Author Topic: Auto ETTR jumps from 1sec to max ISO and max shutter speed (Read 7062 times)

hugoz3335 · « **on:** November 10, 2015, 08:28:34 PM »

Hello, I tried to make a timelapse with the Canon 5d Mark II. Everything goes well until the values need to go beyond 1sec at 100 ISO. It jumps then directly to the max shutter speed setting (i.e. 30 sec) and 1600 ISO and as a result an overexposed image. I can change SNR Midtone / Shadow limits, the problem persists (even at 0). Same for highlight clipping, except 0% (which gives me a dark image). Also I can turn off the intervalometer but the problem still persists. Auto ETTR is on "always on" (also tried with auto snap) and Live View. The problem happens after sunset with some lights from buildings in the scene. ML version magiclantern-Nightly.2015Nov07.5D2212

a1ex · « **Reply #1 on:** November 10, 2015, 08:32:41 PM »

When the scene gets dark and requires long exposures, it can no longer be metered from a 1/30-second LiveView frame. This problem tends to gets worse on older cameras.

Solution: just close LiveView, so ETTR will meter from the actual images, not from LiveView.

hugoz3335 · « **Reply #2 on:** November 10, 2015, 09:11:25 PM »

Hi A1ex,
thanks for your quick answer. I tried without Live View, but the problem persists. I start with a setting (i.e. 2sec at ISO 400) and after one picture it jumps to the max shutter at 1600 ISO. This time with all values for SNR Midtone / Shadow limits and Highlight clipping all at 0.

a1ex · « **Reply #3 on:** November 10, 2015, 09:14:44 PM »

Can you upload some screenshots showing the raw histogram on the test images?

You can take the pictures manually, to get the screenshots easier. The intervalometer should have no effect on exposure decision.

hugoz3335 · « **Reply #4 on:** November 10, 2015, 09:28:22 PM »

Sorry I don't know how to upload the screenshots here… Insert image only gives me that

.

Here is the link to Dropbox with the two screenshots on Lightroom:

https://www.dropbox.com/sh/984953vf49bdxn7/AAB5Kv1IknBpYgT-T-82dr_sa?dl=0

a1ex · « **Reply #5 on:** November 10, 2015, 09:37:33 PM »

I'm interested in the screenshots from the camera (the image review screen, right after you take a picture). ETTR uses the raw histogram from ML to compute the exposure, not the one from Lightroom.

Also, in your link, the first image is brighter. This does not match your description.

hugoz3335 · « **Reply #6 on:** November 10, 2015, 10:36:54 PM »

I managed to take some screenshots finally (no clue how the Screenshot function in ML works, but I guess on the 5d markII its only after 10 seconds)

You find the new pictures under the same link. It doesn't display the first image taken at ISO 800 and 6sec. Hope you see something in those screenshots.

I forgot to mention regarding the former pics. The brighter was the second one (see image number)

nikfreak · « **Reply #7 on:** November 10, 2015, 10:47:59 PM »

Canon menu: image review -> hold
ML: enable raw histogram

10 secs is default. Tricky part is activating screenshot, taking the pic and getting the desired screenshot

a1ex · « **Reply #8 on:** November 10, 2015, 10:50:42 PM »

The zebras and the histogram are clearly not correct - ML thinks your image is severely underexposed.

Does it help if you switch to a full-screen image review, or if you clear Canon and ML settings?

If that helps, can you try to find the setting(s) that cause the issue?

hugoz3335 · « **Reply #9 on:** November 10, 2015, 10:55:55 PM »

I just reinstalled ML with the latest built today and it reproduces the same result. The error starts if the exposure is longer than 1 sec. For ex. 1sec at ISO 100, next exposure is maximum at ISO 1600
I'll try with full-screen image review. Which Canon settings should I clear ?

a1ex · « **Reply #10 on:** November 10, 2015, 10:58:19 PM »

First you need to get proper raw zebras and raw histogram. I can't try it myself right now - other 5D2 owners can confirm the issue?

hugoz3335 · « **Reply #11 on:** November 10, 2015, 11:19:19 PM »

Same result with Full screen review (I put the images on Dropbox). I still don't know which Canon settings I should clear ?

mothaibaphoto · « **Reply #12 on:** November 11, 2015, 08:54:59 PM »

Confirm for markII&markIII:
If ETTR eventually produce extremely overexposed image, it stuck with it till camera restart. This happens occasionally when I shoot timelapses with FRSP, and DualISO.
I reported this (or similar) issue:
http://www.magiclantern.fm/forum/index.php?topic=12523.msg136363#msg136363

hugoz3335 · « **Reply #13 on:** November 15, 2015, 12:09:02 PM »

Did you have this problem only with DualISO and Full Resolution Silent Pics ? I encounter this problem also with normal Shutter actuation without Dual ISO.

mothaibaphoto · « **Reply #14 on:** November 15, 2015, 12:23:45 PM »

Yes, with DualISO and Full Resolution Silent Pics, but, probably due to this is the only combination i tend to use Auto ETTR.

hugoz3335 · « **Reply #15 on:** November 18, 2015, 10:59:26 AM »

This means no holy grail Timelapses with Auto ETTR are possible with magic Lantern for Canon 5D Mark II/III

Any user that has no problem doing so, pless tell.

mothaibaphoto · « **Reply #16 on:** November 18, 2015, 11:19:42 AM »

For me this happens really rare.
I can't even reproduce.
Anyway, as I mention before, Auto ETTR can't change aperture and pull/insert ND filters, which is vital due to FRSP exposure restrictions.
I'm more concerned about the DualISO WB issues.

hugoz3335 · « **Reply #17 on:** November 18, 2015, 02:27:01 PM »

So its different from camera to camera ? Maybe a camera reset would help ? But I would loose all my settings… I am trying now with dslrdashboard and lrtimelapse, unfortunately without all the ML possibilities (Dual ISO etc.)

mothaibaphoto · « **Reply #18 on:** November 18, 2015, 04:41:51 PM »

I had the same (or very similar) issue on different cameras - 5D MKII&5D MKIII, so it's something in common.
Why use external application? You can just disable AutoETTR and control exposure manually looking at the histogram.

hugoz3335 · « **Reply #19 on:** November 24, 2015, 10:47:24 PM »

Sure you can do it manually. But unless your tripod is not super stable, you always risk to move the camera a bit…
Also my goal is to make a Timelase with one camera and take some single shots with another camera in the meantime. And for this AutoETTR would be perfect. You dont have to worry to much about the Timelapse, and can wander around for some other nice shots while your there

a1ex · « **Reply #20 on:** November 24, 2015, 11:10:48 PM »

@hugoz3335: were you able to get correct raw zebras and raw histogram on your 5D2?

I've asked another 5D2 user to check the overlays, and they work fine on his camera:
https://bitbucket.org/hudson/magic-lantern/issues/2402/exposure-correction-value-in-xmp-has-wrong#comment-23321467

hugoz3335 · « **Reply #21 on:** December 09, 2015, 09:27:34 PM »

Hi A1ex,
sorry its a long time I haven't been on the forum. Since our tests I haven't retested it. Should I test it again ? I think I would need to do a reset of the camera to have chance that it changed, right ?

hugoz3335 · « **Reply #22 on:** December 09, 2015, 10:41:33 PM »

Hi A1ex, I think I just found the problem ! It seems that the cameras noise reduction interfers with AETTR. The 5D Mark II noise reduction starts at 1sec. Exactly the exposure where the zebras went wrong. I turnt off noise reduction and the camera is just exposing perfectly fine ! I will test it more intensely to confirm.
Now it seems logic to me: When noise reduction is on, the camera takes a second picture (dark) to reduce the noise. This second dark picture is immediately taken into account of ML's AETTR. And since its dark, AETTR switches to maximum exposure. If I had known about the operating of noise reduction I would never have had it activated !!

DeafEyeJedi · « **Reply #23 on:** December 10, 2015, 05:59:16 AM »

Good catch, @hugoz3335!

mothaibaphoto · « **Reply #24 on:** December 10, 2015, 09:52:06 AM »

Just checked both MKII and MKIII I have similar issue with:
Long exp. noise reduction - OFF
High ISO speed noise reduct'n - Disable

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Author Topic: Auto ETTR jumps from 1sec to max ISO and max shutter speed (Read 7062 times)