Metering problem


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Zaknafein

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#1
hello guys, i need a little help here...
pls spare a moment to take a look at this picture




for this picture, i was using spot metering on my Canon A95.
what i did was: select spot metering and locked spot AE point to the AF frame. then i shifted my AF frame to the dogs eyes. half press shutter to focus, then released the shutter.

i notice the left side of the picture is way over exposed so i tried a couple more times. however , all similar results. the left window is always over exposed while the dog is under expose. couldnt expose the whole picture correctly.

should i use spot metering in the first place, or is my technique of using it wrong?
 

foxtwo

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Mar 11, 2004
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#2
of 'cos the left side will always be overexposed. your subject brightness (dynamic) range is too wide to have both sides share the same exposure.

as of why the dog is underexposed, perhaps there is a problem with your technique in spot metering. try again by metering the dog then opening by 1-2 stops.

ps. actually the exposure on your dog looks fine. just maybe +1/2 stop will be okay.
 

madmacs

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#3
well if you spot meter on the dog which is a relative dark object, then the bright window area will be blown. matrix metering will probably work better here. that said, maybe you should have gone closer and shoot only the dog without the distracting laundry in the background. actually if you had moved to the left, then you would have the dog looking at you, and you won't have the problem of blown highlights... :think:
 

foxtwo

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#5
foxtwo said:
of 'cos the left side will always be overexposed. your subject brightness (dynamic) range is too wide to have both sides share the same exposure.

as of why the dog is underexposed, perhaps there is a problem with your technique in spot metering. try again by metering the dog then opening by 1-2 stops.

ps. actually the exposure on your dog looks fine. just maybe +1/2 stop will be okay.
just remembered. spot metering is based of reflected metering which calculates correct exposure at 18% grey. normally to record black, u will have to close down. in this case, as the dog is dark coloured, open up for more light if you find it dark.
 

Zaknafein

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#6
foxtwo said:
of 'cos the left side will always be overexposed. your subject brightness (dynamic) range is too wide to have both sides share the same exposure.

as of why the dog is underexposed, perhaps there is a problem with your technique in spot metering. try again by metering the dog then opening by 1-2 stops.

ps. actually the exposure on your dog looks fine. just maybe +1/2 stop will be okay.


i think the dog is a little under expose just imo.
do i have to press half shutter to start spot meter the dog or just put the AE spot on the dog? cos once half shutter is pressed, settings cant be changed mah...
 

metallilan

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#7
how bout shooting in potrait? that might cut off the distracting laundry.
 

Zaknafein

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#8
madmacs said:
well if you spot meter on the dog which is a relative dark object, then the bright window area will be blown. matrix metering will probably work better here. that said, maybe you should have gone closer and shoot only the dog without the distracting laundry in the background. actually if you had moved to the left, then you would have the dog looking at you, and you won't have the problem of blown highlights... :think:

my intention was to practice metering mah :) just a test shot so didnt bother about the composition. and the area on my left is actually quite confined...

so a better way to meter is to spot meter on the window, then focus on the dog? hmmm that might not be posible cos my camera does not have AE lock :( gotta wait till i get Fuji S9500! :D
 

Zaknafein

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#9
JediForce4ever said:
Meter the background and use a flash to expose the dog?Is this possible?

i try not to use flash as much as posible because im not good at it. the direct flash blast usually issnt as nice as a properly expose picture :) also, i cant use an external flash with diffuser/bounce card cos its just a compact camera without an hotshoe.


so normally in these sort of situations, what do u guys do? meter properly, just shoot the object but go home to do photoshop, or just re-compose the picture to exclude the bright light source?
 

rebbot

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Mar 24, 2005
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#10
Zaknafein said:
my intention was to practice metering mah :) just a test shot so didnt bother about the composition. and the area on my left is actually quite confined...

so a better way to meter is to spot meter on the window, then focus on the dog? hmmm that might not be posible cos my camera does not have AE lock :( gotta wait till i get Fuji S9500! :D
you might want to know if u use spot meter, you are exposing based on that particular area. In this case, you are exposing based on the dog. hence if you spot meter on the area outside the window, the blown highlights previously will now be exposed properly but everything else will be under.

I think I have tried this before, try metering something outside the window that is as close to 18% grey as possible and the overall result will not be too bad.

Try reading this:-

http://olympusdigitalschool.com/photo_lessons/E-1_How_To_Use_The_Spot_Metering_Mode/index.html
 

Zaknafein

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#11
metallilan said:
how bout shooting in potrait? that might cut off the distracting laundry.

i was practicing how to meter :) thx for the advice
and btw, really appreciate everybody's help here!! thank you
 

Zaknafein

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#13
hmm, so have to use fill in flash to avoid under exposing the subject right? okay point noted, thanks :)
is there any way to soften the flash blast if the distance to subject cannot be changed?
 

Cactus jACK

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#14
Zaknafein said:
i notice the left side of the picture is way over exposed so i tried a couple more times. however , all similar results. the left window is always over exposed while the dog is under expose. couldnt expose the whole picture correctly.

should i use spot metering in the first place, or is my technique of using it wrong?
first and formost, you should try to aviod such shooting conditions where you have such high contrast in the frame. try a different angle, if you can't aviod that, try using the fill flash, etc...

however, for testing sake, your test results seems fine. spot metering evaluates the proper EV value for the "spot", such that that "spot" would be correctly exposed (not saying anything about the rest of the frame yet).

evaluation of your results - the area around the dogs eye appears to have decent exposure (a little under, but thereabouts). the window is blown because the metering was evaluated at a relatively darker spot (dogs eye). Conversely, the dogs ear is a little under because the metering was evaluated at relatively lighter spot (dogs eye).

reading your post, i assume that your aim was to achieve a "uniformed" exposure... you can try other methods of metering (center-weighted or matrix), but i would suggest decreasing the high contrast in the frame by drawing the curtains and / or using a reflector for the near side of the subject.
 

solarii

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#15
Zaknafein said:
hmm, so have to use fill in flash to avoid under exposing the subject right? okay point noted, thanks :)
is there any way to soften the flash blast if the distance to subject cannot be changed?
Looks like your problem has been pretty well defined. If you want to use fill-flash and soften the effect you could
1) Cover your flash with tissue, though this may cause under-exposure if not done properly
2) If you can control flash output dial in an FEC of -1/3 to -1. For me, I usually use -1/3 cos my canon flash already under-exposes a little.

If you really hate to use flash another option is a graduated filter. But this set-up is pretty expensive and not worth the $$ for a compact camera, esp. if all you want to show is your laundry properly exposed! :bsmilie:
 

LittleWolf

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#16
Zaknafein said:
so a better way to meter is to spot meter on the window, then focus on the dog?
One can expose for the highlights and reduce the contrast numerically on the computer. This requires however sufficient dynamic range (low noise levels) of the camera and the file format (e.g. raw or 48bpp TIFF, not vanilla JPEG), or the results will be disappointing. I'm not familiar with your camera model, so I don't know if this is a viable option.

If you spot meter the window, you may want to adjust the exposure correction so that the highlights just don't clip. This makes the best use of the dynamic range of the sensor. For my camera, typically +2 ... 2.5 EV is needed; you may have to experiment a bit to find out what is appropriate for yours.
 

student

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#17
foxtwo said:
as the dog is dark coloured, open up for more light if you find it dark.
??? Heh? Think you might have got it wrong? Spot meter on a dark dog and open up?
 

roti_prata

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#18
its impossible to get good exposure for the whole frame with any current camera since no consumer camera will sync fast enough to fill flash.

u can close ur window or use a grad ND filter which is essentially a piece of glass tt is half tainted. the tainted half will act as sun glasses to reduce the glare from the open window while the clear half will allow light from the dog. the difference is definitely more thn 3 stops so u'll need to stack filters at the cost of img quality. then u can matrix meter(as in meter the whole frame)

manual will help if ur cam allows.

getting the 9500 wont help in such shots.

frankly, i think the window is too bright for all consumer and most prosumer cameras w/o filters. meaning lowest iso+smallest apature+fastest shutter still = over exposed
 

foxtwo

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#19
student said:
??? Heh? Think you might have got it wrong? Spot meter on a dark dog and open up?
TS wants to expose lighter for the dog. based on spot metering that exposes correctly for 18% grey, to get the dog recorded lighter he should open up.
 

student

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#20
foxtwo said:
TS wants to expose lighter for the dog. based on spot metering that exposes correctly for 18% grey, to get the dog recorded lighter he should open up.

So the dark dog becomes a light grey dog? Or even a white dog?
 

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