Depth of Field

Micro Four Thirds and maximum depth of field.

Panasonic Lumix GH1 Leica Vario-Elmar f3.5-5.6 4/3 Zoom

In the article Can a small sensor really produce a decent picture I was "reminiscing" about how the 2/3" sensor on my 2001 Olympus E-10 allowed me to produce images like this:-

dover



On the smaller sensor the 9mm lens on the Olympus produced an image that is "equivalent" to the field of view obtained from a 35mm lens on 35mm/full-frame but with the extreme depth of field that a 9mm lens can produce.

After writing this, and more or less discounting the possibility of modern small sensor compact cameras being able to provide the quality images that I wanted, I began to realise that I may already have the means to create similar images.

Panasonic Lumix GH1 Leica Vario-Elmar f3.5-5.6 4/3 Zoom

What I was looking for was the following. An image that has extreme depth of field, with everything from a few inches to infinity in focus. This should not involve the use of an extreme wide angle lens and should have the look of a 28mm or 35mm lens on 35mm/full-frame to minimise distortions. It should be possible to achieve this hand-held for portability, and also allow reasonably fast shutter speeds and the lowest possible ISO setting. I also wanted to be able to shoot multi-image panoramic stitches.

Most of the time when Depth of Field on Micro Four Thirds cameras is discussed it is usually about the perceived "problem" of the difficulty in achieving minimum depth of field. Because of the 2x crop factor of the sensor, lenses become wider. A "standard" lens on 35mm/full-frame is 50mm. On m4/3, a "standard" lens is 25mm. A 25mm lens will give more depth of field at every aperture than a 50mm lens, thus making the effect of "isolating" an in-focus subject from an out-of-focus background more difficult to achieve, and requiring the use of wider apertures.

Panasonic Lumix GH1 Leica Vario-Elmar f3.5-5.6 4/3 Zoom

However this "problem" becomes an advantage when you are seeking to maximise your depth of field. To obtain the view of a 28mm lens on 35mm/full-frame you need a 14mm lens. A 14mm will give more depth of field at every aperture than a 28mm lens. 

The settings for the poppies/ferry picture above were 1/160th sec at f11 ISO 80. I wondered if using f16 or f22 with a 14mm lens on m4/3 would give me similar results. However using f22 brings problems. Lower shutter speeds are required, and there is the problem of diffraction which means that f22 often produces softer results than wider apertures such as f5.6, f8 or f11. 

Panasonic Lumix GH1 Leica Vario-Elmar f3.5-5.6 4/3 Zoom

A few tests indicated that to achieve the results I was after I would indeed have to use f22 most of the time. So what camera/lens could I use? My lens testing had indicated that my Leica Panasonic Vario-Elmar 14-150mm zoom had the best results at f16 and f22. The small advantages that the Panasonic GH1 sensor possesses in terms of dynamic range would make it my best option. The articulated screen would also prove very useful as I intended to use some low angles. 

I therefore went off to my local canal, which I knew would provide me with a suitable environment to try this out.

Panasonic Lumix GH1 Leica Vario-Elmar f3.5-5.6 4/3 Zoom

The results were very pleasing. I would have liked the lens to be able to focus a little closer ideally but the results were as sharp as I hoped. Not as crisp as the lenses optimum apertures but with a little photoshop sharpening very acceptable. I was able to use the mega OIS image stabilisation on the lens to cope with the lower shutter speeds that were required and found that 1/25th sec was about the lowest I could go to keep the images sharp and minimise subject movement. I did have to raise the ISO occasionally, to cope with the light though I kept this to 400 ISO maximum. In several instances I was able to use ISO 100 for minimum noise. I did manage a few multi-image panoramic stitches, but these proved difficult due the close proximity of some of the subjects.

Panasonic Lumix GH1 Leica Vario-Elmar f3.5-5.6 4/3 Zoom

All in all a successful experiment and I was happy that I could get the results that I wanted using equipment I already have. The images I was able to produce are very much what I was after and give further credibility to the notion of m4/3 as an excellent option for landscape photography.

There is a set of these images, at larger sizes, on my flickr photostream at:-