(Auto) ETTR (Exposure to the Right): -- History & Beginners Guide

Started by RenatoPhoto, May 25, 2013, 07:24:06 PM

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gmr20

Hi, I use EOSM. I have a suggestion for AETTR in ML.

Like Bulb Ramping, can you add a Sunset/Sunrise option to let the exposure only decrease/increase?
I got some terrible flickers during changes occasionally. Say 4" to 5", it's like "...4,4,4,4,5,4,5,4,5,4,5,5,5,5..."

gmr20

I have a problem during a sunset sequence in the city. It's hard to get both day (sunset) and night exposures correct.

In the beginning, both Highlight Ignore and SNR limit affect the brightness of a picture.
However, when night comes, it seems only SNR limit affect the brightness.
It matches the wiki: SNR has higher priority, but there comes a problem.

(I found that Shadow SNR didn't affect exposure as much as Midtone SNR. So I only discuss Midtone SNR below.)
With 5EV, it's ok at daytime (sunset), but too bright at night, inducing too much clips of city lights.
If I use 4EV instead, the clips are ok, but it's way too dark at daytime, even darker than a normal 0EV exposure.

City lights always have clips at night. If clips are too much, it's doomed. I can't control it now because of the priority.
I guess this can be solved if I can set Highlight Ignore with higher priority than SNR.

Is this conclusion correct? Or am I wrong on some points/settings which lead to the failure?
If the conclusion is correct, can you add a priority option on this? Thanks!

garry23

@gmr20

I believe the issue you are experiencing is one I found, which resulted in me 'restricting' ETTR by NOT using the SNR options.

I must emphasis that this in my workflow: it is nether right or wrong :-)

By using the SNR settings you are giving control to ML, ie SNR will force greater clipping etc.

IMHO the power of ETTR is to expose to the right WITHOUT clipping. If you use the SNR settings, you are not really using ETTR but a superior form of 'balanced' exposure control.

I am an ETTR purest, and hence I keep the two SNR settings at 0, and only use  the clipping % and, if required, Dual-ISO.

Finally, as usual, the above is my experience and workflow. Others may disagree :-)

Audionut

If you enable link to dual ISO, you should get the best of both worlds under most exposure conditions, not blown highlights, and less noisy midtones/shadows.

A nighttime scene with city lights is going to have an extreme dynamic range.  You can see this when you try and use SNR settings.  To get the same SNR in the midtones (as a daylight scene) means overexposing the lights.  If you use dual ISO linking, you may be able to use the same SNR settings for day and night, without blowing the lights.

starbase64

Hi,

i wanted to test ETTR, but it does not (70D).





regards

starbase64


starbase64


Walter Schulz

Restore ML defaults, activate ETTR module (and no other) and retry in M mode.

starbase64


Walter Schulz

Turn off ETTR, take a pic and link it here. Link contents of ML\Settings, too.


Walter Schulz

Cannot detect anything smelling fishy.
I suggest restoring cam to factory defaults via Canon menu. Don't forget C.Fn settings. If it doesn't work after (I'm afraid it won't) I'm out and must ask nikfreak to solve this riddle.

starbase64


dmilligan

Is it just the "Press SET" trigger mode that doesn't work? Do any of the other trigger modes work? Does press set work if you are already in LV? Do raw zebras/histogram work correctly in LV and QR?

a1ex

This sounds like a bug - can you mention it in the 70D thread?

There are a few code paths that could return this error, so I'm not yet sure what's wrong.

starbase64


blainesuque

What is the best way to use Auto ETTR with a Controller plugged in?

I just bought a Rhino Timelapse slider with motion. http://rhinocameragear.com/collections/time-lapse-sliders

The motion controller for the slider syncs with the camera Via Bulb Mode on the Canon 6D. I want to use Auto Ettr for day to night shots, but i also bought the slider to add motion to my timelapses. Anyone know if there is any possible way of enabling Auto ETTR to work in Bulb Mode?

As of right now The slider doest sync properly in Manual Mode. And i am not sure if they will ever update the firmware for that.

Usually my workflow is to run a timelapse with Auto Ettr and then do a pass of Deflicker in Bridge in post before i export a video.

Do you think if i just shoot a timelapse with no Auto Ettr the deflicker pass in post will be enough to compensate for flicker?


Any help or workaround would be greatly appreciated. THANKS!

rduenweg

I have a quick question. I'm using ettr for sunset into night timelapses. It's worked amazing so far especially with the de flickering bridge script. But I ran into a problem i'm not sure that can be solved without stopping the intervalometer and turning ettr off after the sun sets. After the sun sets, and after twilight it starts to push my iso to 12,500 which I don't want at all. Is there a way to limit it? idealy I would like it to stop at 30 second exposures at iso 800-1200. Is there a way to do this?

a1ex

ETTR uses maximum auto ISO limit from Canon menu (I know, not completely obvious).

jprovidenza

I have been trying to use ETTR and it has been frustrating. Note I'm using a 70D beta-3 22/Dec version of ML.

The Wiki page (http://wiki.magiclantern.fm/ettr) says that you can use either Av or M mode:

"2. Put the camera in manual M mode or Av mode (either one since you must the aperture yourself), and set ISO to any number except in Auto. It wont work in auto! "

After much frustration using Av mode, I came across the following in the forum:
(http://www.magiclantern.fm/forum/index.php?topic=14948.msg144930#msg144930)
"- Put your camera to M and manual ISO."

I tried that (M mode) and tings got much better.

So which is correct?  Should Av mode work?  It seems like it should, but.... no joy when I try to use it.

Thoughts?

Thanks!

John P
Canon 70D.111A

jprovidenza

I'm playing with ETTR right and I'm trying to use the Half Double Click mode.  Sometimes when
I do the double click, ML does the exposure evaluation and is ready for me to take my photo.

Sometimes I do the double click but it does not trigger the exposure evaluation.  If I change to
using the Set button, every time I push it it works.  Half-Double Click?  many times it works, many
times it doesn't.

Any ideas why Half Double Click is finicky?

I'm using the 12/23 70D Beta firmware.

Thanks!

John P
Canon 70D.111A

garry23

John

I also came to that conclusion and that is the reason I use SET.

I find half-shutter too 'finicky' as you say  :)

Cheers

Garry

Silverleapers

Ironically, the ETTR explanation in the ML user guide is critically flawed. lol
650D/KissX6/T4i (japanese version), 100D/SL1 (Canadian version), many canon and some sigma lenses.

Walter Schulz