Microadjustment shift

I recently noticed that my images werent as sharp as they used to be. I thought perhaps it was me and I was just doing something wrong but last night I was shooting wide open at 1.4 and couldnt get a keeper to save my life. So I broke out the focus chart and sure enough, both of the lenses that I use regulalry needed to be moved negative to get them back to focus. Has anyone else had something like this happen? Is it perhaps the temperature change and expansion and contraction of the components? I last set my MA at Christmas time.

You didn't by any chance do one calibration in artificial light and the other in daylight?

Bob

I did the first one indoors under strong tungsten light and last night inside again but with just daylight coming through the windows. Oddly though, the softish images didnt start showing up until about a few weeks ago.

Probably not related to the light then. I've noticed that the calibration can vary quite a bit between daylight and a warmer tone artificial setup.

Bob

Thanks for the replies Bob. I remember another member (though I dont remember whom) talking about having to send in their 85L every year or so to get it calibrated.

My 85L seems okay it's the 50L that drives me to distraction. I eventually changed it for another and I'm still seeing the same thing (only on the 1Ds3, it's fine on the 1D4's)

Bob

I saw significant difference in MA values when using tungsten light vs. daylight. (Probably more so for fluorescent and LED).