strange image shift behavior
Added by Jim Pulokas over 13 years ago
Reported by Marco:
> After calibrating image shift, the click target navigator reliably > hits the desired spot at 50kx, just as expected. > > I configured Leginon exposure node to move to the target with a > certain not too high precision. I use mover -> navigator, modeled > stage position, and check 'final image shift' > > [behaviour] > During MSI, Leginon then uses the goniometer to reach the > destination at 5kx, adjusts image shift and then calls Preset node > to change to the 50kx preset. > > I see two things which are strange: > * Image shift at 50kx preset is changed, but it's (way) off > * if I have something like exposure near followed by exposure far, > exposure far gets the original preset image shift value of (0,0) > > So my questions are: > Is the described behaviour ( -> Change image shift at 5kx, then > change to 50kx and apply a different image shift ) correct?
Replies (1)
RE: strange image shift behavior - Added by Jim Pulokas over 13 years ago
Marco,
The correct behavior is what is happening with your en preset. There should be a non-zero image shift which corresponds to the final image shift applied by navigator. It will also have an adjustment that takes into account the different between image shift calibration at hl preset compared to the image shift calibration at en preset. Therefore, you need a good calibration at both mags. You can look in the navigator log window to see the final image shift value that was applied.
The 0,0 image shift at ef preset is incorrect. It should be the same as en. I have started a bug report: http://emg.nysbc.org/issues/1236
I'm still not sure about why the image shift would be very far off from the target, but first I will work on the 0,0 problem, then move on to the accuracy problem.
Jim