Why is it that lenses come with an AF option when the camera has the same? Which controls the AF? One would think that they contend with each other for control. Why have two entities doing the same single task? A  photographer friend of mine said to set the lens to Manual. If every photographer does why offer lenses with this setting?
I use my DSLR (Nikon D500) for both photography and video, and I prefer autofocus for photography and manual focus for video (to get rid of autofocus noise).  There is an option for changing between the two on both the body and the lens, and obviously it is very annoying to have to keep flicking 2 switches to do the same thing all of the time.  Do you only have to change one of them, and would doing this cause any damage to the camera and/or the lens?  (I am aware that a similar question has already been asked before, however the answers said more what is "best practice" and not so much if there are any consequences to only changing one of them)  Thanks!
Best way to select a subset of items in a long list One of our clients wants us to build a web application to share information about the magazines he publishes. Each edition of a magazine contains a variable amount of advertisers. These advertisers come from a central pool of advertisers. This pool contains (at the moment) about 150 advertisers. Each edition of a magazine contains a subset (about 70-80) of these advertisers.  Our client wants us to come up with a way for him to add 70-80 advertisers from this list of 150 to an edition of a magazine. It needs to be as fast as possible, as easy as possible and as intuitive as possible.  What would be an ideal solution here? I was thinking about something in the lines of the image below.   List of available advertisers. List of selected advertisers. Advertisers have a delete button. Textbox with auto-suggest for advertisers in the list on the left. &lt;Enter> removes the advertiser from the left list and adds it to the right one. Textbox gets cleared and remains focus.   My colleagues suggested drag-and-drop or just one list with a checkbox for each advertiser, but those approaches force the user to do a lot of searching and clicking. With my approach the user can just keep on typing.  Any other suggestions for this situation? What are the differences between "lay" and "lie"? Was just wondering if there is any solid data available as to how many people are using ubuntu. I was also interested in the attrition rate with ubuntu users, etc. Why is $H(k\mathbin\Vert x)$ not a secure MAC construction? If $H(m)$ is a secure hash function, can't we implement a MAC using $H(k\mathbin\Vert m)$?  However, it seems the more widely used MACs, such as NMAC and  (both originally defined in ) use a much more complicated scheme. Why is this concatenation scheme insecure? How can Linux/Ubuntu be installed safely on ChromeBook? Is installing Ubuntu on my Chromebook potentially dangerous to anything on my Chromebook? I got it as a gift, so I don't want to destroy anything that is important on the laptop. Also, which is better for being able to safely install Ubuntu: ChrUbuntu or Crouton? I'm using the Samsung Chromebook 3 (as described by the quick-start manual). Does that make any other differences as well? Appendix without letter in TOC If I have an adjacency matrix for a graph, can I do a series of matrix operations on the adjacency matrix to find the connected components of the graph? Can you make a custom mouse cursor for the game engine? I would like the mouse to have a custom look like most games and not just the default white.  Is there a way I can make an object as the mouse? How big is my single pattern in Photoshop I pulled a repeating pattern from someone else's PSD. Is there a way to figure out the size of the original pattern? I need to create an image with only one tile. Convert a list to a string in C# find $\left( \frac{x}{x+y} \right)^{2007} + \left( \frac{y}{x+y} \right)^{2007}$ What is the reasoning behind limiting "recidivists" to post one question per week? currently restricts recreated accounts to "posting only one question per week..."  I would like to understand why this rate was picked, and not, say, once a day or once a month?  The reason why I ask is that some users limited or banned at Stack Overflow . I expect that learning more about the limitation would help me better understand its impact on Programmers. Should I put myself last? "me and my friends" vs. "my friends and me" or "my friends and I" I've always been taught to put myself last when referring to myself in the same sentence as others but the usage of "me and..." seems to be everywhere these days. The misuse of the word "me" instead of "I" aside, is there some new rule I haven't heard of? Shouldn't we put ourselves last regardless of the "me"/"I" usage?  Examples of "correct" usage:      My friends and I went for some ice   cream. Did you see my friends and me   at the ice cream stand?   Examples of "incorrect" usage:     Me and my friends went for some ice   cream. Did you see me and my friends   at the ice cream stand?   Note: I was also taught that the only person who could put themselves first was the queen. Prove $r^2+r_1^2+r_2^2+r_3^2=16R^2-a^2-b^2-c^2$ for a triangle with sides $a$, $b$, $c$, circumradius $R$, inradius $r$, exradii $r_1$, $r_2$, $r_3$ Which variables should I transform, center, and/or standardize in my data for Principal Component Analysis? I have multiple datasets that I am attempting to use principal component analysis (PCA) on in order to infer the underlying structure of the data.  I'm attempting to predict growth increment of conifers (the response which apparently needed to be cube root transformed for my original linear models).  My predictor variables include: continuous (some log-transformed like size-related variables, some compositional, and some traditionally scaled); binary; ordinal; and nominal (of which I'm pretty sure I can order with respect to site productivity).  I'm mostly attempting to make inferences because some of my previous models from linear regression have not produced significant terms corresponding to categories like health or climate and I feel that they should have.  I've read in Joliffe (2002) that I might want to leave my compositional data uncentered.  Forgive my naiveté, but I'm wondering if I should also do this for my binary data.  It also seems that I might not want to scale these since they're already on a 0 - 1 scale but I'm not sure.  After only using my continuous predictors (including compositional variables), it appears that a size principal component makes up the largest portion of the variability and Joliffe also mentions that one might want to attempt a "double-centering" of the log-transformed data if this is the case.  I don't know if this is even possible since the log-transformed data only makes up a small portion of my datasets.  Finally, I should ask if having such a combination of data types will complicate analysis so much that it will make inferences unreliable.  I am currently using R for this analysis.  Thank you. remove numbers from filenames in Mac OS X I have a directory full of files with names in this format (with numbers as the start of each filename):  102_file.txt 104_list.txt 242_another_file.txt   I would like to rename them as follows (i.e. removing the numbers):  file.txt list.txt another_file.txt   Can anyone suggest a way to do this (presumably from the terminal)? Take the following script:  #!/bin/sh sed 's/(127\.0\.1\.1)\s/\1/' [some file]   If I try to run this in sh (dash here), it'll fail because of the parentheses, which need to be escaped. But I don't need to escape the backslashes themselves (between the octets, or in the \s or \1). What's the rule here? What about when I need to use {...} or [...]? Is there a list of what I do and don't need to escape? Velocity Maxwell-Boltzmann distribution for dummies I have a volume with $N$ molecules; I need to assign to each particle a velocity vector: $$|\mathbf{v}_{i}|=[v_{x}, v_{y}, v_{z}]^{T}$$ for the $i$-th molecule; the velocities must follow the Maxwell-Boltzmann distribution; here is the question: I know the definition of the M.B. distribution, how do I extract the velocities that I have to assign to each molecule? Basically what I want to know is how to calculate $$v_{x}=?$$ $$v_{y}=?$$ $$v_{z}=?$$ for each molecule. Adjoint pairs, triplets and quadruplets Often we have adjoint pairs $(A, B)$ (meaning $A$ is left adjoint to $B$). Sometimes we have adjoint triplets $(A,B,C)$ (meaning $A$ is left adjoint to $B$ and $B$ is left adjoint to $C$. No adjoint relation between $A$ and $C$ obviously, since they have the same source and target).  So the first question is: can we have quadruplets $(A,B,C,D)$ ? (meaning that $C$ is also left adjoint to $D$).  Second question: It would be then possible that we have $(A,D)$ besides $(A,B)$. But I think not, because I think that it is not possible to have a functor $A$ with two different right adjoints, $B$ and $D$. Is this correct? I was trying to install minted package in TeXLive. I installed it and then run sudo tlmgr update --all. It was running slow so I stopped it using Ctrl+Z in an ubuntu terminal and then I run sudo tlmgr update --list. After that I installed texlive-latex-extra and python-pygments. Later on I run sudo tlmgr update --all again and let it finish.  After that I am trying to run a simple code using listings and greek but I get an error     Bad Character code (256)   A MWE that illustrated the problem is the following  \documentclass{book}  \usepackage[english,greek]{babel} \usepackage[iso-8859-7]{inputenc} % %\usepackage[utf8]{inputenc} \usepackage{kerkis} \usepackage{pifont} % %  \newcommand{\sw}{\selectlanguage{english}} \newcommand{\sq}{\selectlanguage{greek}} \newcommand{\eng}[1]{\latintext#1\greektext} \newcommand{\gre}[1]{\greektext#1\latintext}  \usepackage{xcolor} \usepackage{listings} \usepackage{textcomp}  \definecolor{listinggray}{gray}{0.9} \definecolor{lbcolor}{rgb}{0.9,0.9,0.9}  \lstdefinestyle{JavaStyle}{         backgroundcolor=\color{lbcolor},     tabsize=4, %   rulecolor=,     language=Java,      % choose the language of the code         basicstyle=\scriptsize,     % the size of the fonts that are used for the code         upquote=true,         aboveskip={1.5\baselineskip},         columns=fixed,         showstringspaces=false,         extendedchars=false,         breaklines=true,         prebreak = \raisebox{0ex}[0ex][0ex]{\ensuremath{\hookleftarrow}},         frame=single,         numbers=left,         showtabs=false,         showspaces=false,         showstringspaces=false,         identifierstyle=\ttfamily,         keywordstyle=\color[rgb]{0,0,1},         %commentstyle=\color[rgb]{0.026,0.112,0.095},         commentstyle=\itshape\color{green!40!black},         stringstyle=\itshape\color{red!90!black},         numberstyle=\itshape\color{yellow!50!black} }  \lstdefinestyle{CppStyle}{         backgroundcolor=\color{lbcolor},     tabsize=4, %   rulecolor=,     language=C++,       % choose the language of the code         basicstyle=\scriptsize,     % the size of the fonts that are used for the code         upquote=true,         aboveskip={1.5\baselineskip},         columns=fixed,         showstringspaces=false,         extendedchars=false,         breaklines=true,         prebreak = \raisebox{0ex}[0ex][0ex]{\ensuremath{\hookleftarrow}},         frame=single,         numbers=left,         showtabs=false,         showspaces=false,         showstringspaces=false,         identifierstyle=\ttfamily,         keywordstyle=\color[rgb]{0,0,1},         %commentstyle=\color[rgb]{0.026,0.112,0.095},         commentstyle=\itshape\color{green!40!black},         stringstyle=\itshape\color{red!90!black},         numberstyle=\itshape\color{yellow!50!black} } \begin{document}  This is a dummy text. kjhbki \end{document}   The .aux file says  \relax  \select@language{greek} \@writefile{toc}{\select@language{greek}} \@writefile{lof}{\select@language{greek}} \@writefile{lot}{\select@language{greek}}   while the .log file can be found   Any idea why is this happening and how to fix this? Note that if I remove the listings preamble, delete all produced files and build the document, everything works fine.