T3i Failure to Focus on Low Light

[tconstan]

My T3i with the kit lens (18-55 f3.5) hunts relentlessly when shooting in low light. Tried higher ISO but still cannot grab a proper focus. Additionally, when a flash is added (Sunpak 3000) it still has trouble finding focus. All ideas are welcome.

[Waddizzle]

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@tconstan wrote:
Kvbarkley, the 3000c has infrared assist. I don't understand disco flash reference.

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Cameras with the built-in flash can use it as a "focus assist" beam.  

It is a feature that can be enabled or disabled, depending your mode dial setting on top of the camera.  During a low light focus scenario, the camera will raise the flash, and then rapidly  fire it like a strobe light in a disco.

Whether or not the flash will fire when you take the shot is an entirely different setting.  Again, by "disco flash", he means "focus assist."