Hello,

While putting my UV filter on my 75mm, I noticed a slight variation in the coating (heaven forbid it would be the glass surface!) of my newly-purchased 75mm lux.

Question: does anyone else have a variation appearance on an element in their lens?

It's not like a hugely apparent blemish, but it's there. I like the lens otherwise, reeks of quality. But I am wondering if this will affect image quality. Should I just exchange it for another? If others have this variation in the coatings, I'm thinking I'll just keep it.

Thanks for the info...

-- James (snodoggydogg@hotmail.com), February 02, 2002

Answers

by the way, it's a very small and slight blemish, otherwise one can see through the area. Nonetheless, I would think this would blur the image coming through this area. It's on the 2nd or 3rd element down from the front element, in front of the aperture.

-- James (snodoggydogg@hotmail.com), February 02, 2002.

Are you sure that you aren't just looking at the internal reflections between the lens groups?

-- John (ouroboros_2001@yahoo.com), February 02, 2002.

No it's not a reflection from either something in the lens or outside of it unfortunately. It stays put when I rotate the lens around while looking at it. On 2nd thought it's so slight I doubt any ill-effects would occur, but I'm no expert.

-- James (snodoggydogg@hotmail.com), February 02, 2002.

Now you know why I tend to buy used gear over new... If I buy a used lens and it has a small flaw or two, I don't worry about it. That being said, the only flaw I've ever been saddled with is internal dust, and that doesn't seem to present much of a problem. You really did not give many specifics about the flaw you have, however if I bought a new lens and it was flawed, I send it back and request another one. Problem is with the current QC apparently going on at Leica, the replacement lens may be worse than the one you are returning!

Sorry you got a flaw,

-- Jack Flesher (jbflesher@msn.com), February 03, 2002.

Hehehe that's what I was thinking...might turn into an exchangathon! It's such a slight variation, mainly visible when I stop the aperture down and it becomes more visible against the darkness, but with enough light coming from the back of the lens.

On www.leicapages.com, there's a movie regarding lens design and manufacturing. Apparently they test lenses for collimation of course during assembly, and then test them when completed I guess for image (?). If this is so, and I need to look at my paperwork (I don't have the Leica paperwork with me) then perhaps the signed test sheet mentioned in another post below verifies this.

If that's the case, I don't have a problem with the lens despite what I see. It looks merely like a small oval-shaped and slight variation in the surface appearance of an inner element.

-- James (snodoggydogg@hotmail.com), February 03, 2002.

looking at the blemish further, it seem to have the appearance of a tiny dried water droplet. Seems a bit more of a crisp outline to it on one side of it too. Actually looking through the lens doesn't give any hint of it being there. Only when I look at it from an angle with something dark behind it do I notice the blemish.

Maybe the coating, or maybe someone from Solms dropped it while putting it together? ; )

Got this lens from B&H. Maybe I'll just return it Monday. Thanks for the input.

-- James (snodoggydogg@hotmail.com), February 03, 2002.

Seems this blemish promotes some nasty flaring, as I was looking through the lens from the front and guiding some reflections toward the defect, and the defect would start to "light up" as the reflections got closer to it. I cleaned the front element to make sure it wasn't on the surface, but no avail. Back it goes.

Perhaps the workers decided to play a little frisbee with the element on their break, but seeings how M elements are so small, shouldn't they have tried one of those R 800mm APO Telyt Head front elements instead?

David Alan Harvey recommends 1 camera and 1 lens, maybe I'll just stick to my 35 lux for a while. Simplicity is refreshing.

-- James (snodoggydogg@hotmail.com), February 03, 2002.

James, are you planning to be buried with that lens? If not, send it right back now. It might not detract from the imaging quality but i definitely will detract from the resale value.

-- Jay (infinitydt@aol.com), February 03, 2002.

Yah I'm not planning that. Sorry I rambled last night, stayed up a bit late playing with my lens, not the most productive of activities! I'll just exchange the thing, I love the focal length. Or how about that Noctilux, yum...

-- James (snodoggydogg@hotmail.com), February 03, 2002.

Why don't you take the lens back and exchange it for a life?

-- Jack (jack@jack.com), February 03, 2002.

Oh you're so funny there "Jack". You read a post you don't like didn't you? Well isn't that special for you! Woohoo, you need a lollipop now. Hahaha

-- james (snodoggydogg@hotmail.com), February 03, 2002.

James. Jay is right. Something like that (could be a coating defect, could be separation) may never affect the images (especially if it is peripherally located), but most certainly Can affect the resale value. People who buy used Leica generally look for perfect glass. In many cases, it means that lenses with glass with very minor flaws (that are otherwise of no consequence) are hugely discounted in price. [It also means that knowledgeable users can get great bargains if they are careful.]

As far as any effect on performance, my experience is that if you have to shine a penlight through the lens and rotate it through different angles and still have trouble seeing it, it will not affect the image quality. Generally speaking, image-degrading lens flaws are not that subtle.

-- Eliot (erosen@lij.edu), February 03, 2002.

Let's make sure everybody knows the Jack above at Jack.com is not me!

;-),

-- Jack Flesher (jbflesher@msn.com), February 03, 2002.

I definitely know that's not you, thankfully. I like a "man" who can't stand behind his posts with a consistent name. "Jack" is a pansy.

-- James (snodoggydogg@hotmail.com), February 03, 2002.