hello i'm graham and i hope everyone's having a great day and welcome to today's video now this
is part three in the video tutorial series we're looking at the panasonic lumix bridge camera range
in today's video i'm going to look at exposure and how the camera calculates the exposure
what settings you've got in there to influence the way the camera does make that meter in choice
and how it can be fooled and how you can correct it to make sure you've got perfect exposure either
for stills or for video so today i've got the panasonic lumix fz1000 mark ii out um i've got
my book out for this now it's been out for about three or four months it's available on
my website i'll put a link to that in the video description below or if you're fairly affluent
you can buy it from the amazon website uh across the world so it's out there if you want to have
a look at the fz1000 mark ii user manual enough of the adverts let's get on with today's program
so we're going to look at exposure and how the camera can calculate exposure now the whole
purpose of the camera metering circuit is to make sure that all the mid-tones are correctly exposed
and give us a digital value of about 127 if we were to look at that in a photoshop for
example and we use the eyedropper to measure the luminosity of that part of the image so
traditionally you would use the meter in the whole area mode or in the center weighted mode
to enable you to capture the right exposure green grass is a good mid tone you can use of
course grey cards to give you a more accurate exposure and these are designed to give an 18
reflectance which is midway between the highlights at 255 and the shadows at zero so this should
give you a reading of one two seven for perfect exposure so if you were to take a picture of this
and the camera was exposing correctly if you were to look at that in photoshop you'd see its value
was about 127. so if you've got a tricky lighting situation where you're against the light or
you've got a non-uh standard scene you could actually use your gray card to take an exposure
reading and then take your shot so put that into the manual mode and take the shot i said grass
has got a reflectance of about 18 so that's a good standby if you're out and about and you are
stuck with a tricky lighting situation you can actually meter off the grass set that then as a
manual exposure and take your shot and you'll get a perfect exposure i'm going to demonstrate both
of those methods now so i'll put the grey card in the same light and i'll get an exposure reading
so i'm going to fill the whole area with the gray card and it's giving me an exposure of 1 800 at
f5 iso one two five so i'll set that in the manual mode so i'm going to shut a shutter speed of 1 800
that's f5 and iso
one two five so i'll take that picture in the same light
so that's 1800 f5 iso 125 and you'll see on screen it's a perfect exposure the other method you can
use is to use the palm of your hand um and i think this works across all ethnicities too so if you've
got um dark hands then if you use a palm of your hand i believe this still works for you so if i
take a meter reading off the palm of my hand again in the sunlight for again filling the screen again
i'm getting exposure of 1 800 oh sorry i'm in the manual mode let me go back to aperture priority
i'm getting an exposure reading of a 640th at f5 so
we're within a third of a stop so that would be easily corrected in your after processing
so the three metering modes that the camera can use are the whole area the center weighted and
spot now the spot is an ideal method if you've got something which has got very high contrast against
the background the moon's a very good example of where spot metering is ideal you can use a spot to
meter from a crater on the moon which is mid-tone grey and you'll get a perfect exposure if you use
a whole area or center weighted there's so much darkness in the sky there that the meter is going
to be fooled into thinking that that needs to be brought to mid-gray as well and it will give
you a very overexposed image and you get the white orb rather than the moon with all the detail in it
so which metering mode should you use and when well whole area is good because it evaluates the
whole of the scene tries to work out the contrast ratio between your foreground and background
and set an exposure dependent on that if you're taking portraits better to use so to center weight
because your subject is normally going to be in the middle of the scene so it will concentrate
on getting the subject right and spot is where you want precise metering from either a distant object
or one that's got a lot of gradation across it and you want to take a specific point now
it's quite possible you get a lighting situation which can fool the meter if you've got a subject
for example if you're taking a portrait in snow then you'll find that the whiteness of the scene
fools the meter into thinking that the scene is actually overexposed and it darkens the image and
makes you have a very much underexposed image you get these grayish looking backgrounds rather than
a pure white background and same applies to beach scenes as well bright white sand
can give you a lot of underexposure and then we use what's called exposure compensation and ev
is accessed in different ways on these cameras normally through the push of a button or on the
cursor control depends which camera you're using but exposure compensation allows you to correct
when the meter has got it wrong so for example on this camera the exposure compensation is here on
the function four button so when you push that it brings up the ev scale and you can adjust the
exposure this is of course in the semi-automatic modes if you're in the manual mode then you don't
have exposure compensation you determine that by setting your exposure so if you want underexposure
you either use a faster shutter speed or a smaller aperture that's where you work it in manual mode
on screen now you can see some examples of when i've actually forced the camera to make the
wrong decision so i set the subject up against the neutral gray background and the exposure
is absolutely correct but when i substitute that gray background for a white background
you notice the subject becomes underexposed so the cameras under expose that because of
that white background it's influenced the way the meters worked if i substitute the white background
for a black background you get the converse so the black background is influencing the meter and it
overexposes the image so you get a much bleached out look so this is when you should actually
remember to use your exposure compensation so this is where you use exposure compensation again so
with that same image where it was overexposed because of the black background i dial in
negative ev so minus exposure compensation to bring the subject back to the normal balance and
it's the same with snow you always want to plus ev when you're shooting on snow to brighten up
the background because the camera has been influenced by the amount of whiteness in the scene
now there is an in camera too you can use it's called the histogram and the histogram is just
a visual representation of the tones between the shadows which are at zero digital value two the
highlights were at digital value two five five so the whole of your scene should fall within that
range if you've got it perfect then you'll notice your mid tones sit on the 127 axis so you've got
everything perfectly balanced the best way to do this is actually take your scene and then
review the image rather than look at the live view of the histogram because that's not influenced by
the exposure so take your picture have a look at the histogram and if it's perfectly centered then
you know you've got a good exposure now there is a group of enthusiasts that shoot with what's called
exposed to the right so this means that they're trying to force the highlights to the right hand
side of that graph but without pushing them into overexposure the theory has been that the blacks
in your image are brought above the noise level in digital photography we've always got a noise floor
which might be in the shadow area of your image so if we move everything to the right it means
that those darkest blacks might be above the noise level so when you process that image and bring the
mid-tones back to the mid-tone position you'll find that your blacks are clear without noise
there's some benefit in it but it's a lot of messing around and sometimes you will overexpose
if you're not careful so it's better to try and keep your exposure centered and make sure you've
got it right so if you see that image on screen you'll see that the mid-tone peak is exactly
on the 127 axis so we've got our highlights which are contained within the 255 boundary
um our shadows don't fall down to zero and if you look at the individual color channels the red
the green and the blue again none of them are into the shadow area or into the highlight area
so that shows we've got good exposure even though we've got those bright white clouds in the scene
they've not been overexposed so the histogram when you review it in the replay mode gives you a good
idea of how that subject has been captured there are of course situations where you need to do a
bit of interpretation so if you shot an image on snow then they're going to be a lot of white peaks
in there or conversely if you're taking a picture in shadows there'll be a lot of black peaks so
you've got to use a bit of interpretation when it comes to images which are outside the normal
range of exposures if you want a tip here if you put the image review mode into the hold position
then when you take a picture that image will stay in your viewfinder or on the lcd and if you use
the display button you can actually cycle through until you find the histogram there and then you've
got an immediate view of how that image has been captured so you can see if your neutral grays
are neutral or if you're overexposing you'll see that immediately you've taken the picture
just press the shutter button then to clear that preview and you can go on to shoot your next image
to finish this video off i've got some images here that i've just shot this morning as i walked
around robins village some which are backlit some which are front lit and i've had to vary
the exposure in a couple of the backlit shots to overcome the amount of dynamic range that would
need to be captured in the subject in one shot there of the flower which is severely backlit
it's beyond the dynamic range at which this camera can capture so there's more than nine or ten stops
of dynamic range there so to ensure that i've got enough detail in the shadows as well as returning
the highlights in the petal from the backlight i've used flash to fill that in and that's
reduced the dynamic range so instead of having to try and come accommodate 10 or 12 stops of ray
a light it's now having to only compensate for sort of six or seven because i filled
the shadows with that flash so you can either use a white reflector or a silver reflector to
burn some light back into your shadows if you're shooting in these extreme light conditions where
you're not going to have enough dynamic range with these cameras to be able to capture the scene
you can try the ihdr mode of the camera that will artificially increase the shadows
to try and resolve that dynamic range here's a shot using the standard mode
versus ihdr and you see the the camera as bright in the shadows in the image of the stocks here
well that's it for today's video on the subject of exposure how the camera calculates exposure
how you can use a neutral gray car to give you a correct exposure in very tricky lighting
situations how you can overcome scene tanks which are going to fool the camera by using
exposure compensation and some of the tricks of using the histogram to be able to evaluate your
image that's been captured as to whether you've got enough range there to enable you to process
the shadows and the highlights my next video we're going to be looking at the autofocus and
manual focus mode so we're going to be included in today's video but it would make this whole video
far too long to assimilate so the next video will be on the af and manual focus modes of this range
of cameras so until then thanks very much for watching and of course if you are a new viewer
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watching please do take care and i hope to see you all in the next one goodbye for now