Tags » Histogram

Exercise 4.1 - the problem of reflected-light metering

This exercise demonstrates a well-known issue with reflected-light metering, the problem of calibrating to medium-grey if the scene does not average out. The exercise is useful because it caused me to demonstrate the effect, rather than just read about it and accept it. 295 more words


Statistics: Histograms In R - An Example

Hi there. In this post, I will highlight histograms in the statistical program R using the R base package, ggvis and the ggplot2 data visualization packages. 1,785 more words


A plug-in for real-time histograms in Scanbox

A Scanbox user requested to add the ability to display a histogram of image values in real-time.

Here, I use a the general mechanism of… 340 more words


Lightroom Tutorial!

For the first tutorial, I want to go over some of the basics. I know for me, I couldn’t even figure out how to open images so first things first! 1,247 more words


How to photograph in winter

Protect your camera equipment to photograph in winter

When one wishes to photograph in winter, we must first think about protecting his camera equipment. Know that it does not like being exposed to the cold, especially at temperatures below freezing. 881 more words


Loop over all histograms in pyROOT

Here’s a code snippet to loop over all histograms (and get their names) in pyROOT:

from ROOT import TFile

fname = 'histos.root'
hnames = []

tfile = TFile.Open(fname)
for key in tfile.GetListOfKeys():
    h = key.ReadObj()
    if h.ClassName() == 'TH1F' or h.ClassName() == 'TH2F':

Graphical Representation of Mass Variations

Graphical Representation of Mass Variations
Graphical representations are aimed at providing easy analysis possibilities as well as providing more complete information than the numerical estimates. The following graphical representations are common with the latest generation evenness testers.