Why did my Z9 and Z8 cameras all max at 15 fps when set to 20 fps

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agrumpyoldsod

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Here is an odd one for me.

I run all my new camera bodies through a series of tests to understand their operating limits -- so obviously I had to test the pair of new Z8 I received over the last couple of weeks against the pair of Z9 I have had for 16-18 months with a range of CFE and one SD card.

I consistently saw incredible burst lengths across all cards -- and since all cameras were set to the same settings and set up the same the question was WHY?

First to confirm I placed a stopwatch, which shows 1/100th seconds, on my monitor screen and shots bursts of that and what I discovered was all the tests I had run -- over 40 -- had actually achieved 15 fps -- almost exactly 15 fps. It mattered not that the dial on the Z9 was set to HIGH and I confirmed they were all set to 20 fps. Example shown below

I originally thought the slower FPS was a result of some connection settings - to Snapbridge and/or my Ultra Sync Blue -- nothing changed when these were turned off - so not them.

Therefore -- the only option was to save my settings and RESET ALL Settings. OK - I did that.

Then as a first attempt I loaded the saved settings and guess what after selecting Lossless RAW, Adobe, Manual mode, 20fps and AF-C the camera still repeated 15 fps
Then RESET ALL Settings again -- and just selected Lossless RAW, Adobe, Manual mode, 20fps and AF-C -- and the first run the Z8 hit 20 fps.
Very clearly something in my settings was holding the camera back.
I went through manually adding all my previous settings -- except no connection to iphone or Ultrasync and no copyright and guess what 20 fps is recorded and confirmed on all my 4 bodies.

See the table -- yes no actual FPS hit 20 - this is because I allowed the burst to run through a couple of stutters before stopping. BUT at least the actual fps did not head to 15 or lower.

What I did or why "all of a sudden" the FPS drops from the spectacular 20 fps to more than adequate 15 fps - I would still like to understand. AND so now I am back to baseline more testing is needed.

In the meantime - there can be little doubt that when shooting H-15fps one can almost achieve limitless (well very very large/long bursts) - and when at 20 fps - my fastest cards held to 20fps for all but the last few of ~80+ shots on my fastest cards.

I will now repeat my tests of the various types of RAW and various types of Raw+ sizes/quality JPG to single slot and as back up to both slots. I doubt the buffer test results will be as "long" as when the camera was set to shooting 15 fps (or set itself to this maximum rate).

Any thoughts on which settings may "unwittingly" hold these cameras back to "only" 15 fps would be gratefully received. Not least as a warning to me and others who may blindly fiddle with their tools.

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Do you have AF-C set to focus priority or release priority? I read somewhere(maybe @Steve 's book?) that focus priority can slow fps down a bit. Default is release priority so if you use focus priority that could be why resetting the camera is having an effect.

Early on with the Z9 my tests also showed an essentially bottomless buffer at 15fps. And that's plenty fast IMO so that's where I set my max ss. I shoot 15fps on H and 10fps on L.
 
Below 1/250th the FPS drops down presumably for flash sync purposes. This was widely talked about when everyone was comparing buffer depth shortly after the Z9 was released.... Even Thom hogan screwed this up during a zoom presentation when talking about buffer depth.
 
Do you have AF-C set to focus priority or release priority? I read somewhere(maybe @Steve 's book?) that focus priority can slow fps down a bit. Default is release priority so if you use focus priority that could be why resetting the camera is having an effect.

Early on with the Z9 my tests also showed an essentially bottomless buffer at 15fps. And that's plenty fast IMO so that's where I set my max ss. I shoot 15fps on H and 10fps on L.
a1 == Release
 
On my Z6ii the difference between Continuous High and Continuous High Extended is that extended locke exposure after first shot. Makes a big difference to burst fps. I tried setting exposure lock both on and off on my Z9. No difference, still got a frame rate of 19-20 fps.
 
It appears that shutter speed matters - 4 tests at different shutter speeds. Prove that for shutter speeds 1/250th and quicker 20fps is supported. BUT for shutter speeds 1/200th and slower the fps drops to 15.

I do not remember reading this anywhere -- but I will check AND I hope my "issue" is down to this alone. Reference guide page 134 -- includes an oblique note -- about 1/250 s
There it is in a NOTE in Thom Hogan's books for both the Z8 and Z9 !!!!! I know I should have studied Thom's book in more detail. Thom provides more limitations than Nikon.

All the tests I ran on the Z9 and Z8 Yesterday were taken using shutter speeds below 1/200th. Hence the "fantastic results"!!!

Screenshot 2023-06-04 at 17.11.34.png
 
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