david_goldenberg1

<p>"The lens head unscrews from the DR focusing body, but the non-DR Summicron of the same vintage is fixed."<br>

I'm pretty sure that the rigid Summicron, introduced in 1957, had the same removable optical unit as the DR. I have read in various places that the Leitz technicians hand picked the best optical units for the Dual Range, for instance here:<br>

http://theonlinephotographer.typepad.com/the_online_photographer/2010/05/ebay-treasures-the-7element-summicron.html<br>

But, I have no idea where this story comes from or if it is true.<br>

David</p>

 

<p>There is, in principle, a way to do this without damaging the lens at all. The trick is to find a compatible focusing mount from a "rigid" mount lens of the same era, and then just transfer the optical element (which screws out of the focusing mount) to the other focusing mount. This is completely reversible. But, it is complicated by the fact that different optical elements had different focal lengths, which were matched to the focusing mounts that they were shipped with. My understanding is that the DR models all had the same focal length, so that only one version of the DR focusing mount was needed, but the rigid models had a range of focal lengths. So, you would need not only a rigid focusing mount, but one for the correct focal length. In the past, I have entertained trying to find one, just to have a lighter weight lens on my M3. I imagine that it would take a lot of looking to find a lonely rigid mount, especially of the correct focal length.</p>

<p>David</p>

<p>Rex,<br>

I'll offer another endorsement for the Minolta Dual Scan series as an option for you. I've owned and used a number of scanners, including a Dual Scan III, a Nikon LS V, an Epson V500 (the predecessor of your V550, I think) and a Nikon LS 8000. <br>

The Dual Scan was the first in the series, and it was really quite respectable, and they look to be available now at low prices, admittedly in unknown condition. One of the major limitations, with respect to the Nikons, is the absence of IR-based noise reduction (called ICE by Nikon). This is a very good feature, but it can't be used for conventional black and white negatives, so it probably isn't relevant to your planned uses. (ICE does work with chromogenic black and white films.)<br>

The Nikon LS V had higher resolution than the Dual Scan, and the scans were sharper, but not hugely so. On the other hand, the LS V is very good at picking up the tiniest scratches on a negative, an effect that I think is due to the direct LED illumination. The Dual Scan uses a tiny fluorescent tube that gives more diffuse illumination and seemed less prone to picking up this kind of noise.<br>

One challenge that arises with scanning negatives is the enhancement of grain patterns. This is sometimes called "grain aliasing", but I don't believe it is an aliasing effect. Without going into the argument about what really causes it, it is a real effect and its magnitude seems to depend on multiple factors, including the film type the developer (for conventional B&W) and the scanner. The effect may have been a bit worse with the Dual Scan than the LS V, but I saw it with both. The best solution that I found was one of the noise reduction programs, or careful choice of film and developer. I have had good luck with Neat Image, but there are others.<br>

For the risk involved, I would be very tempted to try a Dual Scan III or IV for your needs. (I think the earlier models had significantly lower resolution.)<br>

I hope that these comments are of some help.<br>

David</p>

<p>I have the Mamiya 7ii polarizer. The important point to be aware of is that it does not mount to the lens using the filter threads. Instead, it mounts using the bayonet tabs used for lens hoods. I don't know anything about the Mamiya 6 lenses, but I would not assume that the polarizer for the 7 will fit these lenses. They might, but might very well not.<br>

David</p>

 

<p>At a workshop, I once saw Al Weber demonstrate a method for developing roll film in a tray. As I remember it, he unrolled the film from one hand, sloshed it through the developer as he rolled it up with the other hand, and then repeated the process continuously. The film was kept saturated with developer and the transfers through the tray provided agitation. Since it was a demonstration with the lights on, we didn't get to see the results, but he swore by the method.<br>

Personally, I stick with a stainless steel reel!<br>

David</p>

<p>I'm not sure, but I think that the answer may be no. I have an LS8000 and NikonScan 4.0.2. When I just tried, it seemed that the DEE feature was not active, in contrast to most of the other Digital Ice features.<br>

Also, I just looked in the manual for Nikon Scan 4. On page 61, the description of DEE says:</p>

<p >Enhances detail in underexposed or overexposed areas of the image (9000 ED, 5000 ED,and COOLSCAN V only).<br>

Sorry,<br>

David</p>

<p>Paul,<br>

Can you tell us more about the Leicanol formula, and where you found it?</p>

<p>Thanks,<br>

David</p>

<p>I have used Neat Image for several years, primarily for scans of black and white negatives (with different scanners, including a Coolscan V and a Coolscan 8000). Like others, I have found that scanning often enhances the graniness of black and white negatives, and I have usually been able to reduce that effect using Neat Image. One has to be careful not to overdo it, or it can definitely lead to a plasticky look. But, I have usually been pretty happy with the result.<br>

Of late, I have had to rely less on Neat Image, as I have been developing my negatives with a staining developer, Pyrocat HD. So far, this has been the best solution for me, but obviously it doesn't help with old negatives.<br>

I've not really tried other noise-reduction tools, but my sense from reading reviews is that Neat Image works about as well as any.<br>

Hope this helps,<br>

David</p>

<p>I should also have said that the graphs were drawn with the correct equation. <br>

The basic assumption is that the point spread function (the form of the blurriness) can be approximated as a Gaussian function, a "bell-shaped" curve. As Alan suggests, this will be the case if the point-spread function has an origin from random noise, but the Gaussian is also commonly used as an approximation to the point-spread function of a diffraction limited lens.<br>

David</p>

<p>Oops! I wrote the equation incorrectly. The correct form is:<br>

b_total = sqrt(b1^2 + b2^2)</p>

<p>For those like Alan who are interested in the scientific aspects of photography, here is a more technical explanation of why "it never ends". <br>

The underlying assumption in many of these discussions is that the film image has some fixed resolution and if it is scanned with that much resolution all of the information will be captured. In fact, when multiple processes, each with limited resolution, are applied to an image (or other signal), the "blurriness" of the individual processes are added together. The fancy term is convolution. The mathematics of the convolution is not always easy to define for real situations, but a commonly used approximation is:<br>

b_total = b1^2 + b2^2<br>

where b1 and b2 are the blurriness of the individual steps, and b_total is the total effective blurriness. We can think of blurriness as the reciprocal of the resolution.<br>

The significance of this relationship is shown in the graph below. The three curves are drawn assuming that the effective resolution of the camera and film are 2000, 4000 and 8000 dpi. In the units that are more often used for optical resolution these correspond to 40, 80 and 160 line-pairs per mm (lppm). The horizontal axis represents the scanner resolution and the vertical axis the resolution of the final scanned image. Notice that a scan resolution of about 6000 dpi is required before the 2,000 dpi image is recorded with nearly all of its resolution, but 4000 dpi comes pretty close. For more resolution in the film image, correspondingly higher scan resolution is required. <br>

What is the resolution of a typical 35mm film image? This can vary greatly, of course. With a very good lens and fine-grained film, 125 lppm (6000 dpi) might be possible, but it probably doesn't happen very often. The same convolution effect applies to the lens and film resolutions, and resolution will also be reduced by focusing errors, camera shake and other factors.<br>

It's worth mentioning that the same thing happens when a negative is printed optically or a slide is projected. Some enlarging lenses have very high resolution, but there are plenty of other degradations to the image. I think that the common experience is that a 4000 dpi scan and inkjet printing can be just about as good as the best optical prints.<br>

I hope this helps,<br>

David</p><div></div>

<p>Martin,<br>

I would echo Sebastian's comments. Variations on this question are asked on photo.net on a regular basis and almost always lead to long heated exchanges. Everyone (myself included!) would like to believe that a $180 scanner will be just as good as a much more expensive film scanner. In my view, the Epson (and others) flatbed scanners are a marvel of engineering, providing remarkable capability at a low price.<br>

But, these scanners have their limits, and there really is a difference between them and an Epson Coolscan, for instance. Whether or not that difference makes the much higher price worthwhile is a very personal question. Because I do all of my photography with film and print digitally, I view the scanner in the same way I might an enlarging lens: Since the quality of every print is influenced by the scanner, it makes sense to me to invest as much in the scanner as in a good lens.<br>

But (again), you can certainly make very good images with MF film and the Epson v500. If that is what you can comfortably afford, go for it! <br>

David</p>

<p>Richard,<br>

Funny you should ask! 2 1/2 years ago I started what turned out to be a very long thread, very similar to this one, by posting scans from the V500 and a Coolscan V:<br>

http://www.photo.net/medium-format-photography-forum/00RS5y?start=0<br>

(Depending on your browser you may have to go to the fourth page of the thread to actually see the scans. I had some file format problems.)<br>

There are lots of other comparisons like this on the web, and one can pixel peep to justify just about any conclusion one wants! As demonstrated by the this and other threads.<br>

David</p>

<p>Here is the graph for the Coolscan 8000</p><div></div>

<blockquote>

<p>I definitely do not think that a 4000 dollar scanner is needed for negative proofing and posting film images to the web. I know I am in the minority here in supporting cheap low cost scanners, but I am just going off what I see.</p>

</blockquote>

<p>I absolutely agree! But, there really is a difference between a flat-bed scanner and a film scanner. I mentioned before that I had performed slanted-edge MTF tests on an Epson V500 and a Coolscan 8000. Here are graphs from those measurements. <br>

For those who aren't used to graphs of this sort, the vertical axis represents the fraction of the orginal contrast that is recovered in the scan, and the horizontal axis represents different spatial frequencies in cycles per inch. For the Epson, the maximum frequency is 3200 cycles per inch (one half of the maximum number of pixels per inch), while the maximum for the Coolscan is 2000 cpi. The individual curves are from scans made at different resolution settings.<br>

For the Epson, the curves with scan resolutions of 6400, 3200 and 2400 ppi are essentially identical, meaning that no additional information is gained by using a setting greater than 2400. At 1200 ppi, the Nyquist limit (600 cpi) is reached before the optical limit is. The relationship between MTF and resolution is somewhat arbitrary, but one interpretation is to say that the maximum frequency at which the MTF is greater than 10% corresponds to the maximum resolution. In this case, this occurs at about 700-800 cpi, which would correspond to about 1500 dpi. This is pretty close to what www.filmscanner.info says for the V600, using a different method (a resolution chart). <br>

For the Coolscan set for 4000 ppi, the MTF curve reaches 10% at about 1400 cpi, or 2800 dpi. Reducing the scan resolution to 3000 dpi causes a noticeable loss in information, and the MTF curve just reaches the Nyquist limit. With a 2000 dpi scan, the result is clearly limited by the scan resolution.<br>

For my slanted edge, I used a double-edged razor blade in a glass slide mount. This may not be ideal, since the blade is very reflective. But, I think that the comparison makes the relative performance of the two scanners pretty clear.<br>

Whether or not this difference is important, depends entirely on the user and application. In my experience, one of the practical differences is that scans from the Coolscan require minimum sharpening, with correspondingly less artifacts.<br>

As always, YMMV.<br>

David<br>

P.S. For more about MTF and the slanted edge test, see this page:<br>

http://www.imatest.com/docs/sharpness.html</p>

<p> </p><div></div>

<p>The "resolution" that manufacturers specify reflects only the number of pixels that are generated in the output files, i.e. the Nyquist-limited resolution (though even that can be fudged by using interpolation). These specifications do not say anything about the ability of the scanner to actually resolve features on the negative or reflective medium. <br>

For those who are interested in a serious evaluation of scanner resolution, I suggest the following paper:<br>

http://www.aspbooks.org/a/volumes/article_details/?paper_id=30173<br>

The author Robert Simcoe is an engineer who recently led a group building a specialized high-resolution scanner to digitize astronomical photographic plates. I think it is reasonable to assume that he knows what he is talking about. In this paper, he compares an Epson V750 and Nikon Coolscan 9000, using a slanted-edge method to measure the modulation transfer function (MTF). In brief, the resolution of the Coolscan approaches its advertised Nyquist resolution (4000 ppi), but the Epson falls far short of its advertised resolution. This is almost certainly due to the optical limitations. In addition, Simcoe explains how the advertised resolutions of flat-bed scanners are "padded" by interpolating data from staggered CCD arrays. This also contributes to the difference between the specifications and real resolution.<br>

I have also used the slanted edge test to measure the MTF of a Coolscan 8000 and an Epson V500. I didn't do it as carefully as Simcoe did, or with as good a target, but my results were quite similar to what he describes.<br>

The reason that Epson and others can get away with the specifications they cite is that the numbers have a carefully-specified meaning, it's just not what most people would expect "resolution" to mean. Personally, I think that this is unfortunate. The real resolution of inexpensive flat-bed scanners is really very impressive for their cost, without any spec-manship. Not surprisingly, though, the resolution is not comparable to much more expensive film scanners.<br>

I have a copy of the paper described above, but it is copyright protected. If you send me a personal message, I will send a pdf to you (assuming that I don't get hundreds of requests!).<br>

David</p>

<p> </p>

<p>There was an amazing reflex finder made by a company called De Mornay Budd. The picture is from a current e-bay listing, so you can actually buy one right now for only $445:<br /> I'm taking the liberty of posting the picture so that it isn't lost.<br /> The finger below the finder rides on the lens focusing mount and adjusts the focus on the ground glass. I think that it may have specifically been designed to be used with a 5cm Summar.<br /> I saw one of these at a sale once, attached to a Leica III, and have always regretted not buying it. <br /> David</p><div></div>

<p>Like this?<br>

David</p><div></div>

<p>I've never used them myself, but I'm pretty sure the diopter correction lenses just pop into the rubber cap of the viewfinder. There's nothing to remove.<br>

Good luck,<br>

David</p>

<p>At the risk of further inflaming this discussion, I would go further and say that a medium format negative scanned with a relatively inexpensive flatbed scanner can *exceed* the quality of a 35mm negative scanned with a Nikon film scanner. When I first started using MF a couple of years ago, I bought an Epson V500 and did some initial comparisons with a Coolscan V. The rather lengthy thread generated from my experiments can be found here:<br>

http://www.photo.net/medium-format-photography-forum/00RS5y<br>

From my experiments at the time, my impression was that scans of the same negative from the two scanners were difficult to tell apart up to magnifications of about 4-5x. For a medium format negative, this means about 8"x10" or maybe 11"x14". But, the same print size requires 8-10x magnification of a 35mm negative, where there is significant image degradation due to grain, dust and other noise, even with the best scan. <br>

I've never seen the article, but legend has it that Geoffrey Crawley of the British Journal of Photography once did a comparison of a cheap Seagull TLR and a 35mm camera with a first-rate lens. Because of the lower magnification required, the Seagull at least tied (or won, depending on who tells the story).<br>

Now, I also have to say that after a few months of using the Epson, I started longing for the last bit of quality in the MF negatives, and I bought a second-hand Coolscan 8000 (and, eventually the glass carrier). There is no question that the Coolscan captures more of the detail in the negatives, with about twice the real resolution. The other issue is that the Epson scans require more sharpening, which can cause artifacts. But, for an 11"x14" print, you only need about 1500 ppi resolution from a 6cmx7cm negative.<br>

So, my view is that, for someone interested in exploring the hybrid way (film and scanning), MF with a flatbed scanner is a perfectly good way to go, at relatively low cost.<br>

David</p>

<p>The Formulary is a small operation, but substantially more than a single person. Things may slip through the cracks occasionally, but they are great people and provide great service, in my experience. I have no direct interest, but I did take a workshop there a few years ago, and it is hard not to leave feeling like family! Even the best of families have an off day.<br>

David</p>

<p>Tim,<br>

The camera does have a frame for the 150. The external viewfinder is offered as an option because the built in frame is relatively small at the reduced magnification of the camera viewfinder. I use the 150 without the external viewfinder and have never found it a big problem. It probably depends on what kinds of subjects you are working with.<br>

David</p>

<p>It is worth noting that Ansel Adams originally developed the Zone System, in the early 1940s, for use with a Weston Master meter, a selenium meter with an acceptance angle of about 30 degrees. In fact, there is a strong historical connection between the Zone System and the design of this meter. At the time, the only spot meter available was an SEI photometer that was extremely expensive and bulky. It wasn't until the 1960s that spotmeters became at all common, with the introduction of the Pentax models. Even then, the Weston Masters were the standard among Zonies for quite a while. <br>

What Adams recommended (and did himself) was a combination of making substitute readings and walking up to his subjects. (Or making educated guesses when he couldn't find the meter; see Moonrise over Hernandez.) He also described making cardboard tubes that narrowed the acceptance angle of the Weston meter. This is described in the second volume of the original Basic Photo Series, first published in the 1940s. Those books are fun to look at, but not as easy to understand as the completely revised books published in the 70s.<br>

My point is just that using the Zone System is not tied to having a spot meter. But, a spot meter certainly helps. If you have an iPhone, you might be interested in one of the spot meter apps that have recently appeared.<br>

Hope this helps.<br>

David</p>

<p>At the risk of adding confusion to the circle, allow me to offer a slightly different perspective on this:<br>

Diffraction is the phenomenon in which light waves originating from different points add either constructively or destructively. It is intrinsic to the wave nature of light. Rather than adding blurriness to an image, constructive and destructive interference is what actually creates the image!<br>

The resolution of an image from an ideal lens (i.e. one with no significant aberrations) is limited by the wavelength of the light and the diameter of the aperture. This is not because of some artifact due to light scattering from the diaphragm (though that could be an additional factor). Rather it is because the size of the aperture limits the angle of over which light can be collected, and limits the ability of the diffraction effect to resolve closely spaced points. In other words, the size of the aperture limits the amount of information that the lens can collect and, therefore, its maximum resolution. In the world of microscopes and telescopes, if a lens is said to be diffraction-limited, this is a good thing: It means that the resolution is limited by the wavelength of light and the diameter of the aperture, rather than any optical aberrations. (Telescopes and microscopes don't usually have diaphragms to adjust the aperture, precisely because they would reduce the resolution.)<br>

Camera lenses (at least of the sort that most of us ever see) are rarely diffraction limited at their maximum apertures. This is because of the various aberrations, which are more difficult to control if the lens is to be used under a variety of conditions and built at a reasonable price and size. Stopping down the lens tends to reduce the aberrations, and this almost always dominates the reduction in optimal resolution, at relatively large apertures. At some point, though, the aperture becomes small enough that the aberrations are largely eliminated, and the lens becomes "diffraction limited". Further stopping down does not significantly reduce aberrations, but does limit the resolution further.<br>

As others have said, the competing effects of aberrations and the diffraction limit usually result in an optimum aperture for a given lens. Further stopping down will reduce resolution, but whether or not this is significant depends on a variety of factors, including the enlargement of the final image. <br>

In my mind, the diffraction limit comes in a third (usually distant third) in considering the aperture I use for an image, following: How much light do I need to expose the negative? and How much depth of field do I need? (It's also worth thinking about how much depth of focus one needs to allow for likely focus errors.)<br>

I hope this helps. I know that it isn't the usual (photography) textbook explanation, but it can be found in texts on microscopy, for instance. <br>

David</p>

<p>Dumitru,<br>

It sounds as if something is loose within the rangefinder mechanism of the camera. The frame should move as you change the focus, to correct for the change in parallax at different distances. Since this is happening, the lens and the camera body are apparently talking to each other, but the linkage to the rangefinder mechanism must be loose. You will probably need to take or send it to a good repair person. I have recently had a good experience with Precision Camera Works: http://www.precisioncameraworks.com<br>

I hope this helps.<br>

David</p>