Author Topic: DOF calculator in live view  (Read 9412 times)

sonus

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DOF calculator in live view
« on: August 01, 2012, 06:06:14 AM »
There's another thread about this. Just bringing up the topic again here.

https://groups.google.com/forum/?fromgroups#!topic/ml-devel/x8Z-CBBjFps

Perhaps the DOF preview button in liveview could act as a popup for all the detailed lens info.

ilguercio

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Re: DOF calculator in live view
« Reply #1 on: August 01, 2012, 04:52:04 PM »
A1ex said DOF button press is not that easy to detect.
Same for flash button.
Canon should have given us more buttons for ML :D
Canon EOS 6D, 60D, 50D.
Sigma 70-200 EX OS HSM, Sigma 70-200 Apo EX HSM, Samyang 14 2.8, Samyang 35 1.4, Samyang 85 1.4.
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WaltMarsh

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Re: DOF calculator in live view
« Reply #2 on: October 05, 2012, 03:40:39 AM »
I would like to see an option where audio levels can be swapped with the Dof view. 
Based on sensor, focalpoint, aperture,  and focal length ML will display something like this at the top of the LV


F2.8/50mm_______|2'5"|_______
F4/50mm_________|5'8"|_______


This would work well with AF Lenses, but a few extra steps would be needed for manual lenses.
Canon 5DMK2, 28mm+50mm+85mm Zeiss Primes, 28-75mm+75-200mm Tamron,Tascam DR-40, other stuff too :-)

Francis

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Re: DOF calculator in live view
« Reply #3 on: October 05, 2012, 06:41:04 AM »
The unfortunate drawback to a feature like this is that not all lenses report focal distance, and no lenses report particularly accurate focal distance. The margin of error would be very great.

1ab

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Re: DOF calculator in live view
« Reply #4 on: October 05, 2012, 11:31:07 AM »
Pity to read that it's not very precise. But for the sake of brainstorming :-), how about creating a completely new shooting mode based on DoF preselection?

The basic idea is: Specify minimum and maximum DoF, so while focusing (->knowing the distance to the subject) and doing the light metering, the camera can choose an aperture which gives a DoF in the specified range; the exposure time should follow the 1/focal length rule of thumb (and a configurable multiplier for either very nervous situations or stabilized lenses is welcome), and the AutoISO (within the AutoISO limits) could do the rest in order to create a correct exposure. If a correct (->standard) exposure is not possible with the specified limits, it should be possible to specify which of the parameters (DoFmin/DoFmax, Tmultiplier/Tmaxcalulated, AutoISOmax) might be violated for a correct exposure, or if strictly none of the parameter limits must be violated, the picture would be over- or underexposed. Of course, if any parameter is violated or the correct exposure goal is not reached, the camera should give a warning, similar as when Canon makes the aperture value blink.

Hope I did not have any obvious misconceptions while I thought this up :-) Implementation possibly by making adjustments to one of the existing CA/Av/P modes..?
But.. how unprecise exactly would it end up to be? So I guess not precise enough for Macro? But would it be good enough for people on a party or on a stage? Trees/Meadows/Landscapes? (To have a purpose, it probably needs to be "better" than Canon's CA mode.)

...just asking... ;-)

ilguercio

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Re: DOF calculator in live view
« Reply #5 on: October 05, 2012, 11:53:08 AM »
Focusing distances aren't the standard in every lens. As far as focusing goes it is not useful because the AF sensor does the job all on its own and doesn't need any distance report from the lens. Distances are only used for E-TTL, so it can dial the precise amount of flash power trying not to ruin your pictures. It won't be precise then, as there are only a few distances stored in the lens and they aren't enough for sure.
Canon EOS 6D, 60D, 50D.
Sigma 70-200 EX OS HSM, Sigma 70-200 Apo EX HSM, Samyang 14 2.8, Samyang 35 1.4, Samyang 85 1.4.
Proud supporter of Magic Lantern.

WaltMarsh

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Re: DOF calculator in live view
« Reply #6 on: October 05, 2012, 04:35:11 PM »
This would be a huge benefit to the ML software and doesn't have to be dependent on any particular lens.  The only variable is the subject distance.  Sensor size, Focal Length, and Aperture are stored in ML.  So as most filmmakers control use manual focus, why not make the focal point/distance manual also. 

I say just add the calculator in ML and leave it up to user to maintain precision.
If all of our measurements are correct then the depth of field calculation will be accurate.

It would be pretty neat to know if I'm working with 1' or 1" of depth of field.



Canon 5DMK2, 28mm+50mm+85mm Zeiss Primes, 28-75mm+75-200mm Tamron,Tascam DR-40, other stuff too :-)

ilguercio

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Re: DOF calculator in live view
« Reply #7 on: October 05, 2012, 04:41:21 PM »
And where are we supposed to get subject distance from?
Canon EOS 6D, 60D, 50D.
Sigma 70-200 EX OS HSM, Sigma 70-200 Apo EX HSM, Samyang 14 2.8, Samyang 35 1.4, Samyang 85 1.4.
Proud supporter of Magic Lantern.

WaltMarsh

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Re: DOF calculator in live view
« Reply #8 on: October 05, 2012, 05:04:11 PM »
You measure it :D.

That little icon on the left of your camera represents the film plane.  Before the digital filmmaking world a tape measure would be stretched from this point to the subject.  This is the focal distance.  The icon is a circle with a line
Canon 5DMK2, 28mm+50mm+85mm Zeiss Primes, 28-75mm+75-200mm Tamron,Tascam DR-40, other stuff too :-)

ilguercio

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Re: DOF calculator in live view
« Reply #9 on: October 05, 2012, 05:12:18 PM »
You measure it :D.

That little icon on the left of your camera represents the film plane.  Before the digital filmmaking world a tape measure would be stretched from this point to the subject.  This is the focal distance.  The icon is a circle with a line
I hope you're kidding me.
Canon EOS 6D, 60D, 50D.
Sigma 70-200 EX OS HSM, Sigma 70-200 Apo EX HSM, Samyang 14 2.8, Samyang 35 1.4, Samyang 85 1.4.
Proud supporter of Magic Lantern.

WaltMarsh

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Re: DOF calculator in live view
« Reply #10 on: October 05, 2012, 05:22:57 PM »
Serious.  This actually still happens on film crews today. 
Canon 5DMK2, 28mm+50mm+85mm Zeiss Primes, 28-75mm+75-200mm Tamron,Tascam DR-40, other stuff too :-)

ilguercio

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Re: DOF calculator in live view
« Reply #11 on: October 05, 2012, 05:24:47 PM »
Serious.  This actually still happens on film crews today.
But then i can't see why you want to do the calculation on camera, since the process is not automated. Get a calculator.
Also, in LV you have all the aids and the visibility to check if DOF is as large or as thin as you want.
Canon EOS 6D, 60D, 50D.
Sigma 70-200 EX OS HSM, Sigma 70-200 Apo EX HSM, Samyang 14 2.8, Samyang 35 1.4, Samyang 85 1.4.
Proud supporter of Magic Lantern.

WaltMarsh

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Re: DOF calculator in live view
« Reply #12 on: October 06, 2012, 05:42:41 AM »
That is my point.  ML built in calculations, so that I don't need an additional calculator.
Say I want to walk with a subject and have 2' of Depth of Field, by having this calculator built in ML I will have that exact measurement.  I would then move my subject to that focal distance that ML provides and walk at the same pace to keep my subject within the 2' depth of field.

https://ml-devel.googlegroups.com/attach/53bd387793e1a030/screen.jpg?view=1&part=2
Canon 5DMK2, 28mm+50mm+85mm Zeiss Primes, 28-75mm+75-200mm Tamron,Tascam DR-40, other stuff too :-)