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11-21-2013, 05:39 PM   #31
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i had an older vivitar lens with the same issue. It was just bayonet mount. I tool off then entire mount (4 screws i believe) and took it to the wire wheel i have in the garage. Took the paint off nicely, and didn't mess with the mount at all. Cleaned it off really well and reattached. Haven't had a problem since.

11-21-2013, 05:49 PM   #32
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QuoteOriginally posted by elliott Quote
You need to keep trying get all of the paint/anodizing off or go for the foil tape method. What does it look like so far?

The M42 lenses are just fine, since they don't have that aperture lever. What it is doing is seeing that K mount lens as an M42 lens, so it is ignoring that lever. You need it to see the lens as a K or M lens for it to let go of the aperture lever and allow the lens to stop down.
I gave the foil option a try and it did work better, but still the photos are a bit washed out (maybe because of the overcast weather). The lens now closes down when I press the green button. I will try to remove all of the paint. Hopefully, that will be answer. Thanks.
11-21-2013, 05:50 PM   #33
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QuoteOriginally posted by link81 Quote
i had an older vivitar lens with the same issue. It was just bayonet mount. I tool off then entire mount (4 screws i believe) and took it to the wire wheel i have in the garage. Took the paint off nicely, and didn't mess with the mount at all. Cleaned it off really well and reattached. Haven't had a problem since.
Thanks for the tip. I will try to remove all the paint. Big job but I've got plenty of time...LOL. Thanks a lot.
11-22-2013, 01:06 AM   #34
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QuoteOriginally posted by elliott Quote
You need to keep trying get all of the paint/anodizing off or go for the foil tape method. What does it look like so far?

The M42 lenses are just fine, since they don't have that aperture lever. What it is doing is seeing that K mount lens as an M42 lens, so it is ignoring that lever. You need it to see the lens as a K or M lens for it to let go of the aperture lever and allow the lens to stop down.
Hi Elliot. Tried the foil option again making sure all the contacts are covered. The result was good. Photos were exposed well and the colours were vivid. Now, I am certain there is nothing wrong with the lens itself. I am at work tonight. I will try to remove all the paint during my shift. Hopefully, I will complete the job by tomorrow morning before going home. Thanks again for your assistance. It is very much appreciated.

11-22-2013, 03:33 AM   #35
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QuoteOriginally posted by el baroda Quote
I gave the foil option a try and it did work better, but still the photos are a bit washed out (maybe because of the overcast weather)

QuoteOriginally posted by el baroda Quote
Hi Elliot. Tried the foil option again making sure all the contacts are covered. The result was good. Photos were exposed well and the colours were vivid. Now, I am certain there is nothing wrong with the lens itself. I am at work tonight. I will try to remove all the paint during my shift. Hopefully, I will complete the job by tomorrow morning before going home. Thanks again for your assistance. It is very much appreciated.
So, it is time to congratulate you with your 'new' lens!

What you have seen in respect of washed-out pictures/colours has, in all likelyhood, nothing to do with the electrical contact issues. Long lenses are simply very sensitive to scattered, diffuse light from mist/dust/turbulence in the air. A good hood may help, but sometimes that is just not enough and one has to adjust contrast in post-processing ('Autofix' will often do the trick) as the following examples may show:


smc Pentax-DA* 200mm @ f/3.2

And a very pronounced example (taken through of an airplane window):


smc Pentax-DA 18-135mm lens at 100mm and f/8

Hope, we shall see some sample images from your Petri lens here at PentaxForums soon.
11-22-2013, 03:53 AM   #36
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QuoteOriginally posted by Stone G. Quote
So, it is time to congratulate you with your 'new' lens!

What you have seen in respect of washed-out pictures/colours has, in all likelyhood, nothing to do with the electrical contact issues. Long lenses are simply very sensitive to scattered, diffuse light from mist/dust/turbulence in the air. A good hood may help, but sometimes that is just not enough and one has to adjust contrast in post-processing ('Autofix' will often do the trick) as the following examples may show:


smc Pentax-DA* 200mm @ f/3.2

And a very pronounced example (taken through of an airplane window):


smc Pentax-DA 18-135mm lens at 100mm and f/8

Hope, we shall see some sample images from your Petri lens here at PentaxForums soon.

Again, thank you very much for your support. I really appreciate it. Hopefully, I can post some photos tomorrow. Cheers.
11-22-2013, 10:13 AM   #37
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I had the same problem with my Porst 55 f/1.2. Remember you don't really have to remove that much of the paint… just the spots where the contacts touch the lens. I bought an old broken film body, removed the lens mount from it, put it on the porst, and marked the spots that needed to be sanded clean.

You could even, if you so desired, only sand off the spots that corresponded to your min and max aperture:
http://www.robertstech.com/matrix.htm

Then if you decided to short the A contact, the camera would at least know the correct min and max aperture for your lens.

Going completely bare tells the camera that you've got a 1.2-22 lens on it. Completely insulated means 2.8-16.

If you do that, you get a little more functionality, but the cameras idea of what stop you're on vs the lenses idea may not be the same, so you may have to mess with exposure compensation a bit.
11-22-2013, 10:57 AM   #38
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QuoteOriginally posted by narual Quote
I had the same problem with my Porst 55 f/1.2. Remember you don't really have to remove that much of the paint… just the spots where the contacts touch the lens. I bought an old broken film body, removed the lens mount from it, put it on the porst, and marked the spots that needed to be sanded clean.

You could even, if you so desired, only sand off the spots that corresponded to your min and max aperture:
http://www.robertstech.com/matrix.htm

Then if you decided to short the A contact, the camera would at least know the correct min and max aperture for your lens.

Going completely bare tells the camera that you've got a 1.2-22 lens on it. Completely insulated means 2.8-16.

If you do that, you get a little more functionality, but the cameras idea of what stop you're on vs the lenses idea may not be the same, so you may have to mess with exposure compensation a bit.
I have already sanded off about 3/4 of the anodized layer (fingers a bit sore already). This should be more than enough. I really hope I can by now replicate the good result that I got yesterday by using the foil method. Keeping fingers crossed. Thanks and regards.

11-24-2013, 05:01 PM   #39
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Hurray! My Petri lens works now.

This morning, I got myself an 80 grade sandpaper. It worked much faster and deeper than the first sandpaper (320 grade). In minutes, I was able to sand off all the anodized layer on the lens mount that was touching and contact points. Presto, the lens now works perfectly. Here are a couple of shots. I did not use the green button but relied only on Sunny 16 Rule. The orchid shot had no post processing at all but the Begonia needed just little exposure correction. I think I'm going to be happy with this cheap, third-party lens.

Last edited by el baroda; 11-24-2013 at 05:07 PM.
11-25-2013, 12:45 AM   #40
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Petri 200mm f/3.5 photo at last

I hope this one loads. Crested pigeon was about 15 feet above. No post-processing, only cropping, involved.
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11-25-2013, 02:05 AM   #41
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Congratulations once again. That truly does look promising!
11-25-2013, 02:25 PM   #42
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QuoteOriginally posted by Stone G. Quote
Congratulations once again. That truly does look promising!
G'day, mate. Thanks for your continuing support. Here's another unprocessed shot. I did not use the green button, but relied solely on the Sunny 16 Rule. I think the photos will even be better when I use the lens on my K5. Thanks again and warm regards from Down Under.
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11-30-2013, 04:43 AM   #43
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Here's another test shot from my Petri 200mm lens. I relied solely on the Sunny 16 Rule (not green button). No post-processing.
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