14 vs 17 vs 20mm

A user on another forum was curious to know how sensible it would be to swap their Panasonic 14mm and 20mm lenses for the Olympus 17/1.8. I'm sure this is a relatively common concern for many M43 users here as well so I thought I would re-post a simple test I did using the 12-35/2.8 to compare the focal lengths. I've owned them all but don't have all three of these primes anymore, so the actual focal lengths will probably be a little different, but I doubt different enough to nullify the findings.

First off, I set up my tripod and shot the same scene at 14, 17 and 20mm. This is roughly the difference in angle of view you can expect:

Here is what the individual shots look like as well:

I then set the focal length to 17mm, and moved the tripod to roughly match the framing of the 14mm and 20mm shots respectively.

17 to 14mm:

17 to 20mm:

What I was really curious to learn was exactly how far forward/back I would need to move with the 17mm to match the framing of the 14 and 20mm lenses. It turns out it's about 7.5 inches (19cm) forward and backwards, or about 1/3rd of a step.

One last thing to note, moving the lens forward or back does alter perspective. Moving closer to simulate 20mm slightly exaggerates the perspective relative to the 20mm shot, and moving back slightly compresses the perspective relative to the 14mm shots.

Anyway, I hope someone finds this useful.

Edit: Looks like DPR resized my images, click the view original link to see them a little bigger (1500px wide).

You were quite close to the subject, so a third of a step made up the differences easily.  However, if the subject is much further away, the difference will not easily be compensated by "zooming with your feet".

clemcam wrote:

You were quite close to the subject, so a third of a step made up the differences easily. However, if the subject is much further away, the difference will not easily be compensated by "zooming with your feet".

Free fitness, yay! 

A couple shots of people might be useful too IMO, that's where you might really prefer 20mm to 14mm or even 17mm IMO... Less inherent distortion. The inverse being true for the landscape scenario already mentioned...

It seems to me your scaling is correct (similar triangles probably). So if the mountains are five miles away, you either take good hiking shoes or carry two lenses.  Or maybe there is something to this zoom lens thing after all.