Data writing speed

This topic was partially addressed in my frame buffer article.

On old cameras, you can come across one feature that few people mention - the maximum speed of writing data to a memory card, which the camera itself can support. I.e, maximum write speed to the memory card is also limited by the camera itselfor rather, its recording system (built-in flash receiver / microcontroller of memory cards).

Users of older cameras know that cameras are like Nikon D100 take photos on a memory card for a very long time. At the same time, the recording time is almost independent of the speed of the memory card. With any fast memory cards, even with the fastest cards, writing files takes an equally large amount of time. The recording speed depends on the capabilities of the recording controller of the camera itself. For example, the same Nikon D100 writes 1 RAW file without compression for 5-6 seconds or 1 RAW file with compression for 35-40 seconds (the restriction is obtained due to the recording controller and the limited processor power of the camera).

В modern cameras also have a limit on the maximum recording speed data by the camera itself. Unfortunately, this speed, expressed in megabytes per second, is almost nowhere to be found. Typically, the maximum recording speed that the camera supports is in accordance with the memory card standard that the camera supports.

Life example # 1

Camera Nikon D90 Supports SD memory cards and SDHC-compatible. The SDHC interface has a maximum read / write speed of 25 megabytes / second (this speed is determined by the developers and depends on the hardware implementation of memory cards and devices for working with them).

One RAW file per camera weighs an average of 10 megabytes. The maximum burst speed is 4.5 frames per second. Thus, the camera produces an average of 45 megabytes of data in one second.

During continuous high speed shooting no memory card will allow continuous shooting at maximum speed for a long time 4.5 frames per second. This follows from the fact that Nikon D90 It can record photos at a maximum speed of 25 Megabytes per second, and it produces much more in one second - approximately 45 Megabytes of data.

Frame buffer Nikon D90 holds a maximum of 9 pictures in RAW format. For the first few seconds (about three seconds), the burst speed will be the declared maximum of 4.5 frames per second, but after filling in the frame buffer, the speed will drop to about 2 frames per second, since the camera can only upload data from the buffer with maximum speed of 25 megabytes in 1 second (25 megabytes is just about 2 pictures in RAW format).

Life example # 2 (learning from our mistakes)

At one time I made a mistake. It was understood that for comfortable work with Nikon D90 you just need to get a memory card whose write speed is above 45 megabytes per second. For these purposes, I started using a memory card. SanDisk Extreme Pro 32 GB V30 UHS-I U3 Class 10 95 MB / s... The instructions stated that the read speed is up to 95 Megabytes per second, and the write speed is up to 90 Megabytes per second. My mistake was that such speeds are supported only if the read / write device (in this case, it is a camera Nikon D90) supports the operation of memory cards with the UHS-I bus. Unfortunately Nikon D90 cannot work with UHS-I. Because memory cards are usually backward compatiblethen SanDisk Extreme Pro 32 GB V30 UHS-I U3 Class 10 95 MB / s in the camera Nikon D90 It works like a regular SDHC card with a maximum speed of 25 megabytes per second.

I have met the above calculations more than once in real life. It turned out that the shooting speed of 4.5 frames per second for a long time continuous high-speed shooting (at least more than four seconds) can not be obtained.

The same calculations can be performed for other cameras. Is the same Nikon D7000 (with UHS-I support) creates an average of 120 Mb / s of data (6 fps, RAW files, 14-bit, lossless compression), and can only write 104 Mb / s (this is the peak / maximum rate unattainable in real conditions).

Additional Information

It is very difficult to find out what maximum write speed a particular camera uses. Usually, even the instructions do not always clearly and accurately indicate which high-speed bus a particular camera supports, and you have to find out everything empirically.

If we talk about SD-cards, then here are their maximum speeds:

  • any simple SD without HIGH SPEED (class 10) or UHS support has top speed 12.5 MB / s
  • SDHC (HIGH SPEED class 10) or SDXC (HIGH SPEED class 10) without UHS support have maximum speed 25 MB / s
  • any SD with UHS-I support has maximum speed 104 MB / s
  • any SD with UHS-II support has maximum speed 312 MB / s
  • any SD with UHS-III support has maximum speed 624 MB / s

Results

  1. frame buffer is a very important indicator, since many cameras do not support working with super-fast memory cards. For such cameras, the duration of continuous high-speed shooting directly rests on frame buffer
  2. in some cases (with some cameras) there is no way to solve the problem with a significant increase in the duration of continuous high-speed shooting. The speed at which the camera writes data to the memory card can be significantly lower than the speed of data creation, which sooner or later causes a significant slowdown in the camera
  3. finding accurate data about the maximum write / read speed of a particular camera is quite difficult
The material was prepared by Arkady Shapoval. My Youtube channeland Radozhiva's group on Facebook и VK.

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Comments: 26, on the topic: Data writing speed

  • Arkady Shapoval

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  • Sergey

    I would like to note a couple of points:
    1. The write speed to the card is basically 2 times lower than the declared read speed.
    2. The lion's share of manufacturers does not indicate the actual technical characteristics of the data transfer of their product.

    • Arkady Shapoval

      1. Not quite so, everything very, very much depends on the specific model of the memory card.
      2. You need to somehow earn :)

    • Jury

      If you test the recording speed on a computer, there is a strong dependence on the source from which the recording is made. I checked one cf card, on one laptop, one usb port and one card reader, copied the same file, but in the first case it was on the ssd disk - the write speed was about 120MB / sec, in the second on hdd - about 40MB / sec.

      • Arkady Shapoval

        In this case, you did not test the recording speed, but the copy speed. In the case of the HDD, the speed rested against the HDD limit.

  • Lynx

    I just want to ask about the speed of recording on the fotik in the title ...
    If I am not mistaken, this is the Olympus 35RC

    • KalekseyG

      The speed is instant, especially considering that there is a very multi-bit uncompressed RAW.)))

  • Michael

    Typo: "which may be supported directly by the camera itself"
    I also wanted to add that some models (D300s for example), in general, during continuous shooting at high speed (Ch), do not write to the memory card until you release the shutter button. Something like this…

    • Arkady Shapoval

      Fixed

  • Alexey Prokopchuk

    Hello, everybody!
    I read the post and decided to check on my old canon 650 D.
    I put a very smart memory card from the action camera into it and started clicking in ROW, at first (for about a couple of seconds) everything went as stated - about 5 frames / sec., But then the speed dropped sharply to 1-2 frames / sec ..
    I stuck an old card - no difference.
    Thanks Arkady for the information - saved from senseless spending on a new quick card))

    • Arkady Shapoval

      Glad I helped

  • anonym

    What kind of anime?)

    • mimocrocodile

      Perhaps Tamayura - there were film cameras.

  • Valentine

    Before the examples, everything is clearly written, but in the examples, I'm sorry, I did not quite understand the logic of expectations. As if you thought the speed of the card is the bottleneck in the camera, but actually why? After all, to record compact jpgs, high speed is not necessary, and the camera still chokes at some point. Despite the fact that jpg is always done, even when we shoot in raw without compression. The camera does all the same with all the applied parameters. And Nikonov has this preview in fact a full-fledged jpg-file with basic quality. That is, by shooting in jpg with all parameters disabled and with the lowest quality, it is already clear that the other nodes are the bottleneck, not the card. Or I'm wrong?

    • Arkady Shapoval

      Not certainly in that way. You most likely tend to the fact that the camera's processor does not have time to process and generate those same JPEG files. So, if we take Nikon D90 JPEG / RAW without enhancements, then in this camera the bottleneck for continuous high-speed shooting is just the memory card, or rather, as I indicated in the article, the speed of writing data to the memory card, associated with the capabilities the camera itself.

      In Nikon D90, indeed, like in other cameras, the camera does a built-in preview in a RAW file, this preview does not weigh so much and in the case of the Nikon D90 does not make a significant contribution to the camera’s brakes (we are talking about JPEG L FINE with disabled improvers at low ISO).

      In support of the above - while shooting in JPEG FINE L Nikon D90 with my previous card Transcend 400x 60MB / S SDHC Class 10 UHS-I 32GB Premium actually did not slow down and shot 4.5 frames as much as I wanted (until the card ran out, but in fact the 'complex' JPEGs with a weight of 6-7MB also rested on the write speed, but not on the processing time). So I thought that with a faster card, RAW files would be recorded on time. But, as it turned out, it was the maximum data writing speed that played a cruel joke on me.

      I understand where you are leading - for many cameras the speed is choked by the processing capabilities of the processor (and it doesn't matter JPEG or RAW). But this is another story, described by me in frame buffer section.

      • Valentine

        Thanks, for the clarification. I usually came across the fact that with jpg cameras do not write for a long time. About D90 did not know that jpg without ext. options can be written in a series limited only by the size of a sufficiently high-speed memory card. This is very interesting, despite the fact that I usually do not need it.

  • Ilya

    the same Nikon D100 writes 1 RAW file without compression for 5-6 seconds or 1 RAW file with compression for 35-40 seconds
    Arkady probably need the opposite?

    • Valentine

      Quote from D100 review “Important: Nikon D100 takes a very long time to record compressed RAW files (about 40 seconds per file). The recording speed depends little on the speed of the memory card. Most likely, such a slow recording of compressed data is due to the fact that the weak Nikon D100 processor compresses data for a very long time. Uncompressed files are written about 5 times faster "

    • Arkady Shapoval

      No. Exactly. The Nikon D100 processor spends a lot of time compressing the file, which is why recording takes so long.

  • Vasyl

    Дякую

  • Molchanov Yuri

    What a useful article. Why didn’t it occur to me to do the simplest arithmetic operation ?! He also overpayed for memory cards. Arkady, thanks!

  • Pawel

    Thanks for the interesting article, but there is still such a factor as the volume of the card. I do not bombard serial reporting (I'm generally an amateur) at a speed of 5.5 fps with my D600, but I needed a lot of volume to record 24MP RAW of 40 MB each. I would buy the slowest, but at 128GB the cheapest was microSd 95Mb / s, and I took it. Now he writes 2.3k.

  • Caelwyn

    I would also like to add my pain about how the camera behaves after the buffer is full. For example, my Fuji XE-1 can even write a single file to the card for several seconds, this doesn’t really bother with single shots, well, maybe it can hang sometimes. But if you shoot in a queue, after filling the buffer, the camera turns into a braking instrument of torture with a blinking red LED and an inscription in the viewfinder about saving files instead of pictures. Map of the tenth grade.
    The Nikon D70 and D200 that I used before did not have such garbage, they continued to shoot, albeit a little slower.

  • Sergei

    It has long been bought an expensive (at that time) SanDisk Ultra 64gb UHS-I U1 card, so it survived several cameras, now it works in the Nikon D7200. I am not fond of serial shooting, so it is quite satisfied. But then I got a SanDisk Extreme Pro 128 gb UHS-I U3 for another device, I decided to see how it works with the camera. On a 64 gb card in a jpg buffer clogged after 7 seconds and the brakes started, on a 128 gb card the camera simply could not be stopped. But the situation is different in Rav: they slow down at about the same length of time, BUT after stopping at 64 gb, files are added for another 20-30 seconds, and at 128 gb it’s literally 5 seconds and you can shoot freely further. I realized for myself that I do not need this, but maybe someone will be useful

  • Vitaly Timushev

    Here is the law of meanness! For a whole month I planned and chose a new memory card for my Samsung NX1000, thinking about speeding it up. I read articles about the right choice and finally bought it yesterday (and today I saw an article)! And all in vain! There was a Kingmax 16 gb card, write-read about the same at 19 mb / s. I bought a Samsung evo 64 gb, write-read 28 and 31 mb / s. Thought how to check whether it became better or not? He began to make single shots and series first on one map, then on another. Timed processing frames. It turned out that the old card coped even a bit faster. I tried several times. Kingmax (K) 1 jpeg 2,1 sec., Samsung (S) 1 jpeg 2,4 sec. K 11 jpeg 13 sec., S 11 jpeg 14,2 sec. I decided at the same time to check RAW, although I do not shoot. It turned out K 1 raw 4,2 sec, S 1 raw 4,2 sec, K 8 raw 24,5 sec, S 8 raw 27 sec. You can say money down the drain. The only plus of the new card is faster files will be downloaded to the computer. Thank you for the article! At the same time I read something else, I see that there is a lot of useful information for me. Thank you for creating such a necessary site.

  • Aleksandr

    With great interest, dear Arkady Shapoval, I read, unfortunately occasionally, your articles, in which you thoroughly, with knowledge of subtleties and details, cover almost all sections of the technique and technology of practical photography. Thank you for sharing your knowledge.

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