Dual memory card slot DSLR vs single memory card slot DSLR

A couple of readers recently sent a message to my Facebook page asking the usage of dual memory card slot DSLR cameras. Most of the professional cameras have dual memory card slots, one as Compact flash card and other as SD card. Some DSLR cameras have a dual SD card slot whereas a very few have dual CF card slot. Compact flash cards are usually supported by professional grade bodies as they offer high speed and thus very fast burst rate handling. If you are looking for a well known dual memory card slot camera, below list will be helpful.

Example of dual memory card slot DSLR cameras from Canon include:

Canon 1D Mark IV

Canon 1D Mark III

Canon 1D Mark II

Canon 5D Mark III

Canon 7D Mark II
Canon 7D

Example of dual memory card slot DSLR cameras from Nikon include:

Nikon D300S

Nikon D3S

Nikon D5

Nikon D800

Nikon D800E
Nikon D7000

Example of dual memory card slot cameras from other manufacturers include:
Pentax 645D
Pentax K-1
Fuji X-T2
Panasonic GH5
Sony A9
Olympus E-M1II

Taken with a single memory card slot DSLR

The bigger question here is why do we need dual memory card slot DSLR cameras and what's the advantage? Let's try to find the answer from a user perspective. Professional cameras have 2 memory card slots for a variety of purposes, although the ability to use both cards at the same time varies from brand to brand. The major reasons can be broadly summarized into three categories:

Better Redundancy: Same image across multiple memory cards. This offers to mirror the same files, which in turn serves as back up. As a professional photographer, the worst scenario would be a failing memory card in the middle of a wedding. Professional photographers charge money, and clients expect them to be reliable no matter what happens. The camera writes twice in this scenario, as it has to mirror the same exact file. 

Different file format to a different card: This can save a lot of buffer space and improve the speed by a major gap. You can write RAW files to one memory card and JPEG files to the other. This saves a lot of time as it prevents the double passing of data going through the camera every time. If speed if your top priority for a dual card slot camera, this method works wonders. 

Auto Switching: 

This category applies to users who are more relaxed about the redundancy and speed of capturing photographs. It basically means the camera switches to the second card once the first card is filled.

Lastly, every manufacturer is coming up with unique ways to store different format data on multiple cards. Some Nikon DSLRs allow users to write video to one memory card and photos to the other. Canon allows a user to use both compact flash (cf slots) type I and II cards in some DSLR cameras. Sandisk Extreme Pro is a good example of a decent quality memory card with good write speed. The ability to use existing memory cards when upgrading bodies is another way to save some decent amount of money. Last but not least, a card reader can solve all these problems.

Hope this post helped you learned something new. Share the photography love by sharing this post.