Author Topic: "On demand" spot metering  (Read 9285 times)

epozar

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"On demand" spot metering
« on: February 19, 2013, 03:04:17 PM »
My suggestion:
I sorely miss "on demand" (active only when button-pressed and keep pressed) spot metering. Assignable to any of thumb-reached buttons.
To explain: I want to use average/or any "normal" metering/ for most of time but in strong contrast situations I will press the button for precise spot-metering of important area. The way Canon wants me to do - switching to spot metering, pressing the memory button.. and than back to average is very cumbersome.
You might offer the option "toggle" .. and please don't do it re-settable after one shot, because is is usually needed for several shots in succession.

Francis

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Re: "On demand" spot metering
« Reply #1 on: February 19, 2013, 10:53:34 PM »
I would love this also. It would be great if it could be combined with the Exposure Lock back button. So when pressed it spot meters and locks the exposure settings, while metering done via half-press would be in evaluative or whatever other metering mode you have set.

epozar

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Re: "On demand" spot metering
« Reply #2 on: February 20, 2013, 12:14:11 AM »
.. and when the spot-metering is engaged this way - there should be some kind of visual indication whether an exposure compensation is also engaged (blinking exposure comp. indicator perhaps?) - because for usual spot metering this usually must be at "0".

Another possibility is to have "disregard any exposure compensation set when engaging on-demand spot".
It may confuse some people and is better set in the menu .. however this one would be very practical in most real-world situations because I usually already have some compensation set when I decided "spot metering is better for this". So make this an option.

Marsu42

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Re: "On demand" spot metering
« Reply #3 on: February 20, 2013, 07:15:51 AM »
.. and when the spot-metering is engaged this way - there should be some kind of visual indication whether an exposure compensation is also engaged (blinking exposure comp. indicator perhaps?) - because for usual spot metering this usually must be at "0".

This imho is not necessarily true, there are situations where ec with spot metering might make sense, i.e. when overriding systematically biased camera metering (the 6d is said to underexpose a bit all the time) or deliberately exposing to the left (clipping safety) or right (maximize resolution, minimize noise).

epozar

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Re: "On demand" spot metering
« Reply #4 on: February 20, 2013, 08:44:31 AM »
Of course, so let's it be an option :)
BTW, I had had once in ancient Olympus OM-4 both "shadow" and "highlight" spot-metering biases (cca 2.5 stops in either direction..)

ghideg

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Re: "On demand" spot metering
« Reply #5 on: July 22, 2013, 11:02:56 AM »
This is what i also need! My old 300D (and the film EOS 500 also)  works like this. It was meter in evaulate mode, but when you press the * button it switched to partial metering and lock that exposure. I used it very, very lot. You  can use it during you look into the wievfinder, you do not need to waste time with menu browsing....

Just upgraded to a 650D and I am very disappointed that I am should  go to menu or Q menu to change to spot metering,  take the picture, than go again to menu and change back to evaulate metering...

Waiting for the release for 650D  :)   Hopefully with this feature.

Marsu42

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Re: "On demand" spot metering
« Reply #6 on: July 31, 2013, 10:23:36 AM »
(obsolete)

Marsu42

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Re: "On demand" spot metering
« Reply #7 on: July 31, 2013, 02:12:55 PM »
(obsolete)

1%

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Re: "On demand" spot metering
« Reply #8 on: July 31, 2013, 05:19:37 PM »
Why not have spot metering on 1/2 shutter? Thats when canon meters anyway.

Marsu42

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Re: "On demand" spot metering
« Reply #9 on: July 31, 2013, 06:57:23 PM »
Why not have spot metering on 1/2 shutter? Thats when canon meters anyway.

The idea from the ol' days as far as I understand is to first press half shutter to eval meter, then realize this won't work and then press * to do spot metering for the next shot only or (I don't quite remember) spot meter as long as you hold * pressed and then press full shutter.

The problem here is the "next shot" part, because I know of no sound way to detect if a shot was done from shoot_task (alex used the img review, which is really awkward). So my alternative idea was to stop spot metering when releasing the * button again (only set would work, there's no hook for *) but that's doomed since ml also cannot detect SET unpress on my 60d :-(

If someone comes up with a really nice way to detect if a shot was done then I could have another go to add this.

Btw: The hotkey module I recently wrote already can toggle spot/eval metering with one of the hotkeys and metakey to enable them, but not for the next shot only, but's at least a faster operation than through the menus or top lcd is already covered.

1%

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Re: "On demand" spot metering
« Reply #10 on: July 31, 2013, 07:18:56 PM »
Turn on event spy? Unpress isn't detected?

I had the opposite issue on 600D and others with voice tags. It didn't detect press, only unpress.

Marsu42

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Re: "On demand" spot metering
« Reply #11 on: August 01, 2013, 12:37:29 AM »
Turn on event spy? Unpress isn't detected?

I didn't use event spy, but since press works at the same code place and unpress doesn't I guess it's obvious - alex said so himelf that it's model-specific.

I had the opposite issue on 600D and others with voice tags. It didn't detect press, only unpress.

:-( I hope someone with access to all cameras sometime just takes a couple of hours and figures out what keypresses are detected on which models, i.e. what is portable and what isn't and puts this information in the source code (good place: module.h with the key constants)

ghideg

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Re: "On demand" spot metering
« Reply #12 on: August 02, 2013, 08:58:12 AM »
I think it is enough that the camera detect the press  of the * button, and not the unpress, If the aim to have the function of the old bodies (like 300D).
I write here how the old cameras working: When you press the * button, then it meter in spot and lock that value. It is does not matter that you keep hold or release the button, the metering and locking is done on press. If you press again, it will meter again and lock the new value. So it is working the same as the  lock funkction of the * button on the new bodies, but with the difference that it loks the metering of the spot area even if the evaulate mode is set in menu. 
So it will lock the metering value for the next shots also (like the normal operation of * button) unitl you turn the lock off (I used to press the focus point selector button to release the lock)

I have a 650D and it is loks AE at press, and nothing happen when hold or at unpress, I think the 600D operates the same. So it is strange that you can detect only unpress.
I hope it is helped some...

Pinto

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Re: "On demand" spot metering
« Reply #13 on: February 10, 2014, 01:52:05 PM »
Any progress in impelmenting?

Marsu42

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Re: "On demand" spot metering
« Reply #14 on: February 18, 2014, 08:10:00 AM »
Any progress in impelmenting?

As a first step, I asked what button events are available at all on the various models - if * press/unpress only works on one model, it's no good starting coding: http://www.magiclantern.fm/forum/index.php?topic=10554.msg102380;topicseen#msg102380