geoffrey_poulton

<p>Thanks Joe, there's a lot of information there, and the idea that the lipped washer is for fitting to a len element is something I thought might be the case. However, there seemed to be a couple of ways it could be implemented (or at least I thought so at first). I placed it over the smaller miniscus lens at first, but on reassembly it allowed movement and rattled a little when shaken.<br> I made the mistake of thinking of the washers as spacers, but over at the Large Format Forum, it was pointed out to me that they were for centering. Once I had that in mind the idea of securing the elements became the main concern. <br> There seemed to be three ways of reasembling the washers, but only one of them held the elements without movement. I found that by placing the lip edged washer behind the front cemented element that it held everything without movement on reassembly.<br> Kevin Crisp, over at the Large Format site has kindly said he will open his 240mm G Claron next week to let me know if the way I have assembled it is correct. I'm hoping it is, and think that it might possibly be so.<br> I did consider having the lens cleaned professionally, but the cost was more than I paid for the lens and shutter, and having cleaned Tessar lenses I thought it might be straight forward job, which I believe it is. I've learned several important things here. Thank you very much for all your help, your comments have been really helpful, and not just on this matter either, you've responded to several questions I've asked. I've been a photographer up to the point, and dismantling lenses is a new departure for me. I saw that you made a comment about watching out for the washers on earlier reply - which made me feel a bit foolish when I realised I had made that elementary mistake. Thanks for all you help, Best regards, Geoff</p>

<p>I'm slightly reluctant to ask this question as I ought to know better.<br> I have dismantled my 240mm G Claron for cleaning, but on reassembling the lens I found that one of the spacers within the lens elements has a lipped edge and the other is flat. When I took the lens apart I did not notice that they were different until it was too late, and now I'm not sure of the orientation of the lip edged washer. I believe it is probably placed nearer the shutter than the flat washer (but I'm now not 100% sure of this), but I don't know whether the lipped part faces the shutter or the front of the lens. <br> I know there are some folks on here who will know for sure. At present the lipped edge is facing the shutter with the back element sitting within it, however there is a little rattling noise if I shake the lens so I'm doubting now that even this is right.<br> Help !!!</p> <p> </p>

<p>I cleaned a 152mm Ektar recently with the same light coating that I see in the 240mm G Claron. It came off without leaving much behind. That cleaning is not complete as I didn't approach it with acetone, which I think may remove the remaining 1% of whatever it is that's there.<br> Some lenses do go beyond their usefulness I must say!!</p>

<p>Thanks John,<br> The question of collimation had lurked in the back of my mind. I contacted a repair technician recently who quoted for lens and shutter servicing, when I said the shutter was in good repair his price for cleaning the lens literally doubled. Also when I spoke to him on the phone he made out that the job was such a difficult and time consuming job, all to justify the high cost. I think dealing with these things myself is the way to go. I have lens spanners and rubber gloves and the various cleaning equipment, I'm sure I'll accomplish it without too many problems. </p>

<p>Hi Joe,<br> No it's not Schneideritis, it was spread across the optics very faintly in an even pattern with some of the lenses, and with other it's was in irregular patches. I'm hoping for the best with the 240mm G Claron I have, as the fungus is mainly around the edge of the lens elements, and is occupying a very small area just now. There is also a very, very faint spread of something across one of the elements which is really difficult to see until the lens is orientated just right to catch the light - even then it's very faint. I'm hoping it will clean without leaving a mark.<br> I've cleaned a number of lenses with acetone, a goat's hair or sable brush and Zeiss lens wipes - everything used very lightly and carefully, but the lenses have been Tessars, which only involved opening up the front group for the rear of the front element and the front of the second element. I guess cleaning a plasmat won't me much different from that. I may have a go myself, at least I know I will be gentle with the cleaning. <br> I will certainly get hold of some of the baby-bottle steriliser solution, that's an excellent tip. I tend to hold the shutter facing downward when I'm putting the thing back together, so that dust would have to go upwards to enter. It's more likely that dust will be settling from above.<br> I did wonder if many of you large format folks cleaned your own lenses, your reply suggest that you yourself do. I wasn't sure whether things needed collimating afterward, I guess not, there isn't much you can to change anything if you've put it back together the way it came apart! It's very expensive having them done too.<br> Thanks for all your help.<br> Geoff</p> <p> </p>

<p>I have been trying over the past few months to find a 150mm G Claron and 240 G Claron in good condition. Four such lenses have passed through my hands including a 240mm 'Dagor' G Claron & a couple of 150mm's. At present I have an order on a 210mm Repro Claron which is described as like new and without marks or fungus. It's a 1966 lens, so I'm keeping my fingers crossed. With the Repro being a dialyte I won't have any problem with separation! <br /> My point is that all of the lenses have suffered from fungus to a greater or lesser degree and yet all were described as having no fungus when the subject was discussed with the seller. I'm hoping for the best with Repro Claron.<br /> I have one 240mm G Claron which I think will be ok when cleaned, I'm in England and wondering if there are any technicians who are recommended for lens cleaning. I've had quotes/estimates from a few, but have no way of knowing how good their work is, it would be nice not to have scratches added during the cleaning process. If anyone has a recommendation I will follow it up. The gentleman who used to work on my cameras and lenses is now retired.<br /> In the USA I read recommendations from various quarters for work on shutters and lenses, and have sent things along to S K Grimes from here, but in Gt Britain large format is not as prevalent as it is in the U.S.<br /> Any recommendation would be gratefully received (as would comments on the Clarons if anyone feels like it).<br /> <br />Thanks, Geoff</p>

<p>Hi Michael,<br> I wonder if your lens not focussing too well at infinity might have something to do with the spacing of the element groups in the shutter.<br> I see that my G Clarons have shims, so someone at some time must have made a measurement to implement those shims.</p>

<p>Hi Dan,<br> I'll bet you're loving this! For the aperture to be fully open at "round" my lens needs to be turned a tad to f8 (a very small move) turning it to f9 brings in the "shaped" aperture into view.<br> I think it's slightly out, but not by very much - it may, of course, be the wrong aperture scale, but I'm hoping it's the right scale but just not precise. I have other lenses performing the same way, whilst other behave themselves properly!<br> Thanks for your help Dan - I appreciate it very much. Knowledge removes fear (if only I had enough of it!).</p>

<p>Hi Q.G.<br> I have several lenses myself here that get up to this trick! The movement from the round open aperture of the shutter to the first aperture of the lens can be very slight, at that point the aperture blades can just be seen coming into the hexagon shape, and perhaps not as precise as you would might wish. Any adjustment to f9 being completely open would mean a movement of the aperture scale of a fraction of an inch or perhaps about a mm. <br> In the lounge with time to spare, the measurement might be troubling, but out in the field while you're standing in a patch of thorny briars getting your blood sucked by mosquitos and being buzzed by wasps - it might not seem quite as important!! Or just waiting to catch the light just right - that's wonderful feeling.</p>

<p>Thanks Dan<br> I think a little paranoia might have set in here! I say a little, and paranoia might be too strong a word, but as this 240mm G-Claron started life as graphic lens, I may be looking harder than I might otherwise.<br> I can see that at f9 that there is the start of the blades forming a hexagon shape, at what would be f8 (a tiny move of the aperture lever) the shape is the shutter's round aperture. The movement is so small I could hardly name it as part of the stop. I suspect the lens has the right aperture scale. The front group of elements have been mounted using two shims, so I suspect whoever mounted the lens must have had an idea of what he was up to - I am hoping for that!<br> I think this more or less fits in with you information, it's pretty close to what you have described. The movement from round to forming a shaped aperture is very small.<br /></p>

<p>There are two lenses that I am looking at here, with the similar feature of the widest lens aperture not reaching to the full extent of the shutter aperture. The 100mm f5.6 apo-symmar has a stop on the aperture lever to prevent it going wider than f5.6, but without this stop it looks like the lens aperture would go to around perhap f3.5 or so. The other lens, a 240mm f9 G-Claron opens up all the way the maximum aperture of the shutter, possibly around f5.6/f8 or so, and when the lens is closed down to select f9, the aperture blades move in. So when I focus I could select the f5.6/f8 (it's a guess) for better vision, then stop down to whatever aperture I need.<br> I think I have possibley said the same thing several times during this thread now!!</p> <p> </p>

<p>I must say Q.G that this has been my thinking too so far. My 240mm f9 G-Claron in the Copal Press 1 does the same thing, but does not stop opening at f9 but carries on opening another half stop or so. The only difference between the G-Claron and 100mm apo symmar is that the apo symmar stops before it reaches wide open, and the G Claron goes beyong the f9 another half stop or so. To achieve f9 you move the aperture lever to f9 and it stops down a little. The preview lever opens the lens wider than the indicated f9 to full extent of the shutter opening.<br> These description get to be an exercise in the use of English!!</p> <p> </p>

<p>Yes, I understand what you mean. It is a bit of a Chinese puzzle though, and what's confusing it for me is the 100mm f5.6 apo symmar, which closes down about 1/2 a stop or so from the fullest aperture extent of the shutter to obtain its f5.6. This is what Schneider confirmed to me as being correct.<br> I think this calls for further investigation!</p> <p> </p>

<p>Ah! I see. Yet fully open it would be letting more light in than when stopped down to f9, wouldn't it?</p>

<p>It appears that some of Jose's lenses do the same thing.<br /> If the same shutter is used for various lenses with varying maximum apertures, then I guess this would happen. For example, if you had two 105mm tessars, one at f3.5 and another at f4.7. It might be the case that the f3.5 opened to the full extent the shutter had available, whereas on the same shutter the f4.7 would be wider than f4.7 (in fact f3.5) when in preview and close down to f4.7 to shoot.</p>