Long Exposure Sharpness

[Pozo]

Hi forum.

I like to shoot long exposures with a very dark ND filter. Should I be turning IS off on my lens for these captures?? I am basically using the 18-135 3.5-5.6 IS lens, on a tripod of course, with a remote trigger, locking up the mirror. I have tried making captures with IS on and with it off, and I'm not certain which gives consistently sharper results. My tripod is not the best, but I currently don't have the budget for a better tripod so I'm trying to maximize my results from the gear I have. 

Thanks community

[TCampbell]

If the camera is on a solid tripod... switch the IS feature off.

There are some lenses that can auto-sense when the camera is on a tripod, but you'd need a list to know which lenses can detect this automatically.  So when in doubt.... just switch IS off whenever you are on a triopd.

[Skirball]

I'm not fully convinced about the IS off on a tripod argument, for most modern lenses.  Regardless, if you're tripod isn't that good, you might considering leaving it on anyway.  The alleged loss of sharpness from using IS on a tripod is pretty small with most lenses.  The impact of a rickety tripod and a long exposure will most likely be much greater.

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