Pixelsize and Distortion Info on K2/3 Cameras¶
- Author
Chen Xu
- Contact
- Date_Created
2017-2-23
- Last_Updated
2019-3-28
- Abstract
We have K2 on Talos Arctica and GIF/K2 on Krios.
This doc lists pixelsize information for K2 cameras so you can decide which magnification you want to use for your final image. I also try to give information about image distortion on these cameras.
On Talos Arctica¶
According to FEI document http://www.fei.co.jp/_documents/DS0189-10-2014_Talos_Arctica_WEB.pdf, the Cs value for Talos Arctica is 2.7mm.
Below are pixelsizes on K2 for a few magnifications.
Table.1 Pixelsize (Å) of K2 camera on Talos
Magnifications (X) |
Counted (Å) |
Super resolution (Å) |
|---|---|---|
17,500 |
2.425 |
1.213 |
22,000 |
1.888 |
0.944 |
28,000 |
1.485 |
0.742 |
36,000 |
1.169 |
0.584 |
45,000 |
0.914 |
0.457 |
57,000 |
0.719 |
0.360 |
Also the distortion information at these few mags. This mag distortion is believed due to stretch on projection lens system. The measurement and correction programs are used and available from http://grigoriefflab.janelia.org/magdistortion .
Table.2 Mag Distortion Parameters for K2 camera
(Note: this is for images saved by SerialEM directly. So this is after rotation and flip applied. Please do not use this with raw frame saved by plugin without rotation and flip, as it will have different but related values.)
Magnifications (X) |
Dist.Angle(degree) |
Major Scale |
Minor Scale |
Total Distortion (%) |
|---|---|---|---|---|
11,000 |
||||
17,500 |
||||
22,000 |
65.9 |
1.016 |
1.000 |
1.56 |
28,000 |
24.5 |
1.015 |
1.000 |
1.51 |
36,000 |
22.5 |
1.015 |
1.000 |
1.51 |
45,000 |
21.3 |
1.016 |
1.000 |
1.56 |
57,000 |
22.6 |
1.017 |
1.000 |
1.66 |
On Titan Krios¶
Table.3 Pixelsize (Å) of GIF K2 camera on Titan Krios - BEFORE Sept. 27, 2017
Magnifications (X) |
Counted (Å) |
Super resolution (Å) |
|---|---|---|
26,000 |
4.505 |
2.253 |
33,000 |
3.588 |
1.794 |
42,000 |
2.939 |
1.470 |
53,000 |
2.274 |
1.137 |
64,000 |
1.863 |
0.931 |
81,000 |
1.485 |
0.742 |
105,000 |
1.170 |
0.585 |
130,000 |
0.910 |
0.455 |
165,000 |
0.720 |
0.360 |
215,000 |
0.569 |
0.279 |
On September 2017, Gatan serviced GIF/K2 system on Krios and they removed a housing block between column and GIF, so the pixelsize changed. The new set of values is below in Table. 4.
Table.4 Pixelsize (Å) of GIF K2 camera on Titan Krios - AFTER Sept. 27, 2017
Magnifications (X) |
Counted (Å) |
Super resolution (Å) |
|---|---|---|
64,000 |
2.147 |
1.087 |
81,000 |
1.714 |
0.857 |
105,000 |
1.353 |
0.677 |
130,000 |
1.059 |
0.529 |
165,000 |
0.832 |
0.416 |
215,000 |
0.654 |
0.327 |
275,000 |
0.516 |
0.258 |
From March 10, 2019, K3 was upgraded on Krios to replace the K2. GIF alignment has changes too. The pixelsizes changed a lot.
Table.5 Pixelsize (Å) of GIF K3 camera on Titan Krios - AFTER March 10, 2019
Magnifications (X) |
Counted (Å) |
Super resolution (Å) |
|---|---|---|
81,000 |
1.060 |
0.530 |
105,000 |
0.830 |
0.415 |
130,000 |
0.650 |
0.325 |