If you want something done right...

An inconvenience that plagues most of the cheaper lenses is the lack of a focus distance markings.

Of course, "cheap" is relative.

One may wonder what's the point of having such a quaint feature given the level of automation employed by today's digital cameras. "Why not just rely on the camera's autofocus feature?"

And wonder you will until you wander into scenes such as these.

In low light, contrast detection autofocus fails, phase detection autofocus fails, manual confirmation using the optical viewfinder is impractical even for eagle-eyed photographers (especially for cameras with 1.5-1.6 crop factor), and the viewfinder turns into a shitty haze at ISO 1600 and higher.

Technically speaking, one only has to twist the focus ring to the proper position in order to get the subject into focus (that is, if your camera/lens supports manual focusing); the problem is knowing to what degree the focus ring must be adjusted. It is in situations such as these where the focus distance markings becomes indispensable since they allow the user to compensate somewhat for the machine's shortcomings.

Recognizing this and not having enough cash at the moment to get more sophisticated gear with the proper markings, I chose to improvise again.

A total of 7 evenly spaced marking from the minimum focus distance (MFD) to infinity.

Plotting out focusing distances for the prime lens was easy enough, but doing the same for the zoom lens raises the issue of it being NOT parfocal. For example, the MFD at 18mm is approx. 41cm, but the MFD at 135mm is approx. 21cm. The MFD changes even if the position of the focus ring is exactly the same in both cases.

It's also interesting to note that the focusing distances of the 2 lenses scaled very differently. The focusing distances on the 18-135mm zoom lens are somewhat "evenly" distributed. At the 5th notch, the camera was already 586cm away from the subject.

In contrast to this, the focus distances of the 50mm prime lens jumps very sharply as the focusing ring approaches the position for infinity. At the 6th notch, the camera was just 329cm away from the subject. Basically, anything between 329cm and infinty would require very steady hands since the difference between the 6th and 7th notch on the focus ring is an 11-degree twist.

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