Pentax 645D Memory Card Compatibility

By Nathaniel Stephan
Last Updated: October 24, 2019
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Olympus SD Memory Card Compatibility

The Pentax 645D has an memory card slot that supports SD cards. memory cards with a maximum storage size of 32GB will work in the Pentax 645D.

Attempting to use an SD memory card that is 64GB or larger will cause the Pentax 645D to display an error code. For more storage space, you will need to purchase several cards. The key specifications to look at should be the transfer speeds the card is capable of.

Faster read speeds will minimize the time needed to copy images, especially if your Pentax 645D will get used often. A feature that is very good to have is UHS-I as it allows for faster transfer speeds with a UHS-I memory card reader.

To make sure the card will be compatible with as many other devices in the future as possible, get a high-quality memory card. To prevent finding yourself with a camera upgrade causing you to need to buy a replacement SD memory card that is fast enough for shooting 4k video.

Here's my recommendation for the best SD memory card for the Pentax 645D:

SanDisk Extreme Pro UHS-I SDHC Memory Card

SanDisk Extreme Pro 32GB

  • Best SD card available
  • Largest compatible storage capacity.
  • Read speeds of up to 95MB/s.
  • Write speeds of up to 90MB/s.
  • Shock-proof, temperature-proof, waterproof, and x-ray proof.

Best SD Cards

Since the Pentax 645D was launched, SD card prices have dropped and capacities have become massive. The difference in price between the fastest SD card and a mediocre option is unexpectedly little. Cost is related to storage, with the largest memory cards being more expensive.

Purchasing the highest capacity cards is a good idea if you're going to shoot a large amount of RAW files for sports, action, event, or wildlife photography. Another contributing factor could be if you intend to replace your camera or use the memory card in other devices.

I think that the SanDisk Extreme Pro line of sd cards are frequently the best choice for most circumstances. They are very fast cards which means they have the best prospect of working in future digital cameras or devices that also use SD cards.

I have also had positive experiences with PNY Elite Performance And Lexar Professional cards. I have not had images or files become corrupted or lost on these brands. If that's a situation that did take place, all of the manufacturers provide image recovery software.

Troubles I have encountered have been with generic SD cards. Having a low price or being a bundled accessory are the main attractions of these cards. Unfortunately, this is also the most commonly encountered type of SD card to have an incorrect product description.

A sticker that promises Class 10 speed is effortless to put on a Class 4 card. When the camera image processor starts writing data there is destined to be an error message or corrupted photos if the card's write speed isn't fast enough.

Storage size controls a large part of the cost. You will be better off by going one step down in capacity to reduce cost as opposed to using a generic brand. Read and write speeds are important factors that will impact your enjoyment of the Pentax 645D.

Recommended SD Cards

Lexar 633x 23GB UHS-I SDHC Memory Card

Lexar Professional 633X 32GB

  • High-speed, Class 10 performance.
  • UHS-I technology for a read transfer speeds up to 633x (95MB/s).
  • High-speed file transfer from card to computer to dramatically accelerate workflow.

The Lexar Professional will have comparable performance to the SanDisk Extreme Pro card when used in the Pentax 645D. The only difference is that the Lexar memory card features a slower write speed.

Sometimes there can be a big difference in cost between the Lexar and SanDisk memory cards. I would not pay more for the Lexar, but also would have no problem purchasing it if it was less expensive.

SanDisk Ultra UHS-I SDHC Memory Card

SanDisk Ultra 32GB

  • Good value to save some money.
  • Quick transfer read up to 80MB/s.
  • Class 10 rating for Full HD video (1080p).
  • Waterproof, temperature proof, X-ray Proof, magnet-Proof, and shockproof.

The SanDisk Ultra is a step down from the Extreme Pro when comparing specs. That also comes with a little decrease in price.

You won't detect a difference in workflow except if you need to write a large number of files onto the card. It is not the most desirable choice if you plan to use the card to shoot 4k video at some point.

SanDisk Extreme Pro UHS-I SDHC Memory Card

SanDisk Extreme Pro 32GB

  • Read speeds of up to 95MB/s; write speeds of up to 90MB/s.
  • Shock-proof, temperature-proof, waterproof, and x-ray proof.

Memory Card Reader

UGreen 4-in-1 Card Reader
There's a bright blue LED that bothered me. It is now covered in gaff tape.

The UGreen 4-in-1 memory card reader is compatible with four memory card formats. These include all memory cards camera manufacturers use in all but the newest professional-level cameras.

The UGREEN reader has a USB 3.0 connection. Transfer speeds over USB 3.0 will have faster transfer speeds than what the Pentax 645D can achieve transferring files with the USB mode.

There are overwhelmingly favorable customer reviews for the reader, which I agree with. I would recommend it because the reader has worked with all the computers (Windows, Mac, and Linux) I have tried it with.

The cable keeps memory card slots from being blocked by other devices or accessories that are being used in an adjacent port.

When I searched for a smaller card reader that would be easier to travel with, I needed to return a couple of orders. I encountered the most frequently found problem mentioned in customer reviews, the card readers would not work with my computer.

The UGREEN card reader supports the following cards:

  • CompactFlash Cards
  • SD, SDHC, & SDXC Cards (UHS-I supported)
  • Memory Stick (MS), MS Pro, MS PRO-HG, & MS XC DUO
  • MicroSD, Micro SDHC, & Micro SDXC Cards

Pentax 645D SD Card Compatibility

Only use SD and SDHC memory cards in the Pentax 645D. Check to be sure that your camera has the latest firmware installed.

SDXC or SDUC cards are not able to be used in the 645D.

You should be aware of the 4 types of Secure Digital (SD) memory cards that exist. SD cards can be identified based on the card's storage capacity.

  • Secure Digital (SD) - 128MB to 2GB.
  • Secure Digital High Capacity (SDHC) - 4GB to 32GB.
  • Secure Digital eXtended Capacity (SDXC) - 64GB to 2TB.
  • Secure Digital Ultra Capacity (SDUC) - 4TB to 128TB.

Image Capacity

Olympus SD Memory Card Contacts

Image quality settings on the Pentax 645D will effect the quantity of image files you can store at once. Higher image quality settings will result in larger image sizes.

If you're intending to shoot hundreds of RAW files, getting a card with a larger storage capacity can make sense.

If you shoot JPEGs, you would likely be much better off purchasing another battery in place of a larger card. A memory card that has 32GB of space will have enough room for days worth of images that would require the batteries to be recharged several times.

In reality, the controlling factor to just how many pictures you can take will be your camera batteries. Keep in mind that, any time the camera is powered on, even if you are just scrolling through menu settings or using the live view, that will still reduce the battery life.

For low light environments, like indoors or at night, the flash built-in to the camera can be helpful. Without the flash, shutter speeds will not be fast enough to eliminate motion blur. Using the built-in flash will fairly quickly drain the camera batteries. These environments are when you'll need to have at least two Pentax D-LI90 rechargeable batteries.

The following is an estimation of how many high-quality JPG images you can save on a card for the given storage size:

  • 4GB - 1,160 images
  • 8GB - 2,320 images
  • 16GB - 4,640 images
  • 32GB - 9,280 images

Speed, Class, & UHS Ratings

Card Speed

The speed rating of an SD card is determined by the sequential read and write speeds. The transfer speed of a card is very important for clearing the buffer for continuous shooting and recording video.

A slow memory card can cause a reduction in the number of continuous frames the Pentax 645D can take. This is due to the camera's buffer not being able to write to the card fast enough.

When recording video, a slow SD card can cause recording to stop. The video file might also be corrupted. If you are going to shoot video, it is critical the SD card you use meets the requirements of the camera.

Card read speed is important for transferring files to a computer or laptop. If you are filling up cards with images or video, a card with a fast read speed will decrease the transfer time.

Speed Class Rating

Example of where to find SD Card Speed Class
The 10 inside of the C means the card is Class 10.

The Class rating of a card is related to the sustained write speed. SD cards that have a minimum write speed of at least 10MB/s are rated as Class 10.

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

Every name-brand SD card that you can get will have a Class 10 rating. To determine the class rating of a memory card, look for a number inside of a C on the label.

Ultra High Speed (UHS)

Example of an SD memory card with a UHS-I rating.
The UHS rating of a card can be determined by a Roman numeral I, II, or III on the label of the card.

The Ultra High Speed (UHS) bus is built into SDHC, SDXC, and SDUC cards. UHS makes it possible provides a way to increase file transfer rates.

There are three different specifications. They are UHS-I, UHS-II, and UHS-III.

Look at the front of the SD card to find the rating of an SD card. If the memory card has UHS, a Roman numeral I, II, or III can be found on the SD card label.

  • UHS-I - Maximum transfer rate of 104 MB/s
  • UHS-II - Maximum transfer rate of 312 MB/s
  • UHS-III - Maximum transfer rate of 624 MB/s

Related Cameras

Taking the specifics into consideration, SanDisk 32GB Extreme Pro is the best Pentax 645D memory card. Any future camera you own, you will know what sd memory card to buy.

Listed below are more posts on cameras related to the 645D:

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