Lens sharpness
optimization

Martijn Kort

Sal, Cape Verde

DJI Mavic Pro

24mm f/2.2

ISO 100 - 1/465 - f/2.8 - 5mm

DxO PhotoLab

Meticulous measurements
mean better images.

Even images produced by the most expensive lenses can benefit from sharpening, but only DxO software guarantees the best possible results. Find out why.

Manufacturers do their best to make lenses as sharp as possible, but even the most well-engineered optics are subject to the laws of physics. One of the hardest problems is achieving homogeneous sharpness across the frame.

What is lens softness?

AG Photographe

Sainte-Chapelle, Paris, France

Nikon D850

16mm f/2.8

ISO 64 - 1/40 - f/14 - 16mm

DxO PureRAW - PhotoLab

The vast majority of lenses produce images that are sharper in the center than the edges. This is particularly obvious at a lens’s maximum apertures, while zoom lenses often show more of a deterioration in sharpness than primes because of their inherent complexity.

The softer corners often even out by using apertures at a lens’s “sweet spot” — often around f/5.6 on a full-frame lens. Smaller apertures offer improvements but diffraction becomes an issue at the smallest apertures, and this diffraction will affect sharpness across the entire frame.

Sharpening images:
A brief history

In any good photo editing software, you can apply sharpening. Effectively, you amplify textures and edges to give the appearance that the lens has greater resolving power.

If you start with an image that is crisper in the center than at the edges, then applying sharpening uniformly across the frame will not produce the best results. And even if the softness is homogeneous, the amount of sharpening will still vary between different apertures. Sharpening a single image is manageable, but being consistent across a number of different images is challenging, and the task can soon become tedious.

Martijn Kort

Sal, Cape Verde

DJI Mavic Pro

24mm f/2.2

ISO 100 - 1/465 - f/2.8 - 5mm

DxO PhotoLab

In 2003, DxO realized that by analyzing a lens, it could then use that data profile to apply sharpening in software automatically, saving the photographer a job, and making the process far more precise. DxO Modules were invented, and we’ve now produced more than 100,000 of them.

Since then, our approach has been copied. However, generic lens profiles fail to consider that the softness of a lens can vary across different parts of the frame. As a result, images are simply not as sharp as they could be, especially in the corners.

Stefan Forster

Iceland

DJI Mavic 2 Pro

24mm f/2.8

ISO 100 - 1/100 - f/4.5 - 10mm

DxO PureRAW - Adobe Lightroom

DxO’s approach delivers
the best results

In short, DxO’s comprehensive analysis produces more complex profiles that ensure that you get the best possible results from your equipment.

To discover why, it’s useful to understand the Modulation Transfer Function (MTF) charts that manufacturers publish with each lens.

The chart below indicates the optical performance of a lens, showing the levels of resolution and contrast that it can achieve from the center to the edge of the frame. Most charts show the lens at its maximum aperture and present results in comparison to a theoretically perfect performance where all spatial frequencies are captured with their original intensity.

While MTF charts typically show lens performance for two specific frequencies (e.g., 10 and 30 line pairs per millimeter), in our lab we measure the performance for all frequencies. We then aggregate these measurements by considering how each contributes to the human eye’s perception of softness — a measurement we call a Blur eXperience Unit (BxU).

A complete lens calibration consists of measuring BxU across the entire field, for each focal length setting, and for each aperture setting.

Based on the specific BxU data, in conjunction with an image’s EXIF data, our software can therefore select the right amount of sharpening to apply, to each individual pixel in each individual image. Thanks to DxO Modules, the result is an evenly crisp photo, from center to edge. 

AG Photographe

Paris, Palais Garnier and Eiffel Tower

Nikon D810

70 - 200mm f/2.8

ISO 200 - 1/2 - f/13 - 135mm

DxO PureRAW - PhotoLab

Increase sharpness
without increasing noise

Sharpening a high-ISO image can mean amplifying noise — unless you use DxO software. Because our lens sharpness optimization was designed conjointly with our other raw conversion algorithms

— specifically with our world-class DeepPRIME noise reduction technology — lens softness can be compensated without compromising other aspects of image quality. Noise is not amplified and bokeh remains smooth.

We continue to add more DxO Modules, supporting the very latest cameras and lenses. Why not download a free trial of DxO PhotoLab or DxO PureRAW and find out for yourself how much difference it can make to your images?

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