Pentax 645D Memory Card Compatibility

Pentax 645D SD Memory Card Compatibility

The Pentax 645D needs SD memory cards. The biggest capacity SD card that can be used in the 645D is 32GB.

SD memory cards labeled as SDUC or SDXC are not going to function properly in the 645D. These cards will be At least 64GB or larger, so they are easy to avoid.

The SDHC format was announced in 2006. All 32GB cards that are currently being produced will have almost identical performance. You cannot go wrong buying the cheapest class 10 name brand card. At the time of writing this, the PNY Elite 32GB SD memory card has the best price.

Here are several choices to choose between that are compatible in the 645D. With all of the cards below, you won’t have to be concerned about reduced functionality or card glitches.

PNY Elite 32GB SD Card
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  • Sequential read speed of up to 100MB/s
  • Class 10, U1 rating delivers speed and performance for full HD photography and HD videography.
  • V10 video speed rating to capture uninterrupted HD video at 1920x1080 format
  • Compatible with point & shoot cameras, DSLR cameras, standard & advanced HD-enabled video cameras, and more
  • Reliable & Durable: Magnet Proof, Shock Proof, Temperature Proof, Waterproof

SanDisk Ultra 32GB SD Card
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  • Quick transfer read speeds up to 90MB/s.
  • Write speeds are not capable of recording 4k video.
  • Class 10 rating for Full HD video (1080p).
  • Waterproof, temperature proof, X-ray Proof, magnet-Proof, and shockproof.

Samsung EVO Plus 32GB SD Card
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  • UHS Speed Class 1 (U1) supports Full HD video and burst shots. 130MB/s transfer speeds1 let you upload footage to your PC in an instant.
  • Built to survive tough conditions and heavy usage, whether you’re at home, outside, or on the go. Backed by 10-year limited warranty.
  • Highly durable with comprehensive 7-proof protection.
  • Backed by a 10 year warranty.

Best SD Cards

Lexar, PNY, Samsung, and SanDisk both produce premium quality memory cards. Avoid ordering cards from bargain-priced third party brands.

Memory card troubles, like a complete loss of all your shots due to data corruption, is more probable to take place with low-priced cards. An insignificant amount of savings on cost is not worth the reduction in build quality.

The smart way to save money is to get a card with a smaller capacity. They commonly are a bit more affordable and you won’t need to stress out about the SD card having data failure.

Be aware that, SD card issues are unlikely to occur. Just a couple cards have become corrupted out of the considerable number I have owned over time. Age could have contributed to the failure, as the SD cards were bundled with used digital point & shoots.

Pentax 645D SD Card Compatibility

The Pentax 645D uses SD memory cards. There are four separate technical specs of Secure Digital (SD) cards. Every updated memory card technical spec boosts the read/write speeds and max capacity when compared with the prior spec.

Secure Digital memory card readers are backward compatible. A card reader built into a digital camera that can use SDXC cards will also be able to use SDHC and SD memory cards.

The card reader in the Pentax 645D can only read the original two SD card standards. SDXC or SDUC SD cards will not operate correctly.

  • Secure Digital (SD) - These memory cards have a maximum capacity of 2GB and are compatible with the 645D.
  • Secure Digital High Capacity (SDHC) - The capacity of these memory cards range from 4GB to 32GB and are also compatible with the 645D.
  • Secure Digital eXtended Capacity (SDXC) - The capacity of these memory cards range from 64GB to 2TiB.
  • Secure Digital Ultra Capacity (SDUC) - The capacity of these memory cards range from 4TiB to 128TiB.

Pentax 645D Memory Card Full Error

SD Card Contacts

Trying to use an SD memory card that has a storage capacity of 64GB or larger in the 645D will cause the digital point and shoot camera to show an error.

Get a card which has a storage capacity of 32GB or smaller to resolve the problem.

If you are using a memory card that is 32GB or smaller, and it is not working correctly, try to format the SD memory card while it is in the camera.

Speed, Class, & Capacity

SD Card Image Capacity

This is an estimate of how many large JPEGs you can expect to store on an SD card.

  • 4GB - 1920 images
  • 8GB - 3840 images
  • 16GB - 7680 images
  • 32GB - 15360 images

Memory Card Speed

The speed rating for SD cards is established by sequential read and write speeds. The speed of the SD memory card is important in cases where many shots need to be written or read from the SD card.

SD Card Speed Class Rating

SD Card Speed Class

The Class speed rating of an SD memory card is determined by the sustained write speed of the memory card. A Class speed rating of 2 means that the card can sustain a write speed of more than 2MB per second.

  • Class 2 - 2MB/s
  • Class 4 - 4MB/s
  • Class 6 - 6MB/s
  • Class 8 - 8MB/s
  • Class 10 - 10MB/s

The top rating a card can attain is Class 10. There are SD memory cards that are substantially faster than 10MB/s. Those cards use other solutions, such as UHS (Ultra Highspeed Bus), which use a different rating criteria.

Sustained write speeds of 2MB, 4MB, 6MB, or 8MB per second means the card has a speed class of 2, 4, 6, or 8. Cards that have write speeds of 10MB/s or faster are rated as Class 10.


Buy an SD memory card for the Pentax 645D based on price. An expensive card isn’t going to improve performance. As long as it is a speed class 10 card, you will be fine. My recommendation is the PNY Elite 32GB SD memory card.