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Old Apr 21, 2010, 11:41 AM   #1
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Default XSi help: Writing speed and flash setting issues

I've got a couple of issues with my XSi that I'm hoping people can help me with.

The first problem is that my camera seems to have a very low writing speed, even when using good memory cards. While I was on holiday last year I had it set to continuous and was using a fast shutter speed, and although the first two photos were taken extremely quick, at a rate of about 3 per second, after those two photos it slowed down rapidly to about 2 photos every 3 seconds and would not speed up until I let go of the shutter and waited a few seconds. The memory card I use is a SanDisk Extreme III 4gb which records as 30mb/s, but I've also used 'slower' kingston 4gb cards and the speed is exactly the same, the first two photos taken are still just as quick and the remainder just as slow. Is there likely to be a seeting I'm using that is restricting the shooting speed?

My other question is about the built in flash; why on earth won't it let me go beyond 1/200 shutter speed? If it's getting dark and I need flash, sometimes 1/200 is not enough to stop the photo then being too bright but no matter what I do the camera won't let me go over that while the flash is up. Is this normal? If so...why?? And if not what else can I do to compensate for this?

Thanks in advance for your help!
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Old Apr 21, 2010, 12:36 PM   #2
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In what conditions were you testing throughput (outside in good light, inside in low light, mode being used, etc.)?

With a fast card, your XSi should be able to maintain approx. 3fps shooting JPEG fine for an unlimited number of frames. But, if light is low, Autofocus time may be causing it to slow down. Or, if your shutter speeds are too slow (again, because you're trying to shoot in low light), that's going to slow down your frame rate.

If you're trying to use a flash, that's going to increase cycle times *significantly* (due to flash recharge time between shots). You'll see the same thing with virtually any other camera using the built in flash (especially with a full power flash), as the flash capacitor has to recharge before it can fire another full powered flash.

As for the 1/200 second limitation, that's your camera's maximum flash sync speed (a.k.a., x sync speed). You'll see similar limitations with other dSLR models. The problem is that the shutter curtains are limiting the maximum shutter speed you can use with a flash. See this page for more information about how that works:

http://www.mir.com.my/rb/photography...lane/index.htm

Basically, the shutter is only fully open at shutter speeds of 1/200 second or slower with your camera. Otherwise, you'll end up with a traveling slit of light (because the entire frame is never fully exposed without shutter curtains in the way at faster shutter speeds).

To get around that problem, flash manufacturers have developed a feature known as FP (Focal Plane shutter) mode (a.k.a., High Speed Sync), that allows a flash to "pulse" the light as the traveling slit of light from shutter curtain travel moves across the frame (versus a single short flash burst). But, you're not going to have that feature with a built in flash.

However, you really don't need shutter speeds very fast to freeze action in darker conditions anyway. High Speed Sync is more useful when you're trying to use a flash for fill outdoors in brighter lighting at wider aperture settings.

In darker conditions, the flash itself can freeze the action, because the subjects would not be properly exposed except during the short flash burst length (which is usually 1/1000 second or faster with most flashes). IOW, as long as your ISO speed is kept relatively low (and/or you don't open up your aperture too much in a typical indoor environment), so that the exposure would be dark without the flash), you can use very slow shutter speeds and still freeze rapid movement (because the subjects are only exposed enough during the 1/1000 second or faster flash burst length).

If you're going to shoot in non Auto modes with flash, don't use Aperture Priority (as that will try to expose for Ambient light versus light from the flash). Instead, use manual exposure setting an appropriate ISO speed and Aperture (for example, ISO 400 at f/5.6); setting shutter speed to make sure that ambient light isn't contributing to much (for example, 1/100 second), and the flash can freeze the action for you, using the appropriate amount of light from the flash for the reflected light it sees from the metering preflash a camera uses).

As you get to be more proficient (if you don't want to use plain Auto, which should handle that kind of thing for you), you can then use shutter speed when shooting in manual exposure mode to vary the amount of ambient light the image sees (versus light from the flash). You just need to make sure your camera settings for ambient light exposure are two or three stops down from what you'd need for proper exposure. Then, the flash can freeze the action. Note that shutter speed makes zero difference as to how much light the camera sees from the flash itself if you're within the x-sync speed limits (1/200 second or slower with your camera), since the flash burst itself is always going to be 1/1000 second or faster. Only aperture and ISO speed matter for light seen from the flash if you stay within your camera's x-speed limits. Shutter speed is only used to vary the amount of ambient light that supplements the flash.
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Old Apr 21, 2010, 1:54 PM   #3
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I always shoot using manual mode, and the conditions don't seem to matter. The time when I first noticed it I was outside in relatively good lighting, my settings were always between f4-5.6, ISO-100 to 400, and 1/320 to 1/2000, depending on the area I was shooting. I'm also shooting at Large, Fine, and have tried turning off Auto focus but the problem is still present. The flash was a separate problem, I understand it would slow everything down anyway.

Thanks for the information about the flash, answered my question perfectly!
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Old Apr 21, 2010, 1:58 PM   #4
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Your Sandisk card could be a fake, too (it's the most counterfeited brand of memory card), if your settings are not influencing performance. ;-)

Here is one of many articles on the subject:

http://www.overclockers.com.au/wiki/Fake_Memory_Cards

Tests I've seen show that your camera model should be able to maintain 3fps with a 30MB/Second Extreme III (and not that not all Extreme III cards are 30MB/Second -- you have to have one that's specifically marked that way).
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Old Apr 21, 2010, 2:08 PM   #5
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But, if you're only getting 2 frames every 3 seconds with drive mode set to continuous, I'd suspect a settings issue of some kind causing the problem (as even slower memory cards should do better than that). You may want to try resetting your camera back to factory defaults and see if that makes any difference (you should find some reset choices in the setup menus).
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Old Apr 21, 2010, 2:17 PM   #6
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I bought two of the cards from amazon, and actually from the amazon company. I doubt they'd sell fake ones, but I compared mine to the fake ones at the link and on other websites and mine look genuine =]
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Old Apr 21, 2010, 2:22 PM   #7
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I'd try resetting everything back to factory defaults using the Clear Settings menu choice and see how it behaves. You could have an odd settings combination causing a problem.

Setup Menu


  • Auto power off - 30 secs., 1, 2, 4, 8, 15 minutes or Off
  • File numbering - Sequentially number, auto reset, or manual reset
  • Auto rotate - Enable auto rotation of portrait mode images in camera, on computer or both
  • Format - Format the CF card
  • LCD auto off - Enable or Disable the display-off sensor from turning the LCD off
  • Screen color - Choose from 4 color menu choices
  • LCD brightness - LCD back light intensity, 7 levels
  • Date / Time - Set date and time
  • Language - Sets the menu language
  • Video system - NTSC or PAL video output
  • Sensor cleaning:Auto - Live View shoot.: Disable or Enable, Grid display: Off or On, Metering time: 4 sec. to 30 min.
  • Live View function settings - Reset camera settings or Custom Functions
  • Flash control - Flash firing, Built-in flash, External flash or Custom flash function settings
  • Custom Functions - See above
  • Clear settings - Clear all camera or Custom Function settings
  • Firmware Ver. - Display camera firmware rev#, can be user-updated
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Old Apr 21, 2010, 2:46 PM   #8
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Sorted! Restored everything to factory settings and it's working fine! Not sure what the problem was because I've since put everything BACK to the settings I had them on but oh well! Thanks for the help everyone =D
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Old Apr 21, 2010, 2:56 PM   #9
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Good.

Sometimes an odd settings combination can cause issues (metering, af area, color space, picture style, tone priority, etc.).

It's hard for a manufacturer to test every possible combination of settings in all conditions. So, if you run into a problem that nothing else solves, it's usually a good idea to try resetting a camera back to factory defaults to see if that fixes it (and sometimes it does). ;-)
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