Computers / Buying Guide

Top Memory Cards for Photo and Video Recording


It’s safe to say that in today’s predominantly digital world, memory cards have overtaken film as the primary recording media for consumer and professional photo and video use. As much as analog cameras were designed to work with a specific film format, such as 35mm or 120 roll film, or large-format sheet film, digital cameras are likewise built to work with one or two specific memory card formats. However, once you’ve established which memory card format is compatible with your camera, such as CompactFlash (CF), Secure Digital (SD), XQD, or CFast, how does one go about choosing from the available models that each card format offers?

While the purpose of this article is to discuss suitable memory cards for photo and video use, there are a few technical details that need to be cleared up first. First, there is a difference between bits and bytes. 8 bits equals 1 byte, and consequently, 8 megabits, or 8 Mb equals 1 megabyte, or 1MB. This is an important detail to realize, because people will often see that their camera records video at 100 megabits per second (Mb/s) and think “Oh, I need a card that records at 100 megabytes per second (MB/s)” when 100 Mb/s converts to 12.5 MB/s.

Second, it’s important to be familiar with read speeds versus write speeds. Manufacturers don’t always advertise their write speeds, so unless a card’s write speed is explicitly stated, any speed written on the front of a card, such as a CF or SD card, is the maximum achievable read speed, but not the sustained read speed. Much in the way a CPU has a base clock speed and an over-clocked speed, sustained and maximum read and write speeds function in a similar fashion. While a memory card may be able to achieve a read speed of 160 MB/s, or a write speed of 90 MB/s, it will rarely be able to sustain those speeds for long periods of time. This is not to say that sustained read/write speeds can’t reach high values. They can, but they won’t be able to sustain their maximum advertised speeds consistently.

Along the lines of speed ratings, it’s also important to be able to convert card speeds with an “x,” such as 1066x, into MB/s. This is accomplished by multiplying 1066 by 150 and then dividing by 1,000. Thus, a card with a speed rating of 1066x has a maximum read speed of 160 MB/s.

Lexar 256GB Professional 1066x CompactFlash Memory Card

When working with SD cards, it’s not uncommon to see things such as the number 4, 6, or 10 enclosed within the letter C, or perhaps a roman numeral I or II, and even a 1 or 3 within the letter U. A 4, 6, or 10 refers to the “Class” of a card, or its minimum-rated sustained write speed. A Class 10 card is rated to never write slower than 10 MB/s, and the number 1 or 3 within the letter U refers to the U1 or U3 speed class rating. U1 is identical to Class 10 and means that a card is certified to write at a minimum of 10 MB/s, while U3 cards have been certified to never write slower than 30 MB/s, with the difference being that “U” cards are designed for SD cards that employ the UHS-I or UHS-II bus.

Lexar 64GB Professional 1000x UHS-II SDXC Memory Card

It’s also important to note that not all U3 cards have the same minimum write speed. A card could be rated U3 and write at 60 MB/s. Along these lines, the SD Association created the Video Speed Class rating, designed to identify cards capable of 8K, 4K, 3D, and 360° video. This speed class is just another way of verifying the minimum sustained write speeds of cards, but it goes higher than both Standard Class ratings and UHS Speed Class ratings. It is made up of V6 (6 MB/s), V10 (10 MB/s), V30 (30 MB/s), and V90 (90 MB/s).

SanDisk 32GB Extreme UHS-I U3 SDHC Memory Card

All in all, what does this discussion about card speeds mean? Essentially, if your card is rated to handle faster bitrates, it will be able to record more advanced types of media. Raw files from the Nikon D810 can reach around 73MB, while the D5 delivers raw files around 45MB. The D5 is also able to shoot with a burst mode of 12 frames per second, and while DSLR cameras have an internal buffer to store photos as they’re being taken, the buffer can only hold so much. If a memory card has a faster write speed, a camera’s buffer will be cleared more quickly, allowing new photos to be taken. The same stands true for video—cards with faster write speeds will be able to record video that requires higher bitrates, such as 3D and 4K.

Hoodman HCFAST STEEL 128GB Memory Card

Stepping back briefly to burst speeds versus sustained speeds, burst speeds are more important for photography, while sustained speeds are more important for video. The D5’s buffer can hold up to 20 seconds’ worth of raw files at 12 fps, for a maximum of 240 photos. In this case, a card’s burst speed, which cannot be sustained for long periods, would be beneficial in quickly clearing out the camera’s buffer over a short period. However, video cameras cannot have the card’s speed drop below the video codec’s bitrate, otherwise there will be dropped frames—hence, the reason video relies on sustained write speeds.

Moving on to cards that are suitable for actual use, the first are CompactFlash (CF) cards. Available in capacities up to 512GB, CF cards are interesting because while they are still widely used in DSLRs, they are based on the now defunct PATA standard. The current CF standard, UDMA 7, allows for read speeds of up to 167 MB/s, which is fast enough for most photo and video uses. SanDisk offers its Extreme Pro, Extreme, and Ultra series, while Lexar offers a 1066x version. Also notable is Delkin Devices’ Cinema Memory Card series.

Delkin Devices 128GB CF 1050X UDMA 7 Cinema Memory Card

Much more common than CF cards are Secure Digital (SD) cards. Able to support capacities up to 2TB, although the largest cards on the market are 512GB, non-UHS SD media read speeds max out at 25 MB/s, while UHS-I cards max out at 104 MB/s and UHS-II cards max out at 312 MB/s. UHS-II media has a second row of pins, allowing it to achieve this extra speed, but if your device does not have this second row of pins, the card will default to UHS-I speeds. The same standards hold true for microSD cards. SanDisk offers its Extreme PRO UHS-II cards in both SD and microSD formats, plus Extreme PRO UHS-I SDXC media in capacities of 16GB and 512GB, while Lexar produces 1000x SD and microSD, as well as and 2000x SD media.

SanDisk 128GB Extreme Pro UHS-II microSDXC Memory Card

If you’re interested in SD cards that have been labeled with the Video Speed Class rating, SanDisk makes V30-rated Extreme PRO UHS-I media in capacities of 128GB, 256GB, and 512GB. If minimum write speeds of 30 MB/s aren’t sufficient for your needs, Delkin Devices offers V60 UHS-II media in SD and microSD formats. For those working with cameras and codecs that have intensive bandwidth requirements, Delkin Devices and Angelbird deliver with V90 SDXC UHS-II media.

While less common and only supported in a handful of devices, such as the Nikon D4, D4S, D5, D500, and Sony FS7, XQD cards are the official replacement for CF cards, although these two formats are not interchangeable. XQD cards are based on the PCIe standard (with an 8 Gb/s bus speed), feature read speeds up to 440 MB/s, write speeds up to 400 MB/s, and are currently available in sizes up to 256GB. Sony produces the G Series and M Series, while Lexar offers 2933x media.

Sony 128GB XQD G Series Memory Card

CFast cards are based on the SATA standard most commonly found on computer drives, though CFast card slots are used in cameras such as the Canon EOS-1D X Mark II, the Blackmagic URSA, and URSA Mini. CFast 1.0 uses the SATA I (1.5 Gb/s) standard, while CFast 2.0 uses the SATA III (6 Gb/s) standard. These cards are currently available in capacities up to 512GB and feature read speeds up to 560 MB/s and write speeds up to 495 MB/s. CFast cards are manufactured by SanDisk, Delkin, Transcend, and Hoodman, while Lexar makes 3600x and 3500x versions.

Delkin Devices 256GB Cinema CFast 2.0 Memory Card

Moving further up, SxS cards are a flash memory standard designed to interface with ExpressCard slots usually found in laptops. SxS cards use a PCIe interface and are the standard storage medium for Sony’s XDCAM EX line of professional video cameras. SxS and SxS PRO+ cards, which are offered in the D Series and E Series, are designed for 4K video, with a minimum recording speed of 163 MB/s and a theoretical maximum of 1,000 MB/s. SxS cards are used in Sony’s CineAlta cameras and SxS PRO+ feature improved read and write durability.

Sony 64GB SxS-1 (G1B) Memory Card

For those shooting with Sony’s F65, don’t forget about the SRMemory Card platform. Available in capacities up to 1TB and with read/write speeds up to 688 MB/s via its PCIe bus, these cards are able to handle demanding 3D, HFR, and 4K media from the F65’s 20.4-megapixel CMOS sensor.

Sony 1TB S55 Series SRMemory Card

So, what kind of card will you need? That’s dependent on which camera you have and what you intend to use it for. But if it’s performance you’re after, fear not, at this article provides many worthy options. What are your thoughts? Please share them in the Comments section, below.

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Hi John,

how are you? I've just acquired a Panasonic Lumix G 80 and I'd like to know which are the recommended SD cards for it, especially thinking of recording videos. (To begin with, I think that 128 GB would be more than enough). Thanks a lot.

Hello John,

A SanDisk 128GB Extreme PRO UHS-II SDXC Memory Card B&H # SAEPSDU128GA is a suitable option for use with the Panasonic G80/G85 camera for shooting video or stills.

 Hi John Paul ,

recently purchased the Nikon 7100. I plan to shoot stills as well as video. Just wanted to get your opinion as to which would be the best ST card to use? Thanks again for a wonderful article

Hi George,

The D7100 captures 24.1 megapixel stills and shoots 1080i video up to 60 fps. It supports the UHS-I bus and not UHS-II. So, you’ll be fine with UHS-I media such as U1 or U3 cards that support minimum write speeds of 10 MB/s and 30 MB/s, respectively. You’ll also be fine with non-UHS media, provided you use Class 10 card, which also support minimum write speeds of 10 MB/s. For Class 10 or U1 cards, try the SanDisk Ultra SD Memory Card or Sony UHS-I SD Memory Card. For U3 cards, try the Sony High Speed UHS-I SDXC U3 Memory Card, SanDisk Extreme UHS-I SD Memory Card, or SanDisk Extreme PRO UHS-I SD Memory Card.

If you’re interested in future-proofing your memory cards with UHS-II media, there are plenty of great options mentioned in this article, but I’d be happy to further assist you.

 Hi John Paul ,

recently purchased the Nikon 7100. I plan to shoot stills as well as video. Just wanted to get your opinion as to which would be the best ST card to use? Thanks again for a wonderful article

I shoot with a Canon, so show canon camera's sometimes please!  

Hi John,

The Canon EOS-1D X Mark II is mentioned in this article, but if you have questions about card compatibility for a specific Canon model, feel free to ask and we'll help you out!











Hi Jerry,

Thanks for your response. I've used the 5DS R before and as far as I know, there are no capacity limits or brand requirements for the individual CF and SD cards. You can use virtually any CF or SD card from any manufacturer, although I will make suggestions below.

As I stated in my article, CF cards are interesting because they are based on the now defunct PATA standard. A few years ago, the CompactFlash Association announced there would be no more updates to the format, leaving card performance with a glass ceiling. Today, CompactFlash cards have hit their performance ceiling, and are slower than the fastest SD cards, though they are still quite fast. So, when it comes to CompactFlash cards, there is no future-proofing.

When selecting a CompactFlash card, definitely buy a UDMA 7 card, as the interface has a maximum possible transfer speed of 167 MB/s, which is fast enough for most photo and video uses. CompactFlash cards explicitly state their maximum read speed on the front of the card, either or MB/s, an “x” value, such as 1066x, or both. In the chance that a number like 1066x is used, it can be converted to MB/s by multiplying it by 150 and dividing the result by 1,000. So, a CF cards with its maximum read speed listed as 1066x converts to 160 MB/s.

CF cards often also list their minimum write speed on the front of the card, although this number isn’t anything that’s standardized within the CompactFlash Association. If a CF cards has a number on the front within a movie slate, such as 65, that’s it’s minimum write speed (65 MB/s).

Anyways, for CF cards, look no further than SanDisk Extreme Pro CompactFlash Memory Card. It's available in capacities of 16GB, 32GB, 64GB, 128GB, and 256GB and its rated UDMA 7 with maximum read speeds of 160 MB/s, maximum write speeds of 150 MB/s, and minimum write speeds of 65 MB/s. Just to give you some variety, the Lexar Professional 1066x CompactFlash Memory Card features the same capacities, maximum read speed, and minumum write speed as the SanDisk Extreme Pro, yet offers a maximum write speed of 155 MB/s. Delkin Devices also makes the CF 1050X UDMA 7 Cinema Memory Card in capacities of 32GB, 64GB, 128GB, and 256GB. These cards offer a maximum read speed of 160 MB/s, and maximum write speed of 120 MB/s, and a minimum write speed of 20 MB/s.

Moving on to SD cards, since you said you want to future-proof, I’ll only discuss UHS-II media. However, bear in mind that since the 5DS R doesn’t support UHS-II, it won’t benefit from any of the improved read or write speeds that UHS-II offers. However, if you have a card reader that supports UHS-II, such as the Lexar Professional USB 3.0 Dual-Slot Reader, you may see some performance benefits when transferring media to your computer. This card reader also supports UDMA 7 and would be a good fit for you needs with the 5DS R.

As for UHS-II cards that I’d recommend, the SanDisk Extreme PRO UHS-II SD Memory Card is available in capacities on 32GB, 64GB, and 128GB. It features a minimum write speed of 30 MB/s, a maximum write speed of 260 MB/s, and a maximum read speed of 300 MB/s. The Lexar 64GB Professional 2000x UHS-II SD Memory Card offers the same capacities and performance specs, and includes a UHS-II SD card reader. However, as Micron recently announce they were discontinuing Lexar media, including the CF cards mentioned above, I’d contact them to see how this affects the lifetime warranty.

If you like Sony, the offer their SF-G Series UHS-II SD Memory Card in capacities of 32GB, 64GB, and 128GB, with a minimum write speed of 30 MB/s, a maximum write speed of 299 MB/s, and a maximum read speed of 300 MB/s. If you need something more durable, check out the Hoodman Steel 2000x SDXC UHS-II Memory Card. Built using steel construction and available in capacities of 64GB and 128GB, it has a minimum write speed of 30 MB/s, a maximum write speed of 260 MB/s, and a maximum read speed of 300 MB/s.

If you need cards that deliver minimum write speeds that are faster than 30 MB/s, check out media with the Video Speed Class rating. The Delkin Devices UHS-II SDXC Memory Card is available in capacities of 64GB, 128GB, and 256GB, plus its V60 class rating guarantees a minimum write speed of 60 MB/s. It also delivers a maximum write speed of 100 MB/s and a maximum read speed of 285 MB/s. Moving up to the V90 speed class rating, which guarantees minimum write speed of 90 MB/s, Delkin Devices offers their Cinema SDXC UHS-II Memory Card in capacities of 64GB and 128GB. Each card also has a maximum write speed of 250 MB/s and a maximum read speed of 280 MB/s. Angelbird also offers V90 media in capacities of 64GB and 128GB. Both cards deliver minimum write speeds of 90 MB/s, maximum write speeds of 260 MB/s, and maximum read speeds of 300 MB/s.

Those are the absolute fastest SD cards that B&H sells. There are others, and while they aren't as fast, they will be cheaper. If you want larger capacity cards, there are some 512GB SD cards available, but they don't support UHS-II, only UHS-I. Again, please remember that since the 5DS R doesn't support UHS-II, you won't see these speeds.

Hope this helps and please let me know if you have more questions!





Hi, i need a little advice, you have a good sale on the lexer professional 633x and woild like to purchase a few. Since Micron has discontinued production off all Lexar memory cards i'm affraid of how will their lifetime warrenty be honored?

Hi Kim,

As per Micron's site, "The company will continue to provide support to existing customers through this transition period. Customers should contact their Lexar sales representative to discuss specific requirements."

As per Micron's announcement, I would contact them directly to find out how Lexar cards will be supported moving forward. If you're looking for SD media cards whose parent company isn't discontinuing memory cards and thus putting the warranty in question, here are some suggestions. For U1 media with minimum write speeds of 10 MB/s, look at the SanDisk Ultra UHS-I SD Memory Card and the Sony UHS-I SD Memory Card. For U3 or V30 media with minimum write speeds of 30 MB/s, check out the Sony 64GB High Speed UHS-I SD Memory CardSanDisk Extreme UHS-I SD Memory Card, and the SanDisk Extreme PRO UHS-I SD Memory Card.

Hope this helps and let me know if you have any further questions. 

still confusing with so much data, I think what I need to learn is what speed my camera, Nikon D5300, can handle. (I take photos, no videos) then to get the card that matches it's capacity, correct?

Hi Barb,

The Nikon D5300 has a 24.2 megapixel sensor, a max burst rate of 5 fps, and can shoot Full HD video at 24, 25, 30, 50, and 60 fps. Since you don't shoot video and its SD card slot only supports UHS-I and not UHS-II, you'd be fine using a Class 10 / U1 card, such as the SanDisk Ultra SD Memory CardSony UHS-I SD Memory CardLexar Platinum UHS-I SD Memory Card, or the Lexar Professional UHS-I SD Memory Card (only the 16, 32, 64, and 128GB cards are U1).

However, if you may be shooting using the 5 fps burst mode or just want faster card speeds, there's nothing wrong with equipping your D5300 with any of the U3 cards mentioned in this article, such as the Sony High Speed UHS-I SDXC U3 Memory CardSanDisk Extreme UHS-I SD Memory CardSanDisk Extreme PRO UHS-I SD Memory Card, or the Lexar Professional UHS-I SD Memory Card (only the 256 and 512GB varieties are U3).

Hope this helps and let me know if you have any other questions!

Leica M9 & Mono SD card recommenditions....

I have read so many different stories about which cards to use with these cameras, is totally confusing. They are slow cameras and I would like to know what is the best card to use, i.e....32gb 45mbs are faster or slower? I am using Samsung SD EVO 48MB/s cards at the moment.....

any postive help would be appreciated.....

Hi Lawrence,

The Leica M9 has an 18 megapixel sensor with a burst rate of 2 fps. It also doesn’t shoot video, which helps to simplify which card you may need for this camera. Honestly, you’d be fine a Class 10 / U1 card, such as the SanDisk Ultra SD Memory Card, Sony UHS-I SD Memory CardLexar Platinum UHS-I SD Memory Card, or the Lexar Professional UHS-I SD Memory Card, all of which feature minimum write speed of 10 MB/s. However, there's also nothing wrong with equipping your M9 with any of the U3 cards mentioned in this article, such as the SanDisk Extreme UHS-I SD Memory CardSanDisk Extreme PRO UHS-I SD Memory Card, or Lexar Professional UHS-I SD Memory Card.

The Leica M Monochrom has a 24 megapixel sensor and also shoots Full HD video at 24 or 25 fps. Given those specs, my card recommendations for this camera would be the same as for the M9.

If you have any other questions, please let me know!

Thanks for all of the useful information and your responsiveness to reader questions.  I have a D500 that I am using with a fast XQD card.  If I have the second card slot (SD) set up for back up, will it slow the buffer clearing if that second  card has slower write speeds than the XQD card? 

Hi Paul,

In order to provide you with a more informative response, I did a quick test using a Nikon D850, a Sony 32GB XQD G Series Memory Card, and a Lexar 64GB Professional 1000x UHS-II SDXC Memory Card

I had the D850 set to shoot large raw files in the continuous burst mode and here's what I found. Using just the XQD card, the camera's buffer cleared out in 3-5 seconds. Using just the SD card, the buffer cleared in around 18 seconds. Using the XQD card as the primary one and the SD as backup, the buffer cleared in around 20 seconds.

The interesting thing was that with the XQD card, the camera never really stopped shooting while I had the shutter button pressed down. Sure, when the buffer filled up, it wasn't shooting at its maximum burst rate, but it also never stopped shooting and merely captured photos more slowly. This can probably be attributed to the XQD card’s maximum write speed of 400 MB/s. Once the buffer was filled while using the SD card, which has a maximum write speed of 75 MB/s, the camera stopped shooting.

I hope this helps and feel free to ask more questions!

John-Paul, thank you for responding and doing the test. It is very helpful information.  Correct me if I am wrong, but my interpretation of your test results is that for most types of shooting using a regular SD card as back up won't be an issue. However, if there are heavy action sequences it might be better to have a more expensive but faster SD card, like the SanDisk Extreme PRO SD UHS-II.

Hi Paul,

Since the D500 supports UHS-II media, yes, the SanDisk Extreme PRO UHS-II SD Memory Card would be a very good option, with a minimum write speed of 30 MB/s, a maximum write speed of 260 MB/s, and a maximum read speed of 300 MB/s. The Lexar Professional 2000x UHS-II SD Memory Card offers the same read and write speeds and also includes a UHS-II card reader. If you want to go even faster, the Delkin Devices UHS-II SD Memory Card (V60) offers minimum write speeds of 60 MB/s. maximum write speeds of 100 MB/s, and maximum read speeds of 285 MB/s. At the absolute top is V90-rated media and on this level, Delkin Devices Cinema SDXC UHS-II Memory Card offers minimum write speeds of 90 MB/s, maximum write speeds of 250 MB/s, and maximum read speeds of 280 MB/s. There are also V90 offerings from the Angelbird AV Pro UHS-II SDXC Memory Card lineup, which offers minimum write speeds of 90 MB/s, maximum write speeds of 260 MB/s, and maximum read speeds of 300 MB/s.

Just bear in mind that these maximum read or write speeds cannot be sustained for long periods of time, but you should notice a performance boost from faster UHS-II media.

Desculpe mais o artigo sobre cartoes é muito complexo pra min , realmente nao entendo.

Por favor me ajude tenho uma camera Nikon 7200 uso um cartao  SanDisk 32GB Extreme UHS-I U3 SDHC Memory Card velocidade 90 mb/s. E adequado para minha camera?

Agradeco o retorno

Hi Cleidy -

That memory card should work fine with your camera.

Comprehensive article but still difficult to understand for a non-tech person.  I have a Canon EOS 70D with a 75-300 L Series zoom, and mostly take wildlife (whales) shots.  I'm currently using a San Disk Extreme Pro 95 mb/s 32 GB.  I feel like I'm missing some shots (moving boat, moving water, moving animals!) and they're not always as crisp as I'd expect, even with a high speed, at least 1000, ISO 640, and usually about f10.  Would a faster card help?  Thanks!

Hi Bonnie,

Are you shooting using the camera’s burst mode? The Canon EOS 70D can shoot with a maximum burst speed of 7 fps. So, in theory, faster cards will be able to clear out the camera’s buffer more quickly. This would especially be beneficial if you’re shooting at 7 fps, but will also help when shooting in a non-burst mode. However, the 70D also only supports the UHS-I bus, meaning you’re guaranteed minimum write speeds of 30 MB/s. The SanDisk Extreme Pro card you’re using supports write speeds of up to 90 MB/s, but that maximum speed can’t be sustained for long periods of time. Since

If you’re pressing the 70D’s shutter button and no photos are being captured, it’s likely that its buffer hasn’t been cleared out yet, or perhaps your camera’s electronics are slightly laggy? Since you’re already using a UHS-I / U3 card, this camera wouldn’t benefit from using a faster card, since it doesn’t support UHS-II.

Thanks for the info....I am shooting in burst mode at 7fps..  I didn't mean that no photos were being captured, just that I might be missing a few.  Helpful to know that it wouldn't be worth it to get a different card.  The camera is 2 years old, would it benefit from a service?  Thank you!

Hi Bonnie,

All of what Kevin said sounds good. Lack of crispness could be related to the shutter speed, but you did say you're already shooting at 1/1000, which should deliver crisp shots, especially since you're also shooting at f/10. ISO 640 shouldn't be terribly noisy, but you could experiment with different aperture, shutter, and ISO combinations to find one that really works.

Also, bear in mind that if you are pressing the shutter button and no photos are being captured, it's probably because your camera's buffer is full. Give it a few seconds to clear out. I have an older SanDisk SDHC card at home where the write speeds are noticeably slower than other Class 10 and U3 cards that I have. As such, that card is only used when everything else is full.

The other reason you may not be capturing photos as quickly as you’d like may be electronic. Perhaps you have some oxidation in the internal circuitry that is preventing the shutter button from being as responsive as it could? You mention you do a lot of whale photography, so always make sure your camera is well protected from the elements, especially water and salt. Many years ago, I was shooting a thesis project for an NYU student on Super16 using an Arri SR3. The entire film was shot either on the ocean or the beaches of Montauk and the director didn’t want to invest in any protection for the camera. Suffice to say that when the camera was returned, it needed $15,000 of repairs. Luckily the director had insurance, but always protect your gear!

Thank you!  I'll play around with it.


The photo is saved as it was captured.  The speed it saves is contingent upon the speed of the camera and card combination.

Your lack of crispness is more likely you shutter speed.  Try increasing your shutter speed.  You may need to increase your f/stop (lower number) to reduce your ISO setting to reduce noise (depending on your camera capabilities).  

I hope this helps.  I hope you get some good shots!


After reading your add on,  make sure your camera is set to continuously focus as you take your burst shot. 

Thanks for your help!

I am an old guy who spent many years with Leica-M film cameras, but now use digital.  So here are my questions: 1. What do you mean by "read speed" and "write speed"?  What is the difference?   2.  I have experienced annoying shutter lag with my Canon G-12.  Could that be because I am using an old Kodak 2GB card?  If I use the 32 GB card that came with my new Nikon D500, would I eliminate the shutter lag?  Thanks very much for your help.

Hi Stuart,

Read speeds generally refer to the speed at which data is transferred from the memory card to a target destination, such as your computer. During this transfer process, data is “read” from the memory card and the speed at which is copied to the target destination is the read speed. In addition to the read speed that is supported by whichever memory card, read speeds are also determined by the connection you’re using to copy data, such as Thunderbolt, USB 3.0, USB 2.0, etc.

Write speeds refer to the speed at which data is written to a memory card. Different cards support different minimum write speeds. U1 support minimum write speeds of 10 MB/s, U3 and V30 support 30 MB/s, V60 supports 60 MB/s, and V90 supports 90 MB/s. Once you determine which video format you’re using and what requirements its video codec has, then you can select a card that best suits your needs.

Regarding shutter lag, could you elaborate a bit more? Is the lag from when you press the shutter button to when the shutter engages, or does it just take the file a while to be written to your Kodak 2GB card?

Thanks very much for your very helpful answer.  With regard to the shutter lag:  I think the problem is that it takes a while for the image to be recorded.  This happens in two ways: (1) sometimes I am unable to take two shots in rapid sucession; and (2) there are times when I shoot a moving subject but by the time the image is recorded the subject has moved out of the picture.  I have a lot of experience shooting moving subjects (mostly sports), so I'm sure the problem is not that I waited too long to press the shutter.  Thanks again for your help. 

Hi Stuart,

I'd say your 2GB card is likely the culprit here, especially since it's made by Kodak. Not that there's anything wrong with a card made by Kodak, but it just sounds old and probably isn't updated with more recent read and write speeds. I'm sure if you were to use the 32GB card that came with your D500, you'll have better results.

Also, let me clarify a bit more on read and write speeds. What I wrote yesterday wasn't as clear as it could've been. When you're transferring data off your card, how quickly it can be copied off begins with the card's read speed, as the data needs to be read off your memory card before it can be written to a target destination. However, when transferring data from a card, the read speed is only one part of the equation. The next step is how fast your card reader can transfer data. Does your card reader support USB 3.0, USB 2.0, or one of the variations of Thunderbolt? If you’re using USB 3.0 or Thunderbolt, then your card’s read speed won’t be limited by the bandwidth of your connection, but if you’re using USB 2.0, then chances are you’ll hit a bottleneck. The final part of the equation is how quickly your data can be written to its target destination, such as a hard drive or SSD. SSDs will have faster write speeds than hard drives.

Hope all of this helps and feel free to ask more questions!


Hey, Stuart:  Read speed is the speed at which the SD card can take information from the camera; write speed is the speed at which the camera will actually write to the SD card.  As the article says, sometimes the card rating is a minimum standard for the card with the real value being higher. At the same time, sometimes the camera's write speed is physically lower than the rate of information the SD card can suck up (read speed); that doesn't limit the card, but means perhaps that you don't need a super-quick one. For instance, my Sony a6000, for as cool as it is, won't write to the SD card much faster than 35 MB/sec. It will write to a card that CAN read at 90 or more, but won't feed information that fast, so I don't need a super fast card.  To the extent that I might be thinking about upgrading to a camera that incidentally writes data faster, I might get the faster card so I can switch more easily after the purchase. 

Shutter lag may be caused by the card not being able to read all the data you're feeding it if you're shooting bursts of photos. Given that you're using a 2GB card, that might be the deal.  By all means, I'd take a shot at using the 32 GB card you have and see if things improve.  Happy shooting!


 I excellent article. You would think picking out an SD card is a simple process but you would have to walk into a store or pick on a web store a card you think is correct. The article really breaks down all the language the card manufacturers use. What sd card would you recommend for a Sony a6300 that can handle 4K video, is there a better card than another card or is it pretty much standard to buy a card that works for your camera and they all record at the same quality?

Hi Geo,

The Sony a6300 supports the UHS-I bus, so you're best off using U3 cards that support minimum guaranteed write speeds of 30 MB/s, which is sufficient for 4K video. Both the SanDisk Extreme UHS-I SD Memory Card and the SanDisk Extreme PRO UHS-I SD Memory Card would serve your needs. B&H also sells the Lexar Professional UHS-I SD Memory Card which supports U3 in capacities of 256GB and 512GB. Since the a6300 doesn't support UHS-II media, you won't benefit from any of those performance gains, but could always pre-emptively purchase UHS-II now in case you acquire any compatible devices in the future. UHS-II definitely supports 4K and excellent offerings from SanDisk, Lexar, Delkin Devices, and Angelbird can be found within the article.

Hi, i have tried several SD cards in my new Pentax K-1 and have not found one that does not give me long lag times clearing the cameras buffer. I have missed many photo's due to this, can you please recommend an SD card that will help eliminate my problem.

Hi Kim,

The Pentax K-1 uses the UHS-I bus, so you should be fine using U3 cards, which support minimum write speeds of 30 MB/s. UHS-I cards that would be suitable for you include the SanDisk Extreme UHS-I SDHC Memory Card or SanDisk Extreme PRO UHS-I SDHC Memory Card. Since your camera doesn't support UHS-II, you woudn't see any benefit to using that media in your K-1 to clear out the buffer more quickly, but you could always buy UHS-II media now in order to future-proof any upcoming camera purchases that may support UHS-II. If you're interested in UHS-II SD media, there are several options listed in this article from SanDisk, Lexar, Delkin Devices, and Angelbird.

Thank you John-Paul

Hello! I'm planning to use a D810 to shoot a wedding ceremony and reception on video. What card do you recommend I buy?

Hi Alexis - 

For a wedding shoot I would go with:

The 128GB Professional 1066x CompactFlash Memory Card (UDMA 7, 2-Pack) from Lexar features a 128GB storage capacity perfect for storing large files including high-quality photos, 1080p Full-HD, 3D, and 4K video. With a 1066x speed rating, this card is capable of achieving data read speeds of up to 160 MB/s and data write speeds of up to 155 MB/s, allowing you to transfer your files via the card-to-computer transfer method via a UDMA 7-enabled card reader (sold separately).

In addition to enhanced data transfer rates, this CompactFlash card supports the Video Performance Guarantee specification. With a VPG of 65 MB/s you can rest assured this card will capture video streams at a minimum data rate of 65 MB/s for compatible host devices and recording media. You also benefit from Lexar Image Rescue Software designed to protect your data in the event the data is accidentally erased or the card becomes corrupted.

thanks so much Mark!

is there an options that delivers similar quality and storage but for a more affordable price?

Hi Alexis - 

Shoot 3D and Full HD video with the 128GB Professional UHS-I SDXC Memory Card from Lexar. This memory card features UHS Speed Class 1 compatibility denoting a minimum write speed 10 MB/s. Along with enhanced speed class compatibility, you benefit from maximum data read speeds of up to 95 MB/s and maximum data write speeds of up to 20 MB/s making it easy to transfer even large files quickly. The downloadable Image Rescue Software included with this card provides added peace of mind with the ability to recover most photos and select videos if the card becomes corrupted or files are accidentally erased.

awesome - thank you again!

I just purchased a SONY Alpha A6000, primarily for taking pictures of real estate. I'm wanting to purchase a media card that is within the speed range of the camera. Any suggestions? Thanks in advance!

The instruction manual recommends a Class 4 or faster card for use with the Sony Alpha, but we find the faster Class 10 card is better for sustained transfer speeds for 1080 HD video, and would be compatible with your camera.  Also, the faster transfer speed of a Class 10 UHS-I card would also be beneficial when transferring the files from your memory card to your computer.  The SanDisk 32GB Ultra UHS-I SDHC Memory Card (Class 10)B&H # SAUSD32GBA, would be my recommendation for your needs.

Thanks for the great info. But No mention of P2 cards which I have been using for four years now. They are great and have never failed me

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