peer1012dj

<p>29-03-2016<br /><br />Hi,<br /><br />I have a request: how to repair the <strong>photocell</strong> from my <strong>Prolite 82</strong>. <br /><br />This fashunit does not respond on flashes from other strobes. <br />I paid attention to be close enough to get the unit respond, another one did indeed (same distance/power), but not this one. <br />It fires a flash with the open flash button indeed, also with a wired contact from a camera. <br />This means the firing circuitry inside the Prolite is allright.<br> <br />The omission not to fire by the photocell, but only by open flash and by wired contacts, means the photocell is broken. <br /><br />Do I get it right?<br />Is it difficult to repair, also without a repairmanual or a schematic? <br />What kind of photocell, type/number/sensitivity may be needed to replace? <br /><br />I am afraid Bowens of London is not very helpfull to provide me with sufficient information. <br />I tried before, no succes. <br /><br />If anyone knows the answer, please let me know. <br> peer1012dj<br />(Peter C.)<br /><br /></p>

<p>Bob,<br /><br />With the nonsense as you see it, I found it appears to be a Tessar alike lens and I know now what I may expect from the S: a Tessar-way result for optical performances. <br />The chance it is different does exist, but is close to nothing. <br /><br />That is what’s needed to know.<br /><br /></p>

<p>Bob,<br /><br />Your questions implies a profound research after characteristics from the Sironar as well as from the Fujinon S. That is not what I wanted to know. <br />But if I did as like your questions, nr 1 and nr 2, my post would have been far more detailed and perhaps far too long. This one is long enough. <br />I tell you this: my equipment is, among more, around four viewcamera’s. Three at 4x5”, one at 5x7”. To examine a 300mm lens 7x10” is needed at the screen, for this size a 300mm lens is standard. <br />I could perhaps examine a 300mm lens on my enlarger. It is a 18x24-er and has a very long bellows. It also works nice for reproducing flat models, like paintings and drawings. It is equipped with a revolving lensboard for 135, 180, 240 and, indeed, 300mm lenses, all ApoSaphirs, with a single Apo Artar R.D. and a Componon aside. But then, shots at infinity are not possible. <br /><br />My concerns were to find out what kind of lens the Fujinon S 300mm f5.6 is: construction, amounts of elements, if and where cemented, and type. <br />I read the post from Robert. He is curious about the S lens, as I am, and he did not find any information about the lens at all, same as myself. I did quite a lot of search in the internet. <br />However, the Fujinon S 300mm f5.6 seems to be a complete stranger. This is per se strange. Most lensmakers don’t keep back information about their lenses, especially when it comes to performance, like you suggest: circle of illumination, optically, centre/edge sharpness, for which purposes, a.s.o. <br /><br />If a lensmaker but only once had published the lens characteristics, then there could be anywhere some user who had filed this publication for future reading and told something about the lens at any moment. This info was travelled further, kept apart by other users, and so on. Nothing of this, it is complete silent about the Fujinon S 300mm f5.6. <br />So, having no info but only the lens and its shutter, you can only start with comparing it by watching another lens preferred with the same focal distance and opening from a lensmaker who publishes on regular basis the characteristics, and lay-out, from all of his lenses, like Rodenstock. That was my input. <br /><br />I also consider the fact that the most important, in lenshistory determined, inventions from different lensdesigns are roughly made in Europe and England and some in the USA. Lensmakes from other parts from the globe may easily be copies from original design. This comes true by examining the comments about well known types. Especially in the years after a patent runs dead (Tessar ended in 1922 >Wikipedia) you could find similar lensmakes from other parts of the globe, as also happened later with camera’s, taperecorders, turntables. <br /><br />Wiki sais, quote: The Tessar design patent was held by Zeiss for two decades, and licensed to Ross (optics) in the United Kingdom, Bausch & Lomb in the United States and to Krauss in France. Only licensed manufacturers were allowed to use the brand name "Tessar". However, Tessar-type lenses were widely made by many manufacturers under different trade names. Other Tessar-type lenses include the Schneider Xenar, Agfa Solinar, Rodenstock Ysar, Kodak Ektar, KMZ Industar, Yashica Yashinon 80mm (twin-lens-reflex design), and Minolta Rokkor 75mm (twin-lens-reflex design).<br />So, the Tessar was a big money maker with an overwhelming amount of users.<br /><br />To pin-point my attitude: at first sight, the Fujinon S 300mm F5.6 is a lens intended for use on large format: changeable in the frontplane; big shutter; big lensboardhole; heavy in weight; only operable by wire release. For the Sironar 300mm f5.6 this is also true. <br />Both are no lenses for medium or smaller, but for large, say 5x7”or 7x10”. Both lenses could be used commonly spoken for the same kind of l.f. photography: portrait, landscapes, packshots, fashion, commercials. If you have both on the shelf, you could choose which one to take. Two viewcamera’s at 5x7”, one fitted with the Fujinon S lens, the other with the Sironar, both 300mm, should show the same angle of view on the screen and if not, then one of them is no 300mm lens, period. In this view they are the same, at least I see them as the same. Indeed, I must trust the engraving on the lensring. <br />Till now I have nothing said yet about circle of illumination, sharpness, colour rendition and so on, and it is not needed to do in order to answer the question what the Fujinon S is for a lens.<br /><br />To give a start to end the quest about the S lens from Fuji, I took the Sironar 300mm F5.6 for these reasons. Of course, the Sironar is different. I have the older Sironar, just “Sironar” without any other description. I know this lens is symmetrical, Rodenstock’s brochure tells me. I can also see it is symmetrical, the reflections tell me so. <br />I know too the Fujinon is an older lens, allthough no info can be found about the date of manufacturing, the date is a guess. The Fujinon however is not symmetrical. Both may possibly have been produced in the same era, considering the progress of development, especially that of coating. <br /><br />But now my findings. The S has four reflections on front, no cemented reflections. On the rear only two, and a single cemented reflection. The colour from the coating is orangeish and blueish and also quite brillant. Knowing how it is it tells me: single coating. Also the amount of reflections tells me: two elements in front without cement, two element in rear with cement.<br />Conclusion till now without dismantling the lens: four elements from which two in the rear cemented. I am quite sure about this and with this in my hand I could search for comparable lenses. I found the Tessar to come closest. <br /><br />Why the Tessar? <br />This lens is well known. It gives good performances, good sharpness (not the utmost), it is in large amounts and many focal distances produced, see above. In short: not a lens with a build-in disappoinment like lenses from exotic design. A Tessar has tremendous been proven in practice. You can trust on a Tessar. You can also trust on a Tessar clone or look alike, for its formulea has tremendous been proven: what means a name? <br />(A well known politician once stated: when it looks like a duck, it walks like a duck and it croakes like a duck, it IS a duck. In the same manner you may say: when it looks like a Tessar, it reflects like a Tessar, it has the same elements and build as a Tessar, it IS a Tessar. Only the name may be arbitrairy.) <br /><br />Secondly, I started to design a cut away. With the kind of reflection I noticed I found the direction of curvatory for all elements in my cut away. I could not found how exactly the roundness of curvartory from the S lens was. To find thát, dismantling was needed, and of course also special equipment for determining curves only lensmakers have. In meantime I had a cut away which gave me the impression I wanted. And here ended my quest. <br />I hope Robert enjoys also.<br /><br />Just during answerring your post I remembered another Tessar type lens: The Anticomar from Plaubel. Perhaps made before 1950 (I have this lens for at least 30 years, bought second hand), 210mm F4.2, nr 124391, Compound shutter. This lens is easier to examine, frontpart can be unscrewed apart from the two elements it has, the rear is also cemented. Just as the Tessar is. <br />Now, with both lenses in my hand, the Fujinon S and the Anticomar, I don’t see no more difference in apperance than only caused by the curvs: the Anticomar is 210mm while the Fujinon S is 300mm. The curvatory from both points into the same direction. The Anticomar has F4.2 as widest opening while the Fujnon S has F5.6, so the curvatory from the Anticomar is a little stronger compared to its opening. Next, reflections are the same in count and the same in colour. <br /><br />The Fujinon S 300mm F5.6 is in my opinion a Tessar clone, a look alike, with the same performance as a Tessar named lens. Also the Anticomar is a Tessar clone.<br /><br /></p>

<p>Info on Fujinon f5.6 300 "S"<br /><br />For Robert Brown.<br /><br />Since a year of two I have this lens: Fujinon S 300mm F5.6, engraved nr. 150301, purchased from Japan. It has a silver front Copal 3 shutter, 10 blades aperture, weights with Wista lensboard and both metal caps 844 gramms. I own a Rodenstock Sironar 300mm F5.6 on Compur 3, it weights 1300 gramms, to compair with (both lenses do quite the same). Compaired with the weight from large viewcamera’s, some 5 Kg., 800 gramms is not much.<br />Now, I tried several times to find more info about the S lens on the internet, on Wiki, on some deep sites involved into large format a.s.o. and I searched also my own documents. Nothing found. Not even another buyer who purchased this lens. Untill now. <br /><br />Just this week I decided to find out myself what kind of lens the Fujinon S is.<br />Between the Sironar and the Fujinon S I found meaningfull differences, allthough both are ment to do the same, one better than the other. The Sironar is half more weighted from the Fujinon S and has more and thicker glass, according to its construction, 6 elements from which two times two cemented. It is a symmetrical build lens. The symmetrical design is noticable by the reflections, which shows also “shadow” reflections on both sides (by shadow reflections I mean the almost not visible reflections caused by cemented surfaces).<br />The Fujinon S did not. The Fujinon is also less in weight, thus less glass. A difference in weight from almost a half is meaningfull. So I searched on.<br /><br />Of course dismounting front and rear cells was needed, as well as a look inside the shutter (I noticed slight deviations in shuttertimes). Concerning reflections from lensglass there are different types: an orangish or blueish reflection; and reflections with more than two colours, also changing in colour according to the angle of view. But the kind of reflections and the view-through is to be noticable. Briljant reflections mean the coating is only slight, but viewing the shutterblades very clear (not disturbed by brillant reflections) mean the coating is against reflections from many wavelenghts. The Fujinon S shows only orangish or blueish reflections (not at the same surface). It says there is only a single coating applied.<br />There is much to do about modern coatings. Manufacturers manage to coat lenses against reflections from light in a far wider wavelenghts than before, in the years 40-80 former century. Modern caotings result in very clear sight on the attributes underneath the lens. There is almost no loss in light energy during taking a shot, perhaps 1-2 percents, or even less.<br /><br />The frontcells show, as said, single reflections in four, two orangish, two blueish. I found no shadow reflections caused by cemented surfaces. The rear cells show two reflections, only orange, and a shadow one. Rethinking about this I searched for a lensconstruction having two elements in front of the shutter, and a cemented pair of elements on the rear. It showed the Tessar to come the closest to this. This does not mean no other type of lens could fall into this explanation, but considering the popularity of the Tessar I am almost certain the Fujinon S is a Tessar type.<br />Next I designed a cut-out from this lens with the help from software but I can't show. I did not yet find out how attachments to insert into this website page. I may you show also a cross section from a Tessar, but the same reason prvent me to do so. However, you may find Tessar at many internet sites, like Wikipedia.<br /><br />My conclusion is that the Fujinon S 300mm F5.6 is a clone from Tessar for large format, which is no problem. The Teassar is a well admired and well known type of lens and Fuji may have choosen for this type to have a cheap large format lens. And in the same time being sure about its succes, for the Tessar is many times scrutenized. The characteristics from a lenstype will not change when bigger designed, if just the measures (thickness, curvatory a.s.o.) are kept and multiplied equally for the bigger size.<br /><br />Perhaps it is a too large message, but I continue with the shutter.<br />Next I decided to check the times from the shutter. To make it possible to fine tune a short responding set-up is needed. Also more knowledge about how a shutter works is needed. I found both by studying on the subject and by examining early clockworks. Shutters have different times. They all, except for the shortest time, work with time delay devices. The delay in time is managed by gear also found in clocks working with springs, or loads.<br />Now, there are many opinions about how to measure shuttertimes: electronically with photocells or with contactwires and a frequencycounter, or with high speed videocamera’s. There are also many interpretations about what exactly the real shuttertime is and when: between the moments the blades are going to open and are going to close, or the time the aperture from the shutter is only wide open and with this ignoring the light entering during the move of the blades. I read them, but I never read an article about what effect it may have about only little more or a little less light on film. That is what counts: a good exposed film. Some percents more or less do not matter. <br />Considering for black/white film under- or overexposure around the advised amount of light (according to a well functioning lightmeter and translated in shuttertime versus aperture and film sensitivity), a mismatch of 30% means almost nothing. It starts to mean a little with 50% deviation. And it is on the negative true noticable with 100%, if you really want to have a perfect exposed negative. So, when a shutter is set on 1/8, 125 ms., and the actual time is noted in milliseconds 150 ms, the deviation is only 20% and the negative is perfect exposed. Also, the shuttermanufacturers I know, Prontor and Compur, accept deviation in their shutters between 20 (Compur) and 30% (Prontor) new from factory. I suppose Copal does the same. But since the mechanics from Copal is slightly less solid than from Compur, as I noticed, I suppose in the same time that Copals deviations are even larger. It is the seriousness of manufacturing which plays a role. <br /><br />For colour reversal film and perhaps also colour negative film it is more critical to have good shuttertimes, colour may change when the time is too far from what the lightmeter says.<br />Too much mismatch may alter to what a perfect exposed negative or reversal should show. But still a deviation from 20% is not bad at all.<br />At least, large format lenses, starting from 4x5”, do not have shorter times than 1/400 or 1/500 sec.: the light entering during the move from the blades can’t possible mean a serious matter. Some calculations made it clear to me that shutterblades may have a speed between 36 and 180 Km/h. according to the size from the blades (between 0,5 and 3,5 ms.).<br />So, I decided to keep myself on the clicksounds from the shutterblades for these are the sounds expressing the blades had a hard stop. Stop when wide open and stop when very closed. <br /><br />There is also some logic about the settings fot the different times. The delay device runs at equal speed in every setting (there are two, somtimes three, speeds to switch on). Beyond the use from the delay device (called echappement) only the mainspring is left for delay, and this is the fastest time. The other times do delay by letting the echappement running during the time the shutter is open, driven by the mainspring, and when the echappement is ready the mainspring closes the blades. The logic is the time the echappement is running, it makes a travel, and travel means distance. Shortening the distance means shortening delay and vice versa. This is how this type of shutter gets fine tuned, close to its engraving on the scale. <br /><br />I took a microphone, put it into the inlet for mic’s in my notebook, started SoundForge, and recorded the clicks from the Copal 3 set on every setting. SoundForge makes it possible to zoom into the recorded file and to select the clicks and read out the time in milliseconds noted untill 0,00x. I looked for the hardest clicks in the recorded file for these are the hard stops from the blades. Only the shorter times made it a bit difficult to see the clicks between other sounds, see what I said above about the speed from the (1/500 sec is exactly 2 ms, with an average speed of 100 Km/h you must count 0,7 ms extra, 30 %). <br />Checking your shutter this way and you find speeds within 20% of the engraved speeds, you are save.<br />I checked the Copal 3 from the Fujinon S 300mm F5.6 and found the times close to their supposed durations. Nothing to worry about.<br /><br />peer1012dj<br /><br /></p><div></div>