How to control aperture with auto/limited ISO and shutter on autoexpo module

Started by KicK-Azz, May 02, 2020, 10:25:26 PM

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KicK-Azz

I've tried numerous settings. Maybe i'm missing something. I'm on a canon 5D MKii. Low on funds and needed something i could actually work on. Camera is great however, for a guy who's never had the funds for his own top notch shit, I'm usually working on some higher end models and cameras. I assumed i'd be able to find a way to do this resorting to ML if needed. My goal is a cleaner aperture priority. Simply put I want to control aperture at will while shutter and iso change automatically within my desired range. 1/30 + for shutter and a 400-3200 ISO. Those ranges appear to be set when i use the module but my aperture snaps back after a single shot. I've disabled aperture and set to lens in settings. doing something with the LV settings somehow keeps it with halfpress but reverts back after shot. A huge part of me feels like i'm just missing something. Regardless, these things are computers, i find it hard to believe there's no simple way to set a value that already exist. maybe it can't be done :(  Would like the camera to not think long shutter speeds are gonna help me.

Walter Schulz

Build version in use?
Lens in use?
Zip contents of ML\Settings folder. Upload it somewhere and share link.

KicK-Azz

May 2018 nightly 

simple non luxury ef canon 75-33

https://mega.nz/file/mYg32b4K#mkZEcXiDJArhTaC865SYXMjWsJKOxogmABM3GQEW7h

Maybe the build? I went one lower due to a failed test. Honestly didn't look too much into it. So that is how the autoexpo is supposed to work?


Walter Schulz

There are 7 lenses having this zoom range, all called 75-300. Doesn't really matter, they are all quite dated (which actually is good).
Can't open link, getting a crypto key error.

KicK-Azz

Yeah, one of those grey boxes, thought there was a red stripe on logo. I guess III would be the model? f/4-5.6. Honestly, seems pretty solid and there's apparently a surplus as I've seen many around for pretty darn cheap when shopping locally. Here's another link. I'll use a different host if seems to be bad. should be a simple mega link, works when i attempt. any suggestion?

https://mega.nz/folder/TBRHyKZT#6C0N2ge92QjtogpoKax_Sw

if its asking for a key the characters after the '#' sign are the key.

KicK-Azz

Would be equally awesome if someone could confirm such usage is possible.

Audionut

From memory that's how the module works. Every time you take a shot it will use the settings in the module.
Maybe the settings stick in M mode, I don't remember.

What's the problem with the current functionality?

Walter Schulz

@KicK-Azz:
This is what I understood, please correct me if I'm wrong.

- You want Tv to be 1/30 s or faster. (There is a menu bug. Menu item is called "Tv minimum" but is in fact "Tv maximum").
- You want aperture set manually. It should not be changed by Auto exposure.
- ISO may float free between 400-3200.

Correct? And you are working in M (auto expo is not designed to work in Tv, Av).

If this is correct you are not using it properly: With your settings Autoexpo will adjust aperture on its own. Running between 1.4 and 32 with default settings.
To keep aperture constant you need to set "AV range" to something like "f/8.0-f/8.0".

KicK-Azz

You are absolutely correct. See, feeling like im missing something. Alright I'm gonna go mess with this now. Messed with a lot of settings before I was to make my original reply but am gonna look into this first. However! Maybe I missed something again but the iso ranges if manually set to auto but reverts to 3200 after shot. Maybe this'll change when this new knowledge but i did notice that last night. Furthermore, I'm sure I could look into it but, in a gist, why have av range equal? Is this like a if this then that situation? Oh, and viewfinder mode seems to be even more harsh on reverting values.

KicK-Azz

So I understand, at least for me, half pressing starts the actual "Auto Exposure" runs for a few seconds to find its sweet spot. Not really much of a problem if it weren't for the others. After this finishes I'm able to change the aperture... with a catch. If i half press it jumps to the minimum aperture set. Doesn't even bounce around like the shutter speed does. Only avoidance is full pressing, absolutely no half press after set. Doesn't retain set up after shot either. Next, I would assume you set your ISO to auto. Doesn't seem to matter cause whenever I half press it jumps to whatever is the maximum iso i set. Nothing appears to change this. And it fully changes this. If set to auto jumps to a fixed 3200. Unless you set a single iso manually it is never anything but the maximum set value within range. Maybe it stays when manually set can't recall at the moment. The shutter speed seems to change accordingly but with nothing but high iso and largest aperture it's always incredibly fast when unnecessary. I disabled the aperture setting. Changed the av range but like i said whatever is set to minimum it jumps to, equal or not. In short, after half press and autoexpo doing its thing it'll work like normal M mode. Full press may take shot but will revert settings afterwards. Half press just reverts aperture and iso, changes shutter according to shot. Set up is never retained after shot. Someone guide me. Am I hopeless!? Am I just an idiot? lol

Audionut

From memory in the autoexposure module settings, in the graph of settings, there is a blue horizontal line after taking an exposure, or metering a scene with half shutter.

This blue line represents the EV value of the scene you just metered.

So....the module will use the settings on the graph that match with the blue line.

If you want the module to be using different settings at that metered exposure, then you need to adjust the module and tell it to use different settings.

The module doesn't care what happens when the shutter button isn't being pressed. When the shutter is pressed, the module grabs the EV and sets the exposure settings accordinally, for that shot.

Walter Schulz

As Audionut wrote: If you want another behauviour in autoexpo you have to tweak it. It can be done by adjusting "ISO curve" and/or "Av curve". Some limited additonal info can be found on https://wiki.magiclantern.fm/camera_help#auto_exposure (copied from first post of pravdomil's Autoexpo thread: https://www.magiclantern.fm/forum/index.php?topic=7208.0 ).

It's easy to get lost in the woods. Document your steps. You can go back to default by deleting \ML\Settings\autoexpo.cfg

KicK-Azz

My apologies for the tardiness guys. Phone was recently sacrificed and corona has many of us forced to spend more time with kids. Anyway, YES! I feel really stupid but success. It does seem to be reacting more as expected. I get the steroid reference now. A little weird, a little fun. Sorta see myself using it to experiment more. There's a few laggy points I'm sure I can work on, can't help but think there's a reference somewhere to mimic certain camera algorithms. Maybe that sounded too nerdy lol. I guess at this point I'm trying my best to mimic the mk4 Av mode. I've worked a bit more on the cinema end but, somehow doing more still work the past few years and more recently borrowing one, it's custom Av mode with a grip literally changed my whole approach like an epiphany. Haha And amount of time spent when little is available. Anywho, it does work quite well for what it is. Changing aperture can be weird sometimes but it is the curve. Still forces some points if it doesn't agree, rejecting my choices but, i guess for the best. Really only having trouble with those flat areas especially with the iso. Could use a bit more curve lol. Maybe missing something with the relationship with each other. Will try to find some clearer understanding along with trial and error.