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Author Topic: Do memory cards matter?  (Read 2319 times)

JPAZ

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Do memory cards matter?
« on: July 15, 2013, 06:01:43 PM »
The M is far from perfect but fits a niche.  Given the "blackout" after taking a shot, does anyone know it the speed of the memory cards have any appreciable effect on this recycle time?
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Do memory cards matter?
« on: July 15, 2013, 06:01:43 PM »

bholliman

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Re: Do memory cards matter?
« Reply #1 on: July 15, 2013, 08:06:43 PM »
Good question!

I did a very informal test with two different SD cards and got the exact same recovery time between shots = 8 seconds.  One shot, flexi-zone single.  Five shots each on two different targets.

(1) 16GB Kingston Class 4, 15mb/s
(2) 32GB Sandisk Extreme Class 10, 45mb/s

It will be interesting to see if anybody else has other observations.
« Last Edit: July 15, 2013, 08:08:45 PM by bholliman »
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brianboru

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Re: Do memory cards matter?
« Reply #2 on: July 15, 2013, 08:56:58 PM »
I set the EOS M to "Sports Mode", RAW, tripod, prefocussed on a door and then shot for ten seconds continuously with three different cards lying around.  The "Burst" shots count is the number of frames before there was a pause in shooting to flush the buffer.

CardSpeedShots in 10s"Burst" shots
Lexar Pro. 32GB 400X SDHCClass 10 UHS-I128
GSkill 32GB SDHCClass 1096
Sandisk 8GB SDHCClass 465

So there is a difference with some cards and some scenarios.
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JPAZ

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Re: Do memory cards matter?
« Reply #3 on: July 15, 2013, 09:37:32 PM »
Wow.  Thanks.  I still am playing with the camera and really was wondering about the time between single shots.  I never thought about the buffer for bursts.

Since I only have two SD cards right now (all my other stuff is CF), I was just trying to find out if investing in faster cards matter that much for single shots.  Right now I have Sandisk Extreme (10) at 45/sec.  Would investing in Extreme Pro up to 95/sec make a substantial difference in terms of time between single shots, do you think?

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« Last Edit: July 15, 2013, 09:57:14 PM by JPAZ »
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GDub

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Re: Do memory cards matter?
« Reply #4 on: July 15, 2013, 09:57:42 PM »
JPAZ, I think you'll want to take advantage of the "UHS-I" distinction with some SD cards because the M is compatible with the "Ultra High Speed" class. A common complaint about the 5D Mark III's SD slot is that it was NOT made compatible.
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brianboru

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Re: Do memory cards matter?
« Reply #5 on: July 15, 2013, 10:35:41 PM »
I'm not seeing a difference in black-out time between cards for a single shot - just how long the write lamp stays on.

Av, Flexi-Zone-Single, One Shot, RAW: is a consistent 1.8 seconds for me.  Changing to JPEG-L still was 1.8s. Interestingly, changing to Servo dropped recovery to 1.5s.
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Swphoto

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Re: Do memory cards matter?
« Reply #6 on: July 15, 2013, 11:10:04 PM »
I just did a few tests with some interesting results.

Class 6 Patriot card:
Continuous burst for 10 seconds: 9 shots total, 26 seconds from start of burst to finish writing to card
Single mode, pressing shutter immediately after blackout for 10 seconds: 5 shots
Continuous mode (but only taking one shot at a time), pressing shutter immediately after blackout for 10 seconds: 6 shots

Class 10 Sandisk Extreme 45MB/s:
Continuous burst for 10 seconds: 21 shots total, 13 seconds from start of burst to finish writing to card
Single mode, pressing shutter immediately after blackout for 10 seconds: 6 shots
Continuous mode (but only taking one shot at a time), pressing shutter immediately after blackout for 10 seconds: 8 shots

Manual mode, manual focus, 1/200, ISO 100, f/2, RAW.

The blackout time, on both cards, seems shorter when in continuous mode. Can someone else test this and see if they get similar results?

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Re: Do memory cards matter?
« Reply #6 on: July 15, 2013, 11:10:04 PM »

Mt Spokane Photography

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Re: Do memory cards matter?
« Reply #7 on: July 16, 2013, 12:07:54 AM »
Card speed only matters when you need to shoot continuously at high FPS, or shoot video.  The camera has a very fast internal buffer memory, so the card type has no affect until the buffer is full.
The specifications for cards are based on a new, fully erased card.  Once its been used and formatted, the card is not actually empty so it must first erase a block of space before writing to it.  This makes it very slow.  A non UHS-1 type maxes out at 10 MB/sec, while a UHS-1 can write at 20 MB/sec because it uses twice the internal bus speed.
 
If you want to see those high advertised speeds, erase the card or do a low level format, which accomplished the same thing.  The problem is that a low level format is very slow ...  very very slow.

Swphoto

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Re: Do memory cards matter?
« Reply #8 on: July 16, 2013, 12:23:32 AM »
Card speed only matters when you need to shoot continuously at high FPS, or shoot video.  The camera has a very fast internal buffer memory, so the card type has no affect until the buffer is full.

Based on the tests I just did, this is not correct (at least for the M). Shot to shot times were improved, over the course of several tests, with the faster card. I consistently got 1-2 extra shots in a 10 second window, only taking 1 shot at a time (never filling the buffer).

A non UHS-1 type maxes out at 10 MB/sec, while a UHS-1 can write at 20 MB/sec because it uses twice the internal bus speed.

My Sandisk Extreme UHS-1 45MB/s cards consistently gets 42-45MB/s write speed via a USB3 reader. I don't know what the camera's max write speed is, but I'm sure someone has tested it to find out.

It would be interesting to know if the Extreme Pro, with the 90MB/s write speed, has any significant effect on the M's blackout time.

JPAZ

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Re: Do memory cards matter?
« Reply #9 on: July 16, 2013, 12:49:49 AM »
Pulling back a bit, first of all, I like the M.  I am not complaining about it.  For the price, it was worthwhile. 

But, it is a bit paradoxical that my big kit with a mirror to move during the photo taking process can capture an image faster than this little guy whose only moving part is a shutter.  I know this greatly oversimplifies the process and the sensor/circuitry/buffer flush/read-write also add to the time to record an exposure.  It just feels like it should be quicker.

I guess I am looking at this as though the M is a small speedboat while the 5Diii is the Queen Mary.  While the ship can offer a lot more, it is not so lithe and maneuverable.  But, in reality, the M is a Cessna and the 5Diii is a 747 (OK.  My metaphor is poor but it's late!!).  Even though one is bigger and heavier, it is way more capable and powerful and actually can do more and do it faster.

So, if I invest in faster cards, will that matter?  Will I notice any more quickness?  I really appreciate the testing you all are doing, because I cannot find any specs on the read/write speed for the M anywhere.

« Last Edit: July 16, 2013, 01:09:12 AM by JPAZ »
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Swphoto

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Re: Do memory cards matter?
« Reply #10 on: July 16, 2013, 01:06:03 AM »
So, if I invest in faster cards, will that matter?  I really appreciate the testing you all are doing, because I cannot find any specs on the read/write speed for the M anywhere.


You can find the results of some tests done with the old firmware on a SanDisk 95MB/s card here: http://www.imaging-resource.com/PRODS/canon-eos-m/canon-eos-mA6.HTM

They noted that they will be updating the page "soon" to reflect performance with the new firmware.

JPAZ

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Re: Do memory cards matter?
« Reply #11 on: July 16, 2013, 01:12:00 AM »
You can find the results of some tests done with the old firmware on a SanDisk 95MB/s card here: http://www.imaging-resource.com/PRODS/canon-eos-m/canon-eos-mA6.HTM

They noted that they will be updating the page "soon" to reflect performance with the new firmware.


Ah.  Thanks!  Still wonder how much of the shot to shot time is the card and how much is the hardware.
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Swphoto

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Re: Do memory cards matter?
« Reply #12 on: July 16, 2013, 01:25:06 AM »
Ah.  Thanks!  Still wonder how much of the shot to shot time is the card and how much is the hardware.

If it helps, my Class 6 card tests at 10MB/s (vs 45MB/s for my Class 10 card) via my card reader. I'm not seeing anywhere near a 4x improvement in shot to shot time with the fast card, which suggests that the card doesn't play a big part. On the other hand, the faster card did speed things up slightly.

On the write-intensive 10 second continuous test, though, the faster card allowed the buffer to clear in exactly half the time - so it's very valuable for that use case.

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Re: Do memory cards matter?
« Reply #12 on: July 16, 2013, 01:25:06 AM »

tpatana

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Re: Do memory cards matter?
« Reply #13 on: July 16, 2013, 01:25:58 AM »
Card speed only matters when you need to shoot continuously at high FPS, or shoot video.  The camera has a very fast internal buffer memory, so the card type has no affect until the buffer is full.

Sort of true, but the buffer is being flushed to the card even before the buffer gets full, so the card type affects even before the buffer is full. With really fast card you can shoot quite many more pictures until the buffer gets full, as it already had time to save more pics on the card compared to a slower card. (I know you knew this, but how you wrote it might not be clear to everyone)

For video I don't know what bitrates typical SLRs do, but e.g. my Panasonic Camcorder records 1080p60, and I can use Class4 SD -cards with that. The manual says Class4 is minimum requirement for 1080p60, and I've used such cards successfully. It mostly depends on the codec, so if you don't compress the video too much, then you need really fast card. Someone knows how much is the bitrate on e.g. 5D3?

cookinghusband

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Re: Do memory cards matter?
« Reply #14 on: July 16, 2013, 10:28:06 AM »
Just be careful when you buy the Sd card, please only get the ones with faster write speed, if you are looking for buffer recovery time.
Some of the ones from samsung have very fast read speed but the write speed is just normal. While the more expensive model from sandisk have fast write speed but normal read speed.

As said above shooting speed will not slow down until the buffer is full.

The 8 second waiting time is for the CPU to think while changing the display mode I guess.

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Re: Do memory cards matter?
« Reply #14 on: July 16, 2013, 10:28:06 AM »