> I also agree with Godfrey on ease of manual use. I'm glad we agree on something. ;-)
> Part of the issue with digital exposure is that there is so much more > information potentially available that a simple match needle would through > away too much useful information. I disagree. Until sensors data can be addressed to manipulate the capture data by photosite address, you will always have one exposure addressing all the photosites the same way. Whether you get there with some ultra-smart evaluative metering system, or you use your brain as the computational system and a meter as the dumb data input, the end result is always an ISO @ aperture @ exposure time. Knowing the characteristic curve of a sensor and how digital image data exposure operates, it's very easy to 'place' the exposure where you want it with a spot meter and a moment's thought: with the brightest area of significant detail 5% below the saturation limit. That's in practical terms the only thing you can do ... anything else you do is a matter of processing the raw data (setting the appropriate blackpoint, colorspace, and rendering curve to suit the dynamics of the scene). Writing computational automation to understand the characteristic curve of the sensor @ a specific ISO setting, analyzing the scene to determine what is or isn't important, and setting that single exposure point consistently ... Well, it's not that it can't be done, but it's way more than most current in-camera computational processing is capable of. I do this in my head faster than I can think about it. My E-5 had Spot-Hi and Spot-Lo modes for metering complex scenes that simplify manual metering (by comparison to just Spot in most other cameras, which is based on 18% reflectance reference). With almost all cameras, I set my metering to centerweighted averaging, evaluate the pattern, and use aperture priority AE or manual mode. With the APAE mode, I look at the scene, see the dynamics of the hot and dark areas, and tweak the EV comp to suit. With Manual, I set it to the meter's null point then tweak it up or down the same way, OR I just know what the scene type requires from past experience and set it. My brain does this without me consciously thinking about it, and FAR more consistently than any exposure automation I've ever seen. > Another issue is that digital isn't as tolerant of missed exposures as film, > though at ISO 100 the K-5 may be far more tolerant of underexposure than most > film. I don't find this to be true in general. Digital capture is more sensitive to the saturation point than film because it's a hard clip rather than a slow roll off, but it generally has more dynamic range and, as long as you're under the clip point, is much much much more manipulable. What's important to keep aware of is that as ISO increases, DR decreases so if you're looking at scenes that require elevated ISOs for hand-holdability or subject movement, you have to understand that the DR will be decreased and pick your important detail areas more carefully. I don't know of any automation system that can do this pre-exposure ... they simply don't have enough data to work with like your eye and mind does. On Sun, Jan 29, 2012 at 12:33 PM, Larry Colen <[email protected]> wrote: > Steve, > > I get the feeling that you are the only one that actually understands what > I'm saying. > > On Jan 29, 2012, at 11:20 AM, steve harley wrote: > >> on 2012-01-29 05:29 Paul Stenquist wrote >>> >>> On Jan 29, 2012, at 12:16 AM, steve harley wrote: >>> >>>> on 2012-01-28 21:57 Paul Stenquist wrote >>>>> That's basically what today's best meters do. But they still can't gauge >>>>> reflectivity and color as well as the human eye can. The meter makes a >>>>> call and a good photographer makes the necessary adjustment. Most of the >>>>> time the meter will come close enough for all practical purposes. for >>>>> those times when it can't the photographer has to lend a hand. It >>>>> wouldn't be much fun if machines did all the work. >>>> >>>> i submit that most of us don't have "today's best meters" >>> >>> The K-5 comes somewhat close, but no it's not at the top of the heap. But >>> it's more than good enough when photographers use their brain as well as >>> their meters. >> >> that may be, but i suspect that 1) most of us don't have K-5s, and 2) even >> much worse metering systems are "good enough" — we can learn to compensate >> for anything; some of us whose professions are to designs ways to exploit >> technology, however, will instinctively imagine extending tools as far as is >> possible and efficient > > This is exactly what I'm doing. My career is to write embedded systems > software. Designing and writing the software for setting the exposure of a > camera would be a job that my 30 years of professional experience is almost > ideally suited for. I recognize the limitations of the automatic systems, > know to check the exposure against the aids (histogram and blinkies). What > is frustrating is that those tools could give me exactly what I need, but > they don't. They tell me if the JPEG, which I don't use, would be properly > exposed, I want to know what is happening on the sensor. > Rather than red blinkies for over exposed and blue for underexposed portions > of the jpeg, which will change if you change the color balance, how about > red blinkies if you are clipping the data on the sensor, and yellow blinkies > if you are close enough to the limit of resolution that you'll get > posterization (or whatever you call it when you get those annoying lines in > the sky). > >> >> so as i gravitate toward a more manual process, i imagine the kind of tool i >> want to work with; the histogram (preferably representing RAW exposure, and >> live) simply offers a more direct means to an end; a camera's meter just >> gives one data point; we have to guess how it has evaluated the scene to get >> the what histogram gives us directly (or spot meter several points); i think >> the histogram is a better tool for using our brain in conjunction with our >> meters, and is better suited to intelligent but spontaneous photography > > Exactly. There are times when metering off the sensor would slow things down > too much, use too much power, generate too much heat etc. But there are also > times when it is the perfect tool. > >> >> i could even appreciate an interface that applies a little more calculus to >> image data to indicate where in the image, and at what levels, the angle of >> the histogram's curve is steepest and shallowest, which is part of what i >> sort out (less effectively) with my brain now > > > I also wish that they'd tell me exactly what each of these modes does, rather > than when I'm supposed to use them, and let me guess what the camera is > doing. I understand that most people are happy with a magic box that does > their thinking for them, so that they don't have to think about anything but > composition, but at least tell those of us that want to know so that we can > decide when to let the camera think for us, and when we should think for > ourselves. Instead, I'm left with having to always check the histogram and > blinkies, which *almost* tell me what I need to know. > > It's interesting how many people seem to despise the viewfinder that doesn't > show the whole image, but don't seem to mind the histogram that doesn't show > all of the information. > > I also agree with Godfrey on ease of manual use. Part of the issue with > digital exposure is that there is so much more information potentially > available that a simple match needle would through away too much useful > information. Another issue is that digital isn't as tolerant of missed > exposures as film, though at ISO 100 the K-5 may be far more tolerant of > underexposure than most film. When I got my K-5 I thought that I would not > need to get a katzeye screen for it. The stock screen seems a lot better > than previous cameras, and the autofocus is a lot better. However, I still > find myself missing focus in so many cases where if I had a good manual focus > screen, it would be trivial to nail focus perfectly. > > Again, it's a case of optimizing the system for the automatic functions, that > don't always work as well as manual. > > >> >> -- >> PDML Pentax-Discuss Mail List >> [email protected] >> http://pdml.net/mailman/listinfo/pdml_pdml.net >> to UNSUBSCRIBE from the PDML, please visit the link directly above and >> follow the directions. > > -- > Larry Colen [email protected] sent from i4est > > > > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- Godfrey godfreydigiorgi.posterous.com -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
