07 April, 2015

Why 15mm, and why this 15mm (the Voigtlander f/4.5 III)?

Voigtlander 15mm - The recreated Margaret Olley House, Murwillumbah, New South Wales [click to enlarge]

Why 15mm?

I need a good reason to go to 35mm, so I need a really good reason to go ultra wide; and the Voigtlander Heliar 15mm (version III) is definitely an ultra wide.

For me, 15mm is about the limit of useful rectilinear lenses — lenses that limit the pincushion and barrel distortion, but at the expense of size distortion at the edges and particularly in the corners. That is, elements at the edges are rendered large and distorted. (The lower-left corner, above, is a good example.)

The image above is at 15mm, but was slightly trimmed by some lens correction done in Lightroom. (There's no automatic Lightroom lens profile for the 15mm "III" version yet.) Occasionally the corrections can cause the loss of a bit of real estate.

A fisheye lens, on the other hand, prevents the size distortion, but allows barrel distortion that corresponds to the field of view — the wider, then the more circular. I don't have a fisheye lens, so I don't have an example of my own for you.

About these images

Margaret Olley was an Australian Painter (1923-2011).  She was born in northern New South Wales, grew up in Brisbane, but moved to Sydney in the '60s. Her house in Sydney has been recreated in the Tweed Regional Gallery in Murwillumbah, New South Wales. Her house/studio was called the "Hat Factory" because of its earlier use. It seems cluttered, and it was, due in part to Olley's practice of moving her furniture pieces closer together as her mobility declined — allowing her to use them for stability. (Both pictures were shot at ISO 3200, f/4.5 and 1/20 of a second. Also, I've brightened them more than they appear in real life.)

Why the Voigtlander 15mm f/4.5 III?

This is an m-mount lens, but it works beautifully on the Sony A7 series cameras (for which it was also designed) with a adaptor. I use the Metabones M-to-E adaptor, keeping it permanently on the lens. (Sadly, I suppose, the 15mm is my only m-mount lens.)

It seems to be quite sharp, and the contrast is good, but I haven't been printing from it just yet. Watch for an update.

This is an all-metal lens with a great manual focus ring. You just don't need it much. When I do it's to zone focus. Using the electronic viewfinder to focus is a waste of time, as everything is already in focus. The viewfinder is perfect, however, for composition.

The aperture ring has nice crisp, half-stop clicks. I'm used to thirds, but it's not a problem.

An f/4.5 lens is not fast. But it's a usable stop. Even "wide open" the Voigtlander 15mm affords incredible depth of field. Wide open and set to infinity, everything is in focus from about 2 metres. And, of course, you can back off infinity and still have everything sharp slightly closer in.

The newest "III" version lens is bigger than its Voigtlander predecessors, but is still quite small. It's an easy fit into the bag.

Unlike 35mm film, sensors have more of a problem with light arriving at very acute angles. This has meant that most ultra-wide lenses on mirrorless cameras have been beset by both vignetting and colour casts (magenta) in the corners. The best ways to deal with these has been by using either Adobe's "DNG Flat Field" plug in or using the separate program, "Cornerfix."

Hello Voigtlander 15mm f/4.5 III, goodbye colour cast. There's still substantial vignetting, but, if there's a cast (I haven't seen it yet), it's too minor to cause me troubles.

Almost paradoxically, for me the ultra-wide lenses have two uses: They are great at squeezing things in; but also for spreading things out. These Olley pictures are of the squeezing in variety. A "spreading out" example is at the foot of the post.


Voigtlander 15mm - The modest Olley kitchen with more paint than pasta.
If I'm going wider than 35mm, then I'm usually going for an effect — and 15mm will give it to me. And, if I need to do some lens correction in post, to keep the verticals vertical for example, then even if the task in Lightroom eats up a bit of the scene, 15mm still gives me a bit of room to work with. (That does require thinking ahead.)


Voigtlander 15mm - An example of spreading things out. Mt Coot-tha, Brisbane
The competition

Wide zooms are popular. I used the 7-14mm f/4 Panasonic with Micro Four-Thirds, and the 10-18mm f/4 on the Sony NEX (that lens also works pretty well on the A7 series from about 14mm). I just found that I was using the zooms only at their widest. And at its widest I was getting a colour cast on the Sony's 10-18mm's corners.

And now there's the Sony/Zeiss FE 16-35mm f/4. I haven't used that lens, so I can't comment. But I won't be buying it, as I have a great, and faster 35mm lens as well as the Voigtlander. I just don't work in that middle area.

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