Spots at ISO 320

Discussion in 'Olympus Cameras' started by Harvey Melvin Richards, Sep 12, 2017.

  1. I attempted to take some photos of flying herons yesterday and I ended up with strange spots on photos where I had the sky in the background. All of these photos are small sized, and all have been overdeveloped in LR with the dehaze pushed up to 86 which emphasizes the spots. All were taken with the E-M1 II, and the 300 f/4 w MC-14. Some of the spots seem to move, others don't.

    I tried these again this morning and the photos at 320 ISO have the spots. Most below that don't.

    1/400, f/14, ISO 320
    EM121284-1 (Medium).jpg

    1/400, f/13, ISO 320
    EM121286-1 (Medium).jpg

    1/400, f/16, ISO 320
    EM121318-1 (Medium).jpg

    From today, 1/400, f/14, ISO 320
    EM121460-1 (Medium).jpg

    1/1000, f/7.1, ISO 200 EM121462-1 (Medium).jpg

    1/1250, f/6.3, ISO 200
    EM121459-1 (Medium).jpg

    And another from this afternoon at ISO 200 and it has one big spot in the upper middle.
    1/1000, f/7.1, ISO 320
    EM121495-2-1 (Medium).jpg

    My lens looks clean, I don't see any water spots or dust. What's the problem here, or what else should I try? Also, I have never seen this before.
    • Wow Wow x 1
  2. SVQuant

    SVQuant Mu-43 Hall of Famer

    Sep 20, 2015
    SF Bay Area, California, USA
    Sensor dust?
    • Agree Agree x 4
  3. It looks clean to me, even under 15X magnification.
  4. masayoshi

    masayoshi Mu-43 Veteran

    Dec 5, 2016
    Salt Lake City
    Just double checking....lens AND MC-14 are both clean, right? They look like coming from optics to me, but if not lens or TC, I have no idea...
  5. SVQuant

    SVQuant Mu-43 Hall of Famer

    Sep 20, 2015
    SF Bay Area, California, USA
    And the MC-14 looks clean?
  6. dirtdevil

    dirtdevil Mu-43 Veteran

    Apr 9, 2017
    You can try it out if you want, but I experienced the same phenomenon on a smaller scale, and I had just cleaned my glass with water and a cotton swab. After I noticed it by lookiing at my pictures, I cleaned it like I usually do with an organic cotton cloth and everything seems good now. So maybe those were like "badly dried micro-water-droplets" by using too much water when I used the cotton swab...?

    The lens looked very clean when I was having that problem.
    Last edited: Sep 12, 2017
  7. Yes, all the glass looks good.
  8. pellicle

    pellicle Mu-43 Hall of Famer

    Feb 10, 2010
    Southport, OzTrailEYa
    well, looks like sensor dust to me.

    have you tried illumination from the side by a point source (such as a light bulb not a fluro) and examine it?
    When you move from image to image are the dots all in the same (physical) place?
    Take some shots of anything (you don't even need to focus) at f11 or 16 (a plain wall is best) on Av and see if they appear ... no need to hold the camera steady. That will clarify if its on the sensor.

    I see that your exposure information supports my theory, they are more defined at f11 and smaller aperture diameters ... if not dust then its from residue left when sensor cleaning. I'd say you failed to dry properly.

    I've never (ever) seen dust appear in the image (because its too far into the diffuse part of the image), certainly not like that with sharp edges

    a reference guide:
    in my view ...: Colonial boy sensor cleaning

    key points from that :
    Armed with a small section of a type of thin sponge available here , a paddlepop stick and some windex (applied to one end of the paddlepop cleaner, the other left dry) I now have a clean as a whistle sensor.

    The swab applicator is made so that its narrower than the sensor and I can sweep across in two overlapping wipes from left to right.

    The technique is to drag (not push) the wetted (with windex) sponge across the front of the sensor so as to sweep the items off and the windex will assist in the dislodging (and being moist prevent any static attraction).

    When you've done that then use the dry end (again, dragging) to re-sweep the area and the dry applicator sponge will absorb any remaining windex and give you a nice dry surface.

    Job done.

    Total cost was around 2 bucks ... which was the icecream ... which I ate to get the stick.

    do not (repeat do not) apply the cleaner to the sensor directly, always wet the swab
    Last edited: Sep 12, 2017
    • Like Like x 1
  9. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    Take a picture at F/22 or 32, whatever it goes up to. The spots are always most visible in the stopped down pictures.

    My guess would would be dust on the optics, it's too big for sensor imo.
    Last edited: Sep 13, 2017
  10. I've never cleaned my sensor, so it's nothing I have left.. I'll try some shots at a smaller aperture.
    • Like Like x 1
  11. pellicle

    pellicle Mu-43 Hall of Famer

    Feb 10, 2010
    Southport, OzTrailEYa
    btw, here is a quick demo of how it can't be on the lens, it must be further away from the lens or on the sensor:

    I put this on the lens ... its a rather large spec isn't it:


    I set my 300mm (you sure weren't using wide on those bird shots right?) to f32 and hand held this shot:

    no trace right ... its an easy experiment to replicate. Its also why its pointless to obsess about the tiny specks of dandruff which may get onto the surface of the lens ... they're invisible to the image
    • Informative Informative x 1
  12. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    Wide angle retrofocal designs show spots on the front element, telephoto designs show anything on the rear element.


    Here's a 300mm f/4 at f/22 with a cock and balls drawn on the rear element, immature maybe however I believe it proves my point.
    • Funny Funny x 3
    • Sad Sad x 1
  13. pellicle

    pellicle Mu-43 Hall of Famer

    Feb 10, 2010
    Southport, OzTrailEYa
    I guess that you missed the point where the OP said:
    hardly a wide angle ....

    and is that clearly visible on the back element of the lens? I understood that the OP was unable to see anything on his lens elements
    ... so, yes, it proves you are correct, you are immature and are uninterested in discussion in a helpful way.

    If you weren't just like your diagram you may have just said "it doesn't discount dust on the rear element and done something more like dust than your drawing ...
    Last edited: Sep 13, 2017
    • Wow Wow x 1
  14. pellicle

    pellicle Mu-43 Hall of Famer

    Feb 10, 2010
    Southport, OzTrailEYa
    out of interest (assuming no typo here) why not give your sensor a clean? Dust is hard to see on the sensors as its often very tiny. If using a loupe (you mentioned x15 I think) be careful you are not focusing either side of it.

    The f22 shots will be definitive ... also, try another lens too (if its on the sensor it will be still there after a lens change). (thought: it may move around due to the sensor shake self cleaning system)
    • Agree Agree x 2
    • Informative Informative x 1
  15. Giiba

    Giiba Something to someone somewhere

    Aug 19, 2016
    New Westminster, BC
    This is the best way to rule out lens dust.
  16. SVQuant

    SVQuant Mu-43 Hall of Famer

    Sep 20, 2015
    SF Bay Area, California, USA
    Since the m43 sensor stack is somewhat thick, sensor dust can create fairly large spots. Here is an example from the last time I got dust on my sensor. E-M10 + O75-300II converted to b&w and exposure boosted.

    It was mostly noticeable in sky shots at long focal lengths. Testing with another (long) lens is the way to confirm that it is on the sensor and not in the lens. The spots move a little between power cycles because of the sensor cleaning mechanism. FWIW, a couple of puffs with a rocket blower were enough to remove the dust.
    Last edited: Sep 13, 2017
  17. pdk42

    pdk42 One of the "Eh?" team

    Jan 11, 2013
    Leamington Spa, UK
    I'm pretty sure it's sensor dust. Buy a good wet cleaning kit and clean it. It won't do any harm and I'll bet that it's the problem.
  18. junkyardsparkle

    junkyardsparkle haunted scrap heap Subscribing Member

    Nov 17, 2016
    like, The Valley
    Best use for a body cap pinhole "lens" I've found is seeing exactly what's on your sensor. Rules out lens dust rather nicely. Also note that using IBIS can cause the spots to move within the frame, in my experience... making batch spot correction on a bunch of pictures a descent into madness. :/
  19. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    You missed the point, putting bits of sticky note on the front element of a telephoto does nothing, try putting them on the rear element. My drawing was done using a 0.3mm OHP pen and was only a few millimeters tall.

    If I had to guess the dust is moving inside the lens by the image stabilization and internal focus mechanism as it moves around.
  20. pellicle

    pellicle Mu-43 Hall of Famer

    Feb 10, 2010
    Southport, OzTrailEYa
    No, it demonstrates that there is no effect of dust there. Its part of ruling things out logically.

    Well on my lens that is impractical as its too deep too get a dust sample into and I dont wish to put a permanent marker pen ink into my lens. I would doubt it would ever come clean.

    Why not show a picture of the rear of your lens to show where and how it was placed?

    Also 0.3 is quite large and the OP already confimed it was not visibly dirty

    So to me that makes such obvious dirt (and in significant amounts) unlikely.

    I still am not convinced its on the lens at all.
    I await more definitive results by the OP
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