Light Meters vs In Camera Metering


Mac

Link Posted 30/04/2013 - 15:03
I've just watched a video by a cinematographer who discusses the differences between incidental and spot meters. At the end of the day, he leans towards spot meters.

He cautions to always take polarizers and filters into account while determining exposures.

OK, says I, where does the in camera's meter fall into the mix?

I can set it to spot reading, and it is already reading through the lens and filters I'm using. I can aim the camera at the "zone" I think would represent a grey card, and lock the exposure.

What do you all think? Am I going to get the best exposure 9 times out of 10?

I'm too cheap to spend hundreds of dollars on an extra step if it won't buy me much outdoors.

Now, that said, I certainly see the value of incident meters in the studio.

Love to hear your opinions.

Cheers!
Mac from Montreal

SP, SPII, SPF, PZ-10, P30, SFX, K110D, istDS, Optio 60, Z-10, H90, RZ10, I-10, f3.5 28mm, f1.8 55mm, f1.4 50mm, f3.5 135mm, f2.5 135mm, f4 50mm Macro, f4.5 80-200 F, f4 35-70, f3.5 28-80, f3.5 35-135, f3.5 18-55, f1.8 31mm Ltd., two Auto 110's, Auto 110 lenses and filters, tubes, bellows, Manfrottos and a sore back.

gwing

Link Posted 30/04/2013 - 15:39
In general I think you will get the best results from the metering method you are used to and where you know the metering is likely to need adjustment or bracketing - that's probably more important than any technical differences between the methods.

That said my view of pros/cons for some metering methods is:

a) In camera Matrix. Probably going to give the highest success rate if you leave it all up to the camera. Probably not a good choice if you are going to use your brain as you'll have to then not only read the light but also second guess the 'intelligent' metrering logic.
b) In camera Centre Weighted. Old fashioned but my favourite as I know how to work that way. Metering behaviour is predictable so you can easily tell when you need to manually compensate for backlight etc.
c) In camera spot meter. I guess the best of all alternatives if you really want to base exposure just on one particular shade or go to the faff of yourself integrating multiple readings of individual areas. In most hands this generally results in badly exposed photographs.
d) Dedicated off camera spot meter. An extreme form of (c) where you usually gain/suffer a smaller spot but also have to manually compensate for filters, macro tubes etc. I have somewhere a Pentax digital spotmeter I once thought might be usefull but found not so, at least for me.
e) Off camera incident meter (or light integrating dome over camera lens). This is the oldest fashioned method of all - I also found it to give the best results for me back in the days of slide film where most scenes exceeded film dynamic range, note that this was for outdoor landscape and wildlife photography rather than studio. I also found it the most enjoyable method to use but have since succombed to the convenience of in-camera metrering but if you want to play with something different this is what I would recommend.
Last Edited by gwing on 30/04/2013 - 15:40

johnriley

Link Posted 30/04/2013 - 15:56
The cinematographer will be talking about incident light measurement and reflective light measurement. The first measures the light by pointing the meter at the light source. The second measures the light by reading the light reflected from the subject.

This has got nothing to do with spot meters or any other sort of meter. A meter is made into a incident meter by putting a white translucent cap over the meter cell. This can be an Invercone, such as used on the Weston Master, or even a special filter to put over the lens on a DSLR.

Now, the second subject is the type of measurement used. This relates to how much of a subject a reflective meter reading measures. In the camera we can selct centre weighted, measuring most of the frame but concentrating on the centre. We can measure using spot, just the very centre of the frame. We can use matrix metering that uses many areas and also may have algorithms that try to guess what sort of subject we are shooting. If the sky area is very bright, for example, it might think we are shooting a landscape and adjust the exposure accordingly.

Modern in-camera meters are very accurate and very sensitive. You don't need a separate meter.
Best regards, John

Don

Link Posted 30/04/2013 - 16:12
with digital, you can get away with the in camera meter.... adjustments can be made and more shots taken..

but if you are using the built in spot meter, or a separate handheld meter... best to really learn how to use it... the truth is these tools were vital when shooting expensive narrow latitude slide film/movie film in the past... Ansel Adams Zone system saved a lot of money for film makers...
but today is digital, and in camera meters and a little know how all you really need for many applications...
I use a handheld meter for flash (incident or reflected depends), and my camera set to either spot or matrix metering for most applications..
I use the spot meter on my d-slr to meter various brightnesses within a scene and only for critical work..
Fired many shots. Didn't kill anything.

Mac

Link Posted 30/04/2013 - 17:45
Thanks to you all for your thoughtful input.

I agree that I have to practice with whatever metering system I decide upon, and will start with center-weighted, in-camera first. I guess it's a compromise/average starting point.

I've been playing around with in-camera spot metering and boy, is it hairy!

I'm thinking back to my Spotmatic days and really can't remember that little needle ever letting me down in any big way. We learned to add or subtract a stop by instinct after a while.
Anybody remember if those old meters were general or center-weighted?

Havin' fun now!
Mac from Montreal

SP, SPII, SPF, PZ-10, P30, SFX, K110D, istDS, Optio 60, Z-10, H90, RZ10, I-10, f3.5 28mm, f1.8 55mm, f1.4 50mm, f3.5 135mm, f2.5 135mm, f4 50mm Macro, f4.5 80-200 F, f4 35-70, f3.5 28-80, f3.5 35-135, f3.5 18-55, f1.8 31mm Ltd., two Auto 110's, Auto 110 lenses and filters, tubes, bellows, Manfrottos and a sore back.

johnriley

Link Posted 30/04/2013 - 18:03
The Spotmatic was average reading, so all of the image was measured equally. The later bayonet cameras were centre-weighted.

The Spotmatic was originally to have a spot meter, hence its name, but the results were too variable unless in expert hands.
Best regards, John

Mac

Link Posted 30/04/2013 - 19:11
Thanks as always John.

That's what I'm finding even now with my istDS set on "Spot", in inexpert hands (mine).

BTW, thanks for that little piece of history - never knew what the "Spot" was supposed to mean.

I guess the "matic" part was that the meter was coupled with the shutter speed, and we set the lens opening to wherever the needle centered.

OK, moving on the center-weighted.

Cheers!
Mac from Montreal

SP, SPII, SPF, PZ-10, P30, SFX, K110D, istDS, Optio 60, Z-10, H90, RZ10, I-10, f3.5 28mm, f1.8 55mm, f1.4 50mm, f3.5 135mm, f2.5 135mm, f4 50mm Macro, f4.5 80-200 F, f4 35-70, f3.5 28-80, f3.5 35-135, f3.5 18-55, f1.8 31mm Ltd., two Auto 110's, Auto 110 lenses and filters, tubes, bellows, Manfrottos and a sore back.

McGregNi

Link Posted 01/05/2013 - 21:23
An Incident light reading (ie from a hand held meter)in theory should give the most consistency, but involves the extra steps of placing the meter correctly, and the moving away from the camera that might involve.

The different camera metering modes we have now at our disposal at the turn of a dial add much extra flexibility, but the readings are still subject to the inconsistencies caused by the changing 'reflectivity' of different materials and colours.

Matrix mode will meter for the subject, whilst taking 'into account' the light levels surrounding the subject. Spot mode will not take 'into account' these surrounding light levels, so can lead to more extreme exposure errors.

What might look like a grey card can often turn out to have quite different reflective qualities, depending on the surface texture / direction of light for example, so I'd say is difficult to judge in the field.

If spot metering a subject (say a persons face, or animals body) then the normal 'rules' of exposure compensation still apply - ie reduce exposure for darker than 'average' / increase for lighter then 'average'. So in fact theres a lot going on then with all this, especially if you have to zoom or re-compose to get the spot reading - maybe the incident light reading is not such a chore after all?
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
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Last Edited by McGregNi on 01/05/2013 - 21:25

Mac

Link Posted 01/05/2013 - 22:01
Thank's Nigel,

Just went through your gallery and I'd say you certainly know your stuff!

Do you often use an incident meter reading outdoors?

Have you ever compared it to what your K7 would choose to do in matrix mode?

I appreciate your input!
Mac from Montreal

SP, SPII, SPF, PZ-10, P30, SFX, K110D, istDS, Optio 60, Z-10, H90, RZ10, I-10, f3.5 28mm, f1.8 55mm, f1.4 50mm, f3.5 135mm, f2.5 135mm, f4 50mm Macro, f4.5 80-200 F, f4 35-70, f3.5 28-80, f3.5 35-135, f3.5 18-55, f1.8 31mm Ltd., two Auto 110's, Auto 110 lenses and filters, tubes, bellows, Manfrottos and a sore back.

McGregNi

Link Posted 03/05/2013 - 00:25
Mac, it must admit, it is easier to learn about something and then spout off about it (ha ha) than actually do it! The reality is ( as others have alluded to) that in this digital age I find the light meter is slipping further and further towards the bottom of the kit bag.

I guess the main argument in favour of incident readings is that it eliminates the variables caused by surface reflective qualities - you are metering the actual same light that illiminates the subject.

This is all very good if the subject is, say, a vase of flowers 10 feet in front of you - you can place the meter to read the light. But for scenics or a wide view it is not that simple - the light falling on the far distance may be quite different to that falling onto you at the shooting position. In any case, however you meter you can only shoot at one single exposure value, and we have to use the best information we can to decide that value.

These days I am increasingly finding the best way to judge is with the histogram on the camera. With film the main priority was to ensure a correctly exposed subject, because the 'development' options were very limited (unless you had your own darkroom). Now, with the amount of control available, I find I am actually more concerned about the extremes of the exposure - I am thinking how will I be able to keep control at both ends of the histogram, and it is this consideration that weighs mostly on the exposure decisions (ie not so much the subject or midtone).

With processing I find we now have such control over the midtone (I'd say 1-2 stops without much worry), that precise metering in this zone is not so important. The critical decisions are more about the detailing priorities at the extremes - so in a way, this brings us back to spot metering, maybe picking out different spots to make an average to choose an optimum exposure for any single frame. (If thats impossible then we have HDR - but thats for another thread!)

Personally I wish the K7 matrix system was more agressive, at least in reducing the high end tones and highlights. I shoot at ISO 100 mostly when outdoors, and am constantly amazed at the good detail I can pull back up from shadows, so I don't mind a reading that 'underexposes'. I find it harder to restore attractive tones and detail where highlights are overexposed. So when in Matrix mode I am often dialing in -1/2 or -1 stop compensation.
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver
Last Edited by McGregNi on 03/05/2013 - 00:32

johnha

Link Posted 03/05/2013 - 01:03
I've used a handheld meter a lot in the past (mostly with MF cameras which didn't have meters). The options here are usually either spot reflective or incident, both work well, but as non-TTL you have to account for filters (or [yawn] any bellows/lens extension). I've used this a bit with 35mm when shooting film to check my metering (or older non-metered cameras).

On digital you can check the screen/histogram which should give you some idea whether you're in the right ballpark. When in manual I use spot metering (I haven't a clue what the matrix metering has already compensated for). When in a program mode, I usually use matrix as I'm set to shoot quickly, the only time I'd use spot in program is with AE lock, re-framing before shooting.

My handheld meter (Sekonic L408B) has incident and 5 degree 'spot' metering (5 degrees is quite wide when using tele lenses). It allows 3 readings to be taken (i.e. mid-tone, highlight & shadow) so you can see what your dynamic range needs to be - but it doesn't average them for you.

As for the K-7 reducing high end tones - IIRC when the Z-1 was launched it had some kind of highlight compensation programmed into it. Basically if parts of the subject were very bright (at the top of the meter range), the system determined that it was a highlight rather than a mid-tone in unnaturally bright light, so it would add to the exposure to ensure it was recorded as a highlight rather than a mid-tone. This worked for me with slide film, maybe the K-7 uses something similar?
PPG Flickr

pentaxian450

Link Posted 03/05/2013 - 02:28
Mac, if you're interested, I could manage to meet with you somewhere in Montreal and let you play with the incident/reflective light meter. Just let me know if you're interested, and we'll figure out a place and time.
Yves (another one of those crazy Canucks)

Mac

Link Posted 03/05/2013 - 12:14
Bonjour Yves!

Actually, my evil and wealthy Nikon brother-in-law has both a Sekonic Incident studio meter, and a Nikon Spot Meter. We are heading into Les Cantons de L'Est (sp) for the weekend and he is bringing them both with him for us to experiment with.

Merci beaucoup for your very kind offer, however!

I'll let you all know if I discover anything earth shattering.

Fly safely, Mon Ami!
Mac from Montreal

SP, SPII, SPF, PZ-10, P30, SFX, K110D, istDS, Optio 60, Z-10, H90, RZ10, I-10, f3.5 28mm, f1.8 55mm, f1.4 50mm, f3.5 135mm, f2.5 135mm, f4 50mm Macro, f4.5 80-200 F, f4 35-70, f3.5 28-80, f3.5 35-135, f3.5 18-55, f1.8 31mm Ltd., two Auto 110's, Auto 110 lenses and filters, tubes, bellows, Manfrottos and a sore back.

pentaxian450

Link Posted 03/05/2013 - 12:25
Mac wrote:
Fly safely, Mon Ami!

I always do.
Yves (another one of those crazy Canucks)

Mac

Link Posted 03/05/2013 - 12:29
Nigel and John,

You fellows have provided me a great deal of information about this science and if nothing else, I'm beginning to understand the evolution of the internal workings of the newer camera models (not just more pixels etc). Thank you for your insights.

Seems to me that the TTL metering is improving to such a degree that hand-held meters are becoming less and less necessary. Maybe that's why so many are for sale on line.

Gonna play with meters whenever I can to learn all I can about the all-important, and most complex photography component - light.
Mac from Montreal

SP, SPII, SPF, PZ-10, P30, SFX, K110D, istDS, Optio 60, Z-10, H90, RZ10, I-10, f3.5 28mm, f1.8 55mm, f1.4 50mm, f3.5 135mm, f2.5 135mm, f4 50mm Macro, f4.5 80-200 F, f4 35-70, f3.5 28-80, f3.5 35-135, f3.5 18-55, f1.8 31mm Ltd., two Auto 110's, Auto 110 lenses and filters, tubes, bellows, Manfrottos and a sore back.
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