Christopher J Osborne

Olympus Pen F lenses on full-frame digital

The Olympus Pen F system, launched in 1963, is the only interchangeable lens camera system ever designed from the ground up for the 35mm half-frame format. The 35mm half-frame negative is (as its name might lead you to expect!) 24x18mm, exactly half that of the 35mm full-frame format. This make Olympus Pen F lenses specially suitable for use on APS-C digital cameras, the format of which (23.7x15.7mm for most cameras) is only very slightly smaller. This means you are using the lenses mostly within their intended scope.

It also means that these lenses were never intended to be used on full-frame cameras, so you'd be crazy to even consider doing so, wouldn't you? Well, yes and no! It turns out that many of the Pen F lenses have bigger imaging circles that you might think. Several of them produce images with only a little easily correctable vignetting, and many of the other require much less cropping than their intended use on half-frame cameras would suggest. Outside that half-frame area the sharpness drops of considerable, and if you're sensitive to such things you might still want to crop anyway.

But I rather like the effect! I found that whether I like the blurry corners on any particular image depended on a number of factors, but most importantly the type of subject. For example, if you have tree branches in the corners of you image the effect can be quite disturbing. But a piece flat stone wall looked quite good with the burry corners. And of course if shallow depth of field leads the corners to be out-of-focus anyway it's also of less consequence. And this is where using these lenses on full-frame makes a lot of sense: you to crop each individual image on a case-by-case basis to eek out the maximum field of view.

I am lucky to own all but 2 the Pen F lenses with a focal length of 150mm or shorter (I am missing the 38mm f/1.8 and 42mm f/1.2 lenses), and I thought it would be an interesting experiment to see how they all do on full-frame, hence this page. My original intention was to shoot exactly the same brick wall with each lens, but my lack of patience (and my desire to actually have some fun!) defeated that plan. In the end I decided to shoot real-world photos to give you a good idea of the kind of finished results you can create with these lenses on a full-frame digital camera, in my case 24mp a Sony A7 MkII.

You will see 3 versions of each photo: the first, an almost straight out of camera image with only light exposure correction (usually nothing more than hitting 'auto' in the Lightroom 'tone' panel) to make the imaging circle easier to see, especially if the image is a bit dark because of under exposure. I am calling these versions OOC+EC for Out Of Camera + Exposure Correction. The second version has received a simple crop to give the widest view possible with only a little easily correctable vignetting. For those lenses that don't really need cropping, all I have done is apply a some vignetting correction. I am calling these versions 'Cropped'. The third and final version if a finished photograph with all the processing necessary to achieve the photograph I am looking for. This might include further cropping (often to a 4:3 aspect ratio), correction of rotation and converging verticals, further exposure corrections, maybe adding some creative vignetting, and in most cases conversion of black and white using Silver Efex Pro 2. I am calling these versions 'Final'.

For the cropped and finished versions I will give you the resolution in megapixels, and the effective 35mm equivalent lens focal lengths to give you an idea of how much cropping was necessary.