diff --git a/CHANGELOG.md b/CHANGELOG.md
index 03fea60..1152987 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 #### Features ####
 
+*   Added ability to set zoom_factor(Dmytro Budnyk)
+
 #### Bug fixes ####
 
 ### 1.5.0 ###
diff --git a/lib/capybara/poltergeist/driver.rb b/lib/capybara/poltergeist/driver.rb
index 95b9688..a02b95f 100644
--- a/lib/capybara/poltergeist/driver.rb
+++ b/lib/capybara/poltergeist/driver.rb
@@ -165,8 +165,8 @@ module Capybara::Poltergeist
       browser.set_paper_size(size)
     end
 
-    def zoom_factor=(zoom_factor=nil)
-      browser.set_zoom_factor(zoom_factor) if zoom_factor
+    def zoom_factor=(zoom_factor)
+      browser.set_zoom_factor(zoom_factor)
     end
 
     def resize(width, height)