I have been looking at get a polarizer and some nd filters for my sigma 50mm art lense. From my research, it looks like the best are B+W and Hoya. Does anybody have any experience with either brand on full frame or can suggest an alternative?   Also, anybody know of nd filters that will fit on a sigma 12-24? I have see a few "home made" ones on the net, but I'm not crazy about trying to make one.   Shooting a d810 body
It was suggested that I should get myself a polarizer filter to get over my reflection problem. (  )  I found out that a Nikon 52mm Circular Polarizing Filter CPL   while I can get another filter for less than half the price — . (Please note that I know nothing about these filters and googled them just for the example.)  What is the difference between polarizer filters?  I need to remove the glare and nothing else — would either of the two do the magic for me? What filter do you recommend for me?
Can anyone tell me how to get my caption on side of my figure, and at the same time aligned with the top of my figure? I have a .tiff and a .tfw file that I want to change into a GeoTIFF. When I try to open the file in ArcMap and ENVI 5.0, it is successful. However, in Google Earth it is not.  Is there anyway to create the GeoTiff in ArcMap or ENVI? Estimate on the derivative at fixed point Let $D$ be a bounded domain and let $f$ be analytic function from $D$ into $D$. Show that if $z_{0}$ $\in D$ is a fixed point for $f$ , then $|f' (z_{0} )| \leq 1$.  WHAT I WAS THINKING:   To have a conformal mapping from $D$ to the unit disc &amp; after composing it with $f$ ; I was thinking to use Pick's Lemma. So, can anyone tell me any conformal map from any bounded domain to the unit disc?? OR Is there any other way out to solve this problem?? How to remove duplicate values from a multi-dimensional array in PHP Unable to acheive desired effect with ID mask I'm trying to make the render have an effect where the stars (which are exploded fragments) have a glowing glare-like effect and the other objects (i.e. film reel and cubes) are their natural colors.  However, despite having made the star objects all a pass index of 1 and the rest 0 by default, everything seems to render a green glowing effect that's supposed to be only for the objects with a pass index of 1.  To illustrate:  This is the render of the image naturally (I rendered at very low quality but it's just for demonstration purposes):    And this is with the composite nodes:    So in essence I want the objects in the the first render I showed to keep those colors, but the stars to have the colors of the green glowing effect.  As you can see from the 2nd picture everything has the green effect.  My node setup is pretty big so I will provide a link to download the  so you can see the nodes more clearly. Difference between "right of=" and "right=of" in PGF/TikZ In the PGF/TikZ manual, sometimes I see the option right of=somenode instead of right=of somenode. They look very similar, but the effects are different.  The distance between nodes positioned with the latter option is boundary-to-boundary, as stated in the manual. However, with the first option, it seems that the distance is shorter. I couldn't find any explanation of the first option in the manual.  My question is: what is the difference between the two options? Is there any explanation in the manual that I missed? Laplace transform of integral constant Can I Turn Off or Remove Map Layers in QGIS Print Composer The title pretty much says it all.  I have a base map in QGIS that I am using with several Print Composers.  In one of the Print Composers, I don't want one of the layers to show up.  Is there any way to accomplish this? I just updated from Ubuntu 10.10 to 11.04 and have an issue regarding the screen resolution. I have Intel integrated gfx chip and my monitor supports resolutions larger than 1024x768. (in 10.10 I've been using 1280x1024) But as soon as I upgraded, I'm stuck with 1024x768 resolution and seems I can't change it.  running xrandr In terminal yields the following results,   Screen 0: minimum 320 x 200, current 1024 x 768, maximum 4096 x 4096 LVDS1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm    1280x800       58.1 +    1024x768       60.0*     800x600        60.3     56.2      640x480        59.9   VGA1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 344mm x 194mm    1366x768       59.9 +    1360x768       60.0      1024x768       75.1     72.0     70.1     60.0*     832x624        74.6      800x600        72.2     75.0     60.3     56.2      640x480        72.8     75.0     66.7     60.0      720x400        70.1     1280x1024_60.00 (0xce)  109.0MHz         h: width  1280 start 1368 end 1496 total 1712 skew    0 clock   63.7KHz         v: height 1024 start 1027 end 1034 total 1063           clock   59.9Hz   What maybe the problem? Is it a bug? What kind of steps I should take in order to get a higher resolution? (changing xorg.conf maybe?) Any insight is highly appreciated. Thanks in advance.   UPDATE    Screenshot after running xrandr --addmode VGA1 1360x768  As you can see, side bar is not completely visible and Ubuntu logo at the task bar is missing. Also when you open an application, the Task bar of the application (where it should go to the top panel) is missing as well.. If I know the GCD of 20 numbers, and know the 20 numbers, is there a formula such that I input the 20 numbers and input their GCD, and it outputs their LCM? I know that $$\frac{\left| a\cdot b\right|}{\gcd(a,b)} = \text{lcm}(a,b).$$ So is it$$\frac{\left| a\cdot b\cdot c\cdot d\cdot e\cdot f\right|}{\gcd(a,b,c,d,e,f)}?$$If not, what is it? Preview on mobile page I suggest a preview on the mobile page. For questions, answers and edits to both, like on the desktop page.  I messed up formatting often enough to be annoyed that there is no preview on the mobile page and I'm surprised that noone suggested it before (at least I didn't find anything).  If it's too performance heavy to have a live preview update after every change in the text box, there could be a preview button next to the save button which leads to a page with only the preview, a back button and a save button (and the title bar and so on). Here's the very dumb way:  def divisorGenerator(n):     for i in xrange(1,n/2+1):         if n%i == 0: yield i     yield n   The result I'd like to get is similar to this one, but I'd like a smarter algorithm (this one it's too much slow and dumb :-)  I can find prime factors and their multiplicity fast enough.  I've an generator that generates factor in this way:  (factor1, multiplicity1) (factor2, multiplicity2) (factor3, multiplicity3) and so on...  i.e. the output of   for i in factorGenerator(100):     print i   is:  (2, 2) (5, 2)   I don't know how much is this useful for what I want to do (I coded it for other problems), anyway I'd like a smarter way to make  for i in divisorGen(100):     print i   output this:  1 2 4 5 10 20 25 50 100     UPDATE: Many thanks to Greg Hewgill and his "smart way" :) Calculating all divisors of 100000000 took 0.01s with his way against the 39s that the dumb way took on my machine, very cool :D  UPDATE 2: Stop saying this is a duplicate of  post. Calculating the number of divisor of a given number doesn't need to calculate all the divisors. It's a different problem, if you think it's not then look for "Divisor function" on wikipedia. Read the questions and the answer before posting, if you do not understand what is the topic just don't add not useful and already given answers. I am looking for a way to concatenate the strings of a field within a group by query. So for example, I have a table:  ID   COMPANY_ID   EMPLOYEE 1    1            Anna 2    1            Bill 3    2            Carol 4    2            Dave   and I wanted to group by company_id to get something like:  COMPANY_ID   EMPLOYEE 1            Anna, Bill 2            Carol, Dave   There is a built-in function in mySQL to do this How to break a Quagmire 3 cipher? Is voltage the speed of electrons? biblatex: remove commas between last and first names in bibliography How can I set the processor affinity of a process on Linux? How can I set the processor affinity of a process on Linux? Is there a more accurate way to create a Javascript timer than setTimeout? Javascipt component not coming render as pdf How do I get permissions to delete files on Windows 7? I updated my laptop's OS from Windows XP to Windows 7. There are some leftover files from Windows XP on the computer now. If I try deleting them I get the following error:     You need permission to perform this action.      You require permission from S-1-.... to make changes to this folder.   What's weird is that I am logged in with the only user account on this machine and I have administrator privileges. I tried turning UAC off, but I still can't delete the files.  How can I force removal of these files?