“How do you decide what to paint when there is so much to choose from?”

This is a very common question when it comes to painting from real life (whether it's a landscape, a portrait, or a still life)  The answer?  Using a viewfinder can help enormously!  Your naturally vast field of vision can be overwhelming.  Using a viewfinder will help isolate the part of the scene that appeals to you, and help you to compose the lay-out on your painting substrate (canvas, board, paper, etc).

I picked a random picture posted by the NOAA Marine Debris Program.  Imagine you're sitting on the beach and this is your view.  Elements of this view are highly unpleasant and probably not something you want to include in a painting...

But the unpleasant debris can be cropped using any one of several different compositions...

...or like this...

...or like this...

Materials to Make A Viewfinder

  • one 8x10" mounting board or mat board (8 ply)
  • craft knife or box-cutter
  • ruler
  • double sided tape
  • mechanical pencil

Warning: I'm going to be using a combination of imperial and metric measurements.  Some people may lose their mind because of this.  Sorry, it's unavoidable... you'll see.

For greater detail: click directly on images to enlarge




 The viewfinder is essentially finished but we've added a few more optional steps.  First, test the door to make sure it slides in and out alright. You can leave the door long (sticking out the end) if you like, there's no real harm in that, though it's more likely to get bent if stuffed in a backpack or bag.

I chose to cut the sliding door down flush with the frame.  this means I had to also cut an extra notch out of the frame so I can still grab the sliding door when its pushed all the way in.

This is my finished Viewfinder, with the sliding door cut flush and the additional notch taken out, plus ratios measured out.


"No one told me there would be math involved!"

Don't worry, we've worked everything out for you!

Most stretched canvas, boards, papers and such are produced in standard sizes/ratios.  A viewfinder that is marked with known ratios is extremely helpful because you'll know for certain that the dimensions of your viewfinder window will translate to your chosen canvas exactly: this will save you time and frustration in your layout. 

Below is a table of common ratios and some of their corresponding standard canvas sizes

1:3 Ratio 1:2 Ratio 2:3 ratio  3:4 Ratio 4:5 Ratio
8 x 24" 6 x 12" 4 x 6"" 6 x 8" 8 x 10"
12 x 36" 12 x 24" 8 x 12"" 9 x 12" 16 x 20"
18 x 36" 20 x 30" 18 x 24" 22 x 28"
24 x 48" 24 x 36" 30 x 40" 24 x 30"

 Measuring and Marking Ratios:

Warning: This is where we switch to Metric
The 2.75" square cut-out in the centre of your viewfinder is (or should be) a 7 cm (70 mm) square. 
On a flat surface, orient your viewfinder so the sliding door slides down, towards you.  Measuring from the top edge down, duplicate the measurements in this diagram on both the left and right sides of the 7cm square as shown...
1:3 Ratio - 23.3 mm
1:2 Ratio - 35 mm
2:3 Ratio - 46.6 mm
3:4 Ratio - 52.5 mm
4:5 Ratio  - 56 mm
April 05, 2017 — Karen Bullaro