On Jan 29, 2012, at 1:13 PM, Godfrey DiGiorgi wrote: >> I also agree with Godfrey on ease of manual use. > > I'm glad we agree on something. ;-)
Just because I call you rude names doesn't mean that I disagree with you, or even that I dislike you. > >> 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. Yes, a scalar meter for a scalar setting is about all you can do. But there is a lot more information available from a histogram than from a match needle, and even more if the camera takes a test shot and reads the value of every sensor site. There are many times when a match needle, or an AE system that follows the match needle is good enough, or the best available. As to manipulating capture data by photosite address, there are times I'd settle for being able to set the ISO of each color channel separately. I often have to underexpose two of the channels by a couple of stops to keep from blowing out the third channel. > > 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. Very true. How do I find 5% below the saturation limit of my sensor when the histogram only tells me the values on the JPEG, not on the sensor? I'll note that your M9 gives the sensor values, not the jpeg values. > 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. In the time available for action shots. But what if you had a mode where you could press the "analyze" button, and let it churn away for a few seconds? How long would it take to read 16M values into a buffer, and note the maximum and minimum values? > > 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). I suspect I do a lot of this intuitively myself. > > 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. Do you check your results with the histogram, or just decide that you're good to go? > >> 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. All of this is true. > 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. Exactly, that is why I want a mode that will take a test shot, or test shots, analyze the data post exposure and report on the ideal exposure based on the scene, and your tolerance for blown out highlights. Ideally, it could do the test shots, and even set optimal values for an HDR range for scenes that may have something like a neon sign on a dark street where one exposure is ideal for the sign, it skips four stops of exposure where the sign is over exposed and the street is underexposed, and another exposure for the street. This wouldn't work for sports photography, but should be trivial for a lot of slow process situations. >> -- Larry Colen l...@red4est.com sent from i4est -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
