scratch / fungus ?

Have questions about the equipment used for macro- or micro- photography? Post those questions in this forum.

Moderators: Pau, rjlittlefield, ChrisR, Chris S.

Adalbert
Posts: 1255
Joined: Mon Nov 30, 2015 1:09 pm

scratch / fungus ?

Post by Adalbert »

Hello everybody,
Does anybody know if this fungus inside of the lens (rear side) can affect the quality of the image?

1x
Image

4x
Image

Thank you in advance.
BR, ADi
Last edited by Adalbert on Fri Nov 30, 2018 8:48 am, edited 2 times in total.

JohnyM
Posts: 463
Joined: Tue Dec 24, 2013 7:02 am

Post by JohnyM »

Doesnt look like fungus. Can you magnify more?
Shouldnt affect IQ in any way than slight lost of conrast locally.

ray_parkhurst
Posts: 2805
Joined: Sat Nov 20, 2010 10:40 am
Location: Santa Clara, CA, USA
Contact:

Post by ray_parkhurst »

I agree with JohnyM, doesn't look like fungus, but it's not likely to affect the image.

Adalbert
Posts: 1255
Joined: Mon Nov 30, 2015 1:09 pm

Post by Adalbert »

Hello Johny, hello Ray,
It is not easy to take the photographs of that because it is inside of the lens not on its surface.
But I will try :-)
BR, ADi

ray_parkhurst
Posts: 2805
Joined: Sat Nov 20, 2010 10:40 am
Location: Santa Clara, CA, USA
Contact:

Post by ray_parkhurst »

Here's a pic of lens fungus between elements that I took at ~6x. Shows multiple species.

Image

Adalbert
Posts: 1255
Joined: Mon Nov 30, 2015 1:09 pm

Post by Adalbert »

Hi Ray,
Many thanks! It looks like a snowflake :-)
I can see a small grain of dust inside my lens, it is not on its surface.
BTW, the second photographs in following thread has been taken by the usage of this lens:
https://www.photomacrography.net/forum/ ... highlight=
BR, ADi

Adalbert
Posts: 1255
Joined: Mon Nov 30, 2015 1:09 pm

Post by Adalbert »

Hi,
And a little bit more magnified:
Image
BR, ADi

ray_parkhurst
Posts: 2805
Joined: Sat Nov 20, 2010 10:40 am
Location: Santa Clara, CA, USA
Contact:

Post by ray_parkhurst »

Looks inorganic to me. If it's between the lens elements, then it may be a manufacturing defect. For sure, it's so small that you probably won't see any impact on IQ.

Adalbert
Posts: 1255
Joined: Mon Nov 30, 2015 1:09 pm

Post by Adalbert »

Hi Ray,
It is 1mm below the surface, inside of the lens :-(
BR, ADi

ray_parkhurst
Posts: 2805
Joined: Sat Nov 20, 2010 10:40 am
Location: Santa Clara, CA, USA
Contact:

Post by ray_parkhurst »

Adalbert wrote:Hi Ray,
It is 1mm below the surface, inside of the lens :-(
BR, ADi
If you are concerned about the small potential degradation in contrast due to light diffusion from the defect, you can put a small "dab" of black paint onto the lens element to cover the area. This will slightly reduce the maximum aperture (for instance, from f4.00 to f4.01) but will block light from hitting the defect and diffusing to unwanted areas. This is the same type of trick folks use for scratches, ie marking the scratch with a sharpie so that light does not pass through it.

ChrisR
Site Admin
Posts: 8574
Joined: Sat Mar 14, 2009 3:58 am
Location: Near London, UK

Post by ChrisR »

If you turned your yellow arrow into black paper, and extended it to cover the defect, you might see a difference.
I would bet not much, though!
Chris R

Adalbert
Posts: 1255
Joined: Mon Nov 30, 2015 1:09 pm

Post by Adalbert »

Hi Ray, hi Chris,
OK, I’ll check it.
BR, ADi

Pitufo
Posts: 245
Joined: Sun Jun 21, 2015 4:32 am
Location: United Kingdom

Post by Pitufo »

Speaking of fungal growth, this is part of a microscope that landed in front of me today. It had been used at sea (!). Most of the optical surfaces were like this. Surprisingly, it seemed to clean up well (IPA wasn't that good but Zeiss Lens wipes worked much better).

Apologies for the image quality. An over-sharpened mobile phone crop..

Image

Scarodactyl
Posts: 534
Joined: Sat Apr 14, 2018 10:26 am

Post by Scarodactyl »

Yeah, it's amazing but every now and then you get lucky and it just wipes off. I guess not every species produces etchants, maybe seafaring fungus have different priorities.

Adalbert
Posts: 1255
Joined: Mon Nov 30, 2015 1:09 pm

Post by Adalbert »

Hello everybody,
It is a small scratch, which has been detected by the test with a toothpick :-)
Should I try to "fill" it with UV adhesive or synthetic resin ?
BR, ADi

Post Reply Previous topicNext topic