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justtorchit
Joined: 12 Oct 2009 Posts: 269 Location: St. Louis, MO
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Posted: Wed Mar 24, 2010 4:56 pm Post subject: Can someone identify this lens affliction? Spot with a ring |
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justtorchit wrote:
I recently got (what I believe to be) a very reasonable price on a Tokina MF 300mm f/2.8. In my shooting, it is definitely a great lens for the money. Although the exterior shows use, the optics look very good. There is only one ailment that I can see, and since it is so far off the center of the glass, I can't imagine it's affecting image quality. It reminds me of a crumb on a napkin where the moisture or oil creates an outer ring around the crumb. I was wondering if this might be some particulate around which the oil is being drawn out on the optic. If someone could help I would appreciate it!
_________________ David
www.davidkovaluk.com - personal website
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http://makingnottaking.blogspot.com/ - photoblog |
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luisalegria
Joined: 07 Mar 2008 Posts: 6602 Location: San Francisco, USA
Expire: 2018-01-18
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Posted: Wed Mar 24, 2010 7:36 pm Post subject: |
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luisalegria wrote:
Could be a bit of element separation, also could be an area of damaged coating around a bit of acidic debris maybe. It could be many other things also no doubt. Is it on the surface of the front element or behind it ? _________________ I like Pentax DSLR's, Exaktas, M42 bodies of all kinds, strange and cheap Japanese lenses, and am dabbling in medium format/Speed Graphic work. |
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justtorchit
Joined: 12 Oct 2009 Posts: 269 Location: St. Louis, MO
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Posted: Wed Mar 24, 2010 7:53 pm Post subject: |
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justtorchit wrote:
best I can see, it is one of the inner elements. Definitely not the front, 2nd or 3rd in perhaps. _________________ David
www.davidkovaluk.com - personal website
www.instagram.com/davidkovaluk
http://makingnottaking.blogspot.com/ - photoblog |
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themoleman342
Joined: 21 Oct 2007 Posts: 2190 Location: East Coast (CT), U.S.A.
Expire: 2013-01-24
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Posted: Wed Mar 24, 2010 8:14 pm Post subject: |
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themoleman342 wrote:
Might be that the retaining ring was tightened way beyond necessary and a natural weakness in the thinnest part of the glass (edge) cracked in this fashion. |
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egidio
Joined: 02 Sep 2009 Posts: 222 Location: slovenia
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Posted: Wed Mar 24, 2010 10:23 pm Post subject: |
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egidio wrote:
this is probably something that you don't need to worry about _________________ I use: Flektogon 2.8/20, Flektogon 2.8/35, planar 50mm/1.4, Takumar 1.4/50mm, Takumar 1.9/85, MIR 24H, Mir1v, Industar-50-2, Helios-44-2, Pentacon 2.8/135, cyclop 85 1.5 |
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Bruce
Joined: 15 Jan 2008 Posts: 842 Location: Boston, Ma USA
Expire: 2014-11-22
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Posted: Thu Mar 25, 2010 4:14 am Post subject: |
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Bruce wrote:
it looks as a better shot of this is possible, maybe a good macro set-up. From its looks I wouldnt rule out fungus... I see feathering? _________________ Digital: Canon 40d & 5DmkII, Film: Hasselblad 203fe/Zeiss 80/2.8 cfe
Adapters for EOS: Cy; M42; Zenit39; Exakta; LeicaR; OlympusOM; PK; Nikon; Rollei35; Retina; Adaptal; P-6 |
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Pancolart
Joined: 04 Feb 2008 Posts: 3702 Location: Slovenia, EU
Expire: 2013-11-18
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Posted: Thu Mar 25, 2010 4:17 am Post subject: |
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Pancolart wrote:
I think it's fungus too. Put it under UV lamp for 15min few times. _________________ ---------------------------------
The Peculiar Apparatus Of Victorian Steampunk Photography: 100+ Genuine Steampunk Camera Designs https://www.amazon.com/dp/B0B92829NS |
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my_photography
Joined: 03 Nov 2008 Posts: 2772 Location: Pearl of the Orient
Expire: 2016-12-25
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Posted: Thu Mar 25, 2010 5:21 am Post subject: |
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my_photography wrote:
Pancolart wrote: |
I think it's fungus too. Put it under UV lamp for 15min few times. |
UV lamp can remove fungus? _________________
Zeiss: CJZ Flektogon 20/2.8, CJZ Flektogon 20/4, , CJZ Pentacon 29/2.8, CJZ Flektogon 35/2.4, CJZ Pancolar 50/1.8, Tessar 50/2.8, Biotar 7.5cm/1.5, CJZ Pancolar 80/1.8, CJZ Sonnar 135/3.5, CJZ Pentacon 135/2.8 CJZ Sonnar 200/2.8
Other Germany: Meyer Primoplan 50/1.8, Meyer Trioplan 100/2.8
Takumar: SMC 50/1.4 Super Tak 55/2, Super Tak 85/1.9, S-M-C 135/3.5, Super Tak 150/4
Russian: Zenith 16/2.8, Mir-24M 2/35, Volna-9 50/2.8, Helios 44M (58/2), Helios 44M-3 MC (58/2), Helios 40 (85/1.5), Tair 11A (135/2.8 )
Others: Sears 28/2.8, Sankor 35/2.8, Enna M�nchen Tele-Ennalyt 135/3.5
Zoom Sigma Zoom 28-85/3.5-4.5
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martinsmith99
Joined: 31 Aug 2008 Posts: 6950 Location: S Glos, UK
Expire: 2013-11-18
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Posted: Thu Mar 25, 2010 7:10 am Post subject: |
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martinsmith99 wrote:
Not remove but stop the growth.
I don't think it is fungus. It looks like the lens has been exposed to pressure at this point or a flaw in the glass. It may have been dropped or the retaining ring over tightened. _________________ Casual attendance these days |
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justtorchit
Joined: 12 Oct 2009 Posts: 269 Location: St. Louis, MO
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Posted: Thu Mar 25, 2010 8:01 am Post subject: |
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justtorchit wrote:
I don't think I can obtain a better image because the mark is several elements back and the optics in front of this element, like a fish tank, skew the mark as I move about (also it is so near the edge, the optics are rather distorted here). This is the best angle I was able to find and even still it is slightly out of focus. One more observation, as I rotate the lens in my hand, I can see the coating sort of brandish a distinctly different bluish right on this spot, rather than the green of the rest of the element on which this mark sits. No idea if that means anything but thought it worth noting.
Either way. I wouldn't be surprised if it is a pressure mark. Looking closer in the lens, I see a couple screws on one of the inner tubes which appear to be scuffed indicating someone has opened this lens.
My guess is you all are right who believe the ring may have been tightened too far. The lens hasn't shown any focusing issues or optical degradation so as I said, I am not worried about it so much as curious what this mark is. I have seen it in other lenses as well.
It's a great piece of glass and I am getting some great results! here are just a couple (with the color amped up obviously, I love saturated colors):
_________________ David
www.davidkovaluk.com - personal website
www.instagram.com/davidkovaluk
http://makingnottaking.blogspot.com/ - photoblog |
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gaeger
Joined: 16 Jan 2010 Posts: 722 Location: Brier, Wash.
Expire: 2021-03-09
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Posted: Fri Mar 26, 2010 3:12 am Post subject: |
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gaeger wrote:
Fantastic images, so maybe the spot is nothing to worry about! _________________ "Here's to the wonder" -- Alan Boyle
Nikkor/Nikon 20, 24, 28, 35, 50, 55, 85, 105, 135, 180, 200, 300, 10-20, 18-35, 18-55, 28-50, 28-70, 24-85, 35-200, 50-300, 75-150, 80-200, 70-210, 70-300, 200-500
Minolta Rokkor 24, 28, 35, 45, 50, 58, 100, 135, 50-135, 300
My most interesting images | Full photostream
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dnas
Joined: 14 Nov 2008 Posts: 488 Location: Japan
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Posted: Fri Mar 26, 2010 3:20 am Post subject: |
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dnas wrote:
justtorchit wrote: |
One more observation, as I rotate the lens in my hand, I can see the coating sort of brandish a distinctly different bluish right on this spot, rather than the green of the rest of the element on which this mark sits. No idea if that means anything but thought it worth noting. |
Based on this info, I think it's fungus.
I've noticed that on some lenses with a particularly concentrated spot of fungus, there will often be a discoloration of the coating from original green, to a bit of a bluish color. |
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