ISO Settings--highlights vs shadows

[Kayaker72]

Sean just posted some links to Canon "Quick Tips" videos. I watched a couple and, in particular, I found the one on ISO settings interesting.

Basically, for the C100-C500 camera sensors, they are saying the DR range (not just total DR) varies with ISO with respect to 18% gray and, as a result, are advocating that you should shoot at higher ISO in bright light because of better highlight recovery and at lower ISO if you want better shadow recovery.

Anyone know if the same is true with our DSLR sensors?

I've read and shot enough to think that DR is essentially the same from ISO 100-800 on my 5DIII and that the total range of DR decreases after that. But I hadn't every really considered that that total range may vary with respect to the 18% gray over the ISO settings.

[Jayson]

Interesting. I will have to try that. I always shoot for the lowest ISO I can get on any given photo. I'll play around with it in the next couple days and see if there is anything to it. I'm always trying to squeeze more out of the 7D sensor. Thanks for the post both of you!

[HDNitehawk]

I suppose a trip to the lake on the next sunny day to shoot gulls might be in order to check this out.

[Anthony M]

Interesting. I will have to try that. I always shoot for the lowest ISO I can get on any given photo. I'll play around with it in the next couple days and see if there is anything to it. I'm always trying to squeeze more out of the 7D sensor. Thanks for the post both of you!

I too have always set my camera to the lowest possible ISO. I've always known that even much higher ISO in sunny clear conditions doesn't exhibit the same noise I find troublesome in lower light conditions, but I still go to 100. More than once I've forgotten to check from the day before, and shot at something like 800 and been fine with the results if I didn't catch it. If I did catch myself, I've always re-shot assuming I'm not going to like the results.

I'm going to give this a whirl tomorrow as it should be clear and sunny!

Thanks for mentioning this - I've got the videos on my short list but haven't had time to check them out yet.

[Joel Eade]

Is this maybe another way of saying "expose to the right"?

In other words do you risk more noise and loss of tonal range by using a low ISO that could result in underexposing an image than you do by increasing the ISO?

If you push the exposure just to the point of having only a few overexposed pixels in the image it will often appear "washed out" on the camera LCD but it is easy to recover in post and the noise is minimized even up to ISO 6400 on the 1DMKIV and 1DX. Also you will get good details in the shadow areas with this approach. I have not noticed any change in tonal range with different ISO settings but I have not really looked for it either

My standard starting point for bright sunny conditions is ISO 400 f/8.0 1/2000 sec (this is for bird photography)

[Anthony M]

I checked out the video this morning and actually, I'm only seeing half of their example.

While it was clear that shooting at higher ISO was helping to hold the highlights a bit better, their example of lower ISO pulling more detail from shadows (which I would assume is obvious) actually looked better to me at higher ISO. I thought I was losing detail both in the model's hair and the black on her blouse with the lower ISO example. Was it a bad example? My calibrated monitor?

[Busted Knuckles]

Where would this fit w/ETTR w/ highlight priority? I am not the geek on this stuff that I probably should be but....

Can we push to top end that far in post for any DR compression that HP brings?

[HDNitehawk]

CPN's article on the new 5Ds and 5Ds R, you find this,

http://cpn.canon-europe.com/content/...d_eos_5ds_r.do

HIGHLIGHT TONE PRIORITY

Loss of highlight detail is often one of a photographer’s greatest concerns when shooting in brightly lit and high-contrast situations. Canon’s often overlooked Highlight Tone Priority feature can come to the rescue, increasing an image’s dynamic range by approximately one stop and retaining details in the brightest parts of the image. Highlight Tone Priority adjusts how the metering system interprets the scene to ensure that more detail is preserved in highlight areas. Using Highlight Tone Priority limits your lowest ISO setting available to ISO 200.
AUTO LIGHTING OPTIMIZER

Auto Lighting Optimizer (ALO) is featured on every camera in the current EOS line-up. It aims to smooth out high contrast so that detail can be seen in both highlight and shadow areas. ALO uses tone curves adjustments to modify a photo during image processing. Photographers using the EOS 5DS or EOS 5DS R can choose from three levels, plus a ‘Disable’ setting that turns off the effect.
When using the EOS 5DS or EOS 5DS R, ALO gives particularly good results when shooting sunsets, backlit portraits and scenes with highlights that would otherwise look over exposed. ALO can give unexpected results when working in manual shooting mode, so an option to disable the effect automatically when the camera is switched to manual has been included. Auto Lighting Optimizer and Highlight Tone Priority cannot be used in combination with each other.


I thought I read somewhere that Highlight Tone Priority worked by adjusting the ISO settings. Maybe the ALO setting does the opposite?

Side note to this, the 7D II has far less headroom to adjust highlights and shadows in LR than the 5D II and 1D IV. I am hoping this doesn't carry over to the new 5Ds and 5Ds R. With the 1D IV and 5D II I have found LR highlight slider very effective on bringing out detail, shadow slider somewhat less effective