Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?

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martin_sc42 New Member • Posts: 12
Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?

Did anybody check his Olympus pro Zoom Lenses (12-40 f2.8 or 40-150 f2.8) for dust inside in the inner lens (where the aperture control is located) ?

I am just a bit puzzled how much small particle dust is inside my sealed Oly 12-40 f2.8 Pro after 15 months of normal use when compared to my non sealed 3+ years old heavy used Pana 14-140 f3.5-f5.6. (the later one was also in Peru, the dessert and Co.) - luckily it is still under warranty.

In particular where is a lot of dust on the lens that holds the aperture control unit. How to check: You remove it from the camera mount at f2.8 so that the aperture control stays open. Zoom to max (here 40mm) look to down front lens towards bottom, the front element over a weak LED lamp. Looking now into it from behind at a similar distance as the sensor the inner lens and the lens with the aperture control is in focus.

Its difficult to make a picture, its no fungus i always kept the lenses try, it looks all like tiny little dust specs. I did not detect image quality problems so far on RAW.

Image: Oly 12-40 f2.8 Dust on inner lens with the aperture control. Image is not fully sharp.

Valdai21 Regular Member • Posts: 190
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?
1

Seems weird. Did you buy it new ? 
I used two samples of this lens for few months and came to the conclusion that the WR was very effective, especially for a zoom.

I never had a single dust problem with Olympus lenses.

Confusedabit Contributing Member • Posts: 800
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?
1

Valdai21 wrote:

Seems weird. Did you buy it new ?
I used two samples of this lens for few months and came to the conclusion that the WR was very effective, especially for a zoom.

I never had a single dust problem with Olympus lenses.

But have you looked hard enough and deep enough? I am not sure if this is to do with image quality as this is not even mentioned.

On mpb.com any lens not classed as mint like new on the level below excellent warns about dust in the lens.

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ahaslett
ahaslett Veteran Member • Posts: 7,080
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?
2

No dust in mine, but I seem to have scratched another UV filter.

Andrew

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Funny Valentine
Funny Valentine Contributing Member • Posts: 740
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?
1

Does your copy of the lens has an important zoom barrel wobbling or rattling ?

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Valdai21 Regular Member • Posts: 190
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?
1

Confusedabit wrote:

Valdai21 wrote:

Seems weird. Did you buy it new ?
I used two samples of this lens for few months and came to the conclusion that the WR was very effective, especially for a zoom.

I never had a single dust problem with Olympus lenses.

But have you looked hard enough and deep enough? I am not sure if this is to do with image quality as this is not even mentioned.

On mpb.com any lens not classed as mint like new on the level below excellent warns about dust in the lens.

I don't claim mine was absolutely spotless. I never shine a lamp throught my lenses. But there was nothing relevant I could see, and I tend to be a bit obsessed with dust sometimes. I used Olympus gear for years and my lenses, mostly bought second hand, are still very clean.

cba_melbourne Senior Member • Posts: 3,137
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?
7

martin_sc42 wrote:

Did anybody check his Olympus pro Zoom Lenses (12-40 f2.8 or 40-150 f2.8) for dust inside in the inner lens (where the aperture control is located) ?

I am just a bit puzzled how much small particle dust is inside my sealed Oly 12-40 f2.8 Pro after 15 months of normal use when compared to my non sealed 3+ years old heavy used Pana 14-140 f3.5-f5.6. (the later one was also in Peru, the dessert and Co.) - luckily it is still under warranty...................

The 12-40 is an external zoom. It changes it's length (or trombones) when zooming. This means it breathes in air as you expand it. The 12-40 is fitted with a mesh filter to keep out sand and coarse dust particles. But finest dust (as well as vapor and smoke) will obviously get through the mesh, and deposit on interior surfaces.

12-40 lens. The yellow bit is the filter mesh that goes around the barrel. It is just a very thin fine mesh, not something like a felt or a foam that could trap finest dust particles. I have seen somewhere a picture of that filter, but can't remember where.... sorry.

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OP martin_sc42 New Member • Posts: 12
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?

I bought it new 13 months ago. And that's why i assume a product defect.
If dust comes in from outside at all it should settle somewhere else and not on the lens that holds the aperture control unit. Also many of my non sealed lenses are far more heavy used and do not show such a problem.

OP martin_sc42 New Member • Posts: 12
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?

cba_melbourne wrote:

The 12-40 is an external zoom. It changes it's length (or trombones) when zooming. This means it breathes in air as you expand it. The 12-40 is fitted with a mesh filter to keep out sand and coarse dust particles. But finest dust (as well as vapor and smoke) will obviously get through the mesh, and deposit on interior surfaces.

12-40 lens. The yellow bit is the filter mesh that goes around the barrel. It is just a very thin fine mesh, not something like a felt or a foam that could trap finest dust particles. I have seen somewhere a picture of that filter, but can't remember where.... sorry.

Thank's for sharing. That is my point. See also
http://digitalphotographylive.com/olympus-m-zuiko-digital-ed-12-40mm-f2-8-pro-lens/

When extending to 40mm and with some light into the front you can clearly see the Oly front chamber. In the diagram this chamber is closed to 12 mm.

If somehow something comes in via the airflow or even via the tube by slipping under the seals it should settle in the front chamber (front lens or back lens). If it somehow comes in from behind it should settle on the back chamber, maybe the moving inner zoom and focus elements. Yet the lens unit holding the aperture control is exactly in the middle. As it also is the smallest in diameter this amount of dust clearly should cost some sharpness.

I am no photo technician yet an tech engineer. Using a lab control LED you can see this when lightning from back to front as some of the lenses are coated on the back and when reflect some light like halo.

a) I see dust on the lens in the aperture control hole.
b) I see no dust on the lens more closer to the front (front chamber)
c) I see no dust on the inside of the front lens
Similar on the back

So weather sealing works. Even if i wanted to destroy a lens I have now idea how to achieve this effect without dismantling it

I would speculate a product defect in the aperture control
https://en.wikipedia.org/wiki/Aperture#/media/File:Aperture_in_Canon_50mm_f1.8_II_lens.jpg

A rational explanation maybe that the aperture blades have some friction and distribute particles or similar.

I did not check this so strictly as i bought it 13 months ago ... grmpf ...

OP martin_sc42 New Member • Posts: 12
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?

Yes. I bought it new but did not check so strictly at this time.

cba_melbourne Senior Member • Posts: 3,137
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?
7

martin_sc42 wrote:

cba_melbourne wrote:

The 12-40 is an external zoom. It changes it's length (or trombones) when zooming. This means it breathes in air as you expand it. The 12-40 is fitted with a mesh filter to keep out sand and coarse dust particles. But finest dust (as well as vapor and smoke) will obviously get through the mesh, and deposit on interior surfaces.

12-40 lens. The yellow bit is the filter mesh that goes around the barrel. It is just a very thin fine mesh, not something like a felt or a foam that could trap finest dust particles. I have seen somewhere a picture of that filter, but can't remember where.... sorry.

Thank's for sharing. That is my point. See also
http://digitalphotographylive.com/olympus-m-zuiko-digital-ed-12-40mm-f2-8-pro-lens/

When extending to 40mm and with some light into the front you can clearly see the Oly front chamber. In the diagram this chamber is closed to 12 mm.

If somehow something comes in via the airflow or even via the tube by slipping under the seals it should settle in the front chamber (front lens or back lens). If it somehow comes in from behind it should settle on the back chamber, maybe the moving inner zoom and focus elements. Yet the lens unit holding the aperture control is exactly in the middle. As it also is the smallest in diameter this amount of dust clearly should cost some sharpness.

I am no photo technician yet an tech engineer. Using a lab control LED you can see this when lightning from back to front as some of the lenses are coated on the back and when reflect some light like halo.

a) I see dust on the lens in the aperture control hole.
b) I see no dust on the lens more closer to the front (front chamber)
c) I see no dust on the inside of the front lens
Similar on the back

So weather sealing works. Even if i wanted to destroy a lens I have now idea how to achieve this effect without dismantling it

I would speculate a product defect in the aperture control
https://en.wikipedia.org/wiki/Aperture#/media/File:Aperture_in_Canon_50mm_f1.8_II_lens.jpg

A rational explanation maybe that the aperture blades have some friction and distribute particles or similar.

I did not check this so strictly as i bought it 13 months ago ... grmpf ...

The filter mesh is there to prevent water entering. Water drops stay on the outer surface of the mesh. It is not there to "clean" the air.

Look through your lens as you zoom from 12 to 40mm. The front section moves forward, the middle section with the aperture moves also forward but but not as far, the rear section does not move. At the same time, air is sucked into the lens from outside to fill the voids created both before and behind the middle section. Have not taken the lens apart, but I could well imagine that part of the displaced air will be pushed through the aperture iris opening at high velocity, if so any fine dust will deposit with preference onto the lens surfaces in front and behind the aperture.

If you want a dust resistant lens, you have to go for internal zooms or primes, that do not change their outer length when zooming, and do not breathe air but are often filled with Nitrogen or Argon gas. Internal zooms are always larger though. It is a choice you make when buying a lens, and it comes with advantages and disadvantages.

External zooms are never sealed, no matter what marketing tries to make you believe by deceiving implication. They may be weather protected, but just cannot be sealed. Solids ingress such as sand and dust are excluded from warranty.

Whilst dust can enter the lens and fog the glass, sand can be wedged under the o-ring seals and destroy them, or cause mechanical binding. An external zoom is not a good choice if you want to use it during sand storms in the desert.

***

You are a tech engineer. Look up what the rating "weather sealed to IPX1" means. The suffix "1" is the lowest possible sealing grade against water, and the suffix "X" means there is no protection whatsoever against solids. X and 0 have the same meaning:

The Olymus 12-40 when mounted onto a weather sealed Olympus camera is rated IPX1. If dust or sand or water is found inside, you have abused it and warranty will be declined.

For comparison, the Olympus TG cameras are dust and water sealed, and rated IP68 to 15m water depth. Quite a difference. The TG is a diver camera and is suited for a windy sand beach or a desert storm, without precautions. If water or dust is found inside, you have a warranty claim and will get the camera replaced for free (provided there is no previous accident damage like a cracked housing).

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OP martin_sc42 New Member • Posts: 12
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?

preference onto the lens surfaces in front and behind the aperture.

If you want a dust resistant lens, you have to go for internal zooms or primes, that do not change their outer length when zooming, and do not breathe air but are often filled with Nitrogen or Argon gas. Internal zooms are always larger though. It is a choice you make when buying a lens, and it comes with advantages and disadvantages.

up what the rating "weather sealed to IPX1" means. The suffix "1" is the lowest possible sealing grade against water, and the suffix "X" means

The Olymus 12-40 when mounted onto a weather sealed Olympus camera is rated IPX1. If dust or sand or water is found inside, you have abused it and warranty will be declined.

Good point this basically means they are officially advertising "Dust & Drip Proof Yes",
yet do not commit to measurement specifications for the first point (as do most of the other non super special consumer lens manufactures). Good overview:
https://photographylife.com/what-to-do-with-dust-inside-lens

And definitely you are right most of the lens groups move when zooming. The "1" in IPX1 also basically only means that a test was done and passed ... nothing else, it is impossible to proof this conditions when something happens during rain in the normal world, so legally this IPX1 classification is in most areas useless and difficult to proof.

I am just puzzled seeing so much dust on that specific lens group in particular when compared to my by far heavier used Pana 14-140. But this could also be related to internal or lens group specific magnification effects-.

I will check some other used Oly 12-40 f2.8 to get a feeling for it.
Apart from that I am quite satisfied with the lens so far.

petergerritsen
petergerritsen Regular Member • Posts: 362
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?

When zooming to 40mm the tube has a little play/wobble/rattle. maybe thats the reason dust can come in?

Sheers Peter

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Funny Valentine
Funny Valentine Contributing Member • Posts: 740
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?

petergerritsen wrote:

When zooming to 40mm the tube has a little play/wobble/rattle. maybe thats the reason dust can come in?

Sheers Peter

I agree, the 12-40 has a lot of barrel wobbling/play issue. It's potentially a way of entry for large dust particles to get under the hydrophobic mesh and inside the lens.

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petergerritsen
petergerritsen Regular Member • Posts: 362
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?
1

Mine has some rattle/ play at 40mm.  Strange because my other zoom lenses, even the non sealed lenses, have no play. So why has the Olympus pro lens so much play at 40mm. A lot of people are complaining about that.

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OP martin_sc42 New Member • Posts: 12
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?

petergerritsen wrote:

When zooming to 40mm the tube has a little play/wobble/rattle. maybe thats the reason dust can come in?

Sheers Peter

I am from Germany so "wobble" is a bit hard for me to exactly classify. Even at 40mm the tube part has less play as e.g. a non-sealed lens with my copy. Such play would also cause a little de-centering. Where are also no larger dust particles inside my lens.

While zooming from 12<->40 it is true that the tube movement is not fully smooth the rubber is basically a bit "jamming" so something might jump under this seal.

My problem is that at least according to my impression the dust is not in the "front chamber", also rather not in the back-chamber it is on the aperture control lens. What is the smallest lens in diameter and also bundles the light.

The air flow-in entry is under the Zoom ring what makes sense so the moving tube cannot push water in.

A really detailed design image of the lens is not published so i cannot 100% judge. It also might sound a bit arrogant. The most expanding and largest element is the front chamber, also the most easy one open and to clean ... if i had to design the perfect traveler lens i would try to design it a way that all flows through the front chamber fist.
As the shell of the lens is quite thick and layered this maybe even the case.
I will try to dig into this a bit more
Lens design image, not detailed enough.
http://digitalphotographylive.com/olympus-m-zuiko-digital-ed-12-40mm-f2-8-pro-lens/

OP martin_sc42 New Member • Posts: 12
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?

Confusedabit wrote:

Valdai21 wrote:

Seems weird. Did you buy it new ?
I used two samples of this lens for few months and came to the conclusion that the WR was very effective, especially for a zoom.

I never had a single dust problem with Olympus lenses.

But have you looked hard enough and deep enough? I am not sure if this is to do with image quality as this is not even mentioned.

On mpb.com any lens not classed as mint like new on the level below excellent warns about dust in the lens.

Exactly - the picture here from the 1.400 € Nikon 24-70mm f/2.8G looks far more worse as mine so the Oly sealing definitely kept out any larger dust specks. So far i only found very small dust, you will only see with a real LED or control lamp shining through the lens.

https://photographylife.com/what-to-do-with-dust-inside-lens

I am mainly puzzled that i found the tiny dust (and quite a lot of it) mainly on the middle lens where the aperture control is located and that is not in the front chamber and not really the back chamber of the lens, but basically only looking from outside its difficult to be 100% sure

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Maybe I am also a bit too "The Princess and the Pea" like when it comes to that because I also saw no impact on the RAW yet it would be also difficult to quantify sharpness loss.

cba_melbourne Senior Member • Posts: 3,137
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?

martin_sc42 wrote:

petergerritsen wrote:

When zooming to 40mm the tube has a little play/wobble/rattle. maybe thats the reason dust can come in?

Sheers Peter

I am from Germany so "wobble" is a bit hard for me to exactly classify. Even at 40mm the tube part has less play as e.g. a non-sealed lens with my copy. Such play would also cause a little de-centering. Where are also no larger dust particles inside my lens.

While zooming from 12<->40 it is true that the tube movement is not fully smooth the rubber is basically a bit "jamming" so something might jump under this seal.

My problem is that at least according to my impression the dust is not in the "front chamber", also rather not in the back-chamber it is on the aperture control lens. What is the smallest lens in diameter and also bundles the light.

The air flow-in entry is under the Zoom ring what makes sense so the moving tube cannot push water in.

A really detailed design image of the lens is not published so i cannot 100% judge. It also might sound a bit arrogant. The most expanding and largest element is the front chamber, also the most easy one open and to clean ... if i had to design the perfect traveler lens i would try to design it a way that all flows through the front chamber fist.
As the shell of the lens is quite thick and layered this maybe even the case.
I will try to dig into this a bit more
Lens design image, not detailed enough.
http://digitalphotographylive.com/olympus-m-zuiko-digital-ed-12-40mm-f2-8-pro-lens/

Hi Martin,

I found a few cuts through this 12-40 lens that might help understand how it is built. I believe the camera attached is the EM1.1. It is really difficult to make such a cut, you cannot just slice through with a saw, lots of work to make it look as nice...

this is from an old thread in mu-43 from 2013: https://www.mu-43.com/threads/olympus-12-40-ouch.56256/page-3

This I found on a Japanese page http://omd-graph.blogspot.com/2014/02/58-cp-2014.html

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meow Contributing Member • Posts: 878
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?

petergerritsen wrote:

Mine has some rattle/ play at 40mm. Strange because my other zoom lenses, even the non sealed lenses, have no play. So why has the Olympus pro lens so much play at 40mm. A lot of people are complaining about that.

Mine has absolutely no play in the zoom ring.

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meow Contributing Member • Posts: 878
Re: Too much dust inside the inner lens of an Oly 12-40 f2.8 Pro ?

Funny Valentine wrote:

petergerritsen wrote:

When zooming to 40mm the tube has a little play/wobble/rattle. maybe thats the reason dust can come in?

Sheers Peter

I agree, the 12-40 has a lot of barrel wobbling/play issue. It's potentially a way of entry for large dust particles to get under the hydrophobic mesh and inside the lens.

Is mine the only copy that doesn't wobble? Strange.

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