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Forum: Troubleshooting and Beginner Help 04-25-2015, 05:58 PM  
Calibrating lens beyond fine tune?
Posted By phidias81
Replies: 2
Views: 1,164
Hello, my lens SMC Pentax-DA L 50-200mm F4-5.6 ED WR fell on the sand from an eight of 40cm, but that was enough to get the zoom ring stuck in between 100-200mm. But the main problem is that the lens can't focus. The mechanism is working correctly in AF, in the sense that it can spin back and forth without any obstruction, but it find no focus point. And actually even with manual focus I can't get to see sharp edges, the best I can do is to put the focus to infinite, but the image still looks blurry in any position of the zoom ring.
This might mean that the optical elements moved somehow? Or what else?
Apart prom trying to fine tune the lens, (that most probably is not going to help) is there a more drastic, non electronic way to calibrate it DIY?
I've tried to disassemble the lens already, more on this post, to fix the zoom ring and focus, but I couldn't spot any obvious problem, broken part, loose screw or whatever.
Any suggestion to recover the focus at least on the range 100-200mm?
Consider that I'm in Indonesia at the moment with no reliable service center, and to ship it abroad it's no option, it would cost much more than a working second hand lens.
Thank you, Davide
Forum: Pentax SLR Lens Discussion 04-23-2015, 03:38 AM  
Help disassemble and fix a stuck 50-200 WR, video inside
Posted By phidias81
Replies: 2
Views: 1,829
Any help? I would be happy even to fix it even with limitations, in example only range 100-200mm or even fixed at 200mm if no other options are available
Forum: Pentax SLR Lens Discussion 04-22-2015, 09:25 AM  
Help disassemble and fix a stuck 50-200 WR, video inside
Posted By phidias81
Replies: 2
Views: 1,829
Hello my lens SMC Pentax-DA L 50-200mm F4-5.6 ED WR got broken last weekend while shooting during a concert at the beach. It was on the tripod mounted close to the ground, and the tripod whit the camera on just lost the balance and fell in front hitting the lens. The glass had no damages at all, but the zoom mechanism is not working correctly anymore. Its range is limited now between 200mm and 100mm, and even within this range, it cannot focus (either automatic or manual the same), though the focus ring is not blocked and going all the way. So basically the lens is totally unusable at the moment.
I know many would suggest to just take a second hand one, but I want to try to fix it.

I already tried to disassemble it, partly following this guide for a different zoom lens.

I uploaded a video on Youtube (sorry for the awful quality but it gives an idea), that is possible to see on this link














Youtu.be




In the first part I show the problem described above.
At minute 0:30 I start to show the disassembled lens. After taking out the mount, there are basically three main parts. Two of them are totally ok, the problematic one is the central element. I show this piece starting at minute 1:20. Basically it looks like the end of the ridge is getting stuck (1:28) on the rim. It might be also engineered to work like that, I'm not sure. By pushing the ridge a little bit on the side manually, then it goes all the way inside.

It might be possible to disassemble the element more: I can take out the diaphragm and see inside the tip of some screws that are not visible from the opposite view. Probably they are hidden below a black sticky surface, but I haven't tried to remove it.

There is also a little groove (2:06) that is really difficult to keep aligned to reassemble the lens. It was really difficult to do it, maybe because it was my first lens disassembled.
I hope that somebody will be able to give me a good advice on how to fix it!
Forum: Pentax DSLR Discussion 04-06-2015, 07:16 PM  
Iso setting not stored when changing program in the dial: K7
Posted By phidias81
Replies: 5
Views: 1,051
I've never used Sv before, thanks for pointing out. But I don't thing it would help me much in this case, since I wouldn't have any control over aperture and speed. I might still check is the camera automatically select the widest aperture if I set Program Line "Hi speed priority", in that case it would be a good workaround for this particular situation.

---------- Post added 04-07-15 at 11:23 AM ----------


In my case, while it would have the advantage of not using the program dial, it would still be a lot of messing with settings. I'm looking for a way to just have the settings stored and not changing them each time: maybe the Sv program trick might work.

While I understand that the K7 is a quite old model at the moment and no more support is to be expected, since i't just a software setting, it would have been extremely easy to let the user choose from the menu if they wanted to store Iso settings globally or for each separate program. I don't know if this was implemented in the newer models.
Forum: Pentax DSLR Discussion 04-06-2015, 06:33 PM  
Iso setting not stored when changing program in the dial: K7
Posted By phidias81
Replies: 5
Views: 1,051
I couldn't find a specific K7 forum so I try here.
I've noticed this behaviour long time ago, but never bother too much since I was mainly shooting outdoor-landscape photography at daylight, so Iso settings usually low and constant.
But now I have to shoot for an event (Acrobatic dance) indoor, and this things annoy me a lot.
Basically If I choose program Tv and set 1.6 sec Iso 100 (to create trails), and then I go to Av and set f4 Iso 800 (to freeze the scene), when I go back to Tv, my Iso setting is the one I last used in general, that means Iso 800, while it would be much more convenient for me to have the last used setting on that specific program, that means Iso 100. Is there a setting I can change to have this behaviour?
The only way so far for me is to use USER settings, but that's also limited, since I can store only 1 profile, and since in the dial User is at the exact opposite of Tv, so quite annoying and time consuming to go always back and forth. Thanks!
Forum: Troubleshooting and Beginner Help 12-04-2014, 06:34 PM  
Is it better to lose the biggest aperture or to leave some dead mold in the lens?
Posted By phidias81
Replies: 9
Views: 1,324
It doesn't exist to clean it properly apparently since the front element can't be disassembled further.

I think I will do as you all are saying and just leave the dead mold inside. Thank you for the suggestions

---------- Post added 12-05-14 at 10:47 AM ----------


Definitely an educative article, now I have no more doubts :)
Forum: Troubleshooting and Beginner Help 12-04-2014, 10:44 AM  
Is it better to lose the biggest aperture or to leave some dead mold in the lens?
Posted By phidias81
Replies: 9
Views: 1,324
That's not an option for me, since I have no money to invest on a lens now. I could "fix it" at local price, that means 4$
Forum: Troubleshooting and Beginner Help 12-04-2014, 10:24 AM  
Is it better to lose the biggest aperture or to leave some dead mold in the lens?
Posted By phidias81
Replies: 9
Views: 1,324
This is a follow up of this thread but I opened a new topic, since now it's a more general question. After noticing some mold on the back of my front lens, I first tried to disassemble it myself, and then I went to a local business (Indonesia) specialized on fixing lenses, it was the one that everybody suggested me. The owner told me that to remove the front lens he has to un-glue it basically and then put it back. But by doing so I would lose the possibility to use the aperture f/4, I don't know why (if somebody knows it It would be nice to have a short explanation). Checking the statistics of usage of this lens, it looks like out of about 5000 photos, only 15 use f/4. This is probably because I mostly use the 200mm focal lens of this zoom objective. So this means that it wouldn't be a big loss, but at the same time, I don't like the idea of downgrading its capabilities and the technician didn't seem too careful when handling my lens. And I still have the options to just kill the mold with UV lamp, and leave the dead mold there, that shouldn't bother too much since it's still small and peripheral. What would you suggest me to do?
Forum: Troubleshooting and Beginner Help 12-02-2014, 10:04 PM  
Disassemble front element of zoom lens SMC DA 50-200mm WR
Posted By phidias81
Replies: 13
Views: 4,254
I unscrewed the 4 little screw below the sticker, and I removed the ring visible in the second photo of Just1MoreDave. The ring is actually coming from the back, and its only function looks to be the one of having the screw thread. So I'm at the same level of disassemble as the last picture and I can't go further. It looks like the plastic is just one piece, I can't see or imagine any possible way of opening it further. There are 2 opposite grooves on the same plastic rings as the screw holes, but it doesn't really look like there is any possibility to unscrew something, it's just one piece. The only clue I see is a screw thread in the interior of the front element, below the front lens (slightly visible in the last picture), but I don't know if it's there to refract light or if it's a construction thing or whatever. Anybody managed to go further than this point, or has any hint? Or they are just cemented and it's no way to disassemble them?
If so, then I guess my only option is to use UV lamp to kill the mold, that should remain there, withouut affecting too much the quality of the photo. How can I understand when the mold is dead?
Forum: Welcomes and Introductions 12-01-2014, 07:19 PM  
Italian in Indonesian
Posted By phidias81
Replies: 5
Views: 407
Thank Tom, I will do it!
Lens already quarantined ;)
Forum: Troubleshooting and Beginner Help 12-01-2014, 07:18 PM  
Disassemble front element of zoom lens SMC DA 50-200mm WR
Posted By phidias81
Replies: 13
Views: 4,254
Ok perfect! I'm going to try to remove the sticker with your method. And what about the space in between the 2 lenses? Is that an air tight area with a "controlled climate", in the sense that the humidity should be kept low, or is it ok to open it and close it in any environment? Sorry for the basic question, but it's my first time dismantling a lens.

---------- Post added 12-02-14 at 11:55 AM ----------

EDIT: I managed to remove the sticker after sharpening a plastic piece with sandpaper. Now I have access to the screws, that I have verified I can unscrew with a screwdriver of my gf glasses. I'm still not going further because I'm wondering if it would be better to do the operation somewhere else where there is air conditioning and a lower relative humidity, or if that doesn't count
Forum: Troubleshooting and Beginner Help 12-01-2014, 10:43 AM  
Disassemble front element of zoom lens SMC DA 50-200mm WR
Posted By phidias81
Replies: 13
Views: 4,254
Thank you for the tip! Just for confirmation: I see in the last photo that the lens in the image is a Sigma, so a different model than mine. Is it still going to be for sure the same system with glue also in mine, or it's just one of the possibilities? Thank you!
Forum: Troubleshooting and Beginner Help 12-01-2014, 03:48 AM  
Disassemble front element of zoom lens SMC DA 50-200mm WR
Posted By phidias81
Replies: 13
Views: 4,254
Hello, I've just noticed some mold starting to grow on the back of the front lens of my SMC DA 50-200mm WR. It's still at the beginning, it's growing from 2 different sides but just at the outer circumference of the lens, so I would like to stop it as soon as possible. I'm currently in Indonesia, that means high humidity, rainy season, no sun for uv radiations. I will soon buy more silica gel, but in the meanwhile I would like to clean this lens. I don't know if there are any reliable center here that could do the work, and if it would be worth the money. So I would like to try myself. I actually already unscrewed the front element, using a rubber diy tool, but now I'm blocked. As visible in the photo I took out the front element (mold not visible in the photo, but present) and it looks like the ring where are the writing might be unscrewed. I've tried the same system I used to unscrew the element but it's not working. Before pushing harder, I would like to make sure that that's the proper way to disassemble it? I have to unscrew the ring with the writing and below there might be some screw? Rotation to unscrew the ring is still counter clockwise?
I checked the disassembly database, but it's not helping, since it's showing the disassembly starting from the back.
Some may suggest to buy a clean second hand lens instead, but that's not my plan for now, and my budget is really limited.

Sorry for the quality of the photo attached, but it's just to give an idea. thanks for the help! Davide
Forum: Welcomes and Introductions 12-01-2014, 03:29 AM  
Italian in Indonesian
Posted By phidias81
Replies: 5
Views: 407
Hello, I'm Davide from Italy, currently travelling-living for 1 year in Indonesia. I signed up because I have a problem with on eof my lenses (mold), but maybe it's te occasion to participate in other topics!
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