Noise and ETTR

Started Feb 6, 2014 | Questions thread
Shop cameras & lenses ▾
Anders W
Forum ProPosts: 21,391Gear list
Re: Noise and ETTR
In reply to cmpatti, Feb 7, 2014

cmpatti wrote:

Here's an opinion from another real professional that disagrees with you.

When I evaluate people's claims, I try to do it, as far as possible, based on how they can back it up rather on who they are. Ctein makes three elementary mistakes here.

First, he argues that the ETTR criterion is generally difficult to apply. How difficult it is depends on what tools you have available. With the "live-view blinkies" (highlight/shadow warnings) available on the particular camera we are talking about in this thread (and other Oly MFT bodies), it's usually very easy to get it right.

Second, to illustrate his claim that ETTR is a bad criterion, he uses a sample image that is exposed beyond the right rather than some distance away from the right (as he argues is the right choice).

Third, what he illustrates is that shadow pushing can be useful (who has claimed that it isn't) rather than that ETTR is a poor criterion.

In short, all this article demonstrates is that Ctein doesn't know how to ETTR correctly, and therefore finds it dangerous. It's not the first time I see him show that he doesn't know what he is talking about.

Based on my prints and output, ETTR is simply way overrated.

Well, in fairness to Ctein, who was writing in 2011, his point--particularly clear if you read his response to comments--was that as a recommended standard practice ETTR was a bad idea because (1) most people wouldn't be able to do it correctly and would end up blowing highlights, and (2) blown highlights are a bigger, less remediable problem than shadow noise. He states, for example:

Well, first good tools for successfully ETTRing and doing it quickly was available already when Ctein wrote this (live-view histogram, live highlight warnings). Second, it was certainly possible to do it right even without these tools, just a bit more time-consuming.

I bought my first digital camera (Pentax K100D) in 2007 and started ETTRing right away. The technique I used back then (and still use as a back-up strategy now) was to spot meter on the highlights and then dial in a certain amount of positive exposure compensation based on that reading. How much depends on how the meter is calibrated relative to the clipping point of the sensor. I don't remember exactly what figure I used to apply with the Pentax, but it was somewhere between 2 and 3. On the E-M5, it is 3.3 EV (at the normal ISOs, not ISO LOW). This works well if the highlights are large enough to be properly isolated by the spot of the spot meter. If they are scattered and can't be properly isolated by the meter, you have to reduce the EC you dial in, and a certain amount of trial and error may be required to get it right. In the end, you have the ex-post histogram and ex-post highlight warnings to check whether you nailed it or not.

No one, including me, ever said the THEORY of ETTR was wrong. The practice, with current equipment, is what fails (see comment above to Pieter A useful rule of thumb is about practice, not theory.

He specifically allowed for the possibility that improvements in equipment might change that situation:

Well, no, the in-camera and in-computer tools for avoiding blown highlights actually are inadequate to the problem. Currently. Quite possibly, even probably, in another eight years my advice will be as bad as ETTR (which dates from 2003) is now. But right now, highlight problems are hard to avoid if you follow ETTR.

There have certainly been such improvements over time, but the better tools we now have access to were available already when Ctein wrote his article. And it was certainly possible to successfully ETTR without those tools too. It was just a little more time-consuming.

 Anders W's gear list:Anders W's gear list
Panasonic Lumix DMC-G1 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Panasonic Lumix G Vario 7-14mm F4 ASPH +28 more
Reply   Reply with quote   Complain
Post (hide subjects)Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow