Bear with me, please…I beg you! I haven’t suddenly become a bloodthirsty villain!
The title is designed to catch your attention, that’s all! But I do get a steady stream of emails asking me this question; in fact whenever I do an article about twin lens reflex cameras, the emails start rolling in.
Parallax error is most prevalent with twin lens cameras, but it also occurs with 35mm cameras which don’t use the SLR principle. Ok, next question will be, what is the SLR principle? SLR stands for single lens reflex; with this type of camera, whether it is film or digital, the lens that takes the shot is the same lens that you view the subject with. So how exactly does parallax error come about?
Well, once again, in order to keep things as simple as possible, and to keep newcomers’ attention engaged, I will try and explain as simply as possible.
Let’s take the most extreme case as an example. When I’m intending to take a portrait shot with my Rolleiflex twin lens camera, the camera shows me the subject through the top (viewing) lens, while the shot will actually be taken by the lower (taking) lens. That subtle difference between the taking and the viewing lenses, is called the parallax error, very simply.
So, if I were to press the shutter button having framed my portrait shot as seen through the viewing lens, then the result in my photograph will be that the subject’s head will either be cut off at the top, or in extreme cases such as if the portrait is really close up, the head may not show up at all.
But hang on everyone, there’s no need to throw away your twin lens cameras! Luckily the manufacturers were aware of this fact, and so designed their cameras with built-in parallax correction marks on the viewing screen, usually seen marked in red. To avoid parallax error, all I need do is align my shot within these red marks and safely take the photo, safe in the knowledge that it will be fine. The diagram here shows the marks 3 dashes at the top edge of frame in a camera viewfinder:
This also applies to rangefinder cameras, such for example the Yashica Electro series or even the mighty Leica.
Below is a diagram that explains what parallax error in a rangefinder camera does and how:
Here is a diagram showing how parallax error occurs in a TLR camera (twin lens reflex):
And here’s a photo that shows what parallax error can do to your shot:
There we go! Now you know all about parallax errors, too! Happy shooting!