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			 by Photodude on Mon Feb 21, 2005 8:52 am
 Hi Everybody, 
 whilst cleaning my lenses yesterday i noticed that my Tamron 70-300 has two little bubbles in the glass      these bubbles are the size of two pinheads and are a few mms under the surface of the lens 
 noticed my Nikon lenses dont have such bubbles 
 anyone know what these bubbles are? 
 are they normal? 
 can they have any detrimental effects? 
 thanks      John 
			
				 Photodude
Member Posts: 68Joined: Mon Oct 11, 2004 2:44 pmLocation: Wollongong 
 
		
		
			
			
 by sirhc55 on Mon Feb 21, 2005 8:58 am
 It is normal for bubbles to be in glass - how many pics have you shot with this lens and do you see any problems with the pics?
 If the pics are OK - don’t worry
 
 Interestingly, lens can be either plastic or glass - plastic is a solid and glass is a liquid (albeit supercooled liquid)
 Chris--------------------------------
 I started my life with nothing and I’ve still got most of it left
 
			
				 sirhc55
Key Member Posts: 12930Joined: Fri Sep 17, 2004 6:57 pmLocation: Port Macquarie - Olympus EM-10 
 
		
		
			
			
 by fozzie on Mon Feb 21, 2005 9:00 am
 Hi John,
 Sorry I can not help you with the problem to your lens...but, this is very much tongue in check, you haven't been to Bondi Beach taking picture of topless girls/ladies.
 
 
 Cheers,
 fozzie
 When people ask what equipment I use - I tell them my eyes.
 
			
				 fozzie
Key Member Posts: 2806Joined: Tue Oct 12, 2004 9:19 pmLocation: AUADA : Nikon D3/D2x - JPG Shooter 
 
		
		
			
			
 by Photodude on Mon Feb 21, 2005 9:08 am
 thanks Chris 
 yeah have taken 100s of pics with the lens and no probs 
 but was curious as to why bubbles 
 and Fozzie 
 shhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh if my wife finds out what those bubbles really are! LOL 
			
				 Photodude
Member Posts: 68Joined: Mon Oct 11, 2004 2:44 pmLocation: Wollongong 
 
		
		
			
			
 by Matt. K on Mon Feb 21, 2005 9:20 am
 Not unusual for high quality lenses to have a small bubble. They have no effect on image quality. Different story for very large bubbles though. Regards
 Matt. K
 
			
				 Matt. K
Former Outstanding Member Of The Year and KM Posts: 9981Joined: Mon Sep 06, 2004 7:12 pmLocation: North Nowra 
 
		
		
			
			
 by digitor on Mon Feb 21, 2005 9:41 am
 All optical glass can have some bubbles in it - when making high quality lenses the trick is to make them out of the bits without bubbles.  These days though, most lenses (esp. those at the less expensive end of the market) start out as moulded blanks, to minimise the time for grinding and polishing.
 The only effect of a small bubble would be a very slight increase in veiling glare (seen as a decrease in contrast), which wouldn't be noticeable in photographic applications.  The effect of bubbles can be much more spectacular in laser optics though!
 
 Cheers
 What's another word for "thesaurus"? 
			
				 digitor
Senior Member Posts: 925Joined: Tue Nov 16, 2004 9:53 pmLocation: Tea Tree Gully, South Australia 
 
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