p.1 #1 · What is this defect on Zeiss 21mm Distagon glass element?
I have my Zeiss 21mm ZE 2.8 up for sale. Great lens, no issues ever, seemingly perfect, but today I did a more thorough visual inspection of the glass, per interested buyer request, and found an odd imperfection on the front of the lens. I'm attaching two photos from different angle.
It appears as a hazy, sprayed line, about 2-3 mm long starting at the edge of the lens. It appears to be either on the front of the second lens element or back of the first element. It's only visible from some angles. Shining a light on it doesn't show any rainbow colors.
Any thoughts what this could be? Is it delamination? Oil streak? Something else?
p.1 #5 · What is this defect on Zeiss 21mm Distagon glass element?
RoamingScott wrote:
It doesn't line up with the same point of the barrel in the two photos, so it's not something ON an element, IMO.
The photos are misleading for some reason. When I look at it with my eyes and rotate the lens, the spot is in exactly the same spot, right under the 2.8 letters.
p.1 #7 · What is this defect on Zeiss 21mm Distagon glass element?
It would help if you had circled the area in post. It looks like a comets tail. Maybe a moisture penetration? It' s like some sort of liquid blowed up from the edge. Those lenses don't have much of weather seals, so it's weird. A cla might solve the issue
p.1 #8 · What is this defect on Zeiss 21mm Distagon glass element?
Thank you everyone for your feedback. I have also just checked a 10 year old photo I took of the lens and the exact same mark is on it back then. My best guess is that this is something that was there since manufacturing it. The good thing is it hasn't changed shape or size in 10 years and doesn't impact image quality as it's on the extreme edge. It's not a crack nor fungus, it's some sort of smudge or perhaps oil is my guess. Attaching 10 year old photo that shows it.
p.1 #9 · What is this defect on Zeiss 21mm Distagon glass element?
Looks like trailing air residue from blowing something. Giveaway is how it tapers off. Did you blow compressed air or use a can of compressed air for dusting?
Also looks like spores. But the trailing pattern makes me believe hard blowing of some kind took place.
p.1 #10 · What is this defect on Zeiss 21mm Distagon glass element?
Jorge Torralba wrote:
Looks like trailing air residue from blowing something. Giveaway is how it tapers off. Did you blow compressed air or use a can of compressed air for dusting?
Also looks like spores. But the trailing pattern makes me believe hard blowing of some kind took place.
No hard blowing. My best guess is that it has been there since new since it's been there for 10 years and I've had the lens not much longer than that and rarely use it. The only wild guess would be some strong wind perhaps, but I don't go out shooting hurricanes and tornadoes.
p.1 #11 · What is this defect on Zeiss 21mm Distagon glass element?
I would put a good magnifying glass on the spot with good front and back light and see what can be seen. That may tell you what it is.
Given that it has been there for ten years without changing, my guess is that it is an optically meaningless abrasion from when the lens was assembled.
