Partial metering

Ah meng · 26th February 2003

Is EOS 30's partial metering accurate enough to read tricky light situation like snow, no or small area of middle tone background.Will it be fool by e lighting.

If not,what is e potential and purpose of having it.Pls give example.Do i hav to get a gray card or incident/reflected light meter?Thanks

Ah meng · 27th February 2003

No response???

d7t3 · 27th February 2003

Quote:

Is EOS 30's partial metering accurate enough to read tricky light situation like snow, no or small area of middle tone background.Will it be fool by e lighting.

If not,what is e potential and purpose of having it.Pls give example.Do i hav to get a gray card or incident/reflected light meter?

1st, i don't use a canon. but here are my 2c.

1: what is a meter for? usually, the 'standard' subject is a grey card. so the meter will try to reproduce a grey card in the same shade. i think a grey card will help if you place it in the right position, within the partial metering area.

2: partial metering allows you to meter a small area in the viewfinder. so it can still be fooled by snow (it can't tell whether it's white or grey). you can use a grey card, or compensate +1 to +2 without.

ziploc · 27th February 2003

Quote:

Originally posted by Ah meng
Is EOS 30's partial metering accurate enough to read tricky light situation like snow, no or small area of middle tone background.Will it be fool by e lighting.

If not,what is e potential and purpose of having it.Pls give example.Do i hav to get a gray card or incident/reflected light meter?Thanks

Spot/partial metering would only give you an exposure setting which is at grey tone. In other words, yes it will still be fool as it will read the reflected light off the snow and then give you an exposure which will put the snow in the grey tone area. To overcome this, you'll need to do as d7t3 suggested: use an exposure compensation of +1 to +2 ev depends on how "white" you want the snow to appear.

The purpose of spot/partial meter is just that: to meter the reflected light at that spot, and by knowing that the meter will tell you a grey tone exposure, work from there and compensate it for the exposure you want. (Note: this technique does not apply to matrix/evaluative metering, as in this case it is unpredictable how the meter will evaluate the entire scene. You'll just have to trust it, or use spot/partial metering to do it yourself).

If you are interested, read John Shaw's books. He gave very detailed explanation on how this is done.

Btw, I'm not a canon user either.

Hope that helps.

Ah meng · 27th February 2003

Thank you.

kiwitan · 27th February 2003

Does this apply for a beach setting where you have light reflecting from sands and water ? U then have to over-compensate by 1 or 1.5 stop ?

Quote:

Originally posted by ziploc

Spot/partial metering would only give you an exposure setting which is at grey tone. In other words, yes it will still be fool as it will read the reflected light off the snow and then give you an exposure which will put the snow in the grey tone area. To overcome this, you'll need to do as d7t3 suggested: use an exposure compensation of +1 to +2 ev depends on how "white" you want the snow to appear.

ziploc · 27th February 2003

Dry sand is probably slightly brighter then grey tone, so I would guess a compensation of +0.5 to +1.5 ev compensation as you mentioned (also depends on how "white" the sand is and how "white" you want it to look). Wet sand is about at grey tone. Again this is provided you are refering to spot metering and is metering off the sand. Also note that you'll need to lock the AE before you recompose.

26th February 2003	#1
Ah meng Member Join Date: Jan 2003 Location: Jurong Posts: 443	Partial metering Is EOS 30's partial metering accurate enough to read tricky light situation like snow, no or small area of middle tone background.Will it be fool by e lighting. If not,what is e potential and purpose of having it.Pls give example.Do i hav to get a gray card or incident/reflected light meter?Thanks

27th February 2003	#2
Ah meng Member Join Date: Jan 2003 Location: Jurong Posts: 443	No response???

27th February 2003	#7
ziploc Moderator Join Date: Jan 2002 Location: Snoopyland Posts: 3,185	Dry sand is probably slightly brighter then grey tone, so I would guess a compensation of +0.5 to +1.5 ev compensation as you mentioned (also depends on how "white" the sand is and how "white" you want it to look). Wet sand is about at grey tone. Again this is provided you are refering to spot metering and is metering off the sand. Also note that you'll need to lock the AE before you recompose.