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Sean Reid
12-28-2004, 15:53
Of interest perhaps to my R-D1 friends...

The test of lenses is now "live"

http://www.luminous-landscape.com/reviews/lenses/rd-1-lens.shtml

Cheers,

Sean

rover
12-28-2004, 16:01
Excellent article Sean. I love the real world perspective you present in your testing.

Sean Reid
12-28-2004, 16:02
Thank you.

Cheers,

Sean

Huck Finn
12-28-2004, 16:37
Thanks for posting here, Sean. Greatly appreciated.

I found especially interesting your discussion lf lens contrast. A good read! Regardingyour recommendation of Leica & Canon - & some Zeiss - lenses for moderate contrast, I was surprised. I have read that the older Nikon & Leica lenses favored higher resolution while the older Canon & Zeiss lenses favored higher contrast. Any comments?

Sean Reid
12-28-2004, 17:07
Hi Huck,

It depends on which lenses one is looking at. For example, the Canon 28/2.8, 35/2.8 and 50/1.8 (all of which I've tested on the R-D1) are lower contrast lenses. All three companies have produced both higher and lower contrast lenses so I find that finding out which lenses are which is largely a matter of experimentation.

Cheers,

Sean

jlw
12-28-2004, 20:11
I likewise appreciated the work that went into this review, especially the vignetting tests.

But I'm confused by Sean's section on lens contrast, especially his assertions that a higher-contrast lens might "lose" subtle middle tones that would be captured by a lower-contrast lens, and (for example) that "The dynamic range of the Summicron-M 35/2.0 can easily exceed that of the R-D1 in contrasty light."

It sounds as if he is saying that a lens can somehow add contrast to a scene, or that a lens with a high contrast might obliterate tonal differences that a lower-contrast lens would capture.

I always had been under the impression that the contrast of a lens-formed image will always be lower than that of the original scene: that only a mythical "theoretically perfect" lens would reproduce exactly the same brightness values as the original scene (100% contrast.) A "high contrast" lens might reproduce the scene brightness values with 90% accuracy; a "moderate contrast" lens with 70% or 80% accuracy; and so on.

In other words, I believed that ALL lenses lower the contrast of the original scene -- so the only question is how much contrast is lost. And since this definition suggests that lower contrast corresponds to image information being thrown away, it would seem from this that it's a low-contrast lens, not a high-contrast one, that would obliterate subtle tonal differences.

If I'm understanding all that correctly, it seems to suggest that higher lens contrast is always better, even if what we want as an end product is a "low-contrast" rendition of the scene -- low in the sense of tone contrast, which doesn't necessarily have anything to do with lens contrast.

Or as it says in the "Understanding Lens Contrast" (http://www.luminous-landscape.com/tutorials/understanding-series/lens-contrast.shtml) article on Luminous Landscape:

"Contrast" in photo paper, for instance, or in a finished image, refers to overall (sometimes called "global") contrast, meaning how the materials distribute tonal gradation from black to white or lightest to darkest.

When we talk about lens contrast, we're not talking about that quality. What we're talking about is the ability of the lens to differentiate between smaller and smaller details of more and more nearly similar tonal value. This is also referred to as "microcontrast."

The better contrast a lens has (and this has nothing to do with the light_dark range or distribution of tones in the final print or slide) means its ability to take two small areas of slightly different luminance and distinguish the boundary of one from the other.

Now I can see from this explanation that by obscuring the differentiation between these microcontrast details, a low-contrast lens would soften the appearance of skin and other fine-textured surfaces, and this might give a desirable "look" to some scenes such as portraits and landscapes.

But I'd think that, particularly when shooting with a digital camera such as the R-D1, it would be more desirable to capture these details in the initial exposure and then reduce them via other controls (such as the edge-emphasis and image-contrast settings Epson's raw-file converter, or the similar settings that can be made in the camera's "film" presets when shooting JPEG files) rather than by using a lens that fails to capture as much tonal information as possible in the first place.

But maybe Sean is using the term "lens contrast" differently from what I'm thinking. In fact, I've noticed other people on this board expressing a preference for low-contrast lenses also, and it always has puzzled me.

Can someone clarify for me why you consider low lens contrast to be a good thing, and how it benefits your pictures? Thanks...

Sean Reid
12-28-2004, 21:12
Hi jlw,

Michael (Reichman)'s discussion of lens contrast refers only to one aspect of contrast. Not only do lenses vary in micro contrast but also, potentially, in the overall contrast of the image they cast upon the sensor. One can see this looking at histograms of the same scene captured by the same camera using different lenses. The overall spread of the histogram will be wider for the lenses with higher overall contrast.

It's quite true that a contrasty scene can contain a ratio of light to dark tones that far exceeds anything a lens can render. I believe that an ideal match of lens and digital sensor would come when a lens delivered to a sensor the exact dynamic range that the sensor could record. But this, of course, is impossible because subjects in front of a lens will vary tremendously in terms of their inherent contrast. The lens is performing a delicate juggling act, translating brightnesses as they exist in the world into brightnesses which can be recorded by a sensor or film.

Since subjects vary tremendously in terms of their reflectance ratios, no one formula for overall lens contrast will be perfect for all situations. The lens will very often be erring either towards more or less contrast than the sensor can handle. If it's significantly less, the initial file will seem very flat and will require a contrast increase in Photoshop (via curves or another method). If the contrast is more than the sensor can handle, detail will be lost at either one or both ends of the tonal scale. A little bit of that can be regained in RAW conversion, but not much.

Advances in lens design and manufacturing have lead to the creation of lens with contrast ratios that get closer and closer to approximating the contrast ratio of light in the world. Some see the ideal lens as delivering exactly the range of contrast that exists in a given subject in life, with no diminishment. But I believe that that ideal overlooks the very much finite dynamic range limits of both digital sensors and film. Lenses and cameras could certainly progress, over time, in tandem....overall lens contrast increasing as sensors (and associated electronics) become capable of greater and greater dynamic range. But even then, one would have to keep in mind that the usual final goal is a paper print which itself has a limited possible reflectance ratio. That ratio (in a print) can't even begin to approximate the contrast range of natural light.

There's been a great deal of attention paid to the role a sensor plays in managing dynamic range but I've seen very little attention (perhaps none) paid to the role of the lens in this process. It's the combined effect of the exposure, the lens, the sensor and the camera's processing that yields a final dynamic range. I think the ideal of high lens contrast should, at very least, be examined and questioned in light of the net result in the picture file itself.

Andre Kertesz said: "I see the thing. I feel the thing. I make the thing." Inherent in that statement is the realization that the end product (the negative or ultimately the print) is very much distinct from the subject as it exists in life. Garry Winogrand put it differently: "A picture is not the thing itself; it's a new fact." The modulation that transforms things in life into things in pictures on paper is, in part, governed by how the lens interprets the light it receives. Of course, only the photographer can decide what the file should look like. It may be his or her intention to obliterate large amounts of highlight or shadow detail because of the way he or she feels the picture must look. The lens has to suit the camera has to suit the picture intended. But, to my way, of thinking...a lower contrast lens that records as much detail as possible at both ends of the tonal spectrum gives me more options. I can choose to preserve or destroy detail with contrast and other changes in Photoshop.

Finally, an untested hypothesis of mine about minimum contrast in midtones....just thinking aloud mostly....I suspect that the sensor need record only enough differentiation in tone (between similar midtones) to distinguish them as clearly separate. Once there is enough microcontrast to simply distinguish one midtone from another, one can amplify or reduce that effect in Photoshop because the information itself is, indeed, recorded. Perhaps its recorded as just 1/10 of a tonal zone change but that 1/10 can be amplified infinitely. One cannot, however, create detail in shadows or highlights that does not exist in the RAW file.

Cheers,

Sean

Doug
12-28-2004, 21:30
Originally posted by jlw
But I'm confused by Sean's section on lens contrast, especially his assertions that a higher-contrast lens might "lose" subtle middle tones that would be captured by a lower-contrast lens, and (for example) that "The dynamic range of the Summicron-M 35/2.0 can easily exceed that of the R-D1 in contrasty light."
...

I always had been under the impression that the contrast of a lens-formed image will always be lower than that of the original scene: that only a mythical "theoretically perfect" lens would reproduce exactly the same brightness values as the original scene (100% contrast.) A "high contrast" lens might reproduce the scene brightness values with 90% accuracy; a "moderate contrast" lens with 70% or 80% accuracy; and so on.

In other words, I believed that ALL lenses lower the contrast of the original scene -- so the only question is how much contrast is lost. And since this definition suggests that lower contrast corresponds to image information being thrown away, it would seem from this that it's a low-contrast lens, not a high-contrast one, that would obliterate subtle tonal differences.

If I'm understanding all that correctly, it seems to suggest that higher lens contrast is always better, even if what we want as an end product is a "low-contrast" rendition of the scene -- low in the sense of tone contrast, which doesn't necessarily have anything to do with lens contrast. Jim, I share your belief that lenses reproduce the scene contrast to some variable but lower degree. But I think it's not correct to characterize it as a loss of data.

Scenic contrast is conveyed to the sensitive material through the lens, and my view is that the results (say on a slide or CCD to eliminate effects of development and printing) depend on all three elements.

If the lens reduces scene contrast to match the range available in the sensitive material, you may have a happy situation in being able to capture all the available data. Looking at it this way, the lower contrast of the lens has *saved* data...

A lens able to transfer more of the scenic contrast may exceed the ability of the sensitive material to record it, blowing the highlights and/or losing the shadows.

It's been said that the chip in a digital camera is more like slide film in its response, with a more limited ability to capture contrast range than negative film. So a high-contrast lens may result in *losing* data!

I may be off, here, but this is what I think Sean is telling us.

jlw
12-28-2004, 21:38
Okay, that makes sense, now that I understand you're talking about contrast in a different sense than Reichman was.

Being an old graphic-arts guy, I'm even comfortable with the concept of "knocking down" contrast in the initial capture so that you can selectively restore it later (similar to what we used to do with "bump" and "flash" exposures on a process camera -- remember those?)

The only thing that bothers me about the idea of choosing a lens to optimize image contrast to the sensor's bandwidth is that you're using image-forming light to do it, which means there's bound to be some information loss.

I wonder if it's time to revive the old idea I read about in 'Pop Photo' back in the '70s of 'concurrent photon amplification,' an idea for improving shadow detail in low-light pictures? The idea was to install tiny lamps in the camera throat, controlled by the autoexposure system, that would "latensify" (preflash) the film to improve its response to dim light.

I have no idea whether or not digital-camera sensors respond to latensification, but I like the idea of controlling contrast with something OTHER than stray light from the lens!

Of course, I admit that concurrent photon amplification is just pie in a speculative sky, whereas there are lots of aesthetically hazy old LTM lenses that can be stuck onto the front of an R-D1 right now -- which is part of the fun of using it!

Doug
12-28-2004, 21:50
Oops, my typing was way slower than Sean's!

Sean Reid
12-28-2004, 21:52
Doug - exactly.

Thinking about midtones again. As I said in the review, there's something really wonderful that happens to B&W midtones in R-D1 files made with lower contrast lenses. A lens can have high or low overall contrast and high or low local (or micro) contrast. The first type of contrast relates directly to dynamic range.

The second type (local or micro-contrast) is tougher nut to crack. It's been held by many as an ideal that a lens have strong micro-contrast but the result of that can be much more abrubt transitions in the midtones. Let's say, for example, that we have a set of midtones that we'll arbitrarily assign numbers to (in terms of their brightness). Let's say that with a lower-contrast lens these tones are at levels 22,23, 24, 25, 26 and 27. As the lens micro-contrast increases, these tones are forced to become lighter or darker and, thus, to separate from each other tonally. So let's say that tones at level 24 and below are pushed darker to level 22 and tones 25 and above are pushed lighter to 27. The image starts to look crisper, has more "zing" etc. but tones 23, 24, 25 and 26 are gone - forced to become something brighter or darker. This isn't necessarily a bad thing. It depends on how one wants a picture to look. Very often people seeing final B&W prints from large format negatives for the first time think of them as lacking contrast. But what they're seeing, in fact, are very subtle transitions from tone to tone. This creates a very different looking print.

One could extrapolate this idea metaphorically but I won't get into that.

Doug
12-28-2004, 21:54
Originally posted by jlw
... I like the idea of controlling contrast with something OTHER than stray light from the lens! Jim, this implies that lower lens contrast is a result of veiling flare. Is that so? I hope it isn't...

Sean Reid
12-28-2004, 21:59
Hi jlw,

The graphic arts comparison is apt - it's the same basic idea.

I don't think there's information loss at all with lower contrast lenses. That is to say, the overall reflectance ratio appears to be reduced at first but all of the raw materials are there.

Your point about both the R-D1 and many lenses exisiting *right now* is key. I hope people start people start doing all kinds of lens experimentation with this camera.

Cheers,

Sean

...who better get to sleep.

rover
12-29-2004, 00:37
A question regarding the vignetting of the lenses you tested. Is it fair to say that the vignetting demonstrated, or captured, would be greater if the media tested was film. My thought is that the sensor of the R-D1 is smaller than the standard area of a 35mm negative therefore clipping the edges and demonstrating less vignetting.

Sean Reid
12-29-2004, 05:58
Hi Rover,

I think that the vignetting would actually be less on film because it's largely the wells in the digital sensor that start to cause shading with symmetrical and less-telecentric lenses. I didn't test though, so I don't know.

Cheers,

Sean

jlw
12-29-2004, 08:43
WARNING: THE FOLLOWING IS A LONG, RAMBLING POST! IF YOU DON'T LIKE LONG POSTS, SCROLL DOWN NOW!

I have been doing more thinking about Sean's contention that lower-contrast lenses might be desirable on a digital camera. And since it's kind of slow at work between Christmas and the New Year, I had some time today to do some reading and experimenting.

As a result, the whole concept is starting to make sense to me.



TWO KINDS OF CONTRAST LOSS

My initial problem with the idea expressed in Sean's Luminous Landscape review (see exchange above) came from the fact that he seemed to be using the term "contrast" in a different way than I was accustomed to using with lenses (and the way it's used in the Reichmann article, (http://www.luminous-landscape.com/tutorials/understanding-series/lens-contrast.shtml) for example.)

And it turns out that this was the case! From my reading this morning, I've learned that a lens reduces contrast in two different ways: scattering and veiling glare. And these two contrast-reducing mechanisms have different effects on the image.

(This doesn't just apply to camera lenses: a lot of the best info comes from the X-ray and photonics fields.)

Here are a couple of definitions I copied from the online Photonics Dictionary (http://www.photonics.com/dictionary/):

Veiling glare - Diffuse stray light at the image plane of an optical system that results in reduced contrast and resolution.

Scattering - Change of the spatial distribution of a beam of radiation when it interacts with a surface or a heterogeneous medium, in which process there is no change of wavelength of the radiation.

The key difference for us is that veiling glare is diffuse (non-image-forming) while scattering retains its beam characteristics. To oversimplify, you could say that veiling glare reduces contrast by spraying image rays everywhere, while scattering reduces image contrast by sending image rays to the wrong destination.




GRAY BLACKS? OR FUZZY EDGES?

You can think about the effect of this difference on photography by imagining a highly magnified view of a sharp black-to-white edge, the kind of "knife edge" detail used in making MTF tests.

Diffuse veiling glare would fill in the black area of the image, turning it to light gray -- but this wouldn't affect the abruptness of the black-to-light boundary.

Scattering, on the other hand, would let rays that should hit the white part of the image stray over into the black part. They'd do this statistically: most would miss only by a little, some would miss by more, and a few would miss by a lot. The effect would be to turn the knife-edge boundary into a gradated "gray ramp." But, this wouldn't affect the overall dark-to-light contrast of the image, because most of the black area would still be pure black.

At the bottom of this rambling missive, I've attached some example images I diddled up with Photoshop (using a white fill to simulate veiling glare, and Gaussian blur to simulate scattering.)




WHEN GRAY IS GOOD

Sean makes a case in a later reply (above) for the benefits of scattering, but I'm still not sure I'm sold on that one -- I like images with crisply-defined small details such as skin and fabric textures.

But the idea that a certain amount of veiling glare could be helpful is starting to get persuasive for me. The key feature here is that once scattering has reduced contrast by wiping out sharp detail boundaries, there's no way to put them back. But if a certain amount of veiling glare has reduced contrast by lightening dark tones, it's pretty easy to darken them again.

This raises the possibility, as Sean suggested in his review, of choosing lenses that reduce contrast enough to help the scene's brightness range fit the limited capabilities of a digital camera's sensor -- then "reconstituting" the lost contrast later by post-processing with Photoshop or another image editor.

But if this is such a great idea, you might ask, why do lens designers strive to reduce veiling glare in the first place? And why would they tolerate scattering at all, if it obliterates fine details? And (most interesting to us as RF users) why is it that some older lens designs seem to be especially "digital friendly" when we stick them onto an R-D1?


Well, I've got a theory about all this, based on the history of photo technology.




HARD CHOICES IN LENS DESIGN

First, let's concede that all lens design is a matter of compromises, and that someone sitting down to design a new lens accepts that some contrast loss is unavoidable.

Let's also assume that a savvy lens designer (nowadays with the help of a computer, in the old days with the help of experience) can choose design options that would tolerate more contrast loss via veiling glare to get less contrast loss via scattering... or vice-versa.

Now, here's the guts of my theory. At the beginning of the "RF era," most important photographs were made on black-and-white film. In black-and-white, it's easy to control final print contrast through film development or printing controls.

So, designers of the classic old RF lenses would be willing to tolerate some contrast loss through veiling glare -- that could always be fixed later. But they'd try to avoid contrast loss through scattering, because that could not be fixed and would wipe out the subtle textures and microcontrasts that make black-and-white photos beautiful.

The ultimate result of this kind of thinking would be a lens such as the old-design Summicron that Sean mentions in his review: one with high detail sharpness but only moderate image contrast.



Okay -- if low contrast/high sharpness was such a great approach, why would designers ever change it?

One-word answer: color. The first popular color films were slide films, and slide film gives the photographer no control over the final image's contrast: if the lens doesn't get it onto the film, it ain't gonna be there. This didn't change much with the popularization of color-negative films, since they don't respond to the same kinds of print-contrast controls we can use in black-and-white.

Now, it's only a theory, but I submit that this is the factor that led design houses to move in the opposite direction: accepting more scatter to get less veiling glare, pushing more and more for lenses that produced images with high dark-to-light contrast.

It made sense: photographers wanted "snappy-looking" color slides and prints, and since color film is inherently less sharp than black-and-white anyway (more emulsion layers) there was no point in sacrificing snap to retain tiny textural contrasts.




THE CLOCK TURNS BACK

But now, digital imaging has turned back the clock! Once again, it's easy for the photographer to control the contrast and tonal distribution of his final image -- just as it was in the days when any serious photographer developed his own film and made his own prints.

With that shift, the unique optical characteristics of classic RF-era lenses have become relevant again.

And for now, the only way for a digital shooter to exploit those unique characteristics is to use an R-D1! (Neener, neener, EOS-boy...)




LET'S TALK CONTRAST

What we need now to take advantage of this position is to agree on a way to describe some of these characteristics. For example, when you say you've got a "low-contrast" lens, can you distinguish whether you mean it has low detail contrast (via scattering) or low dark-to-light contrast (via veiling glare)?

Think about it. Maybe someone can come up with a few ideas, and we can start compiling lists of what classic and modern RF lenses have especially digital-friendly imaging traits...





Blacker, or edgier? Pick your poison...

Here are a few notes on the attached sample image. I used a "fake subject" in the form of a stepped gray scale generated in Photoshop; this is the middle band of the image.

The two bands above it show reduced detail (or edge) contrast via scattering, which I simulated using the Gaussian Blur filter.

The key thing to notice is that this doesn't change the tonal (dark-to-light) contrast -- the blacks are just as black as on the original center-band image. What gets lost are the edges between the steps.

The bands below the middle one illustrate tonal contrast reduction via veiling glare, which I simulated with a 20% white fill. You can see that the tonal contrast deteriorates (fogged black steps; think how terrible this would look in a color slide!) but the edge contrast is just as high as the original.

And, as shown in the bottom band, the original tonal contrast can be reconstituted by adjusting the Levels control (just as the wet-darkroom photographer would do by extending the film development time a touch, or printing with a higher-contrast filter.) The statistics of this image are just about identical to those of the original, showing that no actual information was lost.

Now, on to my next project: Hanging all my strange old LTM lenses on my R-D1 and finding which ones have the desirable (for me) combination of low scattering and moderate veiling glare...

Sean Reid
12-29-2004, 09:19
jlw!!

Bravo, that's a fascinating post. You're taking this exploration as seriously as I have (for these past few weeks) and I'm glad to see someone else think about this idea so carefully. If you recall, I made the same distinction in the article re: color vs. B&W. Current lens ideals seem to be formulated for color. I wrote:

"The modern trend in high-end lenses seems to be towards a higher contrast, "crisper" image. Specifically, these lenses, understandably, seem to be optimized for color work. In color, their higher contrast does indeed serve to create crisp-looking images. The very subtle mid-tones (in music, we might call them quarter tones) that are lost by this contrast are less problematic in color because the distinct colors in a color picture serve to provide a kind of subtle separation by hue, red separates from blue which separates from light blue, etc.. In black & white, though, there is of course no color to do this work and the result of these higher contrast lenses is sometimes an image with less subtle tonal gradation. Try as one might to adjust for this in Photoshop, the result never quite looks like the real thing: a creamy and subtle image made by a lens with high resolution and moderate contrast. This is true, of course, because Photoshop can only work upon the tones that were captured; it can't invent tones that weren't captured. The Voigtlander 35/1.7 has the lowest contrast of three modern 35mm lenses tested, but its contrast is still too high for the kind of black & white files I like to make. Needless to say, some of this is a function of taste. I primarily work with the R-D1 in black & white now and so will be experimenting more and more with lenses from the 1950s (for example) which often have high resolution and moderate contrast. In the first part of this review I mentioned that black & white files from the R-D1 and the Canon 28/2.8 reminded me of Tri-X exposed at ISO 250-320 and developed in D76 1:1. For anyone who may not have seen negatives made that way, I should note that they're quite flat. That is to say, they're full of information across a broad range of tone. From negatives like that, one can make almost any kind of print he or she wants because increasing contrast is a subtractive process."

I've been looking at this phenomena starting with the files and prints back to the design of the lenses. In other words, I start with what I'm seeing in the pictures and then try to figure out what it is about a given lens that is creating what I'm seeing. It began when I saw the first pictures made with the R-D1 and the Canon 28/2.8. My jaw just dropped open. From that point forward, I've been trying to better and better understand what this interactive effect is.

I haven't actually made any argument in favor of scattering per se. My two working hypothesis right now are:

1. The reduction in overall contrast created by certain lenses can be beneficial for both color and B&W work with the R-D1 because it can better match contrast and dynamic range.

2. The reduction in local contrast created by certain lenses can be particularly beneficial for B&W work with the R-D1.

Neither of those results is necessarily connected with scattering. Both could be connected to veiling glare and/or to other factors that have not yet come into the discussion. I am not an optical expert by any stretch of the imagination but what I am able to do is to observe results (files and prints) carefully and note what lenses seem to be having what effects.

Please keep posting; this is a very interesting discussion. Whenever I make a controversial statement in a review (and it happens regularly) I fully expect argument in the forums but it is not so common for people to really explore the issue themselves (with an open mind) to see where things may lead. So, it's a pleasure to see someone like yourself doing just that.

Cheers,

Sean

Sean Reid
12-29-2004, 09:26
"It made sense: photographers wanted "snappy-looking" color slides and prints, and since color film is inherently less sharp than black-and-white anyway (more emulsion layers) there was no point in sacrificing snap to retain tiny textural contrasts."

And...color distinguishes by hue. The color itself does some of the work that might otherwise be done by microcontrast in B&W.

Sean

Sean Reid
12-29-2004, 09:32
THE CLOCK TURNS BACK

But now, digital imaging has turned back the clock! Once again, it's easy for the photographer to control the contrast and tonal distribution of his final image -- just as it was in the days when any serious photographer developed his own film and made his own prints.

"With that shift, the unique optical characteristics of classic RF-era lenses have become relevant again.

And for now, the only way for a digital shooter to exploit those unique characteristics is to use an R-D1! (Neener, neener, EOS-boy...)"

Not quite true. It's the best and most flexible camera for this kind of experimentation but digital EOS bodies can also use a wide range of older and newer lenses via adaptors. It's a little alkward but, for example, I use Zeiss lenses with my 1Ds.

Cheers,

Sean

Brian Sweeney
12-29-2004, 09:33
I'm just getting over the flu so my brain is not all there but:

All detectors require some level of light to register an image at all. A certain number of photons must hit it before it produces electrons. Veiling flare would serve this purpose. A lens that is completely free from flare and other "false illuminations" (brain malfunction) would lose the darkest portions of the image to the detectors threshold.

Back in the early '70s a company produced some prototype modified film cameras that used "tiny lights" to illuminate film the instant before the shutter opened. This illumination served to put the film at its threshold before the image was taken. It was very different from other techniques such as using chemical vapors (Mercury?) the day before use to super-sensitize the film.

Sean Reid
12-29-2004, 09:38
Hi Brian,

Yes, someone else was taking about that preflashing idea yesterday. Interesting comment about the detectors.

Cheers,

Sean

Sean Reid
12-29-2004, 09:47
With respect to the list of how different lenses work with the R-D1, I can add the following:

Canon 28/2.8: high resolution, low contrast, beautiful B&W lens; very little vignetting

Canon 35/2.8: high resolution on center, low contrast, beautiful B&W lens My example of this lens is soft in the corners at wider apertures. This lens is particularly impressive when working in B&W outdoors in contrasty sunlight. very little vignetting

Voigtlander 28/1.9: very high resolution across the frame, slightly lower contrast than many modern lenses, very little vignetting. I think this is one of the best contemporary lenses made, esp. for B&W.

I tried a Canon 50/1.8 Serenar but the example I bought over the net has a front element with scratches and so it has to go back. Can't judge contrast well because of the scratches but the resolution was excellent across the frame even wide open.

Sean

taffer
12-29-2004, 09:54
Phew, excellent article and what a superb thread this one is becoming, serious stuff here.

Just wanted to say thanks for all this info Sean and JLW !!!!

jlw
12-29-2004, 10:41
Originally posted by Brian Sweeney
I'm just getting over the flu so my brain is not all there but:

All detectors require some level of light to register an image at all. A certain number of photons must hit it before it produces electrons. Veiling flare would serve this purpose. A lens that is completely free from flare and other "false illuminations" (brain malfunction) would lose the darkest portions of the image to the detectors threshold.

Back in the early '70s a company produced some prototype modified film cameras that used "tiny lights" to illuminate film the instant before the shutter opened. This illumination served to put the film at its threshold before the image was taken. It was very different from other techniques such as using chemical vapors (Mercury?) the day before use to super-sensitize the film.

Yup, that was the "concurrent photon amplification" I mentioned reading about back in the '70s. I think Norman Goldberg of Pop Photo thought up the idea.

I've been thinking about it again, along the same lines as you have. It should be easier to implement now, with electroluminescent devices and exposure systems that can measure the whole image area.

Imagine a digital camera with a ring-shaped electroluminescent panel around the inside of the lens mount. This would be able to flood the whole imager with controlled, non-image-forming light.

When you took a picture with this camera, the AE system would peg the exposure to the lightest areas, to avoid blowing them out. Then it would calculate the amount of "flash" exposure needed to bring the shadow areas up to just above the sensor's threshold, and turn on the ring-shaped light for the appropriate period.

Then the camera would post-process the imager data to map the darkest areas back to the appropriate black points, producing a final image with a normal tonal range -- with good detail throughout and less noise in the shadow areas.

So if this is such a great idea, why hasn't someone done it? There's probably some reason, but I dunno...

jlw
12-29-2004, 11:21
Originally posted by Sean Reid
And for now, the only way for a digital shooter to exploit those unique characteristics is to use an R-D1! (Neener, neener, EOS-boy...)

Not quite true. It's the best and most flexible camera for this kind of experimentation but digital EOS bodies can also use a wide range of older and newer lenses via adaptors. It's a little alkward but, for example, I use Zeiss lenses with my 1Ds.


But, Zeiss SLR lenses or Zeiss RF lenses? I would think the old Contax lenses wouldn't have enough back focus to work on an SLR for anything except macro use (okay, you could probably adapt a 180/2.8 Olympic Sonnar if you've got one cluttering up the shelves in the utility room) and I wonder if the SLR optics retained the same design philosophy. I've never shot with a Contarex, so I wouldn't have any way of knowing.

...I do have fond memories and old negatives from a 50/1.5 Opton Sonnar, and would love to be able to try out one of those on the R-D 1...

Brian Sweeney
12-29-2004, 11:46
Deja Vu All over Again. Cute kid on Cover.

"A New Way to shoot Tri-X at EI1600 and get Top Quality Results", Bob Schwalzberg, Popular Photography, June 1976.

"Concurrent Photon Amplification", Mel Cole of Danvers, MA.

I bet that modified Nikon F (Apollo version, prism finder) is a valued addition to someones collection...

Today: Set up a little PIC processor and multi-color LEDS... But that would be for a mechanical Film camera.

Digital Camera: could of course incorporate it in.

stevew
12-29-2004, 11:48
There used to be a slide copying machine with a 45deg glass plane between the slide and the lens. The glass plane could be flashed at the moment of exposure to reduce the contrast when copying slides. Some available light shooters would also hang their film in the darkroom and give a fogging exposure to .10 above base density load it film cartridges for their shooting. It would help salvage shadow detail right on the edge.

Sean Reid
12-29-2004, 11:50
Zeiss SLR lenses...the R-D1 is clearly in the best position (among digital cameras) for lens experimentation but digital EOS owners also have room to experiment with other lenses via adapters such as these: http://www.cameraquest.com/inventor.htm

That said, the broad range of lenses the R-D1 can use is one of its key strengths.

Sean

David Kieltyka
12-30-2004, 18:16
Originally posted by jlw
...I do have fond memories and old negatives from a 50/1.5 Opton Sonnar, and would love to be able to try out one of those on the R-D 1... [/B]

Great thread here.

I own the Zeiss 50 f/1.5 in LTM as well as Contax RF mount. The LTM version, c. 1939, is the pre-WWII design, slightly different than the post-war W. German version. However I've never been able to see any differences between the two in actual photographs. For its time the Sonnar was a high-contrast lens, keeping in mind that "its time" pre-dates lens coating. (The LTM version is coated, though, and is among the earliest production coated lenses extant.) By modern standards the lens is moderate in contrast stopped down and on the low side wide open.

I've found the Sonnar works great on the R-D1. It gives me images with a broad tonal range. Resolution is high stopped down and good enough for crisp photos wide open (taking into consideration the shallow DOF at f/1.5).

Following up on various comments made so far in this thread I've included links to a pair of images. Both are versions of the same photo. I used the Sonnar wide open at ISO 1600 on the R-D1 and converted from RAW to 16-bit monochrome TIF in Epson's PhotoRAW app. The first image, other than being cropped to a 3:4 aspect ratio and scaled down for web display, is straight from the converter. No USM or other tone/contrast tweaking.

http://home.twmi.rr.com/davesden/Graphics/Dad01_R-D1_pre.jpg

The second image shows what I decided to make the photo look like using Photoshop CS. I adjusted local & global contrast, set overall levels and added a mild warm tone. I also applied a slight amount of USM to add zip to the point of focus.

http://home.twmi.rr.com/davesden/Graphics/Dad01_R-D1_post.jpg

IMO I used a fairly light touch here. But because the original is flat tonally there's plenty of raw material for more extreme adjustment if I'd wanted to go that route. This is the nice thing about starting with a low-ish contrast original. As long as local contrast is high enough to record a sufficient amount of detail you have total control over the look of your final photo. And you don't have to do any extra work to reveal shadow content or recover blown highlight info.

-Dave-

jlw
12-30-2004, 18:42
These shots do a great job of showing what I remember liking about the f/1.5 Sonnar. Where it's sharp, it's very sharp, and where it isn't sharp, the image breaks up in a nice way. And although full-aperture contrast is lowish, it's nice and even -- kind of like a slight early-morning fog.

(sigh) Something else to start watching for on eBay, I guess!

mfs
12-31-2004, 04:34
I really enjoyed your two articles on LL.

Will you be able to compare the Voigtlander 24mm, and the Leica 24mm??? (FOV- 35mm)

Also, do you feel that the blend of classic, and new controls makes using this camera more complex than either a true modern design, or a classic design???

Thanks again for the great articles. Are you planning any additional articles??

Martin

Sean Reid
12-31-2004, 06:19
Hi Martin,

Do you by chance mean the Voigtlander 25? I may not get a chance to compare it with the Leica 24 but I have seen samples from the latter. Based on those, I think the Leica 24 is probably a better choice primarily because it's rangefinder coupled. If I get a chance to test it I'll certainly do that.

Using this camera is not complex at all but it requires some tradional skills such as being able to focus manually with a rangefinder mechanism. (Despite the moniker this web site has attached to me, I've actually spent many years working with rangefinders). So the camera is really not much more complex than, say, a Leica M6. What it lacks is not simplicity but automation; it definitely is not a "point and shoot".

I have one more article planned and it will be about the design of the R-D1, following the image from lens to sensor.

Cheers,

Sean

Socke
12-31-2004, 09:28
Originally posted by Sean Reid
(Despite the moniker this web site has attached to me, I've actually spent many years working with rangefinders).

:D

You can change that in your settings.

Put some words in user-cp -> Update Profile -> Biography

Happy new year, I'm off to a party!

Sean Reid
12-31-2004, 09:56
Is that how you do it? Thanks.

Sean

Sean Reid
12-31-2004, 09:57
Tried it. Didn't work. Oh well, no big deal.

Sean

Doug
12-31-2004, 11:35
Hi Sean -- I just traced out the route to where you can change from "Just learning to focus a rangefinder camera" to "RF Guru" or whatever you like... :)

At the top of any page there's a line of buttons; third from the left is "User CP"... click that.
In the resulting page there's a line of links below the line of buttons; second one from the left is "Edit Profile". Click that one.
Halfway down the resulting page there's a profile item called "Custom User Text". This is the title that appears beneath your name on your posts. There's a text entry box over at the right, below the display of your current title.
You may enter up to 25 characters.
Hit "Submit Modifications" at the bottom of the page, and you're done.

Sean Reid
12-31-2004, 15:30
Hi Doug,

"Custom User Text" does not appear in my profile. Maybe the crux of this is that one has to make a certain number of posts before this option appears. Thanks anyway. As I said above, it isn't a big deal - I'll look at the moniker from a Zen perspective <G>.

Cheers,

Sean

Doug
12-31-2004, 15:46
Something very fishy, Sean... Notice several posts above where stevew left a message, and his title is "Old photog-New camera" which I expect is not generated by the site, yet he has fewer posts than you, at 27... Maybe a PM to Jorge could answer the issue.

back alley
12-31-2004, 15:49
lilredspy had this problem but eventually was able to get to the custom text and make changes.
i don't know what the heck is going on there.

joe

Sean Reid
12-31-2004, 15:58
It's not worth bothering Jorge about. As I said, I'll make it a Zen reminder that every day I'm re-learning how to focus a rangefinder. To be sure, each day I'm re-learning what to focus a rangefinder upon.

Happy New Year (almost)

I'm home tonight because we have two young daughters and the baby sittter plans fell through. Nothing like children to keep one living the wild life <G>

Cheers,

Sean

Roman
01-01-2005, 11:50
On my page the changing option only appeared after I turned 'Rangefinder Pro' through the number of my posts...

Roman