Now this is weird

[kipdent]

Advertisement (gone after registration)

I've been thrilled with my new M9, now about two weeks old. The last few days,though, I've noticed an inexplicable (at least to me) issue that I thought was just dust on the sensor, but this is just plain weird. Here's what happened:

 

I few days ago I took at shot that included some clear sky area. I noticed during processing the image what appeared to be a dust blob. Other shots in this sequence did not have any clear areas so I could not tell if the blob was present on any of the other images taken that day.I thought before I tried cleaning the sensor I better confirm something was really there, so I went outside and took a shot that intentionally had some clear area in the same position of the frame, and I used the same lens (Elmarit 21mm ASPH). Low and behold, no spot.

 

Today I was using the camera and when I opened the images, one with some clear area had the spot again--and in PRECISELY the same position! Now I was befuddled. Stranger still, the image with the spot was taken with a different lens than the first spot (a Summicron 35mm ASPH). I took some more shots of a blank wall to confirm the presence of dust, with both the 21mm and the 35mm, and guess what--the spot was now gone!

 

What the heck can be going on here? How can dust (if that is what it is--and it sure looks like it) come and go, and in the same, exact position? Does anyone have any ideas?

 

I've enclosed three crops of the precise area where the spot has come and gone.

 

Thanks--

 

Kip

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[cheewai_m6]

it looks like dust on the sensor. shoot at F16 and the dust spots will be more obvious. take a shot of a white or light coloured wall at f16. if they spots are consistent, then it's dust.

[colorflow]

What settings did you use to shoot the wall?

I would shoot a light colored wall within a few feet without focusing. Set the camera on aperture priority, the lens set at f16 or f22, iso 160 and move the camera in a slight circular motion while the shutter is open.

[Guest roey]

How can dust (if that is what it is--and it sure looks like it) come and go, and in the same, exact position? Does anyone have any ideas?

 

My guess: The image that didn't show the spot was shot (close to) wide open, whereas the ones that showed it were shot stopped down.

[ho_co]

...How can dust (if that is what it is--and it sure looks like it) come and go, and in the same, exact position? Does anyone have any ideas? ...

 

As the others suggested: Try a shot with a lens wide open and another with it stopped down.

 

Wide open, the light comes from many directions and the grungy spot isn't rendered sharply (remember, it's just in front of the imaging surface).

 

With the lens stopped down, the ray cone is more concentrated and casts a shadow of the spot.

 

Same as your shadow: On a cloudless day, the sun casts a relatively sharp outline; on a cloudy day (light coming about equally from various directions), the shadow is diffuse or absent.

[adan]

1) it's dust

 

2) as mentioned, dust spots change visibility substantially with f/stop (and focal length). Sometimes in unexpected ways - my 135 will often show dust more clearly @ f/5.6 than my 21 @ f/5.6 - the midrange lenses tend to reveal dust the least.

 

3) It is possible the dust jumped (due to some static charge) to the shutter blade in front of the sensor and then back again after a few exposures. Not likely, but possible.

[Benoit Petot]

Advertisement (gone after registration)

Are you sure that these spots are “dusts on the sensor” ?

 

I get some of them from time to time, and I have difficulties to consider that the focal length & the f-stop may influence so much the visibility of dusts on the sensor, although I’m new to DP it seems to me that, generally speaking, a sensor dust should be:

· Permanent (visible on all the pictures)

· Sharp (Isn’t it the equivalent of a “contact print” ?)

· Consistent when lighten enough

And the LEICA approach (with the CCD shutter almost always closed) protect a lot the sensor from the dust, thus having already dust after a few days looks improbable.

 

I have these spots mainly in Back-Light conditions, or on light skies and sometimes I’ve multiple identical spots on the same picture. Until now I considered that they are “lenses artifacts” (reflections or dust on the lense itself ?). They are very small and usually invisible on print in “standard sizes” A3 or less, when required they are easy to remove in post-processing.

 

BTW, these spots are by far less troublesome than the spots of the Film-Photography.

Don’t focus too much on the technical & theorical issues through crops. Take real photos, enlarge and print them and you’ll see that your camera is almost perfect.

[mjh]

Are you sure that these spots are “dusts on the sensor” ?

Absolutely. That’s what dust on the sensor looks like. Dust spots are generally fuzzy and their visibility depends on both the aperture – from unmistakable at f16 to invisible at f1.2 – and the focal length – wide-angle lenses suffer more.

[ppolla]

I have had the same issue.....and found out that it wasn't dust...but rather oil and would need a swab to clean....since the clean my situation improved

P

[250swb]

Yes, it absolutely is dust AND/OR oil on the sensor, with a new camera it could be both. Nothing to worry about Kip, you just need to clean it, as you will from time to time during the entire time you have the camera. So no time like the present to start.

 

It shows up because as you stop the lens down the angle of the rays of light become more acute, so casting a shadow of the sensor dust on the image. It is absolutely not a good idea to say to yourself that you'll only shoot wide open because it won't show the dust, all the f/stops are there to be used if you need them.

 

So I'd buy a wet cleaning kit, sensor swabs and fluid. Later, you may want to buy a dry cleaning kit, like an Arctic Butterfly, but first you need to be sure you remove any oil and the wet clean kit will do both.

 

Steve

[kipdent]

Thanks for all the replies! I can't believe I overlooked the obvious--of course dust would show better when the lens is closed down. A test shot just now at f/16 confirmed it. Thank you! I'm a little embarrassed.

 

One thing that came up in the thread that rattled me a bit was the possibility the spot might be oil. Is this common on the M9? I have never heard of this before regarding sensor grunge. I have an Arctic Butterfly, but wouldn't want to get oil on its bristles.

 

Thanks again--

 

Kip

[Baptiste]

I have had the same issue.....and found out that it wasn't dust...but rather oil and would need a swab to clean....since the clean my situation improved

P

 

Mine too, so to say... before, I had oil, now I have dust . Using Sensor Swabs & Eclipse product.

[Alnitak]

Oil will look a bit different as you stop down. Where dust looks like a nice hard spot at f/16, oil will always look a tiny bit diffused since the oil used is clear and can transmit some light. On a new M9 you will have oil and dust as the shutter mechanism "settles in." It will take some regular cleaning for the first two or three months, but after that very little dust or oil will settle in there, unless you live in a dusty environment and/or change lenses a lot.

 

Jeff

[Bill W]

And here I thought the M9 was supposed to be dust and oil free.....!!!! So far mine is but I have only had it about three days.

[vikasmg]

Apparently a brand new camera may occasionally result in a bit of oil splatter from what I've been told but if you have not had this problem yet, you're probably OK. However when cleaning, be careful not to touch other interior surfaces of the camera before the brush or cleaning swab touches the sensor. That is probably a good way to make matters worse.

 

Definitely don't accidentally switch on that Arctic Butterfly in there.

 

- Vikas

 

Thanks for all the replies! I can't believe I overlooked the obvious--of course dust would show better when the lens is closed down. A test shot just now at f/16 confirmed it. Thank you! I'm a little embarrassed.

 

One thing that came up in the thread that rattled me a bit was the possibility the spot might be oil. Is this common on the M9? I have never heard of this before regarding sensor grunge. I have an Arctic Butterfly, but wouldn't want to get oil on its bristles.

 

Thanks again--

 

Kip