I have a perfect lens for use on my OM-3 when photographing heritage steam locomotives trackside. Fast enough, flexible enough, of high enough optical quality, of high enough build quality, yet portable enough to be carried all day as the only lens needed to capture all the action; it was as if it was made for this purpose...

The requirement was for a single lens with the flexibility to go from a wide angle (say 24mm equivalent in 35mm format out to a medium tele (say 200mm equivalent again in 35mm format) with a reasonably bright constant aperture throughout it's (zoom) range but physically not too big and bulky as not to be easily carried around all day. It also needed to feature super duper image stabilisation to enable it to be used hand in adverse conditions.

This optic, the OM System M.Zuiko ED 12-100mm f4 IS Pro 8.3x super zoom, (24-200mm f4 crop factor equivalent) provides an exceptional combination of high IQ, creative flexibility, sturdy construction, a constant f4 open aperture and a preternatural Sync IS (Optical IS in the lens that is synchronised with the camera IBIS - In Body Image Stabilisation) that matches the needs of the trackside MFT photographer to perfection.

When photographing heritage steam trackside as on this steam photo charter, I set up the camera and lens in manual mode with a shutter speed of at least 1/250th an aperture of f5.6 and let the camera auto set the ISO. 

The camera is also set to AI subject tracking AF (trains) and lower speed sequential shooting (around 5 fps).

Then it is simply a question of zooming the lens from the tele towards the wide angle end as train approaches and passes you snapping short bursts of frames as it goes with you panning with it.

It's all too simple and convenient with modern technology, it almost feels like cheating in many ways. You simply need to be aware of where you are standing at all times with several tons of steel locomotive and attached train set running up and down for your delight and edification. As it should be it was safety first and photos next, which is why the 8.3x super zoom was great at keeping me close to the action but at an appropriately safe enough distance if you know what I mean and all without ever having to change lenses?