Image Distortion Field off GIF Camera Since Aug 08, 2008

Chen Xu

$BrandeisEM: doc/en_US.ISO8859-1/articles/GIF-idf-aug08_2008/article.sgml,V.1.0 2008/09/08 17:31 xuchen Exp$

GIF lenses add another field to your final image collected on GIF CCD camera. Correction of the distortion field has been proven to be neccesary. Following the procedure provided by David Mastronarde, I did the correction for our TF30(Tecnai v2.1.5a, DM v1.4.4, SerialEM v2.8.1).

The grid used in this correction was a C-flat holey carbon with 1.0um hole, 4.0um distance. A dense layer of 10nm gold particles were deposited to both sides of the grid. Frame area is used for imaging.

Our TF30 has a new tip since beginning of Auguest, 2008. After analysing the data, the final distortion field files which should be applied to the data since can be found (download) here.

135k_08AUG2008.idf for mag 13.5kX 
18k_08AUG2008.idf for mag 18kX
225k_08AUG2008.idf for mag 22.5kX
275k_08AUG2008.idf for mag 27.5kX


For the data taken earlier than Aug. 08, 2008, you can get the old idf files from the links in the old article GIF Distortion Field Correction.


1. Distortion Field Measuring Data Collection

The date of collecting: Sept 04, 2008. Image conditions are: H.T. = 300kV, Gun lens = 1, Ext.Vol. = 3800V, C2 aperture = 70um, Obj. aperture = 40um. "tune gif" result can be found here.

Overlapping pairs (direction 0,1,2,3) were collected at four magnifications. 13.5k, 18k, 22.5k and 27.5k.

For each above mags, a small tilt series were also collected before and after 90 degree rotate the grids. The range is -4.5 ~ +4.5 The step is 1.5 degree.

dp135k.st
dp18k.st
dp225k.st
dp275k.st

135kts1.st
18kts1.st
225kts1.st
275kts1.st

135kts2.st
18kts2.st
225kts2.st
275kts2.st