CF Express Type A vs Type B

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tomfranic said:
Please tell me what is the minimum card writing speed (CFExpress Type B) for the "future" raw 30fps on the Z9 Z8. For max 2,3sec burst mode for sport, I don't need more. Thnx
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you can do the math to see what speed is needed to support _sustained_ frame rates, just take 65 x framerate and you get the needed megabytes per second needed.

30fps x 65mp per frame = 1950* mb per second

that said as others have said, camera limitations likely apply

also it gets more complicated when it comes to he and he*. file sizes are smaller but compute power needed to encode goes up.

* this speed is within the theoretical possibility of cfe-b, but probably not something actually obtainable. it will be easily obtainable with the emerging cfe-b v4 cards when we have cameras that support them.

antidotally the fastest measured performance i’ve seen in current gen cfe-b is around 1600mb/s
 
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FWIW for my uses (~100% wildlife) with frequent bursts of about 1-2 sec V90 SD cards in the a1 have been perfectly adequate. IIRC I've never filled the buffer. The CF Express type A card is certainly faster but the convenience of the SD card slots in the computers means one less doodad to keep track of.
 
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It seems odd to choose a camera based on what type of card it takes. (Though I still use SD cards so maybe I am blissfully ignorant to the importance of this). I don't know if your friend has access to a shop where she can hold all three, or has the funds to rent all three. I think ergonomics (both physical size and button layout) are underrated factors when choosing a camera. IN MY OPINION, Sony has the best lens lineup and in fact I wanted to go with them for this reason but I never loved the A74 I had for a while (bought to use with the 200-600). I had the opportunity to try a Canon R5 on two different occasions and found the viewfinder awful. Also for my large hands both Sony and Canon require the optional battery grip. Nikon Z8 is perfect size for me (especially when I added the SmallRig L Bracket that covers entire bottom and acts as a short extension). So MY ADVICE (take it or leave it) is to try all three and go with the one that feels most comfortable (including how the viewfinder looks - Nikon is the best of the bunch IMO).
 
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Also, when choosing a camera weight can be a big issue. Although the Z8 is less than .5 lbs heavier than the Canon and Sony cameras, that .5 lbs makes a BIG difference. If size and weight are concerns, those factors should greatly "outweigh" the card types. If it wasn't for the Nikon 800mm PF lens, I would not have chosen the Z8 because of it's size/weight. Since I'm mostly using it on a monopod, the lens was more important to me. If your friend is handholding the camera, then the ergonomics, size, and weight are most important IMO.
 
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tomfranic said:
Please tell me what is the minimum card writing speed (CFExpress Type B) for the "future" raw 30fps on the Z9 Z8. For max 2,3sec burst mode for sport, I don't need more. Thnx
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At 20 fps RAW today the images still fill the buffer completely even if you have the fastest card available. There is a lot more going on with image processing and writing than simply copying data at maximum speed. Both the camera and the card have limits related to what they need to accomplish. There is also a check function to make sure the image was correctly written - and the camera shuts down if there is a problem so you can't shoot more thinking they are being written with a problem. At 55 MB for a raw file, the actual write speed is close to 880 MB/s (file size is larger at high ISO levels). Any images beyond that point get maintained in a cache until the cache is full. So maximum burst length depends on both card speed and internal cache. Once the cache is full, the frame rate slows to the speed in which you can write images to a card and free up space. This is where fast Type B cards payoff. The entire cache clears in under 3 seconds with the fastest card, but with a slow card it could take 20 seconds or longer. Writing to a second card - backup mode - can double this time or more if the backup card is slow - like an SD card.

Bottom line - get the fastest card you can based on minimum sustained write speed. Then leave it up to the camera manufacturer to do the best they can. This might be reducing frame rate, reducing file size, writing some of the files in smaller formats, etc. We don't know how they are handling that yet. Even with fast cards, you face the limits of the hardware and software in the camera at launch. Nikon anticipates upgraded cards, but components required for higher speed may not be available, may be cost prohibitive for future use, or may not be practical because of other issues like heat.
 
To me I am so accustomed to having the extra wheels and dials of the r5 under my thumb, it would take me hours to adjust to a new shooting pattern. That said, I think I and most people adapt to the tools at hand and once acclimated any camera starts to feel natural.
 
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Thanks for the answer Eric 🙏🏻🥂
EricBowles said:
At 20 fps RAW today the images still fill the buffer completely even if you have the fastest card available. There is a lot more going on with image processing and writing than simply copying data at maximum speed. Both the camera and the card have limits related to what they need to accomplish. There is also a check function to make sure the image was correctly written - and the camera shuts down if there is a problem so you can't shoot more thinking they are being written with a problem. At 55 MB for a raw file, the actual write speed is close to 880 MB/s (file size is larger at high ISO levels). Any images beyond that point get maintained in a cache until the cache is full. So maximum burst length depends on both card speed and internal cache. Once the cache is full, the frame rate slows to the speed in which you can write images to a card and free up space. This is where fast Type B cards payoff. The entire cache clears in under 3 seconds with the fastest card, but with a slow card it could take 20 seconds or longer. Writing to a second card - backup mode - can double this time or more if the backup card is slow - like an SD card.
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Wes Peterson said:
This doesnt add up. I shoot HE* with a prograde cobalt and can get around 275 shots before buffering. Sounds more like lossless compressed
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I just tested my Z9, HE*, 1/1600, fresh batter, F/8, 20 FPS, 24-120 lens, VR on, I got 134 shots and then the next second I only got 19 frames. so somewhere between 134 and 153 frames. Better than my 80+ but below the 275. If listen I find the stumble is after 150 frames or so.
 
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RichF said:
I just tested my Z9, HE*, 1/1600, fresh batter, F/8, 20 FPS, 24-120 lens, VR on, I got 134 shots and then the next second I only got 19 frames. so somewhere between 134 and 153 frames. Better than my 80+ but below the 275. If listen I find the stumble is after 150 frames or so.
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If 1 test gets you around 80 then the next gets you nearly 150 I think you may want to get that card checked out. I am for sure getting nearly 300 frames consistently with a prograde cobalt 325 in Raw HE* This has been the experience of just about everyone else using that config.
 
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Wes Peterson said:
If 1 test gets you around 80 then the next gets you nearly 150 I think you may want to get that card checked out. I am for sure getting nearly 300 frames consistently with a prograde cobalt 325 in Raw HE* This has been the experience of just about everyone else using that config.
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No, 80 was from memory. Of course at my age, memory is not solid as it once was ...
 
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KimH said:
Can someone explain the difference in write speeds on CF Express Type A vs Type B cards. For example Delkin Black 150GB has Min Write Speed: 1530 MB/s.
Delkin Black Type A has a max write speed of 790 mb/s.

How significant is this difference for someone who shoots fast action? A friend wants to go mirrorless and is debating Nikon z8 (type B), Canon r5 (type B) and Sony ar7V (Type A). The card size difference concerns me but if Sony is making the a1 and using Type A cards, I'm thinking the difference might not be that significant.

Can anyone with expertise in this help? Thanks.
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I would think the difference in frames per second is much more significant. R5 maxes out at 20 fps. Z8 maxes out at 20 with options to go higher if you’re okay with JPEG and lower resolutions. And the A7RV maxes out at 10. The Sony A1 is much more comparable to the Z8 when it comes to fast action.
 
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