[JPT]

I finally got the K-3 III (and a 55-30 PLM) yesterday and now looking at the mess of SD card specifications to understand which I should get for it. I don't want to overpay for a card if I won't get the benefit of it.

There is a 128GB Lexar 1667x card that is UHS II and has a claimed 90MB/s 250MB/s speed. I seem to have to pay 2-3 times more to get one with a faster write speed, depending on the brand.

If I have this right, the K-3 III won't do much faster in terms of write time even if I get card with a faster write time. On the read side, 250MB/s read time will be pretty fast when importing the files through a ThunderBolt 3 dock. I could get a slower UHS I card for Slot 2, because it wouldn't reach the potential of that Lexar card anyway.

I usually shoot JPEG, no serious video anticipated, and I might try a bit of action photography (birds and rugby) now that I have a camera and lens that can do better continuous autofocus.

Can anyone comment on whether my thinking makes sense?

[gatorguy]

I finally got the K-3 III (and a 55-30 PLM) yesterday and now looking at the mess of SD card specifications to understand which I should get for it. I don't want to overpay for a card if I won't get the benefit of it.

There is a 128GB Lexar 1667x card that is UHS II and has a claimed 90MB/s 250MB/s speed. I seem to have to pay 2-3 times more to get one with a faster write speed, depending on the brand.

If I have this right, the K-3 III won't do much faster in terms of write time even if I get card with a faster write time. On the read side, 250MB/s read time will be pretty fast when importing the files through a ThunderBolt 3 dock. I could get a slower UHS I card for Slot 2, because it wouldn't reach the potential of that Lexar card anyway.

I usually shoot JPEG, no serious video anticipated, and I might try a bit of action photography (birds and rugby) now that I have a camera and lens that can do better continuous autofocus.

Can anyone comment on whether my thinking makes sense?

Personally I couldn't work with just two cards. I shoot too often, and usually in multiples of 100 at an event. It might be a week or more before I get around to loading and processing those photos so I simply load two more fresh.

I've found it far easier to just use all UHS-II cards rather than figuring which is which, and did the right one get put in the proper slot. My opinion is just get the Lexar 1667's which are often discounted if buying in a 2-pack blister card. Get two packs.

[JPT]

Personally I couldn't work with just two cards. I shoot too often, and usually in multiples of 100 a an event. It might be a week or more before I get around to loading and processing hose photos so I simply load two more fresh.

I've found it far easier to just use all UHS-II cards rather than figuring which is which, and did the right one get put in the proper slot. My opinion is just get the Lexar 1667's which are often discounted if buying in a 2-pack blister card. Get two packs.

Gatorguy - Thanks. I like the simplicity of that. Also, perhaps standardizing on 64GB would make more sense for me. I don't shoot nearly as much as you, although my new year's resolution is to go out and shoot more.

After checking on Wikipedia, it seems that these cards will work fine in my other cameras (K-01, K-5 IIs, GR III). The oldest is the K-01 and it has SDXC written on the card slot.

[Mikesul]

It has seemed to me that the main value of UHS-II cards with Pentax is unloading the files to the computer which is lightening fast if you have a UHS-II connection.

[gatorguy]

It has seemed to me that the main value of UHS-II cards with Pentax is unloading the files to the computer which is lightening fast if you have a UHS-II connection.

Yet more reason to stick with UHS-II. I use them in my K1 and K-70's as well, so I've got probably a dozen. Why confuse things, right?

[kwb]

I did an A-B comparison of two UHS-II cards on my K-3 III, one nominally much faster than the other, and there is a measurable difference. The camera is not really fast but the slower card is, well, slow.
See attached, this may or may not be important enough for you, not for me because I rarely make multi-seconds burst (and I often find myself using Continuous M, not the faster Continuous H), but anyway I was able to take more pictures w/o slowing down with faster card, and the wait time until the buffer was fully cleared was shorter.

Note: This is just a single test and I might obtain different results if I repeat.

The cards tested on my K-3 III are Lexar Professional 2000x 300MB/s (reading) 64GB card (~266MB/s sequential writing according to SD Card Reviews - Fastest Secure Digital Memory Cards - Camera Memory Speed Comparison & Performance tests for SD and CF cards) and Lexar Professional 1000x 150MB/s (reading) 32GB card (~88MB/s sequential writing according to the same source).

For each card, I did a burst with Continuous H mode, AF-S center point, ISO 640, 1/200sec and RAW only (DNG), until the buffer was full (i.e. it slowed down) and continued further to make four more shots, then I removed my finger off of the shutter button right away, waited, and said "done" as soon as the card access lamp stopped blinking. I made a recording of the entire thing to measure the total duration etc. Lighting condition and the scene were the same for both cards, and the average file size was about 32.5MB for both.

[JPT]

Thanks for the information and going to trouble to run a test. It's helpful to understand what kind of difference there is. I'm going to go for a 64GB Lexar 1667x UHS II card, which is under 3,000 yen. It seems to have good reviews.

I'll add my findings to this thread once I've formed an opinion.

[gatorguy]

I did an A-B comparison of two UHS-II cards on my K-3 III, one nominally much faster than the other, and there is a measurable difference. .

Thanks for actually testing the difference. The majority of my cards right now are V60, or 250mb/s. I also have at least 4 V90's (a special price on Pro-Grade cards, and a couple of early on "gotta have the fastest") and a few V-30's, in fact the exact ones the OP was specifically asking about. In practice I can't say I've seen any difference in the three card speeds, but I don't really pay close attention to that. The only thing I recognized early on was the much slower read speeds on the UHS1 cards when transferring images to my computer, and that's really where it's most evident.

Actually taking the time to test the speeds is useful info, so again thanks.


To the OP, and in my opinion, unless doing either video or longer bursts I doubt anyone would have an issue even with a fast UHS1 card on a K3III, so I think you'll be happy with your Lexar 1667x's. Based solely on comments I've read, the faster V-60 and up UHS-II cards are needed for long and fast bursts, which previous Pentax cameras could not do anyway. If you're one of those 'togs who always carefully considers each shot and there's a few seconds pause or longer between shutter activations, just about any SD card will work fine in the K3III. Where you'll almost certainly see a significant difference when you go to transfer two or three hundred images on that card to your computer.

[idontstairs]

The hardware is gimped. The hardware is gimped. For the millionth time the hardware is gimped. The UHS-II card slot doesn't write any faster than the UHS-I card slot. You can put a UHS-II card in slot #1 that writes at a million gigahertz a second and the camera cannot keep up. My thoughts on why the UHS-II speed is down throttled so much is so the shutter doesn't shake faster than the IBIS can keep up so your images don't look like someone is karate chopping your elbow while you take photos. Which is the problem I had on the initial few firmware releases when trying to do bursts to test the limits of the camera's buffer, almost a year ago now.

Continuous ShootingMax. approx. 12 fps, JPEG ( L: at Continuous H): up to approx. 37 frames, RAW: up to approx. 32 frames, RAW+: up to approx. 30 frames
Max. approx. 7.0 fps, JPEG (L: at Continuous M): up to approx. 60 frames, RAW: up to approx. 37 frames, RAW+: up to approx. 33 frames
Max. approx. 2.5 fps, JPEG ( L: at Continuous L): up to approx. 90 frames, RAW: up to approx. 39 frames, RAW+: up to approx. 37 frames

^^^^^^^^^^^^^ All those original specs (copy pasted from Adorama Pentax K-3iii info page) are internal Pentax hardware limits. They are NOT UHS-II SD card limits.

[sebberry]

My thoughts on why the UHS-II speed is down throttled so much is so the shutter doesn't shake faster than the IBIS can keep up so your images don't look like someone is karate chopping your elbow while you take photos. Which is the problem I had on the initial few firmware releases when trying to do bursts to test the limits of the camera's buffer, almost a year ago now.

Why would the speed at which it can move images from the buffer to the card have any impact on burst speed and shake reduction?

[idontstairs]

Why would the speed at which it can move images from the buffer to the card have any impact on burst speed and shake reduction?

Throttle the buffer and you reduce the mirror slapping? Ask Pentax not me. I'm not the one who gimped the buffer to keep the camera from shaking apart inside.

[ThorSanchez]

Throttle the buffer and you reduce the mirror slapping? Ask Pentax not me. I'm not the one who gimped the buffer to keep the camera from shaking apart inside.

I don't understand. Are you saying the shutter speed is capped to keep the camera from flying apart and for some reason they also throttled the data pipe to the card, too? Why would they do that? It's not like the sensor data is being directly recorded on the card, there is volatile RAM in between where the information can be stored.


Also, if the reason they throttled the data throughput was to make it only as fast as the camera can take pictures, why is that a problem?

[gatorguy]

I saw a similar discussion regarding the Nikon Z6, and I'd assume it applies to other camera's as well. That one presumably writes to a UHS-II card at roughly 70mb/sec, well under the rated card speed. It was being chalked up to conservative avoidance of overheating.

[idontstairs]

I saw a similar discussion regarding the Nikon Z6, and I'd assume it applies to other camera's as well. That one presumably writes to a UHS-II card at roughly 70mb/sec, well under the rated card speed. It was being chalked up to conservative avoidance of overheating.

The Nikon Z6 doesn't use a UHS-II card. I spent a day shooting 4k UHD in 97 degree high noon sunshine and couldn't get mine to overheat.

---------- Post added 01-06-22 at 10:44 PM ----------

I don't understand. Are you saying the shutter speed is capped to keep the camera from flying apart and for some reason they also throttled the data pipe to the card, too? Why would they do that? It's not like the sensor data is being directly recorded on the card, there is volatile RAM in between where the information can be stored.


Also, if the reason they throttled the data throughput was to make it only as fast as the camera can take pictures, why is that a problem?

I feel we are going in circles slapping a dead mirror here.

We will review again. Two known facts 1) The PentaxK-3iii camera has a UHS-II card slot. 2) The Pentax K-3iii camera doesn't utilize the full write speed of the UHS-II card slot.


Questions asked - Why doesn't Pentax use the full buffer? Why would Pentax purposely gimp the buffer?

Let's take a look at an official Pentax statement...


Photo-shooting Process | PENTAX K-3 Mark III | RICOH IMAGING


"The PENTAX K-3 Mark III features a leaf switch, a mechanism previously used in the PENTAX 645Z and PENTAX K-1. Compared to the tactile switch more commonly used in compact SLR cameras, the leaf switch provides a lighter, smoother shutter action and minimizes the camera shake caused by the shutter-release action. It also helps you by providing effortless hold-down of the shutter-release button during continuous shooting.
The time lag between the shutter release and an image capture has also been reduced, compared to the PENTAX K-3 II, while the camera’s mirror- and shutter-driving mechanisms have also been upgraded. By reducing unwanted mechanical actions such as mirror bounce, it provides crisp, pleasant shutter-release action. You can feel the smooth action and speedy response every time you press the shutter-release button."


Circle back to what I've said. Maybe Pentax gimped the buffer so the mirror doesn't get the snot slapped out of it? Just like what I experienced shooting bursts with the first few firmware releases. It looked like right in the middle of a burst sequence someone karate chopped me in the elbow as I was shooting.

I'm anxiously awaiting your theory as to why Pentax gimped the UHS-II card slot buffer speed.

[gatorguy]

The Nikon Z6 doesn't use a UHS-II card. I spent a day shooting 4k UHD in 97 degree high noon sunshine and couldn't get mine to overheat.

Z6II. Sorry.

https://www.dpreview.com/forums/post/65407828

EDIT: Oh, and some Sony A7III buyers have noted the same thing as you say you experience with UHS-I and UHS-II cards on your Pentax K3III. Is Sony gimping their camera?
https://www.sonyalphaforum.com/topic/11745-a7iii-dual-sd-limiting-write-speed/

Noting that explanation in the above link, have you tried keeping slot 2 empty, and then writing to only a UHS-1 card in slot one followed by only a UHS-II card in slot 1?