Topics

1

Tutorials and Creative Uses / AutoETTR doesn't let you change ISO when LiveView is enabled

« on: December 28, 2015, 01:54:30 PM »

Hello:

Yesterday I was trying to make a sunset hyperlapse using AutoETTR and the advanced intervalometer when something really odd happened. First of all, my data:

  -I'm using a Canon EOS 550D.
  -I'm using a ML build from March 15 2014 (yes, I know, it's old, but I've been using it forever and it has always worked great, so I'd like to know what exactly went wrong before upgrading).
  -My AutoETTR parameters were: Exposure target at -1EV, Midtone SNR limit at 4, Shadows SNR limit at 2, Hightlight ignore at 0.1%, Allow clipping is Off.

Before starting with the time-lapse, I tried taking a couple of test pictures to allow AutoETTR to find the right exposure. I turned on LiveView (because I needed to see the framing for the hyperlapse), and the ISO set itself to 3200 (because it was dark). I took a pic, it came out overexposed (because it was dark, but the street lights were on) and AutoETTR said "the next picture will be taken at 1/2 ISO 100"... but the ISO stayed at 3200. I took another picture, and it came out again at ISO 3200... and of course, it was also overexposed.

I tried changing ISO by hand, but the camera didn't let me. Every time I changed the ISO, it set itself again to 3200, and AutoETTR didn't seem able to change it either. After doing several tests, it looked like:

  -If I turned off LiveView, both AutoETTR and me could change ISO without problems.
  -If I turned off exposure simulation, ISO could also be changed... but AutoETTR needs ExpSim on. (I should mention, BTW, that the Canon "ExpSim" warning was flashing all the time).
  -If I turned off AutoETTR, I also could change ISO.

Thinking now about it, I guess the reason I had never noticed this before is because I had always done day-to-night timelapses, so when I started them, there was always enough light for ExpSim to work properly. Yesterday I started the hyperlapse when it was already pretty dark.

My question is: what was forcing ISO to be at 3200? Was it ExpSim or AutoETTR, or were they interfering with each other? And what can I do in similar circumstances, when I do need LiveView on?

2

Forum and Website / How to quote from a message in a previous page?

« on: September 02, 2014, 01:14:23 AM »

Hi all:

Sorry if this is just me being dense, but I've just spent half an hour looking for a way to reply and quote from a message in the previous page (i.e., one so old that doesn't show up in the "Topic summary" in the Reply page). The SMF manual says:

http://wiki.simplemachines.org/smf/Posting/

"There are two ways of replying to a post by quoting it. The first option is to click on the Quote button on the top right-hand side of the relevant post."

But I'm not seeing any "Quote" button here, on any post.

I wouldn't normally post for something so basic, but as I said, I've been looking for half an hour.

(Of course, I could just copy and paste and quote manually, but I want the link to the older post).

3

General Help Q&A / Follow focus using LCD in 550D: how are you supposed to use it?

« on: March 10, 2014, 11:56:12 AM »

Hello:

I own a 550D and am using ML stable 2.3. How are you supposed to use the "follow focus using LCD" feature? Are you supposed to move your hand right-to-left, left-to-right, or just hold it on the left/right side of the LCD?

I am asking because I'm unable to get any consistent results. No matter what I do, the lens moves one or two steps, and then stops. Actually, what happens most often is that I can get it to go in the "+" direction, but then, when I try to move the lens the other way (in the "-" direction), it doesn't do anything.

4

Tutorials and Creative Uses / Timelapses: controlling aperture by hand and avoiding flicker

« on: February 15, 2014, 09:18:17 PM »

Hello:

I am using ML 2.3 (the stable version) on a 550D, and I'm testing the bulb ramping feature to make sunset timelapses. I have it set on the "sunset" mode, and I also have the manual exposure ramping set to -0.01EV per shot, so that the final night shots are a bit less exposed than the daylight ones.

Anyway, after some trial and error, I managed to get an excellent timelapse without flicker, but today I decided to try it again while opening the aperture by hand at given intervals. I started at F18 and 1.5sec. exposure, and when the scene got darker I opened the iris manually to F14, then to F9 and then to F8.

I expected that, when doing that, the bulb ramping would automatically adjust shutter time to compensate for the changed aperture, but it doesn't do so: if a shot has F18 and 3sec., after I open the iris to F14 it still takes the next picture at 3sec. (with no ISO change). As a result, there's noticeable flicker when I make those changes.

My first question: is this normal? What am I supposed to do to avoid this?

Aside of that, in today's timelapse there was also some higher-frequency flicker that wasn't there in my previous one (both shot on the same location). After having a look, I noticed that the center of the shot had an object that moved slightly with the wind and was directly lit by a streetlight (the center spot metering mark was right on it), so its brightness varied slightly. Could this have caused it? Basically, what I'm asking is: does bulb ramping use the spot metering feature of the camera to measure light?

Thanks in advance.

5

General Help Q&A / Which nightly for 550D?

« on: February 13, 2014, 12:09:22 PM »

Hi all:

Complete newbie here. I just installed Magic Lantern last week, and after getting confused because I couldn't find some features (ETTR) in my stable 2.3 build, I started reading more in detail about the current development model. I'm ready now to try the nightlies, but first I'd like to ask some basic questions, just so I can be sure that I have the right idea (so please bear with me):

-Switching between stable and nightly is as simple as taking the SD card, deleting all the files of one version and copying the other one, right?

-For the 550D, which of the recent nightlies have people here been using? Is there any particular version with serious bugs? (I'm not asking which version do people "recommend", because I know that in the end I have to make that decision for myself; I'm asking for people's experiences using the recent builds).

Thanks in advance.