EPL-2 Red Spots - Reply from Olympus Europe

John Corbett · Feb 15, 2011

Though I haven't found this "issue" problematic, I did however email Olympus Europe with some sample pictures and asked for their opinion.

Below is their response:

Hello,

Thank you for your sample picture.

When you take a picture with a strong spot light in the frame, there is a case some red spots may appear around the light source in a grid or radial pattern. This is a phenomenon caused by reflected images of micro lenses located on the sensor of the camera, and more likely to appear when the brightness gap is broader within the frame. This appears not only with the E-PL2, but with other models depending on the shooting conditions. When you take a picture with a strong light source in the frame, we recommend you to choose wide apertures to make them dimmer and less remarkable. You can choose further wider apertures if you attach an ND filter on the lens.
Please do not directly shoot the sun, as it may cause fire or malfunctions. /

Seems pretty much to match the consensus here on the forum

--
Regards

John

Olympus EPL-2 & Panasonic FZ50
http://www.jcorbett.smugmug.com

Bobo Hodls · Feb 15, 2011

I'm not sure that explanation would have been accepted at face value early on, but it makes sense compared with user's experiences since it was first noted.

John Corbett said:
Hello,

Thank you for your sample picture.

When you take a picture with a strong spot light in the frame, there is a case some red spots may appear around the light source in a grid or radial pattern. This is a phenomenon caused by reflected images of micro lenses located on the sensor of the camera, and more likely to appear when the brightness gap is broader within the frame. This appears not only with the E-PL2, but with other models depending on the shooting conditions. When you take a picture with a strong light source in the frame, we recommend you to choose wide apertures to make them dimmer and less remarkable. You can choose further wider apertures if you attach an ND filter on the lens.
Please do not directly shoot the sun, as it may cause fire or malfunctions. /

Seems pretty much to match the consensus here on the forum

--
Regards

John

Olympus EPL-2 & Panasonic FZ50
http://www.jcorbett.smugmug.com

--
...Bob, NYC

'Well, sometimes the magic works. . . Sometimes, it doesn't.' - Little Big Man

http://www.bobtullis.com

Marla · Feb 15, 2011

Bob Tullis said:
I'm not sure that explanation would have been accepted at face value early on, but it makes sense compared with user's experiences since it was first noted.

Bobo Hodls said:

Hello,

Thank you for your sample picture.

When you take a picture with a strong spot light in the frame, there is a case some red spots may appear around the light source in a grid or radial pattern. This is a phenomenon caused by reflected images of micro lenses located on the sensor of the camera, and more likely to appear when the brightness gap is broader within the frame. This appears not only with the E-PL2, but with other models depending on the shooting conditions. When you take a picture with a strong light source in the frame, we recommend you to choose wide apertures to make them dimmer and less remarkable. You can choose further wider apertures if you attach an ND filter on the lens.
Please do not directly shoot the sun, as it may cause fire or malfunctions. /

Seems pretty much to match the consensus here on the forum

Click to expand...

Thanks for posting this information.

Being the technically challenged person that I am, I am wondering if the following statement cancels out all but "micro lenses." If so, why would this only happen with micro lenses? What would be the cause? OR am I getting too analytical here - digging too much?

Bobo Hodls said:
This is a phenomenon caused by reflected images of micro lenses located on the sensor of the camera, and more likely to appear when the brightness gap is broader within the frame. This appears not only with the E-PL2, but with other models depending on the shooting conditions.

At any rate, I have the E-PL2 - and for now am just going with the flow - love the camera!

Maria

GHB · Feb 15, 2011

Marla said:
Being the technically challenged person that I am, I am wondering if the following statement cancels out all but "micro lenses." If so, why would this only happen with micro lenses? What would be the cause? OR am I getting too analytical here - digging too much?

Marla said:

This is a phenomenon caused by reflected images of micro lenses located on the sensor of the camera, and more likely to appear when the brightness gap is broader within the frame. This appears not only with the E-PL2, but with other models depending on the shooting conditions.

Click to expand...

The micro lenses referred to are not the mFT lenses that you mount to the camera. They are the micro (i.e. microscopic) lenses that are actually a part of the camera's sensor. And, yes, the phenomenon can be observed with other than m43 lenses. I have been able to get the red dots with regular FT lenses.

Marla said:
At any rate, I have the E-PL2 - and for now am just going with the flow

Likewise.

Marla said:
Maria

--
George

Marla · Feb 16, 2011

GHB said:
The micro lenses referred to are not the mFT lenses that you mount to the camera. They are the micro (i.e. microscopic) lenses that are actually a part of the camera's sensor. And, yes, the phenomenon can be observed with other than m43 lenses. I have been able to get the red dots with regular FT lenses.

GHB said:

At any rate, I have the E-PL2 - and for now am just going with the flow

Click to expand...

Likewise.

GHB said:
GHB said:

I appreciate the explanation.....makes sense.

Click to expand...

Thanks.

Maria

Gavin Stapleton · Feb 16, 2011

Can the direct sun's brightness damage the sensor?

DjarumBlack · Feb 16, 2011

Gavin Stapleton said:
Can the direct sun's brightness damage the sensor?

If the camera was held up to the sun too long, it could damage the camera. Similar to a magnifying glass.

Bobo Hodls · Feb 16, 2011

Gavin Stapleton said:
Can the direct sun's brightness damage the sensor?

Just to expound a little more on this - it can, but not in normal usage. You're more likely to hurt your eye pointing at the sun.

However, when doing tripod studies where the camera would be facing the sun, it can be easy to forget to cover the lens while being distracted with other things during the sessions, and/or while waiting for the scene's light to materialize as anticipated. The sensor or other parts of the lens mount chamber can be subjected to intense focusing of the light, which can cause damage (akin to burning paper with a magnifying glass). I recall seeing evidence of the AF sensor area in a Canon DSLR being melted for being left pointed at the sun in that manner.

--
...Bob, NYC

'Well, sometimes the magic works. . . Sometimes, it doesn't.' - Little Big Man

http://www.bobtullis.com

Gavin Stapleton · Feb 16, 2011

DjarumBlack said:
Gavin Stapleton said:

Can the direct sun's brightness damage the sensor?

Click to expand...

If the camera was held up to the sun too long, it could damage the camera. Similar to a magnifying glass.

That's quite a two-edged sword then. As you often need to close down the aperture in A mode on the E-PL1 with the sun behind the subject. Otherwise you hit the 1/2000th shutter limit. I can imagine your magnifying glass analogy when put that way.

I haven't needed to use my ND4 filter yet, but if I was getting red dots, seemingly opening the aperture up spreads the light over a larger area of the sensor so as not to highlight the photosites. The 1/4000th shutter limit on the E-PL2 could help get away with a larger aperture. Too bad if you want a larger DoF and don't have an ND filter handy...

NB: I don't photograph the sun, but I like to halo it behind subjects, which is still quite bright.

safaridon · Feb 16, 2011

Marla said:
Bob Tullis said:

I'm not sure that explanation would have been accepted at face value early on, but it makes sense compared with user's experiences since it was first noted.

Marla said:

Hello,

Thank you for your sample picture.

When you take a picture with a strong spot light in the frame, there is a case some red spots may appear around the light source in a grid or radial pattern. This is a phenomenon caused by reflected images of micro lenses located on the sensor of the camera, and more likely to appear when the brightness gap is broader within the frame. This appears not only with the E-PL2, but with other models depending on the shooting conditions. When you take a picture with a strong light source in the frame, we recommend you to choose wide apertures to make them dimmer and less remarkable. You can choose further wider apertures if you attach an ND filter on the lens.
Please do not directly shoot the sun, as it may cause fire or malfunctions. /

Seems pretty much to match the consensus here on the forum

Click to expand...

Click to expand...

Thanks for posting this information.

Being the technically challenged person that I am, I am wondering if the following statement cancels out all but "micro lenses." If so, why would this only happen with micro lenses? What would be the cause? OR am I getting too analytical here - digging too much?

Marla said:

This is a phenomenon caused by reflected images of micro lenses located on the sensor of the camera, and more likely to appear when the brightness gap is broader within the frame. This appears not only with the E-PL2, but with other models depending on the shooting conditions.

Click to expand...

--I don't have the EPL2 but a GF1 instead. I shoot a lot directly into the sun especially at sunset and no red dots. If reflected images of micro lenses located on the sensor of the camera then why is this problem occurring primarily with the new EPL2 and kit lens and not with all the other m4/3 models out there using the same sensor? Logic would say while red dots can occur because of reflection from micro lenses on the sensor it more likely is occurring in this case because of the micro lenses used in the new kit lens? Oly's answer is very convenient but not the whole story in my opinion.

Gavin Stapleton · Feb 16, 2011

I've asked before: Does the E-PL2 have a thinner IR and AA filter than the E-PL1 that may permit more light to focus on the micro lenses/photosites?

Bobo Hodls · Feb 16, 2011

safaridon said:
--I don't have the EPL2 but a GF1 instead. I shoot a lot directly into the sun especially at sunset and no red dots. If reflected images of micro lenses located on the sensor of the camera then why is this problem occurring primarily with the new EPL2 and kit lens and not with all the other m4/3 models out there using the same sensor? Logic would say while red dots can occur because of reflection from micro lenses on the sensor it more likely is occurring in this case because of the micro lenses used in the new kit lens?
Oly's answer is very convenient but not the whole story in my opinion.

Micro Lenses refers to the teeny lenses that cap each photosite on the sensor. Has nothing at all to do with the lenses that are mounted on the camera.

Gavin,

It's possible that the layers that sit above the sensor itself has been modified, or a different formula of coating that are applied to those layers have been changed, but that's not yet been determined AFAIK. It would be nice to have an answer, for general knowledge and understanding, but personally I'm done with the concern.

--
...Bob, NYC

'Well, sometimes the magic works. . . Sometimes, it doesn't.' - Little Big Man

http://www.bobtullis.com

John Corbett · Feb 16, 2011

I asked why the EPL-2 seemed more prone to this than the EPL-1

Here is Olympus Europe's reply

In fact both models have that issue. It is only more visible on the E-PL2.

The difference between E-PL2 and E-PL1 is due to the difference of the optical construction around CCD.
--
Regards

John

Olympus EPL-2 & Panasonic FZ50
http://www.jcorbett.smugmug.com

cbr09 · Feb 16, 2011

See this go at trying to explain it, I posted a little while ago. Given what Olympus says it looks as if it is reflection from micro-lenses (like in my Fig2a) - though I think given the pattern there might be a diffraction grating effect too - otherwise you would not get such specific points.

Anyway - assuming this is right, you won't see it with halos or with sunsets with longer focal lengths - because the spots are images of the bright light source - and lots of copies of a halo or a larger image of the sun will just merge together and not be noticeable.

cbr09 said:
Just for fun, I thought it might be interesting to consider just how the red spots in the EPL2 (and possibly other cameras) appear. It could even help to understand how to avoid them - or indeed produce them since this seems to be a popular game. There are a few hints as to what the cause might be. As far as I can see from posted images:

1. The red dots are always centred around the bright light source in the image (not around the axis of the lens).

2. The dots are always at about the same spacing.

3. It happens with different lenses

All three of these suggest that it has nothing to do with the lens - and therefore most likely with the sensor/anti-alias filter/IR filter and/or SSWF membrane.

The spacing between the dots looks to be about 0.5mm on the actual sensor - which I imagine is also about the same scale as the gap between some of the elements (membrane, sensor, AA filter etc). In general there does not seem to be a problem with reflection from these elements - because I'm sure they are well coated and also the telecentric design ensures that most of the time light is striking them pretty much straight on - so any reflections will be at almost the same point as the image itself.

Something seems to be causing the image to be reproduced on all sides of the image point. I think, given it has nothing to do with the lens, this is most likely to be diffraction. One of the elements - perhaps most likely the AA filter - or possibly parts of the sensor itself must have a regular pattern in the reflections. I estimate that this needs to be at the scale of about 1-2um - so smaller than the photosites. This regular pattern will give diffraction at specific angles. Fig 1 (see below) comes from Wikipedia:

http://en.wikipedia.org/wiki/Diffraction

and shows how diffraction works through a grating - in this case we imagine more of a grid pattern - hence diffraction in all directions. In the case of the EPL2 the diffraction could be on reflection from the sensor/IR filter (Fig 2a) or in transmission through the AA filter (Fig 2b) - the point is that once you have this diffraction, you get light at an angle in the space between two reflecting surfaces. Surface coatings cannot normally eliminate all reflections at glancing angles and so this light is likely to bounce back and forth producing a regular pattern (Figs 2 show reflections - and Fig 3a the type of pattern you might get).

Several aspects of this tie in with what people see. Since the angles are defined by the geometry of the sensor/filters, the spacing is always the same and centred around the main image of the bright light. Also if the f number is high giving great depth of field, all the subsidiary images will be in focus (like Fig 3a) but if the f number is lower, they will will out of focus - and blur more quickly into insignificance (Fig 3b) as you move away from the central point. It would also imply that the red dots you are seeing are actually images of the bright light - and therefore much more likely for very small lights (eg sun in wide angle pictures, specular reflection points etc) - but probably not with large light sources, however bright (eg photos of light bulbs close up - or more telephoto photos of sunsets. Figs 3c and 3d show what you expect with a larger light source with high or low f number - just more of a halo. In this case all the dots merge into one another.

It would be interesting if those of you with the camera could test this. I expect you could also work out, from the spacing of the dots where the reflections was taking place. If at the sensor, then you'd expect the dots to be evenly spaced with the light source (as in Figs 2a, 3a) - whereas if at some reflecting surface in front (Fig 2b) the 'first' spots if visible, should be closer in and probably not red.

Anyway - if you don't have anything better to do (like taking photos), you might like to think about this - and maybe come up with another idea...

_sem_ · Sep 3, 2012

The issue resurfaces with the recently popular Sony RX100 compact
http://forums.dpreview.com/forums/readflat.asp?forum=1009&thread=42344095&page=1

and several others, including iPhones. And guess what, Samsung copied this flare too

http://www.youtube.com/watch?v=x1pdjLrXAXo

I agree with the reflected-beam-diffraction(interference)-through-a-grating explanation. With no sun around, one can check with a LED flashlight. Careful with the powerful ones not to fry your sensor - my old cameraphone has a short dark arc, probably been on a table in the sun for a while.

Guy Parsons · Sep 3, 2012

Never ever seen that problem with my E-PL1 so it is sensor stack / lens? dependent.

As an aside about the time that E-PL2 red dot issue was "hot", I was watching some documentary on TV and briefly during some arty environmental shot with the sun in the frame, there was a big splash of dot pattern, not red but green for a change.

Regards............ Guy

Gavin Stapleton · Sep 4, 2012

Not only are there no red-dots, I'd like to start a rumour that the E-PL1 also has the best image quality of all the 12MP sensored m43 Oly's.

jpig · Sep 4, 2012

The E-PL2 was the camera that attracted me to m43. I read about the red dot issue before ordering (no store near me carried the camera), but was not troubled by it since I figured all the chatter about red dots was the usual obsessive internet forum nitpicking.

However, when I received it, I found that the E-PL2 produced the red dots all too easily. I read that the E-PL1 did not have the same issue, so I got one to compare. I shot them both side by side in the same lighting and was never able to get the E-PL1 to produce anything resembling the red dots that plagued the E-PL2 when shooting into any light source.

So I returned the E-PL2 and kept the E-PL1, even though the E-PL1 seemed unwieldy, even downright ugly. However, it has grown on me, to the point that I even like the all-button operation (after customization of button functions). And thousands of shots later, I have yet to see red dots in any photo taken with the E-PL1, including sunsets, streetlights at night, etc.

I still think the E-PL2 is a better looking camera, perhaps the most attractive of the PENs, but for my shooting the red dots occurred too frequently to be acceptable.

jpig

ELLIOT P STERN · Sep 4, 2012

I am sorry but Olympus is full of it. I had the same problem with the EPl2 when I first got it as did many others. It is to easy for manufacturers to tell us what is normal and what it is we should live with.

The dots in the image cannot be normal. It is an effect being produced by a poor sensor design.

I had mine replaced and the replacement which was a different serial number run had no problem what so ever.

So as usual, Olympus does not publicly own up to problems. They make a great product but it seems to me that all of the manufacturers or at least most of them in Japan never want to admit that they made a mistake in production.

You must be your own advocate shouting louder and louder until they show you respect and deal with the issue.

--
El

Gear. 2 Omd, all the lenses, Ep3, Ep2, Ep1 infrared, Fuji X100, Fuji x pro 1, all the Fuji lenses, Voigtlander 15,21,28,50,75,90,180. Nikon 55 macro, 200 macro and Zeiss 100mm macro, Induro Tripods and heads, etc. Ricoh GXR and modules including Leica M

Linus M · Sep 4, 2012

Gavin Stapleton said:
Not only are there no red-dots, I'd like to start a rumour that the E-PL1 also has the best image quality of all the 12MP sensored m43 Oly's.

I absolutely agree.
The EPL-1 gave me very nice shots right out of the camera.

With my EPL-3 I had to do alot of tweaking of settings to get it to give decent results.
And even then the results are not as good as the EPL-1.
I have to shoot raw and PP to get really close.

Anyway, the EPL-3 is for me just a camera to get by untill something really interesting comes up ( or the EM-5 gets much cheaper ; )

Linus

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