Extension Tubes and Ring Flash?

January 30th, 2012 Experiments, Photography

A reader asks on my Comparing macro lenses to extension tubes page whether or not hot-shoe or ring flash will work with extension tubes, or whether the working distance is too close.

Answer #1: I don’t know. Answer #2: Let’s find out.

I set up a tripod, put a 6 mm extension tube on a 16 mm lens, and asked Uiharu to model for me. The crinkled paper was intended to give a bit of light bounce from the room lights, but I ended up shining a flashlight into the paper to push up the brightness.

Extension Tube Test Setup.

Setup for the extension tube test.

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One-Liner of the day – generate a random password

September 13th, 2011 Linux


dd if=/dev/urandom bs=1c count=200 | tr -d '\001-\040\042\047\054\077\134\140\173-\377' && echo

Compiling Afner fails with gcc 4.5+

August 26th, 2011 googlefood, Software

WARNING: Googlefood, thus boring…

Issue: Afner compiled fine with GCC 4.4, but when trying to compile Afner with GCC 4.5 or later, the compilation dies with:


suffixtree.h:66:14: error: class ns_suffixtree::suffixtree::node is protected
suffixtree.cpp:208:19: error: within this context
suffixtree.cpp:208:1: error: ns_suffixtree::suffixtree::node::node names the constructor, not the type

Problem: Between GCC 4.4 and 4.5, the compiler changed to support “specializing C++ constructor templates.” This caused the meaning of “class X::Y::Y” to change.

Fix: Edit src/suffixtree.cpp, and at line 208: change suffixtree::node::node * to suffixtree::node * (i.e. delete the trailing ::node.)

I would have sent it upstream, but Afner doesn’t appear to be under development any more, there’s no open repo that I can check if this is already fixed and just not released yet, and I don’t really want to take responsibility for forking the project just to fix one line. :)

Note that the general fix should work for any “X::Y::Y names the constructor, not the type” error – Drop the duplicate ::Y. Of course, your mileage will undoubtedly vary.

References:

Photos from Fanime 2011

June 10th, 2011 Cosplay, pictures

I forgot to link to my galleries of cosplay photos from Fanime 2011… Saturday and Sunday:

How to find which linux distribution you are running from a shell script

June 10th, 2011 googlefood, Howto, Linux, Shell Scripting

sed -n -e ‘s/ *(.*)//g’ -e ‘s/ /-/g’ -e ‘1p’ /etc/issue

Examples:

nethead2:$ sed -n -e 's/ *(.*)//g' -e 's/ /-/g' -e '1p' /etc/issue
Scientific-Linux-release-6.0

dhollowa-106$ sed -n -e 's/ *(.*)//g' -e 's/ /-/g' -e '1p' /etc/issue
CentOS-release-5.6