Exposure for RAW


Today’s Question: With today’s advanced software for processing RAW captures, how important is it really to achieve perfect exposure in the camera?

Tim’s Quick Answer: While software for processing RAW captures is certainly very advanced and capable of compensating for a less-than-ideal exposure, there can still be significant benefits to an optimal exposure in terms of maximizing detail and minimizing noise.

More Detail: Exposure latitude in post-processing is often presented as one of the key reasons to capture in the RAW capture mode rather than JPEG capture. While there is certainly the potential to recover highlight or shadow detail (or both) that could have been lost with a JPEG capture, image quality will likely suffer if you need to apply a strong exposure correction in RAW processing.

Put simply, there is no replacement for recording the light present in the scene with an optimal exposure. You can certainly apply significant adjustments in post-processing, including refining the overall exposure when processing the original RAW capture. But the result in terms of quality won’t be as good as you would have achieved with a proper exposure.

In the context of a digital capture, I would say that an optimal exposure is different from what a photographer would normally think of as a “proper” exposure. That’s because there is an advantage in terms of maximizing detail and minimizing noise by exposing the scene as brightly as possible without blowing out highlight detail.

As a general rule, I highly recommend using the “expose to the right” approach to exposure, capturing an image that is as bright as possible without sacrificing highlight detail. Alternatively, an exposure that is as close to the intended final result will also produce very good results.

There is certainly a good amount of latitude in terms of exposure adjustment when processing the RAW capture. But I highly recommend treating this as a last resort for situations where you inadvertently created a less-than-ideal exposure. In other words, the better the initial exposure in the camera, the better quality you can expect in the final image, regardless of the potential “magic” of today’s advanced image processing software.