Sunday, May 14, 2017

Virtual Depth-of-Field: Bokeh in the Digital World

I saw an ad for a new function on Smartphone cameras – Portrait Mode. It stated that it was pure “magic.”

I like magical things if they promote artistic curiosity. So I read about this new technology.

It seems that the approach is to have both telephoto and wide angle capabilities work simultaneously. The software creates a nine-point depth map, which results in an “artificial depth of field”!

Hmm. In the old days (and many of us are still in those days…) we used to call it blurring the background by manually opening the lens to its widest. It was for this reason that an f1.7 lens was many times more expensive than an f2.8 lens. With slow shutter speed and wide opened lens one could do magical things. Well at least blur all background and have the subject stand out. That is why it is a portrait – it is only the subject in the frame that is in focus.

Artificial depth of field! Nine-point depth map… I could not resist choosing some photos I have taken to show how attractive a REAL depth of field can look.

… But first, let me state that the discussion about the depth of field goes back to the early days of photography. The commonly used word is bokeh which is Japanese for …BLUR!!!! I have written more about it here: https://liveingray.blogspot.com/2016/10/bokeh-or-not-bokeh.html

… So, let’s start with a non-blurred (or no-bokeh) photo. This I took with a 1960s Ukrainian Salyut medium format camera and wide-angle lens pointed at the sun. The clouds are perfectly clear. No blurring anywhere and the sun rays are delightfully shaped.


Here is an avian “portrait” using a 1960s Nikon Nikkor 180mm at f2.8. The subject is quite in focus but the mountain and the morning fog are not. That is the bokeh through the depth of field, which in this case was decreased to blur the background.



But the depth of field does not pertain to outdoor pictures only. Here is my dog, indoors, looking at a Canon Serenar lens from the 1940s opened to f1.9.  The camera is a 1954 Canon rangefinder, demonstrating that a bokeh can be achieved without using a Single-lens Reflex (SLR) camera. No flash of course.



The depth of field blur works also great in street photography when I want to isolate a person from the crowd. Here is one taken with my 1960s Mamiya 645 and the venerable Mamiya Sekor 90mm lens set to f1.9. The creamy bokeh of this lens always delights me.



Finally, there are shades of bokeh, of course. That is, the photographer would decide what f-stop and shutter speed to use to have enough of a blur to be able to identify the background yet isolate the subject in a pleasing way. This is more challenging, because the eye is not capable to appreciate “some” bokeh vs intense blurring. Here is an example:
I took this with a 1960s Olympus OM-1 sporting now relatively rare to find Vivitar 135mm Close Focusing telephoto. I wanted to include the sailboat, the woman atop the mast, and the harbor’s buildings in the frame, with minimal blurring of the buildings.



What woman you ask? Here is the cropped area. Quite amazing that from perhaps 500 meters away, the 35mm ASA 100 film can capture enough details to see the woman clearly when cropped. Perhaps that is why this Vivitar lens is so sought after.



… I know that the bokeh topic will remain a discussion favorite as long as photography exists. In some way, I feel good that smart phones and virtual depth of field magic keeps the topic alive.

But I shall stick to my manual focus lenses and real depth of fields!

May 14, 2017

© Vahé A. Kazandjian, 2017

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