February 2016

- How to build an overhead camera mount that is also a slider (includes Youtube Video).

- New article on how to create a lens distortion target (Also includes Youtube Video).

- Reviewed the book "The 4 Percent Universe: Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality"

- New quick-tip article and video: "Making Multimeter Alligator Probes"

January 2016

- My latest review; the Zhongyi 'Lens Turbo' adapter:


December 2015

- Posted an article showing my experience with several old 50mm lenses adpated to Sony E-mount.

November 2015

- Reviewed the book "Five Golden Rules: Great Theories of 20Th-Century Mathematics-And Why They Matter"

October 2015

- Sometimes a table-top dolly such as the pico-dolly is very useful for video work. In this how-to video, I show how I motorized a standard pico-dolly:


- Introducing the YACS - Yet Another Camera slider. This is a DIY tutorial explaining how to build a slider for video applications. The YACS features variable speed control and automatic reversal.


September 2015

- My review of the Canon nFD 85mm f/1.8 lens is now online:


August 2015

- My second video lens review. This time, the OM 24mm f/2.8 wide-angle lens:


- Big news! I just started a new YouTube channel dedicated to lens reviews. Please check my first video below. If you enjoy it, please support the channel by sharing and/or subscribing!


July 2015

- Reviewed the book "The Information: A History, A Theory, A Flood"

June 2015

- And for something different this month, here's a DIY cat scratching pole idea...

May 2015

- Posted my favorite photography quotes, along with some of my personal favorite images.

April 2015

- Today I'm posting my new photo gallery "American Automobile"

March 2015

- Published my review of the book "Poincare's Prize: The Hundred-Year Quest to Solve One of Math's Greatest Puzzles"

February 2015

- How big is your image? A study of photo sizes when formatted for HDTV projection.

- For those interested in learning statistics online, there has never been a better time. Today I published an article on learning statistics through online video courses.

January 2015

- Published an article on using the statistical package R to find-out if a file is encrypted.

- Reviewed the photography book Photo-Wisdom Master Photographers on Their Art.

December 2014

- Reviewed the excellent book Prime Obsession: Bernhard Riemann and the Greatest Unsolved Problem in Mathematics.

- Published a new article on how to model a LC power filter using the open-source R programming language.

November 2014

- Ever wondered what are the best times of day to book your flights to avoid lengthy delays? Today I published a study for two local airports trying to answer that question.

- Using the R statistical computing language to compare air pollution levels in California.

October 2014

- Ever wondered how one can calculate the number of f-stops between two apertures? Here's how you do it.

- For those interested in Mathematics, you owe it to yourself to read the excellent book "Journey Through Genius". My review is here

September 2014

- Reviewed a vintage Canon FD 50mm f/1.4 lens adpated to a Sony mirror-less camera.

- Published a comparison of various vintage 50mm f/1.4 lenses.

August 2014

- The analysis of a transistor circuit at high-frequency can be somewhat challenging. I developed an Excel-based, common-emitter and common-collector transistor amplifier calculator for high-frequency operation that you can use to simplify this task.

- Published my review of the excellent book "Longitude".

July 2014

- My impressions of two 135mm manual focus lenses adapted to Sony E-mount Cameras.

- Published an article on Rent Prediction Using Linear Regression and Cross-Validation with Excel.

- Added a new photo Gallery: "Fort Ross".

June 2014

- Published my review of the Canon FDn 85mm f/1.8 adapted to a Sony E-mount (NEX) mirror-less camera.

- Wrote a review of Malcolm Galdwell's latest book: David and Goliath.

May 2014

- There's a new photo gallery in this website: the Flora gallery.

- Added an Electronics related article: A capacitive T network calculator in S-math Studio

- New article on Inverted Black and White Conversion.

April 2014

- I developed an Excel-based Depth-of-Field calculator for photography applications. The article can be found here.

- I've been having fun adapting old lenses to my Sony NEX camera. Today, I publish my findings on using 200mm telephoto lenses: "The battle of the 200".

March 2014

- New tutorial on how to use small flash units in manual mode.

- Posted my impressions of the Metabones Speed Booster, Canon EF to Sony E-mount (NEX) lens adapter.

- Added a new "Time" photo gallery. A series of composite images on the meaning of time.

February 2014

- Reviewed the entertaining book "A short history of nearly everything".

- Added a new "Color Portraiture" photo gallery.

January 2014

- Reviewed the excellent book "Excel 2007 Power Programming With VBA".

- Created a new photo gallery: Old Sacramento.

- Published a review of the Rokinon 8mm fish-eye lens for Sony NEX cameras.

December 2013

- Published a new article on "Diode temperature sensor calibration using Arduino and SHT15 module"

- Published my review of the surprisingly good book "The Happiness Advantage".

- Re-organized my "Photography Galleries" and added some new ones, including "Point Lobos" and "Coach Junkyard".

November 2013

- My first Arduino project: "Arduino Astronomical Clock for Automatic Light Control"
  UPDATE: This article was featured in:

- Published a review of the book "Isaac Newton".

October 2013

- In time for Halloween 2013, check-out my new electronic pumpkins project. (Featured now also in hackaday.com).

- Published my review of the excellent book "Supercrunchers".

September 2013

- Published a review of the book "The Story of Mathematics: From Creating the Pyraminds to Exploring Infinity".

- Published a review of the book "All of Statistics: A Concise Course in Statistical Inference".

August 2013

- If you own one of those analog CRT oscilloscopes, you may have trouble taking photos of the screen. The "OscilloCam" comes to the rescue.

- Published a review of the book "The History of Statistics: The Measurement of Uncertainty before 1900".

July 2013

- It's been a "chaotic" summer here at paulorenato.com. Two new articles on Chaos:

 A review of the book Chaos: Making a New Science 

 A new article on Excel based Chaos

June 2013

-Two new and related articles:

 New Life for an old Drill.

 How to measure rpm with an oscilloscope

May 2013

- Reviewed a biography of the great American Physicist Richard Feynman.

- There is no direct way in Excel to implement integration for a continuous function. In this new article, I explain how to approximate the integral for a function using a neat technique know as "Gaussian Quadrature".

Posted a review of the Olympus OM 200mm f/4 lens adapted to a Canon Digital Rebel.

April 2013

- Published a new article analyzing how combining many resistors improves the overall tolerance of the equivalent resistor. A fun little problem that actually required some mathematics:)

- Reviewed the book "The Power of Habit: Why We Do What We Do in Life and Busines".

March 2013

- New article on how to build an ESR meter to find defective capacitors.

  UPDATE: This article was featured in the hackaday.com blog.

- Reviewed the excellent book "Abundance - The Future is Brighter Than You Think".

February 2013

- Published two new and related articles

  - A new article on how to build a A Karaoke mixer and amplifier for the iPhone

    UPDATE: This article was featured in the hackaday.com blog.

  - A transistor amplifier calculator that many electronics hobbyist may find useful

    UPDATE: This article was featured in the Dangerous Prototypes blog.

- Reviewed the book: "RF Circuit Design" by Chris Bowick.

January 2013

- Published a new article on how to build a high-bandwidth "Lo-Z" probe.

- Reviewed the book: "The Mystery of the Aleph".

- Starting the new year with a book review:  "So Good They Can't Ignore You" by Cal Newport.

December 2012

- Tis the season for singing. Today I publish article on how to build a (very) simple mixer for a Karaoke system based on YouTube streaming.

- Added a new review for the book "Makers" by Chris Anderson.

November 2012

- Added a new book review for the excellent book "The Signal and The Noise" by Nate Silver.

- New article: How to make a cheap panel voltmeter from a dollar-store pedometer.

UPDATE: This article was featured in the hackaday.com blog

October 2012

- New article: Fume Extractor for the Electronics Workbench.

- Added a new article on how to build an adjustable constant current load. 

UPDATE: This article was featured in the hackaday.com blog.

September 2012

- Added a new book review for the excellent book "Energy for Future Presidents" by Richad A Mueller.

- Published a new article on how to build a LED fader for home lighting applications with two-level settings. It uses a notebook supply to feed a light strip with Cree XM-L power LEDs.

August 2012

- Completed a new article on how to build a battery operated light-box. Useful for product photography, macro shots and photographing small objects in general.
UPDATE: This article was featured in the hackaday.com blog:)

- Added a new article on how to build a flood detector from a dollar-store "panic" alarm.

July 2012

- Added a new article on how to build an AC-powered USB charger for toys or other devices by re-purposing an old cell-phone charger.

- Added a review for the very entertaining book "Moonwalking with Einstein".

June 2012

- I was recently in the market for a new car and also selling an old one. My experience resulted in two related articles now online: "How to Photograph a Car for Sale" and "How to Negotiate a Car Purchase Online".

- Solar energy experiments can be quite fun. In this new article, I show how to build an important component for many solar powered systems: your own solar charge controller.

May 2012

- Added a new book review for the excellent book "Looking at Photographs".

- Posted a review of the Olympus OM 24mm f/2.8 lens coupled with the Sony NEX-5N.

April 2012

- Ever got frustrated when cleaning your camera sensor? Using  a sensor lopue can make the whole process so much easier. In this new article, I show how you can build one yourself.

- Proud to announce that an article I wrote is now published in the May 2012 edition of the Nuts & Volts Magazine. The article is titled: "Sound Activated Laser Parking System". Be sure to get the Magazine!


- Tired of those uncomfortable "neck straps" for your camera? Today I published an article showing how you can build a much better camera strap yourself. Introducing the "Rapidinha Camera Strap".

- New article reporting my experience using an "old" 50mm f/1.4 Olympus OM lens with the Sony NEX-5N.

March 2012

- New article with some thoughts on panoramic composition.

- Added a new article showing how to build a simple sound activated DSLR camera trigger.

January 2012

- Added several new photos to the "Latest Work Gallery".

April 2011

- Added several new photos to the "Latest Work Gallery".

January 2011

- Point Reyes is one of my favorite spots in Northern California. Today I'm posting a new Gallery from Drake's Beach in Point Reyes.

November 2010

- Following a snow hike in Northern Italy near Lecco, I'm posting a new Gallery.

July 2010

- I'm happy to announce that my photography work is on exhibition at the Butch & Nellies Coffee Shop in Midtown Sacramento (corner of 19th and I Street) from July 4th to August 8th. The "official" opening will be on July 10th on the second Saturday art-walk from 6PM to 9PM so please come on down to see the exhibition.

June 2010

- California's Death Valley and Alabama Hills are some of my favorite locations in the state. Following a weekend trip, I'm posting a new gallery.

May 2010

- California is home to some very interesting "State Historic Parks"; some of them unknown to most people. The Indian Grinding Rock SHP is one good example. Please have a look at the new "Indian Grinding Rock State Park" gallery.

March 2010

- Added a new "Jack London State Park" gallery.

- Added several new photos to the "Latest Work Gallery".

February 2010

- Added a new Doors gallery.

- From time to time, I like to open-up gadgets and see what's inside. This weekend, I came across an old slide projector for $8 and had the idea of re-using one of its lenses with my DSLR. My new "Downtown" series of photos was taken with this new Blurromatic (TM) lens "technology"... Check it out. And if you are interested in building one of these, see this new article.

- Portraiture is a style of photography that intrigues me. While I don't consider myself primarily a "fashion photographer", I do like to experiment new things.. it's a new year after all. In that vein, I started a "Portraiture Section" on the website with local model Kayla. Check it out.

January 2010

- To start the year, I added a new article on my personal camera recommendations. Holidays are a great time to catch-up on your reading and I just finished reading the book "Outliers". My review is now online.

December 2009

- Added a new article on how to control you DSLR from an Ipod (or other MP3 player).

- Editing the number of photographs in a website can be challenging. However, it is important to give viewers a sense of the photographer's style with a limited selection of photographs. With that in mind, I created a new Favorites gallery that is now prominently displayed in the photography section.

- Added a new article on my personal lens collection.

- Added a new article explaining how to shoot HDR images without a tripod.

November 2009

Added a new article on how to build your own DSLR cable release.

October 2009

Added several new photos to the: "Latest Work Gallery".

May 2009

Added a new book review: "The Elements of Style".
Speaking of book reviews, I have now added links to Amazon.com in each of the book review articles. When you buy using these links I do get a nominal commission, but it does not cost you any more than normal. It goes without saying that, even though I don't expect to get rich through this new venture, this does help support the site and your cooperation is very much appreciated. So if you are interested in buying one of the books, don't forget to click the corresponding link... Thanks !

April 2009

HDR photography has been quite a trend in recent years. Today I added a new article on HDR-BW; my personal take on HDR for black and white work.

Preston Castle in Ione, CA is an interesting place for photographers and a short drive for me. I had the opportunity to visit the place this month and practice my new HDR-BW technique (see article above). The new Preston Castle gallery (in black and white) was the result and is now online.

The  Preston Castle Color Gallery is now also posted so you can compare the results...

March 2009

Added a new Midtown Sacramento gallery. Several new photos added to the "Latest Work" gallery.

February 2009

Added a new book review. Several new photos added to the "Latest Work" gallery.

January 2009

Added a new "Portraits" gallery to the photography section. Several new photos added to the "Latest Work" gallery.

November 2008

Added new book reviews and several new photos to the photography section.

October 2008

Added an article about calculating square roots in your head.

September 2008

Big News! The website was completely redesigned using the Joomla CMS. This is a powerful new tool for server-side php website design . It makes it so much easier to maintain and update the site I can't recommend it enough... can't see myself using pure HTML or Flash again. Hopefully, this will allow me to post more frequent updates to the content... I have no excuse now:)

June 2007

New gallery: "Bodie - Ghost Town".

June 2007

Big changes! I finally decided to convert all the photo galleries to a flash format with thumbnails etc (see "photography" area). I hope this will make it much easier to navigate through the many photos I have posted. It was a lot of work, but it should also allow me to update the site more frequently in the future. Plain html, was just too painful. For those of you that preferred the old galleries, they are still here, but I will not update them any longer. I also fixed an issue with the page design which (hopefully) makes the site look cleaner in wide-format monitors.
I'm particularly proud of my new gallery titled "Minimalism". Check it out.
I've been replacing several photos throughout the website with more recent ones. They are spread-out across various galleries so, feel free to browse around:) My philosophy nowadays is to try and replace older, not so good photos, with more recent, presumably "better" photos. It is very easy and somewhat tempting to keep on "dumping" photos onto the website... Instead, I'm going for quality over quantity (or so I like to think:)

November 2006

New home page now includes a random flash gallery. Added a new "Faith" gallery and added/replaced several photos in the "Portugal - The North" , "Miscellaneous II", "Empty Benches", "Cars" and the "Panorama Experiments" galleries.

May 2006

Added photos to the "Panorama Experiments" and "Cars" galleries.

July 2005

Added a new "Miscellaneous II" gallery.
New photos added to "Cars", "Animals", "Landscapes", "Panorama Experiments", "Still Life", "Empty Benches" and "Portugal -The North"

July 2005

Added a new gallery titled "Panorama Experiments" to the photography section.

May 2005

Added an article titled "Automotive Under-The-Hood Inspection" to the "Articles" section of the website.

April 2005

Added articles titled "The rule of 70 demystified" and "Divide by 9" to the "Articles" section of the website. Also made some cosmetic changes to to the site to make the text more readable.

January 2005

- Added an "Articles" section to the website
- Added location and camera info to most photos
- New photos in the"Empty Benches" gallery
- New photos in the "Animals" gallery
- New photos in the "Landscapes" gallery
- New photos in the "Miscellaneous" gallery
- New "Still Life" gallery
- New "Cars" gallery
- New "Reflections" gallery
- New "Trash" gallery

July 2004

Added the "Landscapes" gallery. New pictures in the "Miscellaneous", "Shadows" and '"Animals" galleries.

June 2004

Added the "Flowers" gallery. New pictures in the "Miscellaneous" gallery.
New "Animals" gallery.

April 2004

Added the "Miscellaneous" gallery.

March 2004

Added photos to the "shadows" gallery.

January 2004

Added a gallery on Jenkinson's Lake to the photography section of the website.

December 2003

Actually, everything in this website is "brand-spanking-new". This is the first release of the website. Sorry but these are all the "news" I have for now... you didn't expect to get something like the New York Times through this link, now did you? :)