metering issues with 5D MkII

<p>I'm a professional maritime photographer in San Francisco. And I've been shooting for years. I understand the difference between different metering patterns (spot, center-weighted averaging, and pattern). And I know, too, the kinds of lighting and subjects that are likely to fool a camera's meter, and have learned to compensate when dealing with those.</p>

<p>I almost always shoot in aperture priority, and dial in exposure compensation to compensate as needed. For instance, I'll bump exposure up 1 or even 1 1/3 stops when shooting wide shots under gray skies, preferring to keep the clouds bright, and bring up the detail in my darker subjects. Or if a boat sails in front of a dark background, I'll compensate -1/3 or -2/3 to keep the dark areas dark, and hold detail in the white sails.</p>

<p>Recently some of the exposures calculated by my 5D MkII have me wondering what I'm missing. I don't understand what is causing exposure to be so far off in some scenes.</p>

<p>I will attach some samples below.</p>

<p> </p>

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<p>1/500 f/8, iso 400, +1/3 exposure compensation, pattern metering</p>

<p>5D MkII, 24-105 L, Singh-Ray LB Warming Polarizer</p>

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<p>1/1000 f/8, iso 400, +1/3 exposure compensation, pattern metering</p>

<p>5D MkII, 24-105 L, Singh-Ray LB Warming Polarizer</p>

</p><div></div>

<p>These two exposures were taken seconds apart, with the same camera, of the same subject.</p>

<p>[[of the same subject.]]</p>

<p>With vastly different framing. </p>

<p> </p>

<p>And how about these two. The first of the next two attachments was shot with the 5D MkII at the same settings as above, only this time the camera chose a still lower exposure of 1/1250 at f/8. And yes, this is still with +1/3 of exposure compensation.</p>

<p> </p><div></div>

<p>Compare the above with another shot, similar subjects on the same day, taken with a 5D and 100-400, set to Aperture Priority and iso 800, also set for +1/3 compensation.</p>

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<p>Rob-- Yes, I changed the composition, but I don't see anything in that shot that should fool the meter so badly.</p>

<p>Comapring photos 1 and 2 I would say #2 has much more reflective water in the picture and secondly you are using a polarising filtern and have changed the angle of the shot quite drastically in relation to the position of the sun (maybe by 60 degrees of more).</p>

<p>With Photo 3 and 4 seem almost non-comparable to each other or the other shots. </p>

<p>I'm having the same problem too. Underexposure in certain daylight/overcast conditions in evaluative metering. Spot metering overexposes. I also think the metering is off from exposure to exposure, sometimes even when the subject has not moved at all. This is all under aperture priority.</p>

<p>Your first pair of shots - assuming that we see the whole frame in both - confuses me. It could be that in #1 exposure was largely based on the very large area of shaded sail, and this allowed the much brighter area of directly sunlit boat stern to blow out. I'm not sure why the second is so dark except that it looks like it might have been better without the exposure compensation dialed in.</p>

<p>In the second pair the cause seems more obvious. In the first shot a good percentage of the frame is the very bright boat, and with your compensation dialed in and the meter zeroing in on that the frame ended up dark. In the second, tighter shot the meter picked up on your central subject, the shaded persons in dark clothes, and allowed the bright white sunlit portion of the boat to blow out.</p>

<p>In situation like these, if I had time, I would perhaps go with manual exposure.</p>

<p>I understand that you have shot for years, and that you understand all the basics of metering and so forth. How new are you to digital as opposed to shooting with film? If you thoroughly understand the differences in how you need to deal with exposure issues, I won't offer any more than that question - except to say that film-based exposure methods do not always turn out to ideal for digital.</p>

<p>Dan</p>

<p>I've never used a 5D, but I do know that with the Canon DSLRs that I have used, the matrix metering is highly dependent upon the focus point. Especially when using the cameras set up for using only a single middle focus point, the exposures can be wildly different. Don't know that this has anything to do with your problem, but it's probably a factor to be considered.</p>

<blockquote>

<p>I've never used a 5D, but I do know that with the Canon DSLRs that I have used, the matrix metering is highly dependent upon the focus point. Especially when using the cameras set up for using only a single middle focus point, the exposures can be wildly different. Don't know that this has anything to do with your problem, but it's probably a factor to be considered.</p>

</blockquote>

<p>This must be it. Your explanation *totally* meshes with my experience on the 5DmkII. I was using the central AF point when I noticed much more variation in exposure.</p>

<p>Thanks for all the feedback, folks. The first shot I posted to show an exposure that works for me. The stern may be very bright white, but I have all the detail I need in the RAW exposure, so I'm fine with that. In the second exposure, after recomposing, the whole scene appears very dark to me. There's no cropping there; you're seeing the whole thing. A blue sky isn't going to fool the meter, so I'm not clear about what did.</p>

<p>Dan, while you said the second shot may have been better without compensation dialed in, I think you misunderstood. I had the camera set to OVERexpose by 1/3 stop. Without that, it would have been even darker.</p>

<p>I thought the two tighter shots were pretty similar in lighting angle, but I accept the point that the darker one has more areas of sunlit hull closer to the center. Still, I've never had such trouble before. Exposures missed by such a wide margin are pretty rare for me, and I don't see the cause in these images.</p>

<p>I'll definitely check on the exposure point selection though, to see if that's a factor here. I do select different points for different shots.</p>

<p>Have you tried without the PL? </p>

<p>Dan, I've shot film in the past, but my pro career has been completely digital, so I'm familiar with how to expose best for it. Typically I favor exposing to the right, as long as I'm shooting RAW. I get my highlights as bright as possible without blowing them (gray skies excepted--they can blow out), because shadow detail, especially crew faces, etc., is of primary importance to me.</p>

<p>Arash, no, I almost always use the polarizer. IMO it's a necessity to get good contrast and color on the water, especially on sunny days.</p>

<p>I've been shooting a 5D for over 3 years and a 5D Mark II for over 4 months. I too use a polarizer whenever I'm outside. I almost always use evaulative metering.</p>

<p>I've never encounterd the kinds of stark differences you've shown in your pics. Mine have always been very consistent. The 2nd and 3rd pics I find to be very unusual and not anything I would expect.</p>

<p>My recommendation would be to send it in to Canon, along with the photos, have the check the camera over.</p>

<p>Here's what might be happening here. The exposure dilema seems to be a result of your use of that polarizer. Remember that with any polarizer the exposure value is affected by the relative position of the sun and the degree of rotation of the circular polarizer to attenuate the reflections.<br>

Given that the strongest attenuation of those reflections is 90 degrees to the right or left of your subjects position to the sun and based on what I see here in your posts your subjects all seem to be about 90 to 100 degrees clockwise from the suns position.<br>

My questions are did you adjust the degree of polarization for each shot or did it change, and if so, what type of metering was used? Backtrack your steps and I'll bet your question is easily answered.</p>

 

<p>Peter: First, sorry for my misreading of the exposure compensation info. Second, it sounds like you do understand the ETTR business with digital. Good luck sorting this out.</p>

<p>I'm a 5D and 5DII user and I haven't noticed any camera related exposure problems with my bodies.</p>

<p>Dan</p>

<p>

<p>Peter,<br>

I understand that PL is essential to your work and in principal it should not affect metering because metering is TTL, but it is possible that the sensor is not fully calibrated with the meter when it comes to polarized light because of the various reflective layers that exist on the sensor, and thus at certain angles meter sees more light than the sensor, the best way would be to try without a PL first to see if you can get consistent exposure, this will eliminate the chances of meter being defective. If this turns out to be the case then you have to find a solution for the PL, maybe try a different brand that Canon recommends? <br>

If meter is inconsistent without the PL, I'd send the camera to Canon for calibration. </p>

</p>

 

<p>I've noticed that in each image there is a piece of bright white that is near clipping. It's just a wild guess, but do you have highlight priority turned on?</p>

<p>Probably not, but I just thought I'd ask to get it out of the way.</p>

<p>My recommendation would be to use center weighted average metering with your compensations dialed in as normal, or better yet go full manual and spot meter (or chimp) if you have time to kill. I understand it's a pain to switch the way you operate, but if it was me, I would make sure the meter is working accurately with a grey card, and then avoid matrix metering in that particular lighting situation.</p>

<p>It might also be the filter, as others have said. Perhaps it is somehow partially blocking the wavelengths that the meter responds to?</p>

<p>I couldn't find anything in the manual about pattern metering, but if that also means evalulative metering:</p>

<p>The manual states that when using AF (one shot) and evaluative metering, the metering occurs at the time focus is acheived, not when the shot is taken (like exposure lock). Are you perhaps recomposing, or is the scene recomposing itself on the high seas?</p>

<p>Peter, I have had the camera for 6 months and almost 10k shots. I still can not figure out how it meters. I am not new to photography either but I am puzzeled by the various exposure I get with this camera.<br>

Maybe it does need calibareation as Arash suggested.</p>