Sandisk Versus Lexar; Fast Card versus Slow; Slot 1 Versus Slot 2: What Differences Did I Find In High Speed Sequential Imaging with My Fujifilm X-T2?

 (click to enlarge)

A few weeks ago I was reading an article about how various memory cards affect high speed sequential frame rates in digital cameras.  It was written by Nikon expert, excellent photographer, workshop teacher and author Thom Hogan.  His main website is called By Thom but he also writes about DSLR bodies, mirrorless cameras, film gear and compact cameras.  I believe if you are a Nikon user or if you enjoy reading intelligent, educational and well written photographic related articles, I would suggest you read Thom's work.  But I digress.

Mr. Hogan's recent article contained good information as well as his recommendations on best practices when buying and using memory cards got my attention.  You can find it here.  It is called "QAD Card Practices."   Thom made a couple of statements in the article that caused me to conduct a few tests on one of my cameras so I am armed with the best information and, as I have said numerous times, the better you intricately know your gear, the better chance you have for success in the field.  By knowing your gear well, you can eliminate failures, over expectations and under expectations.

One statement he made was, "Cameras tend to be as slow as the slowest card in them." Another interesting statement was, "Cameras tend to slow a bit with the largest card capacities."  My concern is more with his first statement than the second, as none of my cards are more than 64gb. 

Hogan, in his article, says that if you have a camera with two UHS II SD card slots and place a UHS II card in the primary slot and an older, UHS I card in the secondary slot and have your camera set to write to both simultaneously (backup mode), basically the second slower card will slow the overall performance of the camera in emptying the camera's buffer and writing to the cards.  You will lose some (maybe all) of the UHS II speed you paid for.  

Also, if you have a camera with one fast UHS II slot and one slower, older UHS I slot, placing a card in both slots and writing to both simultaneously will result in speed being reduced to the speed of the second, slower slot.  Interesting stuff.  I had heard this before when UHS II card slots were first included in digital cameras.  However, I had forgotten about it.

Thom's words had me thinking about what effect card and slot speed has in my Fujifilm X-T2 so I set out to test it.  I use both Lexar and Sandisk cards.  I use Lexar 2000X and 1000X cards and Sandisk 300mb/sec. cards.  I know some people don't like one brand of card or another, but in the past 17 years of digital photography, I've not had a single card of any make fail.  But...one will eventually.  We know that.

The X-T2 is equipped with two UHS II card slots.  It makes sense, if you are writing to both cards simultaneously, to have UHS II cards in both slots in order to fully exploit the speed Fujifilm engineered into the camera.  I set out to conduct a number of tests utilizing one card and two cards in my X-T2.  I wanted to see if brand made a difference as well as card speed.  Also, I wanted to know how much of a difference shooting RAW only versus RAW plus JPEG made.  Finally, I wanted to know if there was a difference in speed shooting RAW only, compressed versus uncompressed.  I actually ended up performing 16 different speed tests using all three cards noted above.  Again, this non-scientific test was conducted to give me an idea of how my camera works with the cards I use.  

For the record, here is what Fujifilm says on their official site that the X-T2 is capable when shooting at 10 fps:

"Approx. 11.0fps [with VPB-XT2] (JPEG: 73 frames, Lossless compression RAW: 30 frames, Uncompressed RAW: 27 frames)"

(This statement means I should expect 30 frames in 2.7 seconds @ 11fps with UHS II cards.  There is no mention of subsequent speed after the 30 frames are written.) 

I placed my X-T2 with the Power Grip on a tripod and set all controls to manual to eliminate as much delay as possible.  I manually set shutter speed, aperture, ISO and focus.  I set the aperture to wide open so there was no delay in stopping it down.  I set both camera and grip to Boost mode.  I set the advance to continuous high and in the menu I set the camera for 11 fps.  I then used an electronic timer app, which recorded hundredths of a second, in my mobile phone to conduct the test.  I planned to press the shutter continuously for at least 10 seconds to measure how many frames per second were recorded in each one-second interval.

The way I conducted the test, again, not scientific, was to start the timer at 0, press the shutter button halfway, then as best I could fully press the shutter as the timer reached exactly the 10 second mark, holding it down until it reached exactly the 20 second mark. That is about as accurate as I could make this little experiment with the equipment I have on hand.  Although not exact, for my purposes, it would give me the information I wanted to see to find out what happens with different cards in different slots, RAW and RAW + JPEG, Compressed RAW and Uncompressed RAW.

I planned to conduct tests shooting RAW only as well as RAW + JPEG.  Also, I wanted to find out if there was a difference in uncompressed RAW file recording speeds versus compressed RAW file recording speeds.  Having to compress the files may slow the camera down?  Finally, is there a significant difference between the Lexar 2000X card and the latest Sandisk 300mb/sec. card?  And, this is why I test!

I created a spreadsheet, showing second by second, the number of images recorded until the full 10 second run was completed.  I have included that spreadsheet here as JPEGs for you to see the results. Click to enlarge it to see it better.  You may be surprised.  The biggest surprise I saw was how quickly the frame rate dropped off, no matter what configuration.  11 frames per second sounds really great until you realize you only get that speed for about 2 seconds!

(click to enlarge)

(click to enlarge)

(click to enlarge)

As always, I may have made some errors in my testing procedure.  I've tried to take out all variables except card speed but I may have forgotten something.  If you think I may have, please comment and advise.  The last thing I want to do is give out bad test results or any of us to make decisions on less than the best information.

Also, I only ran one series of tests so repeating these tests may give slightly different results.  Draw your own conclusions about what the data reveals.  Hopefully, you can derive some benefit.

Thanks for looking. Enjoy! 

Dennis A. Mook 

All content on this blog is © 2013-2017 Dennis A. Mook. All Rights Reserved. Feel free to point to this blog from your website with full attribution. Permission may be granted for commercial use. Please contact Mr. Mook to discuss permission to reproduce the blog posts and/or images.