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Thread: circular polariser metering...

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    Default circular polariser metering...

    Hi people, got a question. I know that using Cir Pol cuts out some light, so when using it, do i need to +1 Exp comp? or just use it as metered?
    300D/5d2/40D/1d3/5D3
    17-40L F4, 28-70L F2.8, 24-105L F4, 50 F1.4, 70-200L F2.8

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    Quote Originally Posted by ptwong
    Hi people, got a question. I know that using Cir Pol cuts out some light, so when using it, do i need to +1 Exp comp? or just use it as metered?
    Just meter as you would from what you see in the viewfinder.

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    Yup, just meter as usual.

    The wonders of TTL metering...

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    ... But the photos seemed to darken alot and am glad that bro ptwong posted this question.
    Interestingly, when I upped the Exp, images turn too bright at +1 but +1/3 seemed ok.
    Perhaps the polariser should only be used in bright light conditions?

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    A polariser saturates colours, which explains why you think the photos look darker. Sorry for asking this, but you do know what a polariser is used for, right?

    And there is NO need to Exp compensate, because your TTL meter has already taken the dark polariser into account when doing the metering, which explains why +1 is over exposed while +1/3 looks ok (when it's actually a teeny bit over exposed.)

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    Quote Originally Posted by coldfish
    ... But the photos seemed to darken alot and am glad that bro ptwong posted this question.
    Interestingly, when I upped the Exp, images turn too bright at +1 but +1/3 seemed ok.
    Perhaps the polariser should only be used in bright light conditions?
    Perhaps you might be discovering the limits of the evaluative/matrix metering modes. You were most probably pointing at a scene which includes a lot of sky in this shot and most dummy metering modes will underexpose and require +EV compensation given such circumstances, whether or not a polarizor is used.

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    Thank you all.
    This month's Photography Monthly did mention that Circular Polariser is suitable for spot metering, which the camera has it only in Manual Mode (300D).
    Would that mean I should use a Linear Polariser instead?

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    sorry mate...think you might be mistaken....300D don't have spot metering, only partial metering.

    Circular Polariser is meant for lenses with AF so that the cam can hunt where to focus....pls correct me if i'm wrong
    300D/5d2/40D/1d3/5D3
    17-40L F4, 28-70L F2.8, 24-105L F4, 50 F1.4, 70-200L F2.8

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    Sorry for the term that I'm used to. However, partial metering is just about equal to spot metering.
    I tried it in manual mode just now and yes, the overall results looked better now.
    ARAIK, Polariser existed even before AF and no, it's not there to help the AF to hunt but used mainly on situations where you want to reduce reflections or to enhance colour saturation. By slowly turning the polariser at the correct angle to the light, you'll see marked improvements.

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    ptwong meant that for AF cameras, you need to use a Circular polariser, as opposed to a Linear polariser because a linear polariser may mess up your metering and AF, because the semi-silvered mirror in your AF SLR is also a partial polariser. (pls correct me if I'm wrong). This problem is solved by using a circular polariser, through some optical physics which I have forgotten.

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    Quote Originally Posted by coldfish
    Sorry for the term that I'm used to. However, partial metering is just about equal to spot metering.
    If you continue to believe in this, I think Canon and all the other brands wasted their effort to build spot metering into their cameras as well as the light meters.

    There is a vast difference between 1-2% and 12% in metering coverage.

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    Justarius: I got the point. Thanx for the info.

    Watcher: Do you get spot metering in 300D? Guess Canon didn't waste any effort at all!
    So if your camera doesn't offer spot metering but partial metering instead, wouldn't you consider partial metering as spot comparing to other metering modes? In absolute term, of course you would want to say the exact word. So when I say spot, it's rhetoric.
    If they are that so much different, why would so many books and websites putting lumping spot/partial together instead of separate explanations for each mode?
    Besides, the difference is some what closer the figures you gave: 1~3.5% (leaning towards 3.5%) for spot and 9.5.
    So if I were to take every word from you, Canon and other brands should really waste their efforts.

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    Quote Originally Posted by coldfish
    Justarius: I got the point. Thanx for the info.

    Watcher: Do you get spot metering in 300D? Guess Canon didn't waste any effort at all!
    No, but does Canon has spot metering on 1D, 1Ds 1DMkII? Guess they did spend the effort there, didn't they? I guess they don't have time to put that in your 300D after spending all the time on disabling the functions in firmware.... BTW, all Nikon DSLR has true spot metering in ALL modes. The D70 for example can spot in any of the standard mode without restriction. Canon pro bodies are similar.

    Quote Originally Posted by coldfish
    So if your camera doesn't offer spot metering but partial metering instead, wouldn't you consider partial metering as spot comparing to other metering modes? In absolute term, of course you would want to say the exact word. So when I say spot, it's rhetoric.
    They are not comparable. At best, the partial metering is a poor substitude. By being rhetorical? Please. That is instead being inaccurate at best, misleading is more appropriate.

    Quote Originally Posted by coldfish
    If they are that so much different, why would so many books and websites putting lumping spot/partial together instead of separate explanations for each mode?
    Besides, the difference is some what closer the figures you gave: 1~3.5% (leaning towards 3.5%) for spot and 9.5.
    So if I were to take every word from you, Canon and other brands should really waste their efforts.
    The numbers (1.8% vs 12%) came from the review off Amateur Photographer. Search for it yourself. The concept is similar but in actual shooting, it is totally different between 1+% and something closer to 10%.

    If you're trying to make this a C vs N thing again, try harder. I just said, as ptwong said, "300D don't have spot metering, only partial metering." I brought in the fact that Canon has true spot metering on its pro bodies but the 300D does not. And if you said they are they same, then the Canon engineers wasted time in implementing spot metering. Where did I mention in my post of any other brands? You are the one who goes on a personal brand flamewar, with the inferiority complex and having the need to try defending the 300D
    Last edited by Watcher; 1st August 2004 at 01:14 AM.

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    There is a way to use partial meter as spot meter (almost there) if u are using zoom lens.

    Just zoom in, take partial meter, zoom out, compose.

    There is indeeed some diff between the two, else canon pro series wont have 4 metering mode, ie, partial & spot.
    photography makes one sees things from all angles.

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    Quote Originally Posted by denniskee
    There is a way to use partial meter as spot meter (almost there) if u are using zoom lens.

    Just zoom in, take partial meter, zoom out, compose.

    There is indeeed some diff between the two, else canon pro series wont have 4 metering mode, ie, partial & spot.
    Agree but then, that is not a optimal solution. What if you have a prime? What if you have a moving target and that the lighting changes like a model walking down a runway?
    Last edited by Watcher; 1st August 2004 at 10:30 AM.

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    Quote Originally Posted by Watcher
    No, but does Canon has spot metering on 1D, 1Ds 1DMkII? Guess they did spend the effort there, didn't they? I guess they don't have time to put that in your 300D after spending all the time on disabling the functions in firmware.... BTW, all Nikon DSLR has true spot metering in ALL modes. The D70 for example can spot in any of the standard mode without restriction. Canon pro bodies are similar.

    You still don't get it do you? Both Ptwong & I own a 300D. So what camera body would you refer to in such situation? Any sane person will understand that.
    As I have mentioned earlier and will say this again: Since 300D doesn't have spot metering, I'll treat the partial as spot. Is that hard to understand, dude?
    Besides, my A70 has spot metering built-in and that's the reason why I brought up in much earlier post that I got so used to the term spot metering.
    Does that automatically make it a PRO Digital Compact?


    Quote Originally Posted by Watcher
    They are not comparable. At best, the partial metering is a poor substitude. By being rhetorical? Please. That is instead being inaccurate at best, misleading is more appropriate.

    If you say:' They have different names and thus they are different in some ways.' I would have wholeheartedly agree with you. If partial metering is such poor substitute, I would have noticed a hell lot of difference when shooting at the same subject using my A70 (spot) and 300D (partial). Or perhaps my eyes are not as PRO as yours?


    Quote Originally Posted by Watcher
    The numbers (1.8% vs 12%) came from the review off Amateur Photographer. Search for it yourself. The concept is similar but in actual shooting, it is totally different between 1+% and something closer to 10%.

    'The concept is similar but in actual shooting, it is....' ??? What talk you? Also, please make up your mind what figure you want to use. At one point it's 1-2%, another time 1.8% and finally you settle it as 1+%... ROFL!
    Since you insist on your figures, I'll just stick to mine. Instead of being a snob to ask you to search it yourself, I'll humbly provide the URLs that I got the figures from:

    http://www.photozone.de/4Technique/metering.htm#spot

    Note the spot/partial instead of separate column for each? I guess this guy must have been misleading me all the while!

    Oh, one more from Phil Askey about spot/partial metering:

    http://www.dpreview.com/learn/?/key=metering

    Noticed the title Spot (partial) Metering? Boy, Phil must have conned me right from day 1!


    Quote Originally Posted by Watcher
    If you're trying to make this a C vs N thing again, try harder. I just said, as ptwong said, "300D don't have spot metering, only partial metering." I brought in the fact that Canon has true spot metering on its pro bodies but the 300D does not.

    You don't have to echo this again Polly since Ptwong has already pointed it out very clearly and I have have understood him. Please read again my earlier posts.
    Have I started any 'C vs N' before? Have I said anything like 'C is better than N' in any posts?


    Quote Originally Posted by Watcher
    And if you said they are they same, then the Canon engineers wasted time in implementing spot metering. Where did I mention in my post of any other brands? You are the one who goes on a personal brand flamewar, with the inferiority complex and having the need to try defending the 300D

    Have I accused you of mentioning any other brand? Which post and which paragraph?
    Have I named any model except 300D in any earlier posts? Dude, if you are on drugs, please don't attempt to reply any threads.
    FYI, I was on the verge of getting myself a D70 but upon weighing the pros and cons, I decided to go for 300D and am very very happy with it.
    I can pay for 1D MKII or D2H or whatever 'pro' body you can name in CASH but have chosen not to because I feel that I am not a 'pro' and will only buy exactly what I need.
    I would only envy people who make the best out of their systems and that's real pro.
    Besides, no judge will take what camera system a contestant used into account when judging his photo. It's the quality of the picture taken that is decisive.
    Now that you've mentioned several times 'pro' or 'pro bodies' and now 'personal brand flamewar' and 'inferiority complex', it's your class conciousness that's driving you to want to believe that I was trying to defend 300D in any way.
    It's your self inferiority that made you budge into a thread that was discussing a totally different topic.

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    errr....guys....it was just a innocent question with good answers, there's no need to get personel lah....small thing only...i don't understand the lingo you guys using also ha....I just shoot only...

    Happy Shooting people!!
    300D/5d2/40D/1d3/5D3
    17-40L F4, 28-70L F2.8, 24-105L F4, 50 F1.4, 70-200L F2.8

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    If frankly, coldfish insist that in practise, spot and partial metering is identical, I have nothing to say. The simple reason why both terms are placed together is because the concept is similar but like saying the cooler (say 4 degrees celcius) and the freezer (-18 degrees celcius) compartment of a fridge is the same because they chill and preserve food. True, they do both preserve food for say 3 days with no difference, but try selling a fridge saying that they are the same and you get deceptive sales complaint slap on. Or saying Singapore/Malaysia does not mean that we are now one country (though we were once one country )

    If these two modes provides the same result, why does Canon provide the different mode on the pro bodies like 1D, 1Ds and 1DMkII. Could it be that they are different? Or the Canon engineers too free and just feels like implementing features that are very similar...

    Luckily, I'm not a pro; I have not earned a single cent from shooting, not even weddings (I don't do those). I don't even have the $$$ to try out digital with A80 or any this-millenium P&S; my last P&S is a Kodak DCS 420 bought in 1998 with a sub-megapixel true rez that I'm still using.

    Or else I would have to post tons of link where reviewers say "it even shares some of the inconveniences of the EOS 10D, including a viewfinder that shows only 95 percent of the frame and the absence of spot metering." If they are similar, would this even be mentioned?

    Or this Canon user:
    "For tricky lighting, I use partial metering. This is the most precise metering mode, but obviously, takes a bit more work: you have to select a uniform tonality to meter (b/c of partial's bigger area than a true spot meter, you cannot select a small speck of the area)" (emphasis mine)

    Or this where users were commenting on the fact that the 10D lack spot metering...
    Last edited by Watcher; 2nd August 2004 at 10:36 AM.

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