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Friday, 16 January 2015

Comments

Generally, I would think the benefit of high speed cards is more in getting images off the card quickly versus onto the card quickly. The write speeds would be more relevant for 4k high bitrate video.

I note that this analysis misses the post-shoot part of the workflow: the amount of time it takes to offload images from the card for selection, processing, etc. That can be a pretty substantial time suck for anyone doing high-volume photography. I've known photogs who tended to covet high-speed cards (and card readers capable of keeping up) for this reason alone.

Mike/Ctein,
Would a superfast card like this be likely to help in the other direction? I'm thinking of the excruciatingly slow processing rate of Sigma Photo Pro software.
--Charlie

if you have a card reader that can handle UHS-II speeds, these cards will also download to your computer more quickly

We're starting to see video codecs producing streams above 25MB/s (I've suddenly seen multiple discussions of 50MB/s video, plus of course the excitement that 4K video can bring you). That might be another reason why higher write throughput could be important.

Or, just to make uploading the data faster after a long day of shooting (that's based on read rate of course). For this, the camera doesn't even have to support UHS-II, just the card reader you use to upload.

But yeah, I don't own any UHS-II cards myself and am not particularly faunching after them.

Your points about optimizing things you actually care about are extremely cogent. You might care about max burst speed. You might in addition care about how soon you can perform a second max-speed burst after the last one, or you might not (How fast do the cars come around the race track? Maybe your buffer will be empty in any case, or maybe not. Or it won't matter until the next play. Whatever your action environment needs.) You might care about max long-term burst rate (that is, beyond buffer capacity. You might be fine shooting but have a need to get uploads into your fileserver very fast (especially if one reader is serving multiple photographers at a tournament shoot, say). Or, no doubt, other things I haven't thought of. You probably can't optimize them all at once, you certainly can't optimize them all cheaply. You can pretty likely spend a lot of money optimizing things that don't actually matter to you.

I hardly ever overflow the buffer in the camera, but when I'm downloading from a 64gb card to the computer and there's waiting time to go make a sandwich, but I don't want a sandwich, well then I'd like a faster card.

This is a real concern for modern video cameras; the Blackmagic can shoot 4K video in DNG RAW at 30FPS; that means one minute of recording lays down 1800 4K DNG files.

Another advantage of the faster cards is that with a good card reader, getting the images to a computer can be a good deal quicker. Not important for small batches, but if you tend to shoot a lot at once or don't import very often, it can be useful.

Image capture is seldom my bottleneck, it is in post production when i must download hundreds of images from a project or thousands after travel. But much of that is after the heat of battle has cooled.

Cards should be a matter of balance, fast enough to keep up with one's style of shooting versus capacity, perhaps large enough to shoot a job or for a day, versus speed of downloading at the end of the day.

The last seems the most important to me and that's another bottle neck of the system between Firewire and favors of USB with assorted card readers, not to mention what is under the hood of the system that I use to edit the photos. I simply want to clear out the cards so I can edit and move on.

Take some of the card speeds with a grain of salt since the words "up to..." May be present. The best way to figure out what works best for you is to test just like Ctein. YRMV!

There is another factor to consider when testing cards: electronic noise. Certain SD cards generate electronic noise during write operations that come up in the image of my Leica M9 (due to just questionable shielding in the implementation of the electronics). As a result, I use only Sandisk 8Gb Ultra (or the equivalent to their old generation Sandisk 8Gb Extreme cards) -- this particular card doesn't seem to generate banding noise in the camera. And yes, different sized cards generate different noise profiles, so here size does matter!

To test this in your camera: shoot a predominantly black subject at a range of ISOs in RAW, with continuous shooting (i.e. taking a photo whilst the card is writing). In your raw processor, boost exposure and shadow tones and look for banding -- tell tale signs of electronic noise.

Most modern sensor and sensor integration implementations should handle this without any issues -- but it is something I do check. My Pentax on the other hand passed this test no issues at all.

Pak

A fast card is also interesting when you upload the photos to the computer.

Completely off topic. considering the number of uses of the letters, t, x, and so on, how long before we end up with a Fuji Tri-x 1? presumably with a mono sensor.....

Right now, it's of no use to me at all - I am a boring old plod who takes a good 20s just to take a single frame and chimp the hell out of it.

However I can well understand its general relevance to many others, with cameras like the new NX1 shooting 20 fps with 28MP files, not to mention 4K video at 60fps.

With stacked BSI APSC sensors I suspect the global shutter is closer to reality as well. We could have stills frame rates in the 100s and ultra fast HD video frame rates. Great for slow motion video...

[Except I don't think the NX1 supports UHS-II cards. Its specs say "SD, SDHC, SDXC (up to 64 GB)." --Mike]

Mike or Ctein: something I have been curious about but have not seen mentioned anywhere is if various SD cards offer better download speeds? That is, when the card is slotted in the MacBook will the images transfer at different rates for different cards? Then there is the iPad which seems to take forever to just load the preview from a 32gig SD! I haven't really noticed a camera slow down since the Kodak DCS760 would jam up when auto bracketing was turned on and it would pause after 5 frames. Just curious. Oh ... and nice testing!

I bought the Sandisk UHS II card and tried it with my Nikon knowing that it is not supported but wanting to see if there was any performance gain at all. There wasn't. It actually was much slower than the 90MB Sandisk. Using Blackmagic Speed Test with a UHS I Lexar reader It only made it to 40MB write speed (I didn't test it with the UHS II Reader). All of this was expected, but I had to see it for my self.

Why are we still debating cards? By now high end cameras should come with ample amounts of fast built-in memory and the latest USB and wi-fi specs like any decent smartphone, but the camera world seems to be perpetually stuck in the 90s and 00s.

Conversely, as taking a shot a minute is pretty fast going for me, is there any point in my using anything but the slowest cards?

One thing that takes much of the pain out of this kind of many-shot testing is to set the camera up focused on an online stopwatch (www.online-stopwatch.com , for example). Start the watch running, blast away, and when you stop to watch the buffer drain, press one last time to mark the time when the write-light stops blinking. Then you can analyze the timing of each phase as finely as you like.

This sort of thing has been de rigeur for years with the somewhat rough firmware in the Leica M8, M9 and the like, for which using a faster card did not always produce faster shooting or a more quickly drained buffer.

scott

[Except I don't think the NX1 supports UHS-II cards. Its specs say "SD, SDHC, SDXC (up to 64 GB)." --Mike]

Was surprised by that so I checked.

According to Samsung themselves the specs say SD, SDHC, SDXC(up to 64GB), UHS-I, UHS-II

Not sure of the reason for the 64GB limit but I don't think that relates to the speed.

I would not buy a camera for fast card support alone, so if my camera has it, it's by accident. But I will eventually find good use for a faster card. Then I will buy it.

Whether it's roads or data, never bet against greater bandwidth.

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