What causes this diagonal flare?

[Archiver]

My copy of the Panasonic Leica 12mm f1.4 has this very strong diagonal flare when bright light sources are in frame. Sometimes it is very intrusive, as can be seen here. Is this a defect in the lens, or a characteristic? I haven't seen this in any other photo from this lens online. It is present regardless of what body is used.

 

[Out to Lunch]

AI says that your lens has a lot of lens elements in a lot of groups: 15 lens elements in 12 groups. The more elements, the higher the chance of internal reflections and, especially when the lens is stopped down, a higher chance of distinct streaks. The front element may also just be smudged or otherwise dirty.

 

[Alpsman]

Taking a pix with the sun in the frame is the bonebreaking test for a lens.
Depends on the coating and the number of lenses.
The more lenses in the lens the more flare.
See it from the positive side: others are adding this "effect" in a software ;-)

 

[p.giannakis]

AI says that your lens has a lot of lens elements in a lot of groups: 15 lens elements in 12 groups.

That is an insane amount of elements for a fixed focal length lens! Zooms like 28-200 used to have that many in the '90s.

 

[santino]

AI says that your lens has a lot of lens elements in a lot of groups: 15 lens elements in 12 groups. The more elements, the higher the chance of internal reflections and, especially when the lens is stopped down, a higher chance of distinct streaks. The front element may also just be smudged or otherwise dirty.

Indeed a lot of elements, Leica has (had?) a totally different approach to lens design.

Btw. I guess such a post would be a violation of future rff AI policy.

 

[Alpsman]

Comparing a modern 12mm 1.4 wideangle to the "vintage" Nikon 13mm 5.6 (1976)

Nikkor 13mm f/5.6 - Wikipedia

en.wikipedia.org

makes the progress in optical and glass technology visible.

 

[Archiver]

I posted this question elsewhere and a few people suggested something very simple: is the lens clean? I bought this lens secondhand and it looked perfect, but I had never cleaned the elements as I prefer to leave them as untouched as possible. After cleaning the front and back elements with a microfiber cloth, the flare has gone! Huzzah! Thank you to everyone who commented. 🙏

 

[Richard G]

Microfiber cloth is often recommended and I have always accepted the slight superiority. We have a granite bench in the kitchen one friend loves to plant his greasy mits on as soon as he arrives. Over the years there were patches of uneven sheen and but it held up well after wiping with Windex or Nifti or Spay and Wipe. Until we used a microfiber cloth. It was restored to new condition in minutes.

Cockatoos stripped the Manchurian Pear out the front landing half chewed berries on my wife’s car and the front fence. We washed and scrubbed with minimal effect on the stains. You guessed it: microfiber magic again.

 

[Archiver]

Microfiber cloth is often recommended and I have always accepted the slight superiority. We have a granite bench in the kitchen one friend loves to plant his greasy mits on as soon as he arrives. Over the years there were patches of uneven sheen and but it held up well after wiping with Windex or Nifti or Spay and Wipe. Until we used a microfiber cloth. It was restored to new condition in minutes.

Cockatoos stripped the Manchurian Pear out the front landing half chewed berries on my wife’s car and the front fence. We washed and scrubbed with minimal effect on the stains. You guessed it: microfiber magic again.

I use microfiber towels and cloths of varying types for many jobs: wide weave towels for car detailing and general cleaning, fine lens cloths for lenses, larger microfiber towels for bigger household jobs. They seem better than sponges for household jobs, and definitely better for car detailing than chamois. There's also microfiber noodle brooms for dusting floors, noodle mitts for lathering up cars, and more.

 

[Freakscene]

I was watching this thread waiting to see if someone recommended a good clean, and what that would do.
Non-diffuse flare is almost always caused from a point; this can be a small badly reflection damped internal part (I’m looking at you 50mm Summicron v5), particularly in a photo with a pinpoint source of light (remembering that the sun on a clear day is one of these), the edge of an element, or dirt/scratches on the lens.

I use microfiber towels and cloths of varying types for many jobs: wide weave towels for car detailing and general cleaning, fine lens cloths for lenses, larger microfiber towels for bigger household jobs. They seem better than sponges for household jobs, and definitely better for car detailing than chamois. There's also microfiber noodle brooms for dusting floors, noodle mitts for lathering up cars, and more.

The only downside to microfiber is that cloths made from it produce more microplastic particles than almost any other household item.

 

[Archiver]

I was watching this thread waiting to see if someone recommended a good clean, and what that would do.
Non-diffuse flare is almost always caused from a point; this can be a badly damped internal point in a photo with a pinpoint source of light (remembering that the sun on a clear day is one of these), the edge of an element, or dirt on the lens.

I was kind of expecting you to chime in with an indepth technical explanation of flare, how it pertain to lens design, and offer suggestions. 😄

The only downside to microfiber is that cloths made from it produce more microplastic particles than almost any other household item.

This is unfortunate because I'm also in the process of eliminating as many sources of microplastics as possible... 😳

 

[Archiver]

it held up well after wiping with Windex or Nifti or Spay and Wipe.

I know that was a typo, but 'Spay and Wipe' brought images to my mind which made me giggle like Hannibal Lecter.

 

[Richard G]

I know that was a typo, but 'Spay and Wipe' brought images to my mind which made me giggle like Hannibal Lecter.

Can’t correct it after this comment. No doubt you’re relieved there is no invitation to dinner.