17-55mm usm & low light

[neuroanatomist]

I'd go with the 17-55mm, especially since you already have it. I'm assuming you mean for taking pictures of the exhibits, not people. It's an important difference - f/1.8 is 1.33 stops faster than the f/1.8 of the 17-55mm. An f/1.4 lens is 2 stops faster. But, the 17-55mm has IS which is good for about 3 stops, meaning it's effectively better in low light. But IS only helps with static (non-moving) subjects. So, if you're shooting exhibits in low light the 17-55mm will be better, but if you're shooting people in low light, the faster prime will be better.


EDIT: One more thing to consider - if the museum does not have a no-tripod policy, bring a tripod. That will give you the best possible low-light performance, regardless of lens. Most museums in the US prohibit tripod use, but most will allow a monopod. No matter which lens you use, a support will help in low light.

[clemmb]

Most museums in the US prohibit tripod use, but most will allow a monopod. No matter which lens you use, a support will help in low light.
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Most museums in the US I have been to do not allow photography at all.


Mark

[neuroanatomist]

Most museums in the US I have been to do not allow photography at all.

Interesting! Most that I have been to, in California and New England, prohibit flash photography (potential damage to artwork/exhibits) and tripods (my guess there is liability for someone tripping over the extended legs), but not photography as a whole. Although, since so many people with P&amp;S cameras have no idea how to deactivate the flash, the general prohibition is probably wise...