Compensating for M8 exposure

[gdi]

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After reading the recent posts on exposure I am trying to see if the problems experienced with blown highlights and unusable noise can be handled formulaically. Which of the following are accurate and which need adjustments or more information?

 

- expose to preserve highlights (underexpose) - the M8 has a huge amount of headroom in the shadows which allow for compensation in post (this must be only for low ISO up to 320, because compensating for high ISO shots results in tremendous noise?)

- never underexpose high ISO shots or you will get unacceptable noise if you compensate by increasing exposure in post.

 

So in effect (someone else posted this approach) you must compensate with -ev for good light/low ISO and +ev for low light/high ISO? This way you can generally avoid blown highlights and eliminate the need to add exposure to high ISO shots which results in noise?

 

Thanks

[Jamie Roberts]

Exposure isn't really that complex, but there are things to bear in mind...

• treat the meter as a spot attached to the RF patch. It's job is to turn the reflected light you point it at into 18% (thereabouts) grey. Not black, not white.
  
• If you have trouble imagining what that grey represents, buy a cheap grey card from Kodak (they're under $20).
  
• Learn to meter from significant parts of the scene and exposure lock if you shoot in Av. Me? I shoot in manual so I can place highlights and shadows where I want them (see below).
  
• If you point the RF patch / meter at something white (highlight) that is important to preserve, the Av will turn the white thing grey and will "underexpose" that important white thing, and bring the tonal values down for the rest of the shot. People often have this happen at high ISOs, where they point the RF / meter at the brightest object (which often isn't the subject but a light or something) and the camera consequently underexposes the subject, leading to noise, gnashing of teeth, and complaints about high ISO repsonse.
  
• If you point the meter at something black / dark grey (shadow) that is important to preserve, then the Av will turn the black thing grey and will "overexpose" that important black thing, and bring the tonality up for the rest of the shot. This is often a better technique with digital if the highlights just aren't important, and often they're not. At higher ISOs, shooting RAW, where you can bring down tonal values in post, this often garners better results than "preserving highlights" which often aren't important to the shot anyway. IOW, in a high-contrast situation, you need to make a decision about what's important to the shot and what isn't; if all of it important, you need to modify the light (bring the shadows up with a flash or reflector).

IOW, your meter will turn things "average" grey (which is really quite dark!). That's the way a reflective meter is supposed to work, and the M8's works really well.

 

Now, the hardest thing for me coming from film was to understand high ISOs in digital: you simply don't have the latitude or extra stops of noise-free detail in the shadows you do at lower ISOs with the M8 (or any digicam, actually).

 

At ISO 160-640 the M8 is very forgiving here, due to the fact it captures a lot of data). However, you need to make sure at high ISOs you don't starve the sensor for light. Again, read the above carefully.

 

As an example, if you have a picture of someone blowing out candles, don't meter off the candles! Their face is the important element; let the candle flames blow out and expose for the light surrounding their face (probably darker due to fall off). That way, the whole exposure gets "pushed up" and their face gets a proper exposure; the candles themselves are blown (but who cares?) and you can set a proper blackpoint.

 

But you can see that simply setting -Ev will not work. You need to read how the meter really works.

 

BTW--I recommended this before, and I'll do it again: if this mystifies you buying a cheap incident meter and learning how to use it will improve your exposures till you "get" the built-in meter.

[Dan States]

That's about right, even up to 640. Exposure is most critical at 1250-2500 because compensation creates visible noise. Remember to use minimal sharpening and luminance noise reduction in all M8 images and you will get great results.

 

Dan

[Guest rweisz]

[*]treat the meter as a spot attached to the RF patch.

 

The trouble with that is it isn't a spotmeter. It's a weird oblong center-weighted pattern and it's not always easy to isolate what you want to meter unless you can get in close enough to basically fill the frame with it. I have to conclude that Seiko or whoever makes the shutter offered a light-colored shutterblade as there "solution" to the peculiar off-the-shutter metering the M8 requires, vs a round white spot (like M6) spanning 3 shutterblades. IIRC the Contax G1-G2 had the same deal.

 

 

BTW--I recommended this before, and I'll do it again: if this mystifies you buying a cheap incident meter and learning how to use it will improve your exposures till you "get" the built-in meter.

 

My experiments show that the M8's meter is actually calibrated to underexpose a third of a stop. If the M8 is set to 160, my handheld meters (and my M6) all need 200 (320=400, 640=800 etc.) to equal what the M8 meter indicates (subject filling viewfinder).

[delander †]

Mine does not appear to underexpose by a 1/3 stop, see the other thread.

 

Jeff

[jaapv]

The trouble with that is it isn't a spotmeter. It's a weird oblong center-weighted pattern and it's not always easy to isolate what you want to meter unless you can get in close enough to basically fill the frame with it. I have to conclude that Seiko or whoever makes the shutter offered a light-colored shutterblade as there "solution" to the peculiar off-the-shutter metering the M8 requires, vs a round white spot (like M6) spanning 3 shutterblades. IIRC the Contax G1-G2 had the same deal.

 

 

 

 

My experiments show that the M8's meter is actually calibrated to underexpose a third of a stop. If the M8 is set to 160, my handheld meters (and my M6) all need 200 (320=400, 640=800 etc.) to equal what the M8 meter indicates (subject filling viewfinder).

That is not the esposure meter. The way of determining ISO is different on digital than it is on film. ISO 160 in the digital world is equivalent to ISO 200 on film. To compare you must set your exposure meter (and flash control for that matter) to 200 to level the playing field. 360=400, etc...

Sean Reid noted as much in his first M8 review, back in 2006.

[mboerma]

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It's a weird oblong center-weighted pattern and it's not always easy to isolate what you want to meter unless you can get in close enough to basically fill the frame with it.

 

These are just the blades of the shutter. This does not tell you how the reflected light of these blades is measured and interpreted by the real meter. This could well be a large sport meter, which I think it is, at least it is the way I use it.

[Jamie Roberts]

The trouble with that is it isn't a spotmeter. It's a weird oblong center-weighted pattern and it's not always easy to isolate what you want to meter unless you can get in close enough to basically fill the frame with it. {snipped}

 

Yes, I know it's not an actual spot meter (like my Sekonic). But it's best to treat more like one than like a matrix meter; I've never had any such "oblong" meter pattern discernable through thousands and thousands of shots.

 

YMMV. And Jaap (and Sean) is right about the "absolute ISO" too...

[Guest rweisz]

That is not the esposure meter. The way of determining ISO is different on digital than it is on film. ISO 160 in the digital world is equivalent to ISO 200 on film. To compare you must set your exposure meter (and flash control for that matter) to 200 to level the playing field. 360=400, etc...

Sean Reid noted as much in his first M8 review, back in 2006.

 

The M8's meter, frame-filling uniform wall, at 160 agrees with my Canon 1DS @ 200, which agrees with my Canon IV @ 200 which agrees with my Gossen and my Sekonic @ 200. I won't get into discussing the idea that there's a separate meaning for ISO in digital and film, because obviously your guru has spoken and you believe.

[Guest rweisz]

These are just the blades of the shutter. This does not tell you how the reflected light of these blades is measured and interpreted by the real meter. This could well be a large sport meter, which I think it is, at least it is the way I use it.

 

There's a diagram of the meter pattern in the M8 owner's manual. So either the guys at Leica don't know what they're talking about or.....

[mboerma]

The M8's meter, frame-filling uniform wall, at 160 agrees with my Canon 1DS @ 200, which agrees with my Canon IV @ 200 which agrees with my Gossen and my Sekonic @ 200. I won't get into discussing the idea that there's a separate meaning for ISO in digital and film, because obviously your guru has spoken and you believe.

 

 

But what is your conclusion from your measurements?

[mboerma]

There's a diagram of the meter pattern in the M8 owner's manual. So either the guys at Leica don't know what they're talking about or.....

 

Yes, or ?

 

I just stated that you can not tell from looking at the blades what kind of meter is used and how it is interpreted.

[mat_mcdermott]

 

So in effect (someone else posted this approach) you must compensate with -ev for good light/low ISO and +ev for low light/high ISO? This way you can generally avoid blown highlights and eliminate the need to add exposure to high ISO shots which results in noise?

 

 

I wouldn't monkey around with this on a shot by shot basis. I have mine set to - 1/3 and leave it there to protect the highlights a bit. A better strategy is to follow what Jamie said regarding how the meter works (and the M8's works just fine, though slightly differently than film Ms I'll admit) and then learn to see the light. If it's a dark scene, underexpose off the meter by a stop or a stop and a half (or more if it's a city skyline at night). If it's a bright scene, overexpose from the meter.

 

It's true that at ISO 1250 and 2500 you have little room for error with the M8, but just practice and pretty soon you'll be able to guess exposure pretty well.

 

Besides, don't neglect the histogram as a guide for judging exposure.

 

It seems like people make exposure far more complicated than it actually is.

[jaapv]

The M8's meter, frame-filling uniform wall, at 160 agrees with my Canon 1DS @ 200, which agrees with my Canon IV @ 200 which agrees with my Gossen and my Sekonic @ 200. I won't get into discussing the idea that there's a separate meaning for ISO in digital and film, because obviously your guru has spoken and you believe.

:confused:The only thing this post does is confirm mine, so I fail to see what you mean by that sneer.You have just proved that you can expose a wall correctly.

[Guest rweisz]

Yes, or ?

 

I just stated that you can not tell from looking at the blades what kind of meter is used and how it is interpreted.

 

Re-read what you wrote. You said it functions as a large spot meter. Now look at the diagram in the manual. Leica says it functions like a center-weighted meter...more emphasis in the center, less as it fans out.

[Guest rweisz]

:confused:The only thing this post does is confirm mine, so I fail to see what you mean by that sneer.You have just proved that you can expose a wall correctly.

 

If it makes your ego feel better to think so, be my guest. Or read the next posting, maybe it will be clearer. If not, e-mail the International Standards Organization and ask them if ISO-whatever# is different for film and digital. Honestly it's the first time I've ever heard it said, but not the first time on an internet forum that some photographer came up with a cockamaymie theory and it ended up becoming a myth.

[Guest rweisz]

 

But what is your conclusion from your measurements?

 

That ISO is ISO regardless of whether it's film or digital: the same readings on my 1DS (digital) as 1V (film) and seperate handheld meters (made originally for use with film). And, in addition, those same readings (at ISO 200) agree with what the M8 reads at ISO 160. Therefore maybe the M8's ISO 160=ISO200 but it isn't a universal truth that "digital ISO 160"="film ISO 200".

 

In other words, the M8's ISO 160= everyone else's ISO (film and digital) 200. ISO is a standard. If ISO xxx meant something different for film and digital there would be "Digital ISO" and "Film ISO" put out by the ISO. But there isn't.

[mboerma]

I have to conclude that Seiko or whoever makes the shutter offered a light-colored shutterblade as there "solution" to the peculiar off-the-shutter metering the M8 requires, vs a round white spot (like M6) spanning 3 shutterblades. IIRC the Contax G1-G2 had the same deal.

 

My responses were related to the text above. So you might want to re-read first. I'm afraid we go into some for of argument which isn't one.

[Guest rweisz]

The meters in M6, 7 etc use a round spot on the shutter and if you read those manuals Leica's diagram shows a more or less circular pattern. The M8 has a painted shutterblade, and the diagram shows an oblong pattern. If you want to argue, argue with Kaufmann or Stefan Daniel. I don't claim to know better than Leica.

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[mboerma]

That ISO is ISO regardless of whether it's film or digital: the same readings on my 1DS (digital) as 1V (film) and seperate handheld meters (made originally for use with film). And, in addition, those same readings (at ISO 200) agree with what the M8 reads at ISO 160. Therefore maybe the M8's ISO 160=ISO200 but it isn't a universal truth that "digital ISO 160"="film ISO 200".

 

Or the meter if off? I never said that "digital ISO 160"="film ISO 200". I do know that the ISO values many CCDs and CMOS sensors are not what they state they are. I also remember that many films were not really living up to the values stated on the box.

 

So there are to different things: the value the meter measures (or calculates) and the real ISO sensitivity of the CCD/CMOS or film.