CHDK Forum
Lounge => General Chat => Topic started by: SkyWalker9 on 10 / July / 2011, 15:28:00
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Good... this should be in the wiki somewhere...
1. You can increase the number of shots in a burst substantially by using lower-resolution settings. Reduce the size (resolution) of the images. While using a smaller resolution minimally affects the time to process, there can be a substantial savings in the time when saving the photos to the card.
Reducing resolution slows down JPEG encoding (at least on my old a570 it does -- your camera may be different, and it may have features such as a night mode or a digital telephoto feature that make exceptions) because it needs to resize the RAW image first. You will get a smaller JPEG, but the gain from smaller file size is reduced by the time spent in downscaling. With a fast SD card this could be quite significant.
Reducing JPEG quality from super-fine to fine reduces file size quite a bit compared to the reduction in image quality (sometimes not really noticeable). Reducing quality probably doesn't affect JPEG encoding speed much. Using the poorest quality setting and then batch scaling down on a PC could sometimes be a better than using a lower resolution, especially if you are only scaling down a little bit.
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Thanks @fudgey !
This is exactly the type of real world experience that I was hoping to read about. I haven't tested all of the observations I collected & posted here, but I didn't want to leave anything out before I got a chance to test it. Eventually I will test most of these on my own camera to see what works best for me. If some recommendations don't work on my camera, perhaps they might be useful for someone else with a different camera.
With so many settings available on the PowerShots, it's easy to forget what works best without keeping notes. Reading about what others have found is very helpful.
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FWIW, shutter speed is only relevant in low light conditions. If you are talking about a ~1fps shooting rate, +/- 1/60th really isn't worth worrying about.
If using RAW mode, then disable noise reduction in CHDK RAW menu (if using long exposures)
I'm guessing you are talking about "dark frame subtraction". Despite being in the raw menu, this setting is applied whether or not you are shooting raw.
If left in auto, the camera will generally apply dark frame subtraction if the exposure is longer than about 3 seconds, although this may depend on the model and sensor temperature.
In the Low Light mode, the rate increases to 3 shots per second.
On many recent cameras, this can be called "High ISO" or "ISO 3200" etc. Using CHDK, you can force the ISO lower while still using these modes.