fmath version of M3 Bracketing

Brackets (M3).lua

--[[
@title Brackets (M3)
@chdk_version 1.5

@subtitle Bracketing Options
#mode = 0 "Focus bracket?" {Off X2INF Min2INF}
#bracket = 0 "Exposure bracket?" {Off +4Ev +3Ev +2Ev 2(+2Ev) 3(+2Ev) ISO1600 auto}
#sky = 0 "Sky Bracket?" {Off Sky+2Ev Sky+3Ev Sky+4Ev Sky+5Ev Sky+6Ev}

@subtitle Bracketing Settings
#infinity = 3 "Infinity focus (xH)" [2 4]
#overlap = 15 "Overlap (um)" [5 30]
#hilit = 20 "% histo HiLit" [5 30]
#pmag = 1 "Assumed Pupil Mag" [1 6]

@subtitle Other Settings
#dofs = 0 "DoF display" {Blur DoFs}
#traf = 0 "Traffic Lights" {Off On}
#sleep_time = 2 "Delay (s)"
#bookends = 1 "Bookends?" {Off On}
#screen_off = 0 "Screen?" {Off On}
#log = 0 "Log?" {Off On Reset}
#help = 0 "Console" {Off On}
#lens = 0 "Lens name?" {Off On}

Notes: 
* This version only runs on the M3 with the fmath library version of CHDK
* Can only use registered EF-M lenses
* Script best used with WA lenses ;-)
* For retrofocus lenses use an assumed pupil mag at least as large as your guess. For telephoto use 1
* Register your EF-M lens below in the lens_info() function
* Not designed for macro focus stacking, ie best for deep focus photography only
* To stop flickering, cycle the Canon screen (INFO), eg to not show the Canon histogram
* If you reset/delete the log, you need set the log menu to on or off after
* When paused, at the assess point, you can refocus and see the impact on bracketing. You can also change focal length, but you need to press the RIGHT key to reset things
* If traffic light (TL) feedback is enabled, once an image is captured, the left hand TL shows the near DoF's focus overlap state, relative to the last image captured...
...and the right TL sows the far DoF's overlap state relative to the last image captured. Yellow = same focus; green = a positive overlap; red = a negative overlap (a gap).
In addition, as you manually focus bracket, the centre info area of the bar changes from showing the focal length and the number of bracket, to the fL and the blur at the overlap
* Use pmag to ensure focus overlap insurance. Use 1 for a telephoto lens and a value greater than what you think it is for a retrofocus lens
* Also at the assess point, you can exit ALT mode and change aperture. Reentering ALT and pressing the RIGHT key to reset things.
* Exposure bracketing and Sky Bracketing are mutually exclusive. To undertake sky bracketing you need to set exposure bracketing to zero.
* All console measurements, focus and near DoF, are relative to the sensor.
* Note: the script attempts to detect Canon changes, eg PLAY or MENU etc, but isn't perfect ;-) If the bar disappears, just press ALT on and off, or wait for M3 Bracketing to auto refresh

Release 1.07

photography.grayheron.net
April 2021
--]] 

capmode = require("capmode")
bi = get_buildinfo()

if (bi.platform ~= "m3") then 
    print("Only runs on M3")
    sleep(3000)
    return
end

local s,e = pcall(function() local w=fmath.new(0) end)
if s == false then
    print("Can't use script")
    sleep(3000)
    return
end

require "drawings"
props=require'propcase'
set_console_autoredraw(1)
set_console_layout(0,0,45,1)

if log == 2 then
    print_screen(1)
    print("Log reset")
    print("Reset log menu")
    print_screen(0)
    return
end

press("shoot_half")
repeat sleep(10) until get_shooting()

    dof = get_dofinfo()
    F = fmath.new(dof.focal_length,1000) -- focal length in mm (real)
    s = get_prop(props.TV)
    av = get_prop(props.AV)
    n = fmath.new(av96_to_aperture(av),1000) -- aperture number as a real
    start_s = s
    s_ev = s

release("shoot_half")
repeat sleep(10) until (not get_shooting())

steps = 1
steps_back = 0
inf = 81000 -- infinity trap

function units(xx)
    local xr =""
    if xx:int() > 5000 then 
        xr=(xx/1000):tostr(1).."m"
    elseif xx:int() > 1000 then 
        xr=(xx/10):tostr(0).."cm"
    else
        xr=(xx):tostr(0).."mm"
    end
    return xr
end

function hH() -- calculate the full & short versions of the hyperfocal
    n = fmath.new(av96_to_aperture(get_user_av96()),1000) -- convert to a real aperture number
    h = (1000*F*F)/(n*overlap) -- short hyperfocal (mm)
    H = h + F -- 'full' hyperfocal (mm), as measured from the lens front principal, ie NOT the sensor as reported by Canon
end

function update_DoFs(xx) -- update stuff for DoFs etc
    local q = xx-t
    u = (((q*(q-4*F)):sqrt() + q)/2):int() -- focus distance in mm from front principal
    if xx < inf then
        ndof = F*F/(u-F)
        ndof = ndof+(h*(F-h*pmag))/(pmag*(u+h-F))
        ndof = (ndof+(pmag*(2*F+h+t)-F)/pmag)
    else
        ndof = H
    end
    if u < H:int() then
        fdof = F*F/(u-F)
        fdof = fdof-(h*(F+h*pmag))/(pmag*(u-h-F))
        fdof = (fdof+(pmag*(2*F-h+t)-F)/pmag)
        num = (1+(H/u + 1)/2):int()
    else
        fdof = fmath.new(inf+1)
        num = 1
    end
end

function get_focus_distance_upper() -- returns upper focus distance in mm, but note 'accuracy' is 1cm from Canon. NOTE - NOT USED IN THIS SCRIPT
    local x = -1
    if (bi.platsub == "101a") then
        x = peek(0x00244916, 2)
    elseif (bi.platsub == "120f") then
        x = peek(0x0024495A, 2)
    else
        error('Not 101a or 120f')
    end
    if x ~= -1 then return x*10 else return x end
end

function get_focus_distance_lower() -- returns lower focus distance in mm, but note 'accuracy' is 1cm from Canon
    local x = -1
    if (bi.platsub == "101a") then
        x = peek(0x00244918, 2)
    elseif (bi.platsub == "120f") then
        x = peek(0x0024495C, 2) 
    else
        error('Not 101a or 120f')
    end
    if x == -1 then return -1 else return x*10 end
end

function refocus_to(xx) -- Only moves towards infinity. Returns requested focus distance in mm
    local current_x = get_focus_distance_lower() -- current focus distance in mm to nearest cm. Based on Canon lower EXIF value
    local steps_total = 0
    local last_step_count = steps_total
    if xx < current_x then return -1 end -- don't use
    local last_step_x = current_x
    while current_x < xx do
        call_event_proc("EFLensCom.MoveFocus", steps, 1) -- move smallest step you can towards infinity
        steps_total = steps_total + steps
        sleep(25) -- for system to catch up
        current_x = get_focus_distance_lower() -- Get Canon lower EXIF value
        if (current_x ~= last_step_x) and (current_x < xx) then -- just went through an intermediate step change, ie not yet reached the step that covers xx
            last_step_x = current_x
            last_step_count = steps_total -- close enough
        end
    end
    -- now fine tune position backwards if required
    steps_back = ((current_x - xx) * (steps_total - last_step_count)) / (current_x - last_step_x)
    if steps_back > 0 then
        for i = 1, steps_back do call_event_proc("EFLensCom.MoveFocus", -steps, 1) end
    end
    sleep(25) -- for system to catch up
    current_x = get_focus_distance_lower()
    return xx -- request focus position, eg the 'best' estimate in mm as to where we really are
end

function lens_name()
    local get_lens_name_fn = 0xfc2f3fd5
    if (bi.platsub == "101a") then get_lens_name_fn = 0xfc2f3fc3 end

    if call_event_proc('System.Create') == -1 then error('Unknown Error') end

    local ppname = call_event_proc('AllocateMemory', 8)

    if ppname == -1 or ppname == 0 then error('Unknown Error') end

    local plen = ppname + 4
    poke(ppname, 0)
    poke(plen, 0)
    local status = call_func_ptr(get_lens_name_fn, ppname, plen)
    local pname = peek(ppname)
    local len = peek(plen)
    call_event_proc('FreeMemory', ppname)
    if ppname == -1 or ppname == 0 then error('Unknown Error') end
    local i = 0
    local t = {}
    while i < len do
        local c = peek(pname + i, 1)
        if c == 0 then break end
        table.insert(t, string.char(c))
        i = i + 1
    end
    local name = table.concat(t)
    return name
end

function restore()
    set_tv96_direct(s)
    set_av96_direct(av)
    press("shoot_half")
    repeat sleep(10) until get_shooting()
    sleep(100)
    release("shoot_half")
    repeat sleep(10) until (not get_shooting())
    if current_focus_mode ~= 1 then set_mf(0) end
    if (current_mode ~= "M") then capmode.set(current_mode) end
    set_lcd_display(1)
    exit_alt()
    print_screen(0)
    cls()
end

function set_up()
    current_focus_mode = get_focus_mode()
    current_mode = capmode.get_name()
    if current_focus_mode ~= 1 then set_mf(1) end
    s = get_tv96()
    av = get_av96()
    press("shoot_half")
    repeat sleep(10) until get_shooting()
    if sky > 0 and bracket == 0 then -- reset exposure for the sky/infinity bracket
        set_tv96_direct(s - 96*(sky+1))
        sleep(100)
    end
    if (current_mode ~= "M") then capmode.set("M") end
    s = get_tv96()
    set_tv96_direct(s)
    set_av96_direct(av)
    sleep(100)
    release("shoot_half")
    repeat sleep(10) until (not get_shooting())
    dof = get_dofinfo()
    F = fmath.new(dof.focal_length,1000) -- focal length in mm (real)
    lens_test = lens_info()
    hH() -- update hyperfocal info
end

function myshoot()
    local prevcnt = hook_shoot.count()
    local rawprevcnt = hook_raw.count()
    press 'shoot_full_only'
    repeat sleep(10) until prevcnt ~= hook_shoot.count()
    release 'shoot_full_only'
    repeat sleep(10) until rawprevcnt ~= hook_raw.count()
end

function X_bracket()
    press("shoot_half")
    repeat sleep(10) until (get_shooting())
    set_tv96_direct(s)
    if bracket == 0 or bracket >= 8 then
        myshoot()
    elseif bracket == 1 then
        myshoot()
        set_tv96_direct(s - 96 * 4)
        myshoot()
    elseif bracket == 2 then
        myshoot()
        set_tv96_direct(s - 96 * 3)
        myshoot()
    elseif bracket == 3 then
        myshoot()
        set_tv96_direct(s - 96 * 2)
        myshoot()
    elseif bracket == 4 then
        myshoot()
        set_tv96_direct(s - 96 * 2)
        myshoot()
        set_tv96_direct(s - 96 * 4)
        myshoot()
    elseif bracket == 5 then
        myshoot()
        set_tv96_direct(s - 96 * 2)
        myshoot()
        set_tv96_direct(s - 96 * 4)
        myshoot()
        set_tv96_direct(s - 96 * 6)
        myshoot()
    elseif bracket == 6 then
        local iso = get_iso_mode()
        set_iso_mode(100)
        myshoot()
        set_iso_mode(1600)
        myshoot()
        set_iso_mode(iso)
    elseif bracket == 7 then
        shot_histo_enable(1)
        myshoot()
        sleep(100)
        lower = 1024 - 1024*hilit/100
        test=get_histo_range(lower,1024)
        step = 0
        while test > 0 do
            step = step + 1
            set_tv96_direct(s + 96 * 2 * step)
            myshoot()
            sleep(100)
            test=get_histo_range(lower,1024)
        end
        shot_histo_enable(0)
    end
    set_tv96_direct(s)
    release("shoot_half")
    repeat sleep(10) until (not get_shooting())
end

function bookend()
    set_tv96_direct(960)
    set_av96_direct(get_max_av96())
    local ecnt = get_exp_count()
    shoot()
    set_tv96_direct(s)
    set_av96_direct(av)
    repeat sleep(10) until (get_exp_count() ~= ecnt)
end

function hiatus()
    local M = fmath.new(Mmax,1000)
    local Fr = fmath.new(Fmax,1000)
    -- Note the following is an estimate of the mag at f, based on simply scaling the max mag by the focal length ratio
    -- A better model would be to explicity measure the mag at a focal length, or at least at the zooms and interpolate
    -- Maybe in the future ;-)
    m=M*F/Fr
    t = (F * (1 + m) * (1 + m))
    t = MFD - t/m -- this is an estimate of the spilt thin lens thickness (mm)
    return t
end

function lens_info()
    if lens_name() == "EF-M11-22mm f/4-5.6 IS STM" then -- calculate lens thickness from manufacturer's data
        -- add other lenses as required, ie replace the following for your lens
        -- For the above lens, 300 is the lens max magnification x 1000, ie from manufacturer's data or your measurement
        -- 22000 is the lens maximun zoom, or the prime, focal length in microns
        -- 150 is the lens minimum focus distance (mm), ie from manufacturer's data or your measurement
        Fmax = 22000 -- Longest focal length (mm) * 1000
        Mmax = 300 -- Max magnification * 1000
        MFD = 150 -- Minimum Focus Distance in mm
        t = hiatus() -- distance between front and rear principals
        return true
    elseif lens_name() == "EF-M28mm f/3.5 MACRO IS STM" then
        Fmax = 28000 -- Longest focal length (mm) * 1000
        Mmax = 1000 -- Max magnification * 1000
        MFD = 97 -- Minimum Focus Distance in mm
        t = hiatus() -- distance between front and rear principals
        return true
    elseif lens_name() == "EF-M55-200mm f/4.5-6.3 IS STM" then
        Fmax = 200000 -- Longest focal length (mm) * 1000
        Mmax = 210 -- Max magnification * 1000
        MFD = 960 -- Minimum Focus Distance in mm
        t = hiatus() -- distance between front and rear principals
        return true
    elseif lens_name() == "EF-M18-55mm f/3.5-5.6 IS STM" then
        Fmax = 55000 -- Longest focal length (mm) * 1000
        Mmax = 240 -- Max magnification * 1000
        MFD = 150 -- Minimum Focus Distance in mm
        t = hiatus() -- distance between front and rear principals
        return true
    elseif lens_name() == "EF-M15-45mm f/3.5-6.3 IS STM" then
        Fmax = 45000 -- Longest focal length (mm) * 1000
        Mmax = 250 -- Max magnification * 1000
        MFD = 250 -- Minimum Focus Distance in mm
        t = hiatus() -- distance between front and rear principals
        return true
                --[[
    elseif lens_name() == "10-20mm" then
        Fmax = 20000 -- Longest focal length (mm) * 1000
        Mmax = 130 -- Max magnification * 1000
        MFD = 240 -- Minimum Focus Distance in mm
        t = hiatus() -- distance between front and rear principals
        return true
     elseif lens_name() == "your lens" then
        copy template above
        ]]
    else -- lens not recognised, so don't use
        return false
    end
end

function update()
    update_DoFs(x) -- update u and DoFs

    draw.replace(obj1,"rectf",0,0,lcd,35,"black","black") -- clear the info bar
    
    if x > inf then
        temp = ">=H : INF"
    elseif u >= H:int() then
        temp = ">=H : "..units(fmath.new(x,1))
    else
        temp = " <H : "..units(fmath.new(x,1))
    end
    draw.replace(obj2,"string",(30*lcd)/720,0,temp,"white","black") -- draw focus position info

    inf_blur = ((overlap*(H-F))/(u-F)):int()
    
    if not get_alt_mode() and traf == 1 and not image then -- change to Ev feedback
        temp_s = ((get_user_tv96()-s_ev)*10)/96
        local sign = -1
        if temp_s < 0 then
            sign = 1
            temp_s = -temp_s
        end
        temp = ((sign*temp_s)/10).."."..(temp_s-10*(temp_s/10)).."ev / #"..num
    else    
        temp = F:int().."mm / #"..num
    end
    draw.replace(obj3,"string",(280*lcd)/720, 0,temp,"white","black")
    
    if dofs == 0 then
        temp = units(ndof).." / "..inf_blur.."um"
    else
        if u < H:int() then
            temp = units(ndof).." / "..units(fdof)
        else
            temp = units(ndof).." / INF"
        end
    end
    draw.replace(obj4,"string",(490*lcd)/720,0,temp,"white","black")


    if image and not get_alt_mode() and traf == 1 and last_image_u < inf  then -- display traffic lights
        local clr = "black"
        if x == last_image_x then
            clr = "yellow"
        elseif (ndof >= last_image_ndof) and (ndof <= last_image_fdof) then
            clr = "green"
        elseif (ndof > last_image_fdof) or (ndof < last_image_ndof)  then
            clr = "red"
        end
        draw.replace(obj5,"rectf",5,5,20,25,clr,clr) -- update left traffic light
        if x == last_image_x then
            clr = "yellow"
        elseif (fdof <= last_image_fdof) and (fdof >= last_image_ndof) then
            clr = "green"
        elseif (fdof > last_image_fdof) or (fdof < last_image_ndof) then
            clr = "red"
        end
        draw.replace(obj6,"rectf",(700*lcd)/720,5,(715*lcd)/720,25,clr,clr) -- update right traffic light

        local ee = (F*(pmag-1))/(pmag) -- pupil extension in mm
        local blur = ee*(u+last_image_u)-2*u*last_image_u
        blur = blur + F*(u+last_image_u-2*ee)
        blur = blur*n
        blur = ((1000*F*F*(u-last_image_u))/blur):int() -- blur at overlap in microns
        if blur < 0 then blur = -blur end
        if x < inf  then
            temp = F:int().."mm / "..blur.."um"
        else
            temp = F:int().."mm / ".."???"
        end
        draw.replace(obj3,"string",(280*lcd)/720, 0,temp,"white","black")
    else
        clr = "black"
        draw.replace(obj5,"rectf",5,5,20,25,clr,clr) -- update left traffic light
        draw.replace(obj6,"rectf",(700*lcd)/720,5,(715*lcd)/720,25,clr,clr) -- update right traffic light
    end
    draw.overdraw()
    dirty = false
end

-- Main Section

if lens == 1 then
    print_screen(-1)
    print(lens_name())
    sleep(3000)
    restore()
    return
end

if bracket > 0 and sky > 0  then 
    print("Exposure bracketing clash!")
    sleep(3000)
    restore()
    return
end

set_up()

if lens_test == false then 
    print("Can only use registered EF-M lenses")
    sleep(3000)
    restore()
    return
end

if mode == 2 then -- move to focus minimum
    repeat
        x = get_focus_distance_lower()
        call_event_proc("EFLensCom.FocusSearchNear")
        sleep(50)
    until x == get_focus_distance_lower()
end

print_screen(0) -- switch off logging until bracketing

last_x = 0
dirty = true
lcd = 0

if help == 0 then -- then switch off console display
    set_console_layout(0,0,1,0)
    print("")
    set_console_autoredraw(-1)
end

-- Set up the bar drawing objects
obj1 = draw.add("rectf", 0, 0, 0, 0, "black","black")
obj2 = draw.add("string", 0, 0, "","white","black")
obj3 = draw.add("string", 0,0,"","white","black")
obj4 = draw.add("string",0,0,"","white","black")
obj5 = draw.add("rectf", 0, 0, 0, 0, "black","black")
obj6 = draw.add("rectf", 0, 0, 0, 0, "black","black")

last_alt_state = get_alt_mode() 

image = false -- no image taken yet
last_image_ndof = fmath.new(0)
last_image_fdof = fmath.new(0)
last_image_x = 0
last_image_u = 0
ecnt = get_exp_count()
tsec = get_day_seconds()

repeat -- stay here while in asssess/shooting mode
    x = get_focus_distance_lower()

    if last_x ~= x then dirty = true end
    last_x = x

    wait_click(50) -- check for a button press

    if is_key("right") and get_alt_mode() then -- re-run set up tasks
        set_up() 
        dirty = true
    elseif is_key("shoot_full") and not get_alt_mode() then -- taking an image outside of ALT mode
        last_image_ndof = ndof
        last_image_fdof = fdof
        last_image_x = x
        last_image_u = u
        repeat  sleep(50) until ecnt ~= (get_exp_count())
        ecnt = get_exp_count()
        image = true
        dirty = true
    elseif is_key("shoot_half") and not get_alt_mode() then
        dirty = true
    end

    if get_alt_mode() ~= last_alt_state then -- refresh a few things if ALT state changes
        dirty = true
        last_alt_state = get_alt_mode() 
        image = false 
        s_ev = get_user_tv96() -- reset ev feedback
    end

    if get_gui_screen_width() ~= lcd then -- screens have changed
        if get_gui_screen_width() == 720 then -- potentially show the console if requested
            set_console_autoredraw(1)
            set_console_layout(0,0,45,1)
            dirty = true
        else -- don't show console when using EVF
            set_console_autoredraw(-1)
            set_console_layout(0,0,1,1)
            print("")
            dirty = true
        end
    end

    lcd = get_gui_screen_width()

    if lcd == 720 and help == 1 then -- update console to show help reminder
        print("SET=Run : RIGHT=Reset : FSP = EXIT")
    end

    if ((get_day_seconds()-tsec > 2) and x == last_x) then 
        dirty = true
        tsec = get_day_seconds()
    end

    if dirty then update() end -- update the info bar

    sleep(500) -- no need to check too often

until ((is_key("set") or is_key("shoot_full")) and get_alt_mode())  -- then take brackets or exit

if help == 1 and  lcd == 720 then -- show bracketing progress in main screen
    set_console_autoredraw(1)
    set_console_layout(0,0,45,1)
end

if log == 1 then 
    set_console_autoredraw(-1)
    print_screen(-1)
    print("...")
    print(os.date())
    set_console_autoredraw(1)
end

t1=os.time() -- start the clock
draw.clear()
print_screen(0)
print("Bracketing Started")

if log == 1 then print_screen(-1) end -- switch focus bracketing logging on

update_DoFs(x) -- update stuff

if bookends == 1 then bookend() end
t1=sleep_time-(os.time()-t1)
if t1 > 0 then sleep(t1*1000) end
if screen_off == 1 then set_lcd_display(0) end

print("1/"..num.." @ "..units(fmath.new(x)))

X_bracket() -- First exposure(s)

if mode == 0 then -- exposure bracket only requested so exit script after taking images at current focus
    if sky > 0 and bracket == 0 then -- sky bracket requested
        press("shoot_half")
        repeat sleep(10) until (get_shooting())
        set_tv96_direct(s + 96*(sky+1))
        myshoot()
        set_tv96_direct(s)
        release("shoot_half")
        repeat sleep(10) until (not get_shooting())
    end
    if bookends == 1 then bookend() end
    restore()
    return
end

i = 1
while (u < (H/3):int()) do -- capture the rest of the focus brackets up to H/3
    -- Note that focus bracketing is calculated/updated in u space, but actual refocusing is in x space
    -- All console feedback is in x space, ie distance estimates measured from the sensor
    new_u = 2*F*F*(pmag-1) + F*(u-2*pmag*u) + h*pmag*u
    new_u = (new_u/( F*(2*pmag-1) + pmag*(h-2*u))):int() -- new u in mm, using DOFIS model
    if new_u <= u then new_u = u + 5 end -- move at least 5mm, just in case. Remember: script is not designed for macro work!
    u = new_u
    x = (u + F + (F*F)/(u-F) + t) -- next focus bracket estimate in x space: in mm from f(1+m)+t+u
    refocus_to(x:int())
    i = i + 1 -- keep track of number of images taken
    print(i.."/"..num.." @ "..units(x))
    X_bracket()
end

if u < inf and x:int() < inf then -- take additional images at/beyond H
    if u < H:int() then 
        temp = ((F*F)/(H-F) + F + t + H)
        refocus_to(temp:int())
    else
        temp = ((F*F)/(u-F) + F + t + u)
    end
    print("@H = "..units(temp))
    X_bracket()
    temp = ((F*F)/(infinity*H-F) + F + t + infinity*H)
    if temp:int() > inf then -- adjust as at/beyond lens infinity
        repeat
            infinity = infinity - 1
            temp = ((F*F)/(infinity*H-F) + F + t + infinity*H)
        until temp:int() < inf or infinity == 2
    end
    refocus_to(temp:int())
    print("@"..infinity.."xH = "..units(temp))
    X_bracket()
    if sky > 0 and bracket == 0 then -- take an extra exposure shot for the sky
        press("shoot_half")
        repeat sleep(10) until (get_shooting())
        set_tv96_direct(s + 96*(sky+1))
        myshoot()
        set_tv96_direct(s)
        release("shoot_half")
        repeat sleep(10) until (not get_shooting())
        print("Inf X @ "..units(temp))
    end
end

if bookends == 1 then bookend() end

restore()