It is fair to assume that most photographers use ESP or matrix metering. These average the exposure and works well for most images, but those having a high dynamic range need more control. Prime examples are landscapes into the light, especially over water and interiors that include a window. Images could end up having dark, underexposed areas or bright burnt out highlights and in the same photograph. One way is to spot meter and save the raw, another is HDR, but I will deal with the former as it offers greater control and creative input. Smartmetering is more accurate with an electronic finder. It is easy to get wrong without some kind of visual aid. Furthermore, when editing in Lightroom or Photoshop, saving the raw has greater flexibility in post-production than JPEGs. Using an optical finder is not recommended as it does not preview any changes to exposure, instead use the camera's screen live view. I spot meter everything with an electronic finder because exposure can be charged more accurately as the preview has been processed in the camera's computer. A classic shot is against light across water. Spotmetering off the distant clouds allows those areas of image not picking up light to end up underexposed. This can be corrected in Lightroom as follows. Change profile to Adobe landscape. Increase clarity and vibrance. Increase shadows and black. Decrease highlights and whites. Change white balance to daylight. If I had met at the foreground, the clouds would become overexposed and difficult to correct furthermore. If six months later I changed my mind, I can start all over again. I have not locked myself into something that I cannot get out of, which some camera controls or accessories can do if you're not careful. With Olympus OMD and pen cameras, exposure can be locked by half depressing shutter button. But first, make sure that focusing is on S-hiphon AF in the menu. Use manual focusing if focus point is radically different to metering. Select optimum metering point with electronic finder. It takes a bit of practice. Half-depress shutter button and hold. Recompose image if required and take shot by fully depressing shutter button. I use this technique the whole time regardless of subject because I am in a greater creative control of exposure and not relying on instant answers. An extreme case of this technique is against the light into the sun. Sensor burnout should not be a problem when hand holding, but placing the camera on the tripod is not recommended as it increases the risk of sensor damage. Also, as the camera's computer has processed the preview, possible harm to eyesight is limited, but if unsure, use the camera instead. Here are some further before and after shots exploring spot metering and correcting afterwards in Lightroom. This shutter shot may look straightforward, but the expansive white building on the left can fool the metering on matrix metering. So I underexpose slightly by metering on it and then correct in post production. The church at much when lock is more problematic. There is an enormous difference in light intensity between the windows and interior. Now this is an unaltered jpeg copy of the original raw image straight out of camera and it is quite dark. Now this is what would happen to the windows if I had exposed instead for the interior. It renders them overexposed and therefore difficult to correct. Of course, I have corrected the dark image in Lightroom in post production. Finally, a silhouette shot of late afternoon sun on my local common. First spot metering. And now matrix and what do we end up with? Blown out highlights. Impossible to correct. This is what exposing to the right does. Exposing to the left in this situation can cause noise, but I regard that as the lesser of the two evils and easier to correct. Blown out highlights cannot be corrected except by cloning something over them. If you are interested in trying HDR and why not, see my separate YouTube Olympus photo experience by clicking the tab at the top.