Month: March 2024

What’s the difference between AF Tracking and AI Servo

Jovan Stosic March 31, 2024

Tracking and focusing are two entirely different concepts, but they are joined at the hip.

Focusing is pretty straight forward.  In One Shot AF mode, you put the enabled AF point on the subject, half press the shutter, and the camera should lock focus and beep.  In AI Servo AF mode, the camera focuses, but it does not lock until you fully press the shutter button.  AI Servo AF mode is designed to allow the camera to stay focused on a subject, whose distance to the camera is constantly changing.

You the photographer are primarily responsible for tracking your subject, which means keeping the AF point on the subject as they move.  This often omes into play during sports and wildlife photography shoots.  You must move the camera to not only keep the subject in the viewfinder, but also covered by the active AF point.

In AF Tracking modes, the camera can automatically reselect AF points as your subject moves around the viewfinder.  This is a more advanced mode of using the camera.  The user must go into the menus and tell the camera which AF point to use as the initial AF Tracking point,

https://community.usa.canon.com/t5/EOS-DSLR-Mirrorless-Cameras/What-s-the-difference-between-AF-Tracking-and-AI-Servo/m-p/325465#:~:text=In%20AI%20Servo%20AF%20mode,the%20camera%20is%20constantly%20changing.

What’s the difference between AF Tracking and AI Servo was last modified: March 31st, 2024 by Jovan Stosic

What are the differences between live mode and quick mode on my Canon

Jovan Stosic March 31, 2024

There are two different types of Autofocus in most DSLR’s. There is PDAF (or phase detect autofocus) and CDAF (contrast detect autofocus). PDAF uses a special focus sensor to measure the phase of the light coming from different parts of the lens (which is much faster) while CDAF uses the actual image sensor to look for the highest contrast it can get (which requires moving past the point of ideal focus and then coming back to it, which makes it slower.)

While some recent DSLRs have come up with ways to include PDAF sensors on the main imaging sensor, many models still use a completely separate sensor (either for cost or performance reasons). When you are using Live View, the mirror is flipped up and thus no light is going to the PDAF sensor or the view finder.

Normal live view focusing will use CDAF and hunt for the proper focus, which can have an advantage in certain low light situations and be more accurate in some cases, but it is also much slower. (Things like face detect are also possible depending on your camera model.)

Quick focus on the other hand will flip down the mirror so that the PDAF sensor can be used, make the necessary focus adjustments and then snap the mirror back up to take the photo. It is important to note that the image doesn’t actually capture when you hear the first mirror movement, but rather after the second mirror movement.

https://photo.stackexchange.com/questions/49151/what-are-the-differences-between-live-mode-and-quick-mode-on-my-canon-550d

What are the differences between live mode and quick mode on my Canon was last modified: March 31st, 2024 by Jovan Stosic

6×8 8×10 9×12 I-Shaped Inductor Kit Box 2.2/3.3/4.7/10/15/22/33/47/68/100/220/330/470/680uH/1mH/2.2/3.3/4.7/10/20/30/100mH

Jovan Stosic March 31, 2024

https://www.aliexpress.com/item/1005006459407009.html?spm=a2g0o.productlist.main.49.17c5XejmXejm0x&algo_pvid=c650e626-c73b-4517-b72b-0acf422d81b8&aem_p4p_detail=202403310305091968340333861440002048170&algo_exp_id=c650e626-c73b-4517-b72b-0acf422d81b8-24&pdp_npi=4%40dis%21USD%219.70%219.70%21%21%2170.00%2170.00%21%402101c59517118795090548060e241b%2112000037274379133%21sea%21MK%21781861964%21&curPageLogUid=c3rKQNU8zzk4&utparam-url=scene%3Asearch%7Cquery_from%3A&search_p4p_id=202403310305091968340333861440002048170_5

6×8 8×10 9×12 I-Shaped Inductor Kit Box 2.2/3.3/4.7/10/15/22/33/47/68/100/220/330/470/680uH/1mH/2.2/3.3/4.7/10/20/30/100mH was last modified: March 31st, 2024 by Jovan Stosic

Tensor Field

Jovan Stosic March 30, 2024

A tensor field is a mathematical object that assigns a tensor to each point in a space, such as a manifold or a vector space. Tensors are multidimensional arrays of numbers that represent certain geometric or physical properties. They generalize scalars (which are 0th-order tensors), vectors (1st-order tensors), and matrices (2nd-order tensors). A general tensor field can have components that vary in both magnitude and direction at each point in space. Unlike scalars and vectors, which have single numbers or arrows associated with each point, tensors can represent more complex relationships, such as stress, strain, curvature, or electromagnetic fields. For example, in general relativity, the metric tensor field describes the curvature of spacetime. In fluid dynamics, the stress tensor field describes how forces are distributed within a fluid. In materials science, the strain tensor field describes how materials deform under stress. In summary, a tensor field is a mathematical object that assigns a tensor to each point in a space, and a general tensor field can represent complex relationships or properties that vary across that space.

Tensor Field was last modified: March 30th, 2024 by Jovan Stosic

Temperature vs wind

Jovan Stosic March 30, 2024
  1. Temperature as a Scalar Field: Temperature is a scalar quantity, meaning it has magnitude but not direction. In a given region of space, temperature can vary from point to point, creating what is called a scalar field. Each point in space has a specific temperature value associated with it, but there is no directionality associated with those values.
  2. Wind as a Vector Field: Wind, on the other hand, is a vector quantity, meaning it has both magnitude and direction. Wind speed tells you how fast the wind is blowing, and wind direction tells you where it’s blowing from. Together, these two components create a vector field, where at each point in space, there is a vector representing the wind speed and direction.

So, in summary, temperature behaves as a scalar field because it only has magnitude, while wind behaves as a vector field because it has both magnitude and direction.

Temperature vs wind was last modified: March 30th, 2024 by Jovan Stosic

Ubuntu 18.04 LTS : OpenLDAP : LDAP over SSL/TLS

Jovan Stosic March 27, 2024

root@dlp:~#

cp /etc/ssl/private/server.key \
/etc/ssl/private/server.crt \
/etc/ssl/certs/ca-certificates.crt \
/etc/ldap/sasl2/

root@dlp:~#

chown openldap. /etc/ldap/sasl2/server.key \
/etc/ldap/sasl2/server.crt \
/etc/ldap/sasl2/ca-certificates.crt
root@dlp:~#

vi mod_ssl.ldif
# create new
dn: cn=config
changetype: modify
add: olcTLSCACertificateFile
olcTLSCACertificateFile: /etc/ldap/sasl2/ca-certificates.crt
-
replace: olcTLSCertificateFile
olcTLSCertificateFile: /etc/ldap/sasl2/server.crt
-
replace: olcTLSCertificateKeyFile
olcTLSCertificateKeyFile: /etc/ldap/sasl2/server.key

root@dlp:~#

ldapmodify -Y EXTERNAL -H ldapi:/// -f mod_ssl.ldif
SASL/EXTERNAL authentication started
SASL username: gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth
SASL SSF: 0
modifying entry "cn=config"
[3] Configure LDAP Client
If you’d like to make sure the connection between LDAP server and client is encrypted, use tcpdump and other network capture software on LDAP server.
root@www:~#

echo “TLS_REQCERT allow” >> /etc/ldap/ldap.conf
root@www:~#

vi /etc/ldap.conf
# line 261: uncomment

ssl start_tls

root@www:~#

exit

logout

www login: ubuntu     # LDAP user
Password:
Last login: Tue Jun  5 11:22:06 JST 2018 on ttyS0
Welcome to Ubuntu 18.04 LTS (GNU/Linux 4.15.0-20-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

  System information as of Tue Jun  5 15:05:32 JST 2018

  System load:  0.0               Processes:           93
  Usage of /:   6.4% of 28.45GB   Users logged in:     0
  Memory usage: 3%                IP address for ens3: 10.0.0.31
  Swap usage:   0%

 * Meltdown, Spectre and Ubuntu: What are the attack vectors,
   how the fixes work, and everything else you need to know
   - https://ubu.one/u2Know

16 packages can be updated.
8 updates are security updates.

ubuntu@www:~$      # logined

Source: Ubuntu 18.04 LTS : OpenLDAP : LDAP over SSL/TLS : Server World

Ubuntu 18.04 LTS : OpenLDAP : LDAP over SSL/TLS was last modified: March 27th, 2024 by Jovan Stosic

AC Digital Multifunction Meter Watt Power Volt Amp TTL Current Test Module PZEM-004T With Coil 0-100A 80-260V AC For Arduino – AliExpress

Jovan Stosic March 23, 2024

Source: AC Digital Multifunction Meter Watt Power Volt Amp TTL Current Test Module PZEM-004T With Coil 0-100A 80-260V AC For Arduino – AliExpress

AC Digital Multifunction Meter Watt Power Volt Amp TTL Current Test Module PZEM-004T With Coil 0-100A 80-260V AC For Arduino – AliExpress was last modified: March 23rd, 2024 by Jovan Stosic