The last weekend I used the Canon EF 135mm f/2.0L lens almost exclusively – partly because it was the lens I felt would best suit my subjects – in one case for shallow depth of field and background blurring, and the other case to gain telephoto low light performance.

I was invited to help out a friend who had arranged an impromptu urban shoot to help aspiring models develop a portfolio.

Now the best lens for such shoots tends to be a 70-200mm f/2.8 IS L lens as it gives plenty of versatility while allowing good background blurring, and low light performance without having to change lenses and lose photo opportunities. But, as I am not a professional photographer, I do not really have need of such a big, heavy and expensive lens.

The 135mm f/2.0L lens gives me one more stop of aperture for even more background blurring or shallow DOF when I need it, while it is sharper as long as it is accurately focused and you control camera shake – unfortunately, Canon still has not added image stabilisation to its bodies.

Here is an example of what you can do in a dark alley way on a heavily overcast day on a 1.3x crop camera – the Canon 1D Mark III (note contrast and vignetting added via Photoshop) :

The biggest problem with this lens in this scenario when used wide open, is the shallow depth of field. It is so shallow that your focus has to be precise – and as my subject’s eyes are rarely anywhere near the centre of my frame, I lock the AF using the rear button, then recompose the camera.

Unfortunately, the depth of field is only a couple of inches for critical focus so while you recompose, movement of yourself or the model may place the model’s eyes out of focus which makes this very challenging and chimping of the image with enlargement is almost mandatory.

A further problem with shallow depth of field camera-lens combinations which use dSLR autofocus mechanisms is that the combination must be calibrated to ensure there is no inadvertent front focus or back focus – fortunately most modern dSLRs allow you to do this using the AF microadjustment setting in their menu.

The main other issue I have with this lens is low contrast when bright light sources hit the front element – for this reason, I find that use of the lens hood is mandatory with this lens.

Now for something totally different – low light telephoto – using the 135mm f/2.0L lens as a 270mm focal length reach lens with light gathering of a f/2.0 lens but depth of field of a 270mm f/4 lens – just what one needs for stage shows at night time!

How do we do this – simple use a sensor with lots of pixel density – in this case I used a Micro Four Thirds camera – the Panasonic GH-1 for still images and HD video of the Sunbury Backroad Music Festival – this one is of Australian 1970’s band, Spectrum:

At dusk, I tested out this combination hand held on the band Falloe:

I thought I would push this lens even further, adding a the Canon EF 1.4x tele-extender which when combined with the Panasonic GH-1 gives a focal length field of view of a 378mm lens at light gathering of a f/2.8 lens but depth of field of f/5.6 just perfect – except, no image stabiliser on my Panasonic GH-1 either:

More from the Sunbury Festival here.

This lens is one of my favorite lenses along with the Olympus ZD 50-200mm f/2.8-3.5 SWD, the Panasonic Leica-D 25mm f/1.4 and the Olympus ZD 50mm f/2.0 macro lens, while for special purposes, I also love my Canon tilt shift lenses and my Olympus ZD 7-14mm super wide angle lens.

More examples of photos with the 135mm f/2.0L lens here, and taken with the GH-1 here.