focus issue with HDR

[bs0604]

I have noticed a focusing problem with my D90/Nikkor 18-200 3.5-5.6 GED lens when shooting HDR. Sometimes when shooting with autofocus I notice the "barrel" of the lens rotate a few mm in between the bracketed shots, as if it is trying to refocus. I am using a tripod and remote to trip the shutter. Then when I put the images in to Photomatix the resulting photo is not as sharp as the individual images. I don't understand why the lens should try to refocus, if indeed this is what is going on, in between the bracketed images.

 

[myshkin]

I believe there is a setting for this so it focus locks when in a bracket, but I don't remember which setting it is

 

[myshkin]

How i work qwith this especially in dark places is to find a good focus and then switch to manual focus so it won't hunt and will stay at your desired focus

 

[vipgraphx]

If you use AEB should not have a problem when you fire off your burst of shots. If you are doing single shots fired off it will try to focus each shot. When you merge it will make it soft. So use AEB and CH or the timer