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What is it with the R5 Frame Per Seconds?.... Why does the camera has so many restrictions?

Up to now the FPS was camera based. If I put the 400mm f/5.6L lens (for example) on a Rebel it was 3-4 FPS, on my 7D MK2 it was 10, and on my 1Dx Mk2 it was 14. On the R5 using single curtain shutter the FPS drops to 4-5 and electronic 20 FPS. This is the same lens that was doing 14 FPS on the 1Dx MK2 but now is doing less than 10 on the R5. Why? what is different with this camera. A lens capable of 14 FPS on the 1Dx is unable to hit 12 on the R5?

I reviewed the specs and it looks like there is a page and half on what I call "if this.... that" of conditions before the camera can do the 12 FPS mechanical. The conditions are so diverse that not long ago a fellow photographer asked me about the FPS and I told him that "with full moon before 9PM it was 12 but after 9PM it was down to 5".

I do not understand the logic for this situation. It is frustrating to encounter this issue!!!

Any idea if this is going to change with one of these firmware updates?




The manual is not very clear, but these items all impact frame per sec.  All boils down to how quickly the camera can clear the pictures in the internal memory buffer to the card.  The lens has no impact on FPS, it's largely limited by the camera's megapixel, local memory buffer size/speed, image format you select, and card you write to.

  1. SD vs CF Express Card, SD is slower to write
  2. SD card write speed.  slower write speed on card impacts how quickly files can be written to card.
  3. JPG vs RAW VS JPG+RAW, more data to write, slower to clear buffer
  4. Mechanical vs Electronic shutter, Electronic is faster
  5. Megapixel size (20 vs 45MP).  More megapixels, bigger files, more data to clear out the buffer cache.

So if you want constant 20fps, shooting on CF Express card with jpg only via electronic shutter, you can indefinitely shoot at 20fps with no shutter slowdown (i've tested this).  The slowest would be shooting to slow SD card, using JPG+RAW on a mechanical shutter.  There's enough buffer to go fast for a bit but then it will slow down to match the write speed to the card you are writing to.

Comparing a 1DX mark II to R5 for FPS is like comparing a F1 race car to a BMW.  1DX was built for professional shooting with high FPS requirements (like sports) while R5 is more general shooting like weddings, studio, etc.

Maybe I wasn't clear but the lens has ALL of the impact on the R5 FPS. That is the issue!

While in all other Canon cameras that I have, that is not. for example, the Prime 400mm f/5.6L on the R5 will shoot at a very slow rate, I am going to guess, 5 FPS. The 100-400mm f/5.6L MK2 under the same conditions will shoot at 12 FPS.

You are correct that long term, the clearing of the cache and card used will affect the overall FPS, but initially that is not the case. The initial rate fill the buffer memory and should be the same regardless of lens used, since the file size are the same, or very close to it, as you are shooting RAW. Plus the fact that the file size and memory card used is the same for the Prime 400mm and for the zoom 100-400mm while the FPS is significantly different. 

And that is NOT the case in any other Canon camera. I can shoot 14 frames per sec. on my 1Dx MK2 with the 400 prime, the 100-400 zoom or the 70-200mm f/2.8L MK2 but with the R5 I see differences in FPS under identical conditions depending on what lenses I am using... and I do not understand that!!!

Rising Star

The factors affecting possible fps rates are determined by physics and engineering limitations.

*Obviously, using the electronic shutter is faster than the mechanical simply because of the lack of moving parts and the time required to accelerate and then stop those moving parts.

*If you are using autofocus and a fixed shutter speed (Tv mode) of at least 1/1000 sec, the specific lens in use can  have  a dramatic effect on the range of fps available.  Canon clearly specifies which lenses and which modes (typically Av) work best at high fps settings.  Maximum fps using either electronic or mechanical shutters is only available with lenses with fast internal diaphragm actuators for most exposure modes.

*The combination of the type of storage (CF Express and /or SD Card) you are using and the file type (RAW or jpg) will ONLY affect the available fps AFTER the very fast and relatively large internal buffer is filled.  On the R5 that takes a significant number of shots in a burst.  For instance, card-write speeds will only come into play reducing fps after 405 frames (@ 12fps writing RAW to a CF Express card),  146 frames (@ 20fps writing RAW to a CF Express Card) or 110 frames (@ 20 fps writing RAW to a SD Card).

Used with appropriately chosen settings and a more than "half charged" LP-6NH battery the R5 can provide excellent high-speed bursts for sustained periods.

*Another major factor affecting maximum available fps on the R5 is available battery power.  For maximum rated fps a fully charged (charge between 40% and 100%) LP-E6NH battery OR the BG-R10 Battery Grip is required.  A low battery charge will reduce max fps as will the use of a single LP-E6N battery.  Fast burst rates draw very high current for significant periods of time to power the image sensor, readout electronics, the mechanical shutter, lens aperture actuator, image processor and memory card driver circuits (esp if using a CF Express card). An old battery or one that is low on charge simply cannot supply enough sustained current for maximum speeds.

IMHO, Using appropriately chosen settings the R5 can actually out perform (@ 20fps) a 1DX mark II even when shooting blind on the 1DX mirror locked up (@ 16 fps).  It's all about understanding how to properly use one's tools.

Personally, I've used the R5 for fast bird fly-bys and at automobile race events (much faster than the diving egrets and eagles) at 12 fps and shutter speeds of  1/2000 (mechanical shutter) with excellent results. Shooting RAW into the CF Express card, I've shot 8 to 12 second bursts of 44.8 MP images at car races and have never come close to filling the buffer and/or experiencing any slow-down.

Hope this helps a little.

Thanks.... while all of that is correct, I am shooting under the same conditions. Why will the prime 400mm f/5.6L shoot at say 5 FPS while the 100-400 f/5.6L MK2 does 12 under the same conditions? That is not the case on any other Canon cameras I have.

Yes, battery and temperature affects all of this but I am talking about shooting under the same conditions -side by side

Rising Star

"Why will the prime 400mm f/5.6L shoot at say 5 FPS while the 100-400 f/5.6L MK2 does 12 under the same conditions?"

Pure speculation on this specific case, but it MAY be related to the relative amount of power available in the two camera bodies.  Your settings may be the same, but "conditions" are not. The batteries and internal electronics are completely different, so have different capabilities and different limitations.  The 1DX-Mk-2 uses the large 10.8 volt LP-E19 battery pack while the R5 uses the 7.2 volt LP-E6NH battery pack.  Additionally, the 400 F/5.6L is a 1993 design and probably uses a less efficient, higher current focus motor and aperture actuator than the newer (2014 design) 100-400f/5.6 Mk-2 lens.  The R5 operating system code may have power limit rules that restrict the camera's speed (and thus the power consumption) when the older lens is installed.  There is a reason the 1DX battery costs more than twice as much as the one in the R5.

Not withstanding the excellent family of EF-EOS R adapters, the R5 is definitely intended and optimized for use with RF lenses.  The shorter back-focus distance is just one of the features of RF lenses that make them a better match for the mirrorless camera bodies than "legacy" designs.

Again, this is only a speculative guess, but it may be one possibility.


How many fps with no lens attached?

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