settings. This might result in a lag. This aperture lag is only part of a sum of different lags combined.

This lag consists of frame grap lag, AF lag and Aperture lag.

Frame grap lag is the time until the sensor has been exposed correctly in order to check for correct AF.

AF lag is the time until AF is achieved.

Aperture lag is the time until the aperture blade have been moved to the correct Position.

Usally the Frame grap lag is quite low, because the camera always uses the maximum aperture (low aperture number) to achieve a quick exposure of the sensor. This might not be true for dark situations.

The AF lag can be considered quite low and nearly constant as long as the camera has already achieved focus. This is especially true for manual focus (no AF) or continues AF (AF has probably already been achieved). If you're using a slow focusing lens or even a bright lens, this might be a big factor until you achieve focus.

Aperture lag is inherintly a logical occurance within mirrorless cameras (and maybe DSLR in live mode), because the camera has to close down the aperture blades and has to wait some milliseconds. This can depend strongly on the lens and it's response time to the camera commands and the communication speed throught its mount system.

Possible fix through Canon:

Canon could fix this situation by offering a mode, which actually closes the aperture to the set aperture number and doesn't use the maximum aperture for AF all the time. This will prevent the aperture lag from occuring.

I have and used a couple of MF lenses. Those lenses will always give you the right depth of field preview, because the camera cannot control the aperture. This also means, it will not suffer from AF lag or aperture lag, resulting in a maximum burst rate.

It will suffer from frame grap lag. This can be a negative and a positive side effect. Due to high ISO during manual focusing, you might see your subject very noisy. But you will notice a drop in framerate and thisshould tell you to open up your aperture blades.

Side note: With this mode your focus point might not always be in the middle your depth of field.

So this isn't an issue with mirrorless cameras from other companies or has no one here tested them yet?

When you are looking at time periods of fractions of a second, the human standard of “near instantaneous” is the wrong unit of measure. Anything that physically requires as much movement as an aperture mechanism likely requires many milliseconds to accomplish. Those milliseconds might not seem like much to you, but they can have huge impacts in situations where we are slicing seconds into fractions. What makes matters worse is that there is clearly something in Canon’s aperture mechanism communication protocol that includes confirmation of step-down. If you ever have an aperture mechanism fail, you will find that you can continue to use that lens wide open, but you will get an error when you try to step down and shoot. That error won’t appear until after you press the shutter button all the way down. How does the camera know that the aperture didn’t close as requested? Clearly there is some verification being performed prior to taking the shot. All of this takes time, too. This all happens instantaneously by human standards, but none of this is even close to zero when we look at fractions of seconds.

I didn’t verify in all my DSLR manuals, but the fine print in the 5D3 manual confirms that the maximum fps is only achievable at wide open aperture. It also included two other factors that could slow the frame rate that I found difficult to comprehend, “subject conditions” and “brightness”. I suspect those can affect the processing rate of the image, itself. What you are seeing sounds normal to me.

Wintereater wrote:

So this isn't an issue with mirrorless cameras from other companies or has no one here tested them yet?

Sony uses stopped down focusing, so if you want to do bursts stopped down, Sony is the way to go. The downside is your AF system has less light in low light situations, on of the reasons i stayed with Canon.

Of course you should be able to choose whatever you need with both brands, which isn't possible unfortunately.

thunder storm wrote:

Wintereater wrote:

So this isn't an issue with mirrorless cameras from other companies or has no one here tested them yet?

Sony uses stopped down focusing, so if you want to do bursts stopped down, Sony is the way to go. The downside is your AF system has less light in low light situations, on of the reasons i stayed with Canon.

Of course you should be able to choose whatever you need with both brands, which isn't possible unfortunately.

I guess that's good in theory if you value accuracy over speed, but I find that the autofocus on the M5 when tracking birds (or focusing on anything smallish and far away in general) is pretty crap from my experience (although I use Sigma telephoto lenses, never tried any of canon's). I always find myself punching in on the viewfinder and adjusting manually.

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.

Praefos wrote:

Hi Guys,

I have the M3, M6 and M6 MkII. I also noticed the slow down. My reasoning is the following:

Every mirrorless camera (from Canon) will try to attempt auto focus wide open, because they get a cleaner image and the framerate, they can achieve, is higher.

When you actually take a shot, the camera has to adjust the aperture to your settings. This might result in a lag. This aperture lag is only part of a sum of different lags combined.

This lag consists of frame grap lag, AF lag and Aperture lag.

Frame grap lag is the time until the sensor has been exposed correctly in order to check for correct AF.

AF lag is the time until AF is achieved.

Aperture lag is the time until the aperture blade have been moved to the correct Position.

Usally the Frame grap lag is quite low, because the camera always uses the maximum aperture (low aperture number) to achieve a quick exposure of the sensor. This might not be true for dark situations.

The AF lag can be considered quite low and nearly constant as long as the camera has already achieved focus. This is especially true for manual focus (no AF) or continues AF (AF has probably already been achieved). If you're using a slow focusing lens or even a bright lens, this might be a big factor until you achieve focus.

Aperture lag is inherintly a logical occurance within mirrorless cameras (and maybe DSLR in live mode), because the camera has to close down the aperture blades and has to wait some milliseconds. This can depend strongly on the lens and it's response time to the camera commands and the communication speed throught its mount system.

Possible fix through Canon:

Canon could fix this situation by offering a mode, which actually closes the aperture to the set aperture number and doesn't use the maximum aperture for AF all the time. This will prevent the aperture lag from occuring.

I have and used a couple of MF lenses. Those lenses will always give you the right depth of field preview, because the camera cannot control the aperture. This also means, it will not suffer from AF lag or aperture lag, resulting in a maximum burst rate.

It will suffer from frame grap lag. This can be a negative and a positive side effect. Due to high ISO during manual focusing, you might see your subject very noisy. But you will notice a drop in framerate and thisshould tell you to open up your aperture blades.

Side note: With this mode your focus point might not always be in the middle your depth of field.

This is all well and good, however it doesn’t explain why this slowdown only happens on  adapted  lenses, and not native EF-M lenses.  Something else is at work here.

R2

R2D2 wrote:

This is all well and good, however it doesn’t explain why this slowdown only happens on adapted lenses, and not native EF-M lenses. Something else is at work here.

R2

I just tested it out. The aperture of EF-M lenses (18-150mm for example) doesn't open up while in high speed shooting mode. The aperture of the EF lenses (100mm 2.8 IS for example) closes down and opens up again and again. Therefore, there will always be a lag.

This behavior doesn't need to be EF or EF-M exclusive. It could either be a wrong command to the lens (bus system), a misimplementation in the camera or an old software version in the lens itself.

Depending on the lens, the aperture blades might also need more time to reach their correct position. With the EF 135mm 2.0 L for example the camera or the lens even tries to stop down when you use a smaller aperture.

Praefos wrote:

R2D2 wrote:

This is all well and good, however it doesn’t explain why this slowdown only happens on adapted lenses, and not native EF-M lenses. Something else is at work here.

R2

I just tested it out. The aperture of EF-M lenses (18-150mm for example) doesn't open up while in high speed shooting mode. The aperture of the EF lenses (100mm 2.8 IS for example) closes down and opens up again and again. Therefore, there will always be a lag.

This behavior doesn't need to be EF or EF-M exclusive. It could either be a wrong command to the lens (bus system), a misimplementation in the camera or an old software version in the lens itself.

Depending on the lens, the aperture blades might also need more time to reach their correct position. With the EF 135mm 2.0 L for example the camera or the lens even tries to stop down when you use a smaller aperture.

Yeah, these mirrorless really do operate very differently under the hood.  Not so cut and dried as a DSLR (using OVF).  Plenty of exceptions to the rule(s).

Fortunately I love to shoot wide open, and am usually wide open when shooting bursts (except for being closed down for macros).

R2