Just thinking aloud...

[Ben Rubinstein]

I would love to have your shoulder strength for two 1 series bodies. You shoot a lot of concert stuff don't you? With lights flashing on and off all over the place how can you shoot that way, don't you need to trust your settings to get it right?

[Ben Rubinstein]

So is one option to use raw with say -1 compensation, and then do batch conversion with the corresponding +1 set, and maybe an appropriate constrast level or tone curve? Cases where highlights do awry would probably then need a second custom conversion.

That is precisely what I do, the problem is that calming the highlights down is not that precise in ACR, I use the minus exposure plus brightness and a tweak of the curves. For portraiture I use a standard Highlights=2 contrast =3 in the shadow/highlights tool as I find that it gives a more film like response.

Jonathan, can you not use Av with spot metering on the face? Would that not keep the exposures more even as you don't have to worry about the ambient or spotlighting?
I use an incident meter indoors and outdoors when the light is stable-ish. If the light is changing I can usually see it happening and re-meter. I bought a 1Ds today and am going to experiment with using the spot meter in manual mode to meter off faces which should be more accurate then doing the same thing with partial metering which is all the 10D has.

I found in Av mode that the shutter speeds can jump so far between shot to shot that I can't really trust that I'm shooting at handholdable speeds. My auto flash does not have hi sync so using Av and juggling the ISO to keep the shutter speeds between 1/60 and 1/200 is a pain in the neck.

I'm usually shooting max iso 400 and RAW of course, a stop underexposed doesn't really bother me at all so when I meter off the face, I keep that setting in manual and underexpose a bit. That way I preserve the highlights, keep better tonality in the face and am usually within a stop of the perfect exposure. I check regularly of course.

[BJL]

BJL,
I recall your mentioning this before. Are you implying there's a little man inside the camera that thinks, 'bugger, he's got the wrong exposure again. I'll go easy on the amplification'?

I haven't noticed that high ISO's have a tendency to clip less with overexposure, in RAW mode. But maybe you are right.  

Mainly I am implying that at higher ISO setting, the amount of light reaching the photsites is less (higher exposure index, meaning a shorter exposure time for the same f-stop). Higher ISO settings entail a higher amplification factor in the charge-to-voltage conversion pre-amplifier, used to convert electron counts from photosites into input voltages for the A/D converter.

As far as I know (Jonathan might know in more detail), highlight clipping can have at least three causes, or which only the first is naturally avoided by using higher exposure index ("ISO")
1) over-full electron wells
2) maxed out pre-amplifier or A/D converter
3) at JPEG conversion

Every doubling of ISO above the minimum halves the electron count produced at wells, but then every stop of + compensation has the opposite effect. The electron count from the wells is then amplified (on-chip pre-amplifier with Canon CMOS) before going into the A/D converter, so that, with no exposure compensation, any ISO setting will produce the same signal strength going from the pre-amplifier into the A/D convertor.  So it is possibe that at this stage, the extra amplification used at higher ISO causes pre-amplifier "clipping", or exceeds the maximum input level that the A/D converter can handle.

Finaly, if you use "straight" conversion from RAW to JPEG, whether in-camera or on-computer, the highest output levels might get clipped or compressed. JPEG tends to allow for only about 2 1/2 stops from mid-tone to "level 255", whereas th ndstruy standard for DLSR sensor base ISO speed measurement is placing mid-tones at 18% and the full well  capacity at 170%, a bit over three stops of headroom.

If so, lowering the contrast setting (applied during JPEG conversion) could salvage something.

[Jonathan Wienke]

Just got the 1Ds today, I see what you mean, at iso 400 a stop underexposure makes the shadow noise look as bad as iso 1600 on my 10D, WOW, at least the evaluative metering is far more accurate so I'll need to dial in less 'buffer' underexposure.

For most stuff, I shoot Av mode, evaluative metering, +1/3 EC. For most outdoor/sunlit stuff that'll get you pretty close; I shot an outdoor all-day music festival last Saturday (>3300 frames, a new 1-day personal record!) with those settings on the 1Ds and 1D-MkII for about 80% of the daytime stuff. After dark I had to use a variety of settings for different shots, anywhere from -2 to +2/3, depending on the elements in the shot and the stage lighting.

[pobrien3]

I recently did a wedding in Thailand; shooting everything from indoor, outdoor bright directional sun, heavy shade in same sun, afternoon with low directional sun and finally late evening and fireworks, and hardly shifted off Av mode + evaluative the whole day (except for fireworks, obviously).  No blown highlights, lots of noise-free detail in the shadows which was easily lifted out from the high contrast shots.  I found this a more challenging metering problem than most I've done in the UK, where you're pretty much assured of a nice tupperware-grey sky to light everything pretty evenly and flatly!  I also used a 550EX dialled down half a stop, and the equipment (though heavy) worked beautifully together.

The 1DsMkII is a fantastic camera - the best I have owned by a long mark.

[Ben Rubinstein]

Not really when the overexposure is on the face losing skin detail. The straight evaluative exposure blew the white shirt of my subject completely which is why I decided to go for an incident reading.
With a -1 stop, i.e. the incident reading, the picture was perfect straight out of the camera. Apart from which if I overexpose the subject the the background goes darker which I prefer to avoid.
I've set my '1Ds' custom settings in ACR as:  exposure -1.5, brightness +150. It gives the same result as the standard setting (0.0,+50) but with better highlight control. I also straightened out the highlight end of the curve in ACR for slightly less contrast in the highlights while maintaining good overall contrast at a standard setting of +45.
I usually have to batch a lot of photos at a time, though nothing like you seem to be doing thank G-d, Finding a set of values that I can batch all the photos to so that they need only minor tweaking of exposure afterwards is very important to me.
BTW I'm having difficulty finding a level of USM that works for portraiture on the 1Ds. With the 10D I was using 230,1,0. With these new pics I haven't made up my mind yet, they need more sharpening but they also have worse grain. For custom enlargements I use my own edge sharpening action but a standard setting for the proofs I haven't found yet.

[Jack Flesher]

From a practical standpoint I think it would be easier to dial in any compensations directly myself -- at both ends of the process -- rather than have the meter calibrated so it read some value under and a raw processor compensate for it.  Also, often the difference between a blown or clipped channel and a full DR exposure is just 1/3 stop...

In the end I think it makes a lot more logical sense to learn your system and develop a standardized workflow like Jonathan's article suggests.  

For landscape I am usually in manual mode and double-checking the histogram.  For action, I am lazier and put the cam in Av and dial in -1/3 or -2/3 exposure comp (depending on the camera I'm using), then deal with it later in raw or post.

Bottom line is I prefer to be the one making the decisions....

Cheers,
Jack

[Jonathan Wienke]

Jonathan, I'm a wedding shooter, I cannot allow my self the luxury of checking the histogram and shooting again nor would I have time for bracketing.

That's bovine excrement. I shoot weddings as well, and have no trouble finding time to point the camera down the aisle before the wedding party starts walking it to double-check the histogram. The whole idea is to shoot a scene BEFORE the moment of interest occurs there, so that you can know your settings are appropriate. This is not hard to do, all you need is knowledge of the flow of events so that you know what's going to be happening and where before it happens. If you're not already accomplishing that, you have no business shooting weddings. It's one of several reasons I always shoot the rehearsal; I have a chance to shoot the venue beforehand and familiarize myself with the lighting, see the exact sequence of events and figure out where I want to be, and deal with any restrictions there may be regarding flash usage, movement restrictions, etc. before the actual event. And one can usually get some decent candids as well.

[Jonathan Wienke]

I chimp a lot because I try to get every shot as close to ideal as possible without blowing highlights, so I get anal about 1/3-stop adjustments that most photographers wouldn't worry about. But I know when to chimp and when to just shoot. If I'm off a little bit, it usually doesn't matter, because the difference usually isn't something that would be visible in a print without doing a side-by-side comparison with a loupe.

In your hypothetical grab-shot situation I'd be prepared because A, I'd have already done some test shots in the lighting not under the tree and know what the appropriate settings were, and B, because I shoot weddings and events in general with both my 1-series bodies on my person. If I'm in a situation where there's two significantly different lighing conditions adjacent to each other, I'll have one body set for each lighting condition, and if I see a grab-shot opportunity, I can drop one body, grab the other, and get the shot while you're still fiddling around changing settings. Or I'll have worked out some camera settings that will work well for both lighting conditions; Av mode can be handy for that sort of thing. Don't asssume that meticulous preparation and successfully capturing grab-shots are mutually exclusive, the truth is that the first is often key to the second.

[Ray]

your idea sounds equivalent to selecting a bit of underexposure compensation and then fixing the overall tonal level in the digital domain. If the highlights are blown due to sensor wells filling up, lowering ISO at the same time will not help, but at the elevated ISO setting of ISO 400 and 200 that you mention, the sensor is being "underexposed" anyway, so that is probably not the problem. Instead highlights are probably lost mainly in JPEG conversion.

BJL,
I recall your mentioning this before. Are you implying there's a little man inside the camera that thinks, 'bugger, he's got the wrong exposure again. I'll go easy on the amplification'?

I haven't noticed that high ISO's have a tendency to clip less with overexposure, in RAW mode. But maybe you are right.  

[Jonathan Wienke]

Jonathan, can you not use Av with spot metering on the face? Would that not keep the exposures more even as you don't have to worry about the ambient or spotlighting?

Heh. Not when you're shooting racially mixed groups, and especially not when faces are off-center or you're shooting wide shots. I'm in California, where whites will be a minority in 10 years or so if current demographic trends continue. Black, Hispanic, Filipino, and Asian people are common, as well as every possible combination of the above. One of the bands I shot yesterday had 2 white girls, one of whom was a blonde with a very fair complexion, and  two black girls, one of whom had very dark skin. Spot metering would have made exposure vary nearly two stops, depending on which girl I was shooting. So I used Evaluative with +1/3 EC and things came out pretty consistent.

Also, that idea is totally useless when trying to get wide shots of the whole band and stage setup, as it is fairly unlikely you'll be able to spot meter on a face when the people are moving around too fast to keep a focus point on their face. If there's even one located where you'd need it.
Manual mode is not an option when stage lighting fluctuates 2-4 stops every few seconds, and spot metering is only useful when shooting manual is practical.

I'm usually shooting max iso 400 and RAW of course, a stop underexposed doesn't really bother me at all

Get out of the habit of shooting a stop under with the 1Ds; if you need more than +1 adjustment in ACR then image quality will be negatively impacted, especially when shooting above ISO 200. At ISO 800, you want to be within 1/3 stop of ideal or you'll run into noise issues and occasionally banding. Ideally, you want the ACR exposure slider between 0 and -.4 for best results.

[pobrien3]

I do a lot of events with the sort of lighting variety Jonathan mantioned, with the added fun that action is important (often dance events and night parades, when action moves from stage / TV lighting through to nighttime streets in HK).  Weddings I do rarely, and I'm very happy I don't have to make a living from them.  I've experienced the exposure problems and shot failures you both mention (Jon and Pom), and remain thankful that the client rarely has the sense of quality and criticality that the photographer does.  That was with film and the 10D, before I got the 1DsMkII.

The difference in exposure accuracy between the 10D and 1-series is significant: it's also way better than my 1v.  I can now shoot on evaluative +1/3ev for just about everything, and only really have to move off that (and shift ISO around - need a faster way of doing that) when stage lights dictate.  Pom, I think the 1Ds will change the way you work.

Anyone remember the manual days when exposure for weddings was 'dress highlights +3' to get it in Z8 or 'face +1' to get it in Z6?!  I actually often still use the latter, plus it's ethnic variants, for portraits.

[Jack Flesher]

I think you just may have put the finger on something that's been bothering me about the 20D also.

I've struggled some (but not too often) with highlights in exposures, and of course I've mainly blamed myself and not the tool.

Actually, the 1-series metering accuracy is one of the reasons I have not yet abandoned my 1D2 for the smaller and lighter 20D...

[Jonathan Wienke]

the overexposed images were fully recoverable and when ACR'ed (-.30 exposure) were as good as the correctly exposed images.

-.30 exposure adjustment in ACR means you nailed the exposure dead on with the 1Ds in the vast majority of cases. As long as you haven't clipped non-specular highlights, "overexposure" is a good thing.