7d highlight tone priority - yes or no?

[Chris Sloan]

I just bought a 7D and am about to field test in Peru starting later this week. I have found conflicting recommendations on whether or not to enable highlight tone priority. BAA's user guide recommends enabling it. Many nature photographers and posts I found online recommend against enabling it. The argument against it seems to be that it increases noise in the shadows and that you can accomplish the same result with exposure comp and with applying curves in post.

If it makes a difference (and I gather that it might), I will be using LR 3.0 for RAW processing (DPP is too time consuming for me).

Thoughts?

[Aravind Krishnaswamy]

If you use LR3 for your RAW processing, do NOT enable HTP. Here's what you camera is doing when you enable HTP:

1. It underexposes the image by a stop. Since your aperture and shutter speed remain the same, the camera underexposes by capturing the image at an ISO one stop less than indicated (this is why you can't select ISO 100 when HTP is turned on).

2. In the RAW file's metadata the fact that HTP was turned on is recorded.

3. If you are shooting JPEG and for the embedded JPEG (and when DPP processes the RAW file), the processor applies a different tone curve, one which boosts the shadows while retaining the highlights. This is why you typically see increased shadow noise when you turn on HTP.

When ACR/LR see that a RAW file was captured with HTP turned on, all it does is adjust the exposure up by one stop (again under the hood, not reflected in the UI).

Particularly if you are using ACR/LR, you are much much better off just underexposing your image by how many ever stops you find is necessary to avoid losing highlight detail and then compensating for it by manually tweaking the tone curve.

HTP is predominantly useful for JPEG shooters, though RAW shooters that use DPP, it could be useful if you are going through a lot of volume and don't have time to tweak the tone curve yourself.

[Jeff Cashdollar]

Nice response Aravind, I need to go back and read Artie's guide and contrast the two - nice thread so far.

It will be interesting to see what others say as well.

[Chris Sloan]

Thanks, Aravind. I had reached that same conclusion after researching it, but it's good to hear it from someone who knows more about it than I do. Might be something for Artie to include in an update to the user guide.

[Alfred Forns]

Solid advice from Aravind !! Would keep it off Chris !! Have tried both ways.

[Doug Brown]

Another vote for disabling HTP for all of the reasons outlined above.

[arash_hazeghi]

HTP and ALO OFF in any Canon camera.

[Kaustubh Deshpande]

Tried it with my 40D and found extra noise....turned it off and it has stayed that way since then. While shooting, chimp once in a while to see if there aren't any highlight blinkies(or a few blinkies. I prefer those actually)...you are good to go if shooting RAW. haven't really needed HTP.

[Jonathan Ashton]

What is ALO please?

[Ed Cordes]

ALO = Auto Lighting Optimiser. I also turn ALO and HTP off and do all my image processing of the RAW images in LR and PS

[Robert Amoruso]

If you are shooting RAW, know how to read your histogram and are exposing right, these two settings are a hindrance and not a help for the reasons mentioned.

[Sabyasachi Patra]

I agree with Aravind. Turn off the highlight tone priority and Auto lighting optimiser and you will be better off.

Cheers,
Sabyasachi