Friday, 19 November 2010

Keeping Focus

One common rule in photography is that the subject should be in focus (unless of course you wish to break that particular rule). The question is, what does one do with the rest of the picture?

Well in this first example I wanted all of the picture to be in focus to place the tombstone in context with the church. I used a wide angle lens which helps to get a long depth of field, and I shut the lens down a long way as well, and I was careful where I set the primary focus to make certain I achieved what I wanted.

That is a nice simple task, just get it all in focus..

What if you want to isolate the subject from the background? Simple, you use a longer lens, stand further away, open up the aperture and the background will go out of focus. This is a well trod path, yet it still has pitfalls. How far out of focus should the background be? How does this particular lens render out of focus areas?

This whole study of out of focus imagery seems to be grouped under the term "Bokeh" these days. So, lets look at this next image: You may need to click on the image to get a good look at it.

I have managed to isolate my subject from the background, but look how the out of focus area is fussy and unpleasant (to my eyes anyway). It is not supposed to intrude but it draws the eyes slightly. I used a Meyer Domiplan lens on the Olympus for this. The Domiplan was the cheapest East German optic available in the sixties and was based on the 1895 Cooke triplet. No wonder its performance is less than stellar... This unfortunate effect is nothing to do with its penny pinching 6 blade diaphragm, its just inherent in the very simple optical design.

Now we move to another old lens, but one with a much nicer result:

This is the Industar 50, a Russian copy of the much copied 1905 Tessar design. It may not be super sharp at the point of focus, but the out of focus areas are simply sublime, rounded and smooth and unobtrusive. In this case the lens has an eight blade diaphragm. Its one of the least impressive lenses to look at but it can produce lovely pictures. This picture is a case of less is more as I have discussed elsewhere.

Now we move up to date:

This was taken with the Olympus 70-300mm tele zoom. This turns out to be very sharp indeed in the 70 - 150mm range, if you can hold it still. Furthermore, the bokeh performance is not that bad as well. Most impressed Olympus... In this case I chose to push the background well out of focus. In fact I would almost define this Teazle picture as a texture image...

It may be that you want the background to be just sufficiently out of focus to hint at the location without intruding on the picture. That was how I approached this next picture..

I have programmed one of the buttons on my camera to provide a depth of field preview. This shuts the lens aperture down to the setting it will use for the picture and gives you a darker image in the viewfinder but also shows you what the depth of focus will be in the final image. This is a feature I use a great deal.

So, the parts of the image that are out of focus can be just as important as those that are sharp...

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