A Quick Lens Test Determines Its Sharpest F/Stop (VIDEO)

This eye-opening tutorial from photographer Fil Nenna begins with a statement that you likely haven’t heard in the past: “You won’t get the sharpest photographs without this quick lens test.” And just like that he grabbed our attention.

Nenna posts weekly tutorials with quirky insights and unfamiliar techniques that can make a big difference in the quality of whatever types of images you shoot most. His point today is that the aperture you choose is more than a depth-of-field decision because it also plays a role in how sharp your photos appear.

The big reveal in this five-minute episode is that each lens you own has one aperture that’s sharper than the others, and this “optimum” f/stop varies from one lens to another. Hence, the importance of understanding the sharpness characteristics of every lens in your bag.

So how to you make this critical determination? Just follow Nenna’s simple instructions for testing your most-used lenses (you only have to do this once), and you’ll gain invaluable insight that will improve your photographs forever.

There’s no fancy testing equipment required, and all you’ll need is a tripod to make a reliable evaluation. Depending upon the scene you’re shooting in the field it’s not always possible to shoot at the sharpest aperture, but at least you’ll know what to expect if your’e forced to open up or stop down.

Nenna explains the step-by-step details of this important experiment, but here’s a quick summary. First mount your camera on a tripod with the lens point down on a table with your target, making sure that everything is absolutely flat and aligned. A simple bubble level makes this easy to do.

The target you use can be as simple as a few fine lines on a piece of paper, and then it’s easy to ascertain the sharpness of these lines at various aperture settings. Keep in mind that while you’ll find one optimum aperture you may discover others that are acceptably sharp in a pinch.

There’s a bit more to this test than the foregoing, and Nenna describes everything you need to know for getting the job done with absolute precision, so give it a try and you may never be disappointed by soft photos again.

There’s plenty more to learn on Nenna’s interesting YouTube channel so be sure to take a look. And on a relate note, we suggest watching a tutorial we featured earlier with another accomplished pro who demonstrates five common reasons for unsharp photographs with solutions when shooting with DSLRs and mirrorless cameras.