Are metering systems becoming obsolete?

Started Feb 2, 2013 | Discussions thread
Anders W
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Re: Are metering systems becoming obsolete ?
In reply to Detail Man, Feb 3, 2013

Detail Man wrote:

Anders W wrote:

Detail Man wrote:

marrlin wrote:

Detail Man wrote:

Anders W wrote:

marrlin wrote:

With evf's, and the quick, easily accessible dial, as on the em5, is there any need for evaluative, center, spot metering anymore?

With my previous mirrored cameras, I would spot meter all the time.

I've only had the em5 a week, but I can already see that it won't get as much use.

So far, just leave it on evaluative, and then dial it in depending on the image. With the highlight/shadow display on, I can easily see what the final image will be.

The live-view warnings for highlight clipping has largely but not entirely replaced ordinary metering as far as I am concerned. But there are a few special cases where the warnings fail and where I still use spot metering. See here for details:

http://forums.dpreview.com/forums/post/42348198

It seems (to me) that if the E-M5 preview system is designed to alert the user when in-camera JPG channel-levels are approaching maximum values (equal to or less than sRGB=255), then it would have to incorporate the "gradations soft-clipping" deviations in the JPG RGB tone-curve transfer-functions (deviating from what would be a "linear" sRGB tone-curve transfer function) ?

As each of the 4 gradation modes' tone-curve transfer-functions are different in their shape (and the amounts of non-linear addition gain-reduction implemented at higher sRGB output tone-levels differ), that would seem to have differing effects where it comes to the relation between what peak JPG-channel levels and RAW-channel levels would be (where it comes to the preview Histogram display, and when at any upper JPG output tone-levels other than at absolute maximum, sRGB=255).

It may well affect the distribution in the LV histogram (although I haven't tried to test it). It probably has little or no effect on the highlight clipping level as indicated by the histogram or the LV "blinkies". This particular point should be fixed at the exposure level where the RAWs are clipping.

Right, in the case that one wants to push things to the (JPG-referenced preview) maximum (as you set it for 255). For any approaches that would seek to use less than 255 as a "threshold of pain", though, the ratio of the RAW peak-levels (relative to RAW maximum) to the JPG peak-levels (relative to JPG maximum) begin to drop (by a full 1.0 EV) over the upper range of the JPG output tone-curve transfer-function where "soft-clipping" (over and above the non-linear gamma-correction of the mapping to sRGB or Adobe RGB) is applied.

(Perhaps) this is why users do not seem to report the preview Histogram as being highly useful ?

Not sure why this would make the histogram less useful. Only those shooting OOC jpegs would ever want to fiddle with the in-camera gradations, and for them it might if anything be more useful to have the histogram properly reflect the brightness distribution they will get.

The statement was in reference to users who wish to record JPGs simultaneously along with RAWs. In that usage, they will lose the ability to maximize peak recorded RAW levels using the Histogram (because it would be reflecting the differing in-camera JPG tone-curve transfer function). Some users other than yourself may have an interest in such applications.

As I pointed out above, I think the clipping point would remain correctly indicated by the histogram regardless of how you set the jpeg tone curve. Further, the many ways the E-M5 allows you to adjust the tone curve of the OOC jpegs should make the prospects of getting both the OOC jpegs and the RAWs the way you want them unusually good. However, as you know, I am personally unlikely to do any fiddling for the purpose of optimizing the OOC jpegs. Not a primary concern of mine to say the least.

However, one reason why you don't see so much appreciation of the LV histogram of the E-M5 might be that many find the LV "blinkies" superior and don't bother to use the histogram for that reason. As you know, I am in that camp.

What, don't you want to know when you are "clipping the shadows". The results can be truly catastrophic, you know ! ... ...

Yes, I am having constant nightmares about that.

Seriously, though, it would be nice if the preview Histogram could be meaningfully configured to represent RAW channel-levels (and not be forced to reflect "soft-clipping" in-camera JPG tone-curve transfer-functions) - as in such applications as UniWB configurations. Some users other than yourself may have an interest in such applications.

See above. I would think the highlight clipping warning (whether provided by the LV blinkies or the histogram) would remain well in line with the RAW clipping point under a variety of OOC jpeg tone curves.

I shall not speak lowly of the almighty "Blinkies". I am convinced that they are quite handy indeed, once a user is initiated into the esoteric order of the RAW-shooting acrobats who know their various idiosyncracies (that Olympus would likely not dare include in their Instruction Manual, out of concern for confusing and pehaps the risk of frustrating the average user with complexities).

I wouldn't call them almighty but they do have their "bright sides" (pun intended).

I wonder if perhaps these non-linear "gradation" curves (might, also) affect the E-M5 metering itself ?

Again, that might well be the case although I haven't tried to test it.

It seem like if this is so, one would want to then ensure that they are spot-metering on a scene luminance level that corresponds to absolute maximum (JPG-referenced) recording levels - or else the peak recorded RAW-channel levels would not bear a consistent relation to the preview indicators ? I think that it might work that way. Let me know if you think it would be different.

I would think that ordinary metering changes with the choice of OOC jpeg tone curve, yes, although I don't think the highlight clipping warning is affected.

I have no idea what that means. And honestly, I don't think anyone would.

(Perhaps), don't be so sure about what other readers may or may not understand. Anders W will.

Well, at least in this case he did.

Detail Man is often accused of "speaking in tongues" incomprehensible to (at least some) readers.

Luckily, some of us are there to tell you if you picked the right tongue.

 Anders W's gear list:Anders W's gear list
Panasonic Lumix DMC-G1 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Panasonic Lumix G Vario 7-14mm F4 ASPH +21 more
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