When I shoot in raw instead of jpeg, I can bring out the darks and suppress the lights very easily for pretty much every picture I shoot when I edit in Lightroom. Since HDR is meant to capture detail from extreme darks or lights, when would it be better or more appropriate to take an HDR since shooting in raw seems to do the job just fine?
Mind you, RAW is already a HDR data format. The HDR function in your camera (or software) just allows you to expand the dynamic range beyond the capabilities of the sensor - similar to shooting the same scene twice with different focus, or stitching photos together to provide a panoramatic view with FOV and resolution much higher than the camera is actually capable of.– LuaanNov 4, 2016 at 8:49
2Are you talking about exposure bracketing? I think your terminology is not right. HDR and RAW are not mutually exclusive– Lightness Races in OrbitNov 4, 2016 at 10:13
This is actually an engineering problem. A practical camera snesor has a fixed dynamic range. The dynamic range with a roof over which everything as dead white, and with a floor below which everything is indistinguishable from noise. Camera technology is advancing all the time, and the dynamic range of your camera could exceed your requirement, then you probably won't need a multi-shot HDR. However, ideally, with enough shots, your can get arbitrary SNR and dynamic range out of arbitrary camera sensor, like one in a 10 year old webcam.( but lens matters too)– user3528438Nov 4, 2016 at 12:04
@user3528438 I disagree. The fact that HDRs through exposure bracketing are needed proves that camera dynamic range doesn't exceed our requirement– Janardan SMar 16, 2017 at 3:12
@JanardanS "your"– user3528438Mar 16, 2017 at 11:11
It is appropriate in situations where you can't capture the dynamic range in one shot and in situations where lifting the shadows would reveal too much noise. Certain landscape shots and night time cityscapes are an example where HDR makes sense.
I think it also depends on your style. I personally do not look for maximum detail being captured in images shot against the sun - it does not look natural to me.
The short answer is: When the dynamic range of the scene exceeds the dynamic range you can capture in one shot with raw.
A somewhat longer answer is that is that there are complicating factors, for example, recovered shadows may show more noise than a separate image taken at longer exposure, so the quality of the shadows will be better with multiple shots and an HDR merge than a single shot stretched as you describe. This becomes more noticeable the more aggressively you need to recover, and also varies with sensor.
It is also possible, with multiple exposures, to adjust white balance separately, so (for example) you might warm shadows that in a single shot may be more blue. There are other post processing techniques that can achieve this as well, but you may find it easier to do well with multiple shots later merged. An example might be an interior shot in shadow with windows showing areas in sunlight.
Finally a practical answer: You may not realize by eye if you have adequate raw DR for a given scene, and only find out in post processing when it is too late. It never hurts to get several bracketed shots, then if the middle provides an adequate one-shot result, discard the rest; but if not you are prepared, not only if you guessed wrong, but if you find (for example) too much noise in the shadows, or bad colors in highlight recovery.