RetouchPRO LIVE "ETTR, HDR and Exposure Blending"

[Doug Nelson]

On our next all-new RetouchPRO LIVE, color guru Andrew Rodney provides another opportunity to stretch our digital brains. There will be downloadable notes.

From Andrew:
"In this Webinar, we'll first look at capturing images for the best possible quality and low noise by examining Expose to the Right. From there we'll dive into extending dynamic range of captures using both true HDR and exposure blending in products like Photoshop and Lightroom using a number of 3rd party solutions. The goal is to produce extended dynamic range without creating an image that looks like the color vision of dogs or donkeys (meaning a normal, appealing image that just happens to have an extended tone range). This will not be easy or quick as you'll see a number of 3rd party products demonstrated in real time, all that claim they can produce attractive extended tonal mapping. In this webinar, we'll concentrate on bracketing techniques, exposure and image processing, so get your Ansel Adams attitude on."

I expect we'll have more audience questions than usual during this particular show (Andrew's shows always generate a lot of good questions, and this one is even more thinky than usual).

Saturday, September 10, 4pm CDT (see link below for other time zones)

Click the following link for details and ticket sales:

http://www.retouchpro.com/index.php?page=rodney

[Doug Nelson]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

The ticket sales link will close in a few minutes.

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[Doug Nelson]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

Here is the link for Andrew's notes for this show.

[radiantp]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

Thanks for the informative webinar Andrew.
I asked about testing for DSLR native ISO and didn't see anything in the notes or on your site. Did you have a resource for that testing process?
Thanks,
Ryan in Vegas

[andrewrodney]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

http://www.digitalphotopro.com/technique/camera-technique/exposing-for-raw.html

[khsdt]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

I had to deactivate UAC "User Account Control" on my Vista PC to get the GoToWebinar SW installed.

Greetings, khsdt

[Babble]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

I use Bibble 5 for RAW processing. It allows me to make several layers that are area specific. These are either drawn or a brush is used to select areas of interest. I can then apply most of the settings (Exposure, Highlight recovery, color, etc) to the selected area. I believe this accomplishes the same thing (only with more control) that blending two exposure settings from one RAW original in a HDR program. I don't know if Lightroom allows the same thing but it is very useful.

[Doug Nelson]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

This show is now available for rental.

[bakerfoto]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

I have a question for Andrew about the presentation. Are you advocating using a high ISO (800) and ETTR (under the acceptable circumstances) to achieve the best quality image? Also, I read your article about figuring out your cameras native ETTR ISO and can't say that I'm real clear on how to figure that out. Could you also explain this "For high-ISO shooting, it's clear from the test examples that noise is greatly reduced; however, shooting in this mode effectively provides a much lower initial ISO setting, so this technique might not be that useful." Why does it provide a much lower initial ISO setting? Thanks. - Lane

[andrewrodney]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

Are you advocating using a high ISO (800) and ETTR (under the acceptable circumstances) to achieve the best quality image?

I’m pointing out that with some camera systems (in this case a Canon), a lower non ETTR ISO capture can produce more noise than a higher ISO with ETTR capture. The ISO in this case by itself does not produce more noise (the conventional wisdom).

IF you need high ISO and can’t implement ETTR (which would be like using a lower ISO) you’ll get noise but you probably need the higher shutter or don’t have enough light for a capture. IOW, high(er) ISO without ETTR equals more noise. Say you are shooting with a 35mm 1.4 in a dim restaurant. You are wide open but at a 1/5th of a second and everyone at the table is blurring. You need to raise the ISO (to a point), you’ll get a noisy image but you’ll get a sharp image which is the lesser of two evils.

So you still need to think like a photographer in terms of what your meter is telling you, how to set the ISO in terms of controlling aperture and shutter. If you have lots of light, ETTR is a slam dunk.

[Babble]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

Lane, I'll throw in an answer to one of your questions (assuming I understand Andrew correctly). The Native ISO of your camera is how much over exposure it can handle while not loosing detail in the highlights. Since half of the pixel data is used for highlight info you will give up some of this while shifting more data to the mid and shadow tones. You might take a picture of a bright scene using several steps of 1/3 stop over exposure then examine the pictures on your computer (0.3, 0.7, 1.0, 1.3). Use that to determine how much you can go with ETTR and still retain detail.
Ron

[andrewrodney]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

There are two possible sources of noise added to the signal for processing, lets call them NoisePre and NoisePost. The degree of each is going to depend on the camera system. The path looks something like this:

Sensor> NoisePre> ISO Settings> NoisePost> Analog to Digital converter>

As you see above, NoisePre is added before ISO amplification, while NoisePost is added after ISO amplification. ISO amplification, altering its value alone, doesn't alter the Signal to Noise Ratio. Remember that ETTR produces less noise due to a better Signal to Noise Ratio. The ISO amplification does't improve output Signal to Noise Ratio with respect to NoisePre. However depending on the camera system, with NoisePost this can be quite different. In this case, the higher ISO produces a higher signal versus what we had previously with NoisePost so there is an improvement in Signal to Noise Ratio (so we see less noise of course).

On a camera where a significant portion of the total noise is added after the ISO amplification (my Canon), the higher the ISO the larger the ouput Signal to Noise Ratio is for a given a amount of photons reaching the sensor and the result is less noise.

[bakerfoto]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

Andrew, Thanks for the feedback. In your notes there is a link to your article and this part has me confused. I understand that these results will vary depending on equipment. What was the actual sensor ISO that you extrapolated? Thanks. - Lane

"For the ISO 800 image, I was able to use the normalize exposure preset used for ISO 400 to produce a close match to the base exposure. With this information, I was able to extrapolate the actual-sensor ISO for exposing images to place as much data in the first stop of highlight data without blowing out the highlights."

[andrewrodney]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

The image in my notes was from a Canon 5DMII. In the article I think it was a 5D.

[andrewrodney]

Re: RetouchPRO LIVE "ETTR, HDR and Exposure Blendi

Just a follow up on the request during the Webinar to check out the HDR product from Nik Software. I did download a demo and I’m quite impressed. If you are a fan of their Upoint technology, this can be used within HDR EFEX PRO. The GUI is nice, there’s lots of control and presets. At $159, it appears so far to be worth the extra cost over the deal I got for HDR Express ($85 with coupon). At the very least, download a demo and give it a shot.