Archived posting to the Leica Users Group, 2006/09/20
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I have no real world experience with the DMR, Doug - but on the other hand, other than using the DMR, you have scant experience with digital photography, and you haven't even been using the DMR for all that long yet, never having used any other type of "pro" digital, you somehow 'know' that the digital you're using is the best there is, and behaves differently from every other digital camera out there. (And no, I have never suggested that the E-1 or any other camera I am now using is the best there is. ;-) ) If you don't want to believe that the world is round as Richman views it, try checking out what Adobe has to say - "Linear capture has important implications for exposure. If a camera captures six stops of dynamic range, half of the 4,096 levels are devoted to the brightest stop -" the one you are throwing away. "half of the remainder (1,024 levels) are devoted to the next stop, half of the remainder (512 levels) are devoted to the next stop, and so on. The darkest stop, the extreme shadows, is represented by only 64 levels...You may be tempted to underexpose images to avoid blowing out the highlights, but if you do, you're wasting a lot of the bits the camera can capture, and you're running a significant risk of introducing noise in the midtones and shadows..." And there's more, some of it about the downside of underexposing in the shadows. http://www.adobe.com/products/photoshop/pdfs/linear_gamma.pdf The fact that the DMR captures data in 16 bit mode doesn't change the essential reality of digital capture. And if you are truly finding that in order to get properly exposed images you need to dial in -1 stop, I'd suggest, no, reality would suggest, there's a problem with the camera's reading of light. Perhaps the problem is limited to your particular DMR, or perhaps it's a problem with all DMRs - obviously I can't even guess at the answer to that one.;-) On 9/20/06 1:38 AM, "Douglas Herr" <telyt@earthlink.net> wrote: > B.D, why don't you re-read the article you've thougtfully pointed us > toward and tell me how Reichmann's analysis of a 12-bit device > interpolated to 16 bits applies to a native 16-bit device that he has > never used? How does he support his blanket assertion that digital > cameras are 5-stop devices? Is he assuming a 12-bit camera? As I'm > sure you know with your vast technical background (a background which > no doubt led to your brilliant prediction of the DMR's failure both in > the marketplace and as a competetive image-making device) each > additional bit of real data doubles the number of values that can be > measured and stored. The additional bit can be used either to expand > dynamic range or to produce smoother tonal gradations, or some of both > depending on how the device is programmed. Now, tell me again how > Reichmann's analysis of a 12-bit camera applies to a 16-bit camera? > Let's see, 16-12 = 4 so there's 2^4 = 16 times as many data values > available in the 16-bit camera. > > What real-world experience do you have with the DMR? Re-read my posts > on this subject: by setting the exposure compensation to -.5 to -1 I > avoid clipping the highlights - that's what I wrote. This seems to be > common practice among DMR users, possibly the way the equipment is > calibrated; no doubt you'll say it's an example of how much of a > failure the DMR is. It's done just to keep from throwing highlight > data away. Tell me again how keeping highlight data instead of > clipping means throwing data away? > > Reichmann's assumption - the one you apparently have swallowed hook, > line and sinker - is that all digital cameras behave the same way. > What I'm doing is keeping the full histogram - exclusive of specular > highlights - within the liberal confines of the 16-bit space, snugged > over to the right just as Reichmann suggests. On the DMR, something > you are clearly not familiar with, this is done by setting the exposure > compensation to about -.5 to -1.0. Call it a quirk of the equipment or > of the firmware, that's how it's done. I'm not throwing data away, I'm > keeping highlight data from being thrown away. > > B.D., this is clearly another case of you spouting off thinking that > you've researched the subject when you're taking someone else's > analysis out of context. You're really just displaying your technical > ignorance and how quickly you jump to conclusions. > > Doug Herr > Birdman of Sacramento > http://www.wildlightphoto.com > > > On Sep 19, 2006, at 7:58 PM, B. D. Colen wrote: > >> Being the digital expert you are, Doug, I would have thought that >> you'd know >> that by under exposing a stop, you're throwing away everything at the >> top >> end of the range - in the highlights - not the shadows - and 20% of >> the data >> is in that top stop. But I don't use a DMR, so of course I know nothing >> about digital ;-) - so don't listen to me, but do try reading >> this...from >> the Luminous Landscape site.... >> >> http://www.luminous-landscape.com/tutorials/expose-right.shtml >> >> >>> In my experience with the DMR, setting exposure comp to -.5 or -1 >>> sacrifices very little deep shadow detail if any. It's not what I'd >>> call a 20% loss of data. The histogram (yes it's RGB) is nowhere near >>> clipping at either end aside from specular highlights. Perhaps B.D.'s >>> 20% estimate is based on his experience with the E-1? >>> >>> Doug Herr >>> Birdman of Sacramento >>> http://www.wildlightphoto.com >>> >>> >>> _______________________________________________ >>> Leica Users Group. >>> See http://leica-users.org/mailman/listinfo/lug for more information >> >> >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information >> >> > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information