Velvia 50 - 14 stops

<p>While on a trip I took two pictures at the beach. One with Velvia 50 (when the reflections where subdued) and one with Ektar (when the reflections were too harsh to even look at them). The shots were taken reasonably close to each other.</p>

<p>The shot taken with Ektar (though challenging even for Ektar) would have been impossible with Velvia.</p>

<p>Now with both shots, a simple color match in PS using Velvia as the source and Ektar as the Target, does a SPOT-ON COLOR CONVERSION. (This would not work unless the target and the source are similar pictures).</p>

<p>Et Voila.</p>

<p> </p>

<p>Results:</p><div></div>

<p>I don't see 14 stops.</p>

<p>Mauro, do you have a densitometer? I have found that most people that claim incredible dynamic range from transparency film go only by appearance. IF you have a 21 step step wedge and a densitotmeter, you can accurately determine how many stops your velvia can record. Likely you'll find it's 6 or 7 stops max, if exposure and processing is spot on.</p>

<p>Modern C41 film is really amazing, I measure 10-12 stops easily with 160NC and 160S, the two films I use most often.</p>

<p>Erie, let me clarify:<br>

The stops come from the picture taken with Ektar, the colors from the Velvia shot.</p>

<p>I still don't see 14 stops.. I see Photoshop contrast on the high and low ends no middle tones.</p>

<p>Larry,</p>

<p>You cannot "see" stops on a picture on a screen unless you have the real scene next to it.</p>

<p>A picture on the screen could only go from gray to dark gray (a e.g.) and still reprent a 20 stop scene captured.</p>

<p>For example, cutting the DR of the ektar shot in half (going from 14-12 stops to 7-6 stops) can give you a rough idea of what the shot may have looked with Velvia:</p>

<div></div>

<p>Seeing and putting #'s to them are different.. I like the picture... if that helps but My screen goes pretty high and low and the#'s mean nothing... I am glad you are happy with your creation and keep shooting film.</p>

<p>Larry</p>

<p>Just another tool to use since both films are available on 120 and I can simply swap the loaded backs.</p>

<p>tools are good.. thank you. I also use 120 with different backs...</p>

<p>larry</p>

<p>The shots are nice and the range of color negative film in general is astounding, but I can't see 14 stops in pictures that can be displayed on the www.</p>

<p>I do dimly remember that one of the photo magazines last year or so had a test of how far CN film could go, but it was nothing like 14 stops, more like 7 or 8, I think.</p>

<p>JDM, you are confused; you can display a 14 stop scene capture (or any number) on the www. Same as you can display a 50 stop HDR on the www. Any number of stops on a scene can be represented (compressed) into any output (not considering the step loss).</p>

<p>Regarding the 14 stops of Ektar, I have tested it myself.</p>

<p>Here is the Ektar DR test:<br>

http://www.photo.net/film-and-processing-forum/00Rb8S</p>

 

<p>I'm not sure what can be concluded from this. But what I see is that by colormatching in PS, you have adjusted the contrast of the Ektar image to look like Velvia. Shadows are now blocked. The color balance looks like it has also changed, but the biggest change looks like the contrast. I think the first Ektar picture could have it contrast manipulated to give a better image w/o a colormatch with Velvia. By the way, I recently got a pro pack of 120 Ektar and look forward to using it. It's a great film. But then, so is the Portra line.</p>

<p>Yes, color matching also increased the contrast on the Ektar show (S curve) but the stops are still there.</p>

<p>You can manipulate the Ektar shot to produce different and better results. The example is only if you are looking to get the Velvia colors while capturing additional stops in the scene.</p>

<p>Interesting technique- it wouldn't have occured to me to try this.</p>

<p>The original scene might have had 14 stops from the deepest shadow to the sun's disk, but once on Velvia 50, the top 9 stops are burned through the emulsion by the sun. What Mauro fails to realize is that stops don't count unless one step can be distinguished from the next. All white (clear) is all white - no detail beyond that junction. I'm not sure what kind of light meter you would need to even measure a span of 14 stops - not my Sekonic 508 anyway. Then there's the claim of 50 stops for HDR (2^50 or a ratio of over a quadrillion to one), LOL.</p>

<p>According to Fuji's technical data sheet for Velvia, there are about 5 stops of dynamic range (of capture) - 6 stops if you are extra generous. Anything more is pure fantasy. It's time to end this madness. I see that Stouffer step wedges are not outrageously expensive. That would provide a visual representation for those unable to digest objective data published by the manufacturer.</p>

<p>One part in a quadrillion is like measuring the distance to the moon to within 0.3 millimicrons (3 angstroms, in the hard X-ray band). We should task Mauro with this job.</p>

<blockquote>

<p>JDM, you are confused</p>

</blockquote>

<p>Don't feel bad, you're not the first person to tell me this. ;)</p>

<p>"According to Fuji's technical data sheet for Velvia, there are about 5 stops of dynamic range (of capture) - 6 stops if you are extra generous. Anything more is pure fantasy."</p>

<p>What does this have to do with the dynamic range of color negative film (specifically the Ektar 100 used above)? Nobody is saying Velvia can record 14 stops.</p>

<p><em>the top 9 stops are burned through the emulsion</em><br>

point is that not through the emulsion of ektar 100 ... which has colors of velvia, but dynamic range of ektar ;-)</p>

<p>My Sekonic L-508 supposedly has a dynamic range of 21 stops (EV-2 to +19 at ISO 100). I'm a little skeptical, but that's what the specifications say.</p>

<p>How do you get 14 stops from a film, Ektar 100, capable of only 10 stops dynamic range?</p>

<p>In the attached photo, I start with the characteristic curve for Ektar 100, published by Kodak. I have drawn the exposure range (horizontal axis) over which you get a useable variation in density (vertical axis), which constitutes the dynamic range the film can capture. The scale is logarithmic (base 10), so to find the range in f/stops divide the span (3.2) by log 2 (0.301).</p>

<p>The small boxes on either side are intended to be histograms of a subject, like a box of crayons or a small figurine (per our notable "scientists" on this forum). The subject spans a dynamic range of 3 or 4 stops. Let us vary the exposure of this subject over a range of 14 stops. We see from the diagram that part of the range of the subject still falls inside the usable range of the film, consequently some degree of detail can be discerned. As long as any detail can be seen, the frame is "counted" in these "scientific studies".</p>

<p>The fallacy is that the extra 4 stops or so actually fall outside the true dynamic range, as demonstrated on this diagram, due to the complexity subject under test.</p>

<p>One valid method is to use a step wedge in which the boundary between adjacent steps is either visible or not. Each step has a single density value, with a known ratio to the adjacent steps. The results from a single exposure would approximate the range calculated from the manufacturer's curve.</p><div></div>

<p>To my eye, the original Velvia shot is the best because it looks well saturated and natural. Why muck ariound with it in PS, only to arrive at a similar result? Mauro has been hyjacked by the PS soldiers. Get off the computer and back behind you camera? Maybe the art of exposure bracketing to get the best result has now been lost?</p>