July 14, 2017

Macro Photos at a Bargain for Sony E-Mount APS-C Cameras

Since some time I think about getting a macro lens for my Sony 5100 (E-mount, APS-C). The reason is quite simple: you are not always at interesting places where it is worth taking photos. But with a macro lens you can take nice pictures of insects, flowers, small objects, leaves, mushrooms, … quite everywhere. My problem has been so far that there is no lens for my camera that really excites me. Read more

July 10, 2017

Hosting Nextcloud on a nginx Web Server

A good while ago I ditched my so-far preferred file-synchronization solution Syncthing for Nextcloud. The reason for this step was that Syncthing behaved in odd ways quite often: sometimes it didn't find content that should be synced, at other days the sync process got stuck and wouldn't complete. I really got annoyed fixing my Syncthing cluster manually almost weekly and started to play with Nextcloud. I decided not to have just one Nextcloud instance, but two: one instance on a public vServer (Debian Jessie; mostly to sync calendars and contacts between Mac OS and iOS devices, and sharing files with others), the other instance (Ubuntu 16. Read more

June 10, 2017

FFMPEG vs My 'Go Low' Action Cam

I got myself a really cheap action cam. Think “China copy” and “Go Pro” and you know what I bought. However, for its 35 EUR price tag that thing is pretty cool. One problem with that cam is that it comes without any software. So you need to dig around a bit if you want to get creative with recorded movies and pictures. So far, I tried two things: time lapse videos from a sequence of photos and stabilized videos. Read more

May 31, 2017

Testing Guetzli - Google's Perceptual Image Encoder

… a quick test of the Guetzli JPEG encoder published some weeks ago by Google. To my big surprise, you cannot encode TIFF or another lossless image format into JPEG. You need to export your RAW camera file first to JPEG @ 100% quality. Then you encode that file with Guetzli. Seems a tad odd to me, as you have a lossless compression two times. The speed of Guetzli is furthermore quite disappointing. Read more

May 31, 2017

Using Two Different GitHub Accounts on the same Computer

Some days ago I created next to my private GitHub account another one for work. At first I was a bit confused how to authenticate to two different GitHub accounts. The solution is rather simple as my former colleague R. H. told me. At first, you need to create two different SSH keys id_rsa_work and id_rsa_priv. Of cause you can use your already existing SSH key for one of the GitHub accounts. Read more

May 12, 2017

How to Display a Featured Photo on a Hugo-Powered Photo Blog's Front Page

I use the static website generator Hugo for this homepage. However I find that Hugo's capabilities are somehow restrained if you post a lot of photographs like I do. So far my approach has been to automatically generate markdown that includes the photos I want to show in a post chronologically. Furthermore I enforce that only the first photo is shown on the homepage with the ` Read more

January 20, 2017

Automatically Split and Crop a Multi Page PDF File

My workflow for LaTeX documents with figures is that I typically first draw the figures in MS Visio, then export the drawing to PDF and finally crop the PDF file so that there is no white margin anymore. This is a little tedious when you have lots of figures and lots of updates on these figures… I changed my workflow a bit. Meanwhile I draw all figures in the same Visio file. Read more

January 29, 2015

Python on iOS

Yesterday I stumbled upon something quite amazing: in the Apple App Store there is an App called Pythonista that runs/interprets Python 2.7 scripts, offers an Python IDE, offers some modules which give your Python apps access to iOS functions, e.g., location, camera, … My first impression of the app was quite spoiled because the App does not provide any import function for your Python scripts. For instance, you put your Python script in your Dropbox, select the file and press “open in”. Read more

January 21, 2015

Markdown Magic

I spend a lot of my time at work with typing. Mostly these texts have the nature of simple notes that help me to keep track of my different projects, coordinate my students, etc. So things like Latex or Word, OpenOffice or Pages are overkill. For notes I have been using DokuWiki on a private server for some time. But I am not (never was) really happy with this because a browser is not the best editor in my opinion. Read more

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