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#21
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Put away wet - Why?
Jurgen wrote:
High ISO most definitely compresses dynamic range. Setting your in camera contrast high (or even normal with a Nikon) will do it too. Nikon were so concerned about the effect on their CCD cameras (like the D60) they included a "D lighting" feature to overcome it. I believe Canon also introduced a Highlight preservation feature with the 40D but that one is sort of self defeating because it forces the camera to 200 ISO which itself compresses the dynamic range. Not quite. The highlight preservation mode on the 40D and some other canon cameras doesn't quite work that way. Even though the minimum ISO is 200, it still applies the same sensor gain that they have at ISO 100 in normal mode. What they do is then underexpose by 1 stop (hence ISO 200 - it is using the same exposure that ISO 200 would). They then apply a different curve to the JPG conversion that compresses the extra stop of highlight detail that is recorded, and lifts the shadows. The net result is that the image has the same dynamic range as a normal mode ISO100 shot, but more of that range is above neutral grey than would be without the highlight priority. With the Nikon cameras, you can get a very similar effect by underexposing by 1 stop and then applying the D-Lighting function. Prior to getting my Canon 450, I did a similar thing with my GX10 - nearly every shot I took with it I had -1 exposure dialled in, and then put a custom curve on them in photoshop. I find I almost always use highlight priority mode - the extra highlight rangeis very useful when shooting outdoors, where in normal mode you'd get blown highlights with clouds, people in white clothing, white animals/birds etc. You might try flattening the in camera contrast and pulling the exposure half a stop. I suspect a decent circular polariser will help too. You can put back the contrast in post processing after you do something about the highlights. Yep - and pulling the exposure is exactly what the Canon highlight priority mode does, although it hides the complexity. I think highlight priority is really where the exposure level should be for a digital sensor. I have used a fair variety of Canon, Nikon & Pentax/Samsung cameras and every one of them has clipped the highlights excessively in any scene with moderate contrast. I found that for almost all outdoors shots, -1 compensation needed to be dialled in to get acceptable results (with subsequent ajudstment to lift the mid's and shadows). With the highlight priority mode that is no longer necessary - I can now shoot a scene with only occasional adjustments to the in-camera metering, and without need to tweak the shadows/mids afterwards. |
#22
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Put away wet - Why?
Doug Jewell wrote:
With the highlight priority mode that is no longer necessary - I can now shoot a scene with only occasional adjustments to the in-camera metering, and without need to tweak the shadows/mids afterwards. To me it seems like all these patches trying to tame highlights are circling the issue of poor sensor design. One of my cameras (Fujifilm s5 Pro) uses dual sensors to address the problem. Not many scenes I come across that can't be captured cleanly with this camera. Pity is has other shortcomings! |
#23
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Highlight Priority Modes (was Put away wet - Why?)
Jurgen wrote:
Doug Jewell wrote: With the highlight priority mode that is no longer necessary - I can now shoot a scene with only occasional adjustments to the in-camera metering, and without need to tweak the shadows/mids afterwards. To me it seems like all these patches trying to tame highlights are circling the issue of poor sensor design. Yes and no. I firmly believe that pre-40D, DSLRs (and compacts too), put the wrong curve on the images. As we all know, compared to film, digital has less highlight range, but much more shadow range. Even traditionally tough films like Velvia could hold highlights better than digital cameras. Added to that, when film does roll over into blown highlights, it does so with far more grace than your typical digital. Before highlight priority mode, I found the only way I could get acceptible scenics was to underexpose and then apply a different curve. This compressing of highlights resulted in a more film-like image, and dare I say it, a more human-eye-like response, than what the standard auto-exposure image would. Because of the very good shadow depth of digital, lifting the shadows in this way doesn't significantly hurt the image - yes they become a little noisier, but again, that is more film-like, and again in a bright scene the human eye doesn't do a wonderful job of picking up shadows anyway. Since the 40D, more and more cameras have started doing things like highlight priority mode - the Pentax/Samsung 20D does it now as well. I think ultimately, time will prove that applying this type of curve to an image is a better way of generating images than the previous system. I know Sony and Nikon have had Dynamic-Range-Optimiser and D-Lighting since before the 40D - although to get these functions to deliver similar results to highlight-priority does require a negative exposure compensation at time of shooting. One of my cameras (Fujifilm s5 Pro) uses dual sensors to address the problem. Not many scenes I come across that can't be captured cleanly with this camera. Pity is has other shortcomings! The main shortcoming I noticed with the S5 was it's speed, or complete lack of, whenever the extended range function was turned on. The concept of variable-sized photo-sites is an interesting one, and one I'm surprised more sensor manufacturers haven't explored. An S5 sensor, backed up with a decent processor such as Digic, would really make for a good camera - as long as they put an EOS mount on it :-P |
#24
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Highlight Priority Modes (was Put away wet - Why?)
On Sun, 21 Dec 2008 07:07:08 +1000, Doug Jewell wrote:
The main shortcoming I noticed with the S5 was it's speed, or complete lack of, whenever the extended range function was turned on. The concept of variable-sized photo-sites is an interesting one, and one I'm surprised more sensor manufacturers haven't explored. An S5 sensor, backed up with a decent processor such as Digic, would really make for a good camera - as long as they put an EOS mount on it :-P An EOS mount wouldn't be needed, since if it was put in a new Nikon DSLR (which uses the same F mount as the S# Pro bodies) it would also make for a good, speedy camera, and which could be at least as fast as Canon's fastest, and wouldn't require S5 Pro owners to have to buy a new set of lenses. By your reply can we assume that you own a Canon DSLR and would like to have a new Canon body using Fuji's sensor technology, and don't want to have to start purchasing Nikkor lenses? There's nothing wrong with Fuji licensing that technology to any other manufacturer that want to use it, but my guess is that either Fuji would be unwilling or that the other manufacturers wouldn't have much interest in developing something that wasn't proprietary. |
#25
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Highlight Priority Modes (was Put away wet - Why?)
ASAAR wrote:
On Sun, 21 Dec 2008 07:07:08 +1000, Doug Jewell wrote: The main shortcoming I noticed with the S5 was it's speed, or complete lack of, whenever the extended range function was turned on. The concept of variable-sized photo-sites is an interesting one, and one I'm surprised more sensor manufacturers haven't explored. An S5 sensor, backed up with a decent processor such as Digic, would really make for a good camera - as long as they put an EOS mount on it :-P An EOS mount wouldn't be needed, since if it was put in a new Nikon DSLR (which uses the same F mount as the S# Pro bodies) it would also make for a good, speedy camera, and which could be at least as fast as Canon's fastest, and wouldn't require S5 Pro owners to have to buy a new set of lenses. By your reply can we assume that you own a Canon DSLR and would like to have a new Canon body using Fuji's sensor technology, and don't want to have to start purchasing Nikkor lenses? There's nothing wrong with Fuji licensing that technology to any other manufacturer that want to use it, but my guess is that either Fuji would be unwilling or that the other manufacturers wouldn't have much interest in developing something that wasn't proprietary. Well yes I'm an EOS user, but my comment about EOS mount was more tongue in cheek than anything. Although I'm sure it would open up their potential sales quite a lot more if it was built on a Canon body rather than Nikon (or better yet, a version for each). Not sure about your part of the world, but around these parts the vast majority of the S5's target audience (wedding photogs) are Canon based. Supposedly Nikon hold about 40% market share - they must be all tucked away safe and sound in studios or schools somewhere, because I hardly ever see them in the wild. See as much (if not more) Pentax in the wild than Nikon. Canon are by far the more common cameras to see in the wild. |
#26
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Put away wet - Why?
Mark Thomas wrote:
Alan Browne wrote: Jurgen wrote: Is that not the same as a lens reflecting light brighter (more heat) than that which enters it? Make each hair a micro lens and light gets reflected at a higher rate than the light being absorbed by darker areas. Each hair and water droplet is convex and would scatter reflected light, not focus it. Microlenses focus light passing through them and out their convex or flat side, not reflecting off of them. In fact what is happening is that the wet hair produces a fairly even surface (surface tension) that acts like a mirror and produces the specular reflection. In sum, there is certainly less light reflected off of the horsehair than light arriving on the horsehair - so your "" reflecting light brighter (heat) than that which enters it "" is certainly not holding water. Indeed. And the specularity (?) of the reflections is backed up by the relatively small areas that have the 'problem' - the water is obviously sheeting off the fur and providing a mirror like surface that only causes a problem where the angle of the sun is just right, just like sunlight reflecting off the sea. You can't really 'control' such highlights in a typical scene. I think a lot more is being made of the problem than needs to be You get 100 points for that line. - it's a scene with a huge dynamic range, well in excess of what the sensor (any sensor) could handle. So you have only got two options, given that hdr isn't really applicable: 1. Reduce the problem - a polariser might have helped a *little*, but these are *very* strong reflections of the sun! *It would probably have helped other parts of the image however*. If you haven't used one much, do so! I'm a polariser fan, and believe they should be on for all sunlit shots between 10am and 2pm for latitudes 45°!! This one might be just outside that range, but I'd consider an exception... (O: Hard to say how it could help or hinder. 2. Bring the exposure down. But you would likely have just blocked up the shadows and the highlights would look similar anyway - the edges might have looked a tad better. Being *hyper*critical and just judging from the crop I would guess that maybe 2/3-1 stop less exposure would have kept most shadow detail and given a slightly better result, but frankly I think you (or the camera) did quite well with that compromise, and the shot looks quite good to me, given the circumstances. This is yet another reason why pros shoot in outdoor direct sunlight with scrims to reduce the DR on the subject. And why movies are mainly shot on negative film. As for "Jurgen" (O:, I would love to see a link for his assertion that the water on fur will 'microlense' in some way that refocuses the light to increase its intensity. I'm sure there is an article on this somewhere, "Jurgen"??? I think once made clear to him that you can't microlense in reflection off of convex surfaces he sorta figured it out. Like Alan says, it is just specular reflection. Neither alone nor first in that opinion. -- -- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: Remove FreeLunch. -- usenet posts from gmail.com and googlemail.com are filtered out. |
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