Question re Buffering

[Gemini2261]

I have been experimenting with taking a series of shots on continuos mode (Canon 500D) e.g. dog running around on the beach & birds flying etc. I have noted that after a few shots the shutter button is unresponsive & the viewing panel is telling me it is buffering.

Now can someone tell me ....does the memory card affect the speed of buffering?

Are the more expensive bodies faster in the buffering department, or is there something else going on R/T operator error

[Art Vandelay]

How many images are you taking ?

Just checked the specs on the 500D and it says this

When shooting in RAW after 11 frames the camera's speed will drop from 3.4 fps to 1.0 fps. At the end of a RAW burst it takes 9.1 seconds to write the contents of the buffer onto the memory card. Note that when shooting RAW+JPEG the camera only manages three frames at full speed before the frame rate drops significantly (0.8 fps).

from here, http://www.dpreview.com/reviews/canoneos500d/page13.asp

It's worth noting that the buffering is quicker if on jpeg.

If it's not getting those speeds, then it's worth checking if your card is limiting it. It'll probably have the recomended card specs in that review.

[JM Tran]

hello there!

the speed of the card also plays a part in the speed, but the buffer speed and card speed are something that go hand in hand. In layman's terms, think of the buffer as a large bin with a hole at the bottom which flows to the memory card. Pro cameras which are made for sports have a very very large buffer hence it can hold a lot of shots as it trickles onto the memory card. Entry level cameras have a much smaller buffer so once that buffer is full it will slow down automatically while the camera processes the data onto the memory card. A slow write speed card means that the data written onto the card will be slower - remember that this effect is not as noticeable on entry level cameras with slow cards - but put a cheap card onto a D3s or 1DMK4 and you will see a massive difference.

[rwg717]

Yep, I used to wonder why this was too, after all else fails read the destructions as the saying goes, I use "burst" mode in most of my photography and have found over the past couple of years that the Sandisc Extreme cards are the only way to go, with a 5D at full image I can only get about 8 frames (both JPEG and RAW) in one burst but the recovery rate is not too bad, fire say 5 frames and wait 2 sec. and get another 4-6 usually. Just a matter of timing your frames but it can test your patience
Richard

[Gemini2261]

Thanks guy's for that info...I am using a 32g scandisk extreme it has a 15b/m something or other written on it (have not got it with me here on night duty so can't give the exact detail there). I thought it was probably the camera limitations...thanks for that link I will read up on it & compare with what the 7D has to say.

[rwg717]

Thanks guy's for that info...I am using a 32g scandisk extreme it has a 15b/m something or other written on it (have not got it with me here on night duty so can't give the exact detail there). I thought it was probably the camera limitations...thanks for that link I will read up on it & compare with what the 7D has to say.

Right make of card but if you can get the ones which do 30 MB per sec. or even up to 60 MB per sec. you will get better performance. I think Sandisc are also making a 90 MB per sec. card now but all in all, the transfer rate for big cameras is always a problem. Every time the card makers come up with a faster card the camera manufacturers come up with a bigger sensor
Richard

[Gollum]

One big problem with using faster cards is that, in most cases, the camera will set the fastest card it can use. If the camera can only transfer at 15MBs it doesn’t matter how much faster the card is. At the following web site you are able to see the maximum transfer rate of cameras.

http://www.robgalbraith.com/bins/mul...e.asp?cid=6007

This database has not been updated for a few years now. This is nothing unusual its always 2-4 years between updates. If you take the 450D, the closest to your camera, the best transfer rate is 14MBs so anything faster than Extreme won’t help. Keep an eye on this site for the next round of updates.

For my camera (350D) the best transfer rate is only 6MBs, so to go any faster than Sandisk Ultra is a waste of money.

There is also another problem, many of the cards on the market today are in fact, counterfeit. If you want to check the performance of your cards there is a free tool. This tool will check the speed of your cards and card reader. If you have 30MBs cards here is nothing unusual to get a 20 to 25MBs speed on the benchmark, as you need to have a fast PC and card reader to get full performance. Any measured speed <60% of the rating may be a dud (or you have a very slow PC and reader).

http://www.attotech.com/products/pro...Disk_Benchmark

Something to note is that Sandisk has changed their names and speeds, so you need to go to the Scandisk web site to confirm what's current.

Hope this helps.

[arthurking83]

As per Gollum's reply.

My D70s is slow. Slow to write, so a super fast card is useless, even if it is supposed to clear the buffer more quickly. The fact is that the speed of the buffer is of no help. The camera's write speed is more important.
The camera generally writes quickly to the buffer, but the technology in the chipset of sending data from the buffer to the card is old and slow.
My D300 on the other hand would benefit in a faster card, but I prefer size over speed any day, as I don't tend to shoot fast. I have a slow 8G non name brand card in the D300 simply for the extra storage, when required. When I got it, CF cards were still quite expensive, and this no name brand was half the price of any 8G Sandisk.
it's great to have the fastest cards, that's for sure, and even if you don't end up getting the full performance benefit now with your current camera, a future camera MAY subsequently benefit from it.
Problem is that CF is going to slowly be phased out in cameras over the next few years and replaced with a new type called CFast, and (AFAIK) not directly compatible with the CF card type. hence future compatibility is not really assured. What would I then do with any super fast CF card that exceeds the performance of my camera?

At the moment, with my current (slow) 8G cards, I'm limited to approximately 20 continuous uninterrupted raw shots, whereas the camera with no card can easily capture 24 frames to the buffer.
I can't really remember any time in my past of any importance where I've shot more than about 12 or so frames and really required any more speed from the card. ie. speed is not something I really need and more space is handier to have access too(per dollar spent).

it's all a balancing act.

[Gollum]

Arthurking83

The 500D uses SD/SDHC so the CF/CFast will not be a problem. The reason why cameras are slower than the cards is that one of the priorities of a camera is battery life. They can make the transfers faster but this will reduce the battery life, so this becomes a balancing act for the camera makers.

I think that Medium and Low end cameras will stay on SD/SDHC, unless a new format is cheaper. The top end cameras, Canon xD, series is where there may be a change. As the latest CF 6.0 standard is pushing 167MBs, still way faster than any current camera, I can’t see a change soon. They may offer a second slot for new standard cards but they wouldn’t do anything to upset the pro’s.

http://compactflash.org/2010/cf-6-0-...-enhancements/

[arthurking83]

Arthurking83

The 500D uses SD/SDHC so the CF/CFast will not be a problem. ......

DOH!

[fabian628]

good replies here.
The speed of the camera is usually the limiting factor.
Other things that will kill your buffer is High ISO, also in camera noise reduction, and other things, maybe highlight tone priority etc.
For example, on the 1D3, the buffer for Jpegs is 110 at iso100. If you turn it to iso 800 it becomes 22. Also noise reduction takes it down to approx 12 shots.

One good thing about the faster cards is I have noticed they transfer files to the computer faster. I am not sure what role the cameras speed plays in file transfer however.

[Gollum]

Have just found a note from Canon that they recommend a minimum of Class 6 cards for the 500D (20MBs). Your existing cards (Class 4/15MBs) are just a little too slow therefore would not let you use the full speed of your camera. Of the current SanDisk range, I would recommend that you use Class 10 cards (30MBs).

Hope this fully answers your question.