Thursday, September 10, 2009

What You Don't Understand, You Make Mean Anything

 canon-EOS-450D-XSi-2

About 18 months ago, I bought a Canon Rebel XSi digital SLR camera. 

I love it. 

I love that I can change the lens out to suit a particular situation.  I love that I can use an external flash to bounce artificial light.  I love that the camera fires as soon as I depress the button.

I was just messing around with auto exposure bracketing, and seeing how fast I could take 3 continuous shots (for use with HDR imaging).  Although the camera is rated at 3.5 exposures per second, I was noticing that I was only getting 2, and only for the first second.  Subsequent exposures came at a rate of only 1 per second.  What the heck!?

I shoot in RAW mode, which generates very large files – somewhere on the order of 13-15 MB each.  Maybe the bottleneck was caused by the write-speed from my camera to memory card.  So I tried switching back to JPEGs.  Same problem.  “Hmmm… maybe they’re still too big…”  So I switched to the smallest setting.  Same problem.  Uh oh… prepare for camera repair…

Then I remembered.

When I first got the camera, one of the touted features was on-camera “High ISO Noise Reduction.”  Noise is the digital equivalent to grain.  As you use a higher ISO setting, you can get better exposures with less light – the trade-off is more noise.  This feature helps reduce the noise (read more here).

A720_1600 with detail

40D_1600_f8_1-2000_with_detail

Noise reduction off

Noise reduction on

Excited by the prospect of reduced noise, I turned the feature on.  What I didn’t notice is that it drops the cameras burst rate down to 2.  Well… that explains it.  I turned the feature off and, voila, I can now capture 7 consecutive exposures in 2 seconds.

The worst/best part is: I shoot RAW (and process with Adobe Camera Raw), so the on-camera processing is ignored anyway.

The lesson for me is to not get feature happy.  If you don’t understand how it works, don’t enable it.

2 comments:

michelle garcia. a photographer. said...

Duh Tim! Don't you know anything. J/K Have you used Adobe Lightroom? I used to use Adobe Camera Raw but found Lightroom to be much more user friendly and quicker.

Tim said...

Yeah, I use Lightroom - I love it. I especially love the hierarchical tagging system. I need to go to Tag-Anon. I *way* over-tag.