Forgot Password
Pentax Camera Forums Home

Show Printable Version Search this Thread
06-11-2011, 08:20 PM   #1
Senior Member
dmfw's Avatar

Join Date: Dec 2009
Location: Dallas, Tx
Photos: Albums
Posts: 159
KX: Shooting Many Pic. fast, will a Class 10 SD Card help?

I have a KX, and I will be shooting Many Pic. in a very short time (fireworks). Will a Class 10 SD Card be more helpful with this issue vs. a class 6? Eg. Are the camera buffering issues due to the card class or with the KX.


06-11-2011, 08:42 PM   #2
hcc's Avatar

Join Date: Nov 2009
Location: Brisbane, Australia
Photos: Gallery | Albums
Posts: 3,531
In short, I would go for a class 10 card or faster.

In simplified terms, the Hi continuous shooting capability of your camera is linked with (a) any in-camera processing, (b) the in-camera buffer size, (c) the card writing speed, and (d) the file format.

With your K-x, you need to remember that:

(a) switch off all in-camera processing incl. lens distortion correction, ...

(b) the K-x has a small buffer compared to the K-7 and K-5; do not overload the buffer;

(c) select a fast card to write up rapidly the shots and free up the buffer;

(d) select a JPEG file size that is small enough.

With my K-7 I use JPEG 14 Mp 2 stars [**], and I switch off all in-camera PP. I can shoot more than 60 s at 5.2 fps.

One more thing. You want to shoot fireworks at night. The lens selection will be important. Consider to use a fast lens (f1.8 or better f1.4). Your shutter speed must be faster than the burst rate of your burst shooting and this will place some constraints on your slowest shutter speed.

Hope that the comments will help ...
06-11-2011, 09:09 PM   #3
Veteran Member

Join Date: May 2009
Location: Twin Cities, MN
Posts: 2,869
Fireworks are generally longer exposures, are they not? I've got my best shots using bulb mode and a wired remote for the shutter - if you shoot fast you're just going to get the fireworks as specks in the sky. in order to get the long trails you see in firework photos, a long exposure is required, and it is actually generally a quite slow photo process (you're only going to get one chance per round of fireworks shot from the ground - so if 100 fireworks were shot for example, you'd basically have 100 attempts, with quite awhile between depending on the size of the show).

Also, this subject has been discussed before, but the newest class 10 cards are not even necessarily faster than older, better class 6 cards - its just that when the older, better (something like sandisk ultra or extreme cards) were made, the class 10 designation didn't exist. I have 2 older sandisk extreme IIs that are faster than my new patriot lx class 10 cards, but the difference in relatively small. Go to a site like, read up on the reviews and get the most well reviewed cards and you shouldn't have a problem, whether class 6 or 10.
06-11-2011, 09:50 PM   #4

Join Date: Nov 2008
Location: Bangalore
Photos: Gallery
Posts: 2,450
Class 10 will help but ensure that you get the reputed one. Problems have been reported in this forum about some lesser known brand Class 10 cards are even slower than normal class-4/6 cards.

06-11-2011, 10:09 PM   #5
Site Supporter
Chaos_Realm's Avatar

Join Date: Feb 2011
Location: Melbourne, Australia
Photos: Gallery | Albums
Posts: 1,251
QuoteOriginally posted by pxpaulx Quote
Fireworks are generally longer exposures, are they not?
I generally run between 1/2" and 3" exposures for fireworks depending on how many fireworks I want in the shot so.

On a kx you when shooting at full buffer Ie limited by how fast you can transfer from buffer to SD the camera components limit transfer to 2.2fps according to dpr (which correlates to 12mb X 2.2 = 26.4mb/s in theory) so you pick an SD with write speed > 26.4mb/s. I must warn you their might be factors that I missed but this is how i picked my SD Card and I don't have any issues of the SD slowing things down.
06-17-2011, 03:06 PM   #6
Senior Member
dmfw's Avatar

Join Date: Dec 2009
Location: Dallas, Tx
Photos: Albums
Posts: 159
Original Poster
Thanks for the info. on the cards.

I am shooting about 1 mile from the fireworks. At 60-80mm, F4.5, 1/20, ISO 400, & on a tripod. The pics. are good, but I loose many good shots due to my slower card.
06-17-2011, 03:26 PM   #7
Veteran Member
joe.penn's Avatar

Join Date: Mar 2011
Location: Maryland (Right Outside Washington DC)
Photos: Gallery | Albums
Posts: 2,902
QuoteOriginally posted by dmfw Quote
I am shooting about 1 mile from the fireworks. At 60-80mm, F4.5, 1/20, ISO 400, & on a tripod. The pics. are good, but I loose many good shots due to my slower card.
The buffer size of the K-X is your thorn here. Another issue is more technical, but will also be a huge issue.

Try this test and you will quickly realize what you will have to do:

1. Go outside on a sunny day and shoot a pic - take note of how quick the one pic will pop up on your lcd or write to the card.
2. Go outside at night, set you camera for the settings you noted in your post - take note of the time is takes for it to show up on your lcd and for it to write to your card.
3. Do the same as above at night, bump your iso up quite a bit higher, take note of the speed it writes it to the card.

QuoteOriginally posted by dmfw Quote
ISO 400
Bumping up your ISO speed will considerably improve the write speed from the buffer to the card allowing for a faster rate of shooting, even at the same exact shutter speed. The reason for the slow down is the less light striking the sensor, the more processing the cameras algorithm has to do - this can somewhat be balanced with ISO.

For another demonstration to get a feel for exactly what I am talking about, go outside at night, shoot something with an ISO of 100 with a 20 second shutter speed. After that, shoot the same exact thing and just bump your ISO up till you get a proper exposure at around a 1 second shutter speed - the first image will take somewhere around 5 seconds for the camera to process, the second will take about 1 or 2 seconds.

A little more technical, a cameras buffer is not in place just to hold pictures while writing to the card, it is in place as "SWAP", meaning it is also used by the cameras algorithm to process the actual picture - the more data in the swap buffer, the slower things get. Thus, the more data the sensor has to process, the quicker the swap space gets filled and causes bottle neck issues with the transport of the data.

Edit: BTW, cards give you a minimal boost (unless you are shooting previous generation cards), the actual real issue is the amount of data the camera has to process "IN CAMERA" at the time of the shutter release...


Last edited by joe.penn; 06-17-2011 at 03:33 PM.

  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, card, class, dslr, kx, photography, pic, sd
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Similar Threads
Thread Thread Starter Forum Replies Last Post
Crap! My new class 10 sd card run much slower than my old class 4 sd card... liukaitc Pentax Camera and Field Accessories 15 05-31-2011 01:39 PM
A class 6 32 gb card janstew Pentax K-5 12 03-25-2011 04:00 PM
Class of SDHC card for K-x BobIr Pentax DSLR Discussion 7 01-09-2011 09:00 AM
Verbatim and Transcend class 6 sdhc cards not fast enough for K-7 video pasipasi Pentax DSLR Discussion 17 08-08-2009 08:47 AM
What Class SDHC Card Should I Get. nwahsadude Pentax DSLR Discussion 7 06-29-2009 12:25 PM

All times are GMT -7. The time now is 09:01 AM. | See also:, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]