Do you use either ALO or HTP?

Cooloox wrote:

Hi WilbaW, I have to respectfully disagree with you on this one. I read a similar response to yours recently and would like to see an official explanation by Canon as to how this works!

Don't base what you do on what people say, base it what works for you. Yes, you have said you are doing that, but it's not clear from your first post in this thread that you have done a valid comparison.

HTP seems more intelligent than simply underexposing a stop and then applying a curve to bump the shadow and midtone details back up to correct exposure. I have found it recovers highlight details in situations where, if your theory was correct, the rest of the image would be VASTLY underexposed and would require significant shadow recovery. i.e. if I was to expose for the highlights the rest of the image would be ridiculously underexposed, by far more than one stop.

I can't make sense of what you're saying there, but it probably doesn't matter, read on...

With HTP turned on (on a Canon 80D) I can basically correctly expose for the image, generally, and HTP takes care of the highlights. It does a far better job than anything one could do after the event in software.

That's such a huge claim that I have to assume it's made in ignorance of the facts.

The fact that it "gets it right" across a broad range of lighting conditions tells me that it is varying the amount of recovery to what is needed. There is no way it is simply recovering one stop.

Right, there's a curve, not a simple +1.

Turning the feature off suddenly makes my camera's DR seem very noticeably reduced.

Depends on what you are comparing and how you compare it. Let's set up a valid comparison.

Use a tripod, Av, f/8, manual focus, CWA metering, and RAW, on a normal naturally lit scene. Let's say you get 1/100 at f/8 and ISO 100 without HTP. Take that shot. With HTP you will get 1/200 and ISO 200. Take that shot.

If the effect of HTP is not apparent between those two shots, slow your shutter with +ve EC so that it is apparent. Keep the two shots you're happy with.

Now turn off HTP and set the same shutter as the HTP shot and ISO 100 in M. Take that shot. Post those raw files somewhere and we'll see if we can match the tones in the HTP shot from the manual shot.