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01-21-2019, 07:10 PM   #1
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Help with abnormality on lens

Hey all, I recently noticed something on all my pictures taken with my 18-135mm that has me stumped.
I have tried using a rocket blower on it but it doest appear to budge.
does anything have any idea what this could be or how I can fix it?
Recently I have been doing a lot of Realestate photography and its becoming a pain removing it from every picture.
*This does not appear on any other lens that I use.

Thank you in advanced.

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01-21-2019, 07:39 PM   #2
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My first guess would be the sensor, but since you say it doesn't happen with other lenses I wouldn't know.
Were you using filters? Do you see any imperfections in the glass?
01-21-2019, 07:40 PM   #3
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QuoteOriginally posted by Bethor Quote
Hey all, I recently noticed something on all my pictures taken with my 18-135mm that has me stumped.
I have tried using a rocket blower on it but it doest appear to budge.
does anything have any idea what this could be or how I can fix it?
Recently I have been doing a lot of Realestate photography and its becoming a pain removing it from every picture.
*This does not appear on any other lens that I use.

Thank you in advanced.
Hmm, is this pixel mapping gone wrong? Are you seeing this in the raw file as well?

Adam
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01-21-2019, 08:05 PM   #4
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Stuff on the sensor is not really visible at f4 but is easy to see at f16 or a higher f number. It just keeps getting sharper as you stop down. So it could be that you use one lens pretty stopped down and the rest at wider apertures.

But it's also in different spots in each example, and doesn't look like dust.

01-21-2019, 08:09 PM   #5
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QuoteOriginally posted by sergysergy Quote
My first guess would be the sensor, but since you say it doesn't happen with other lenses I wouldn't know.
Were you using filters? Do you see any imperfections in the glass?
I do use a filter and I did try cleaning it but I didn't try it without the filter. I will test first thing in the AM

---------- Post added 01-21-19 at 08:11 PM ----------

QuoteOriginally posted by Adam Quote
Hmm, is this pixel mapping gone wrong? Are you seeing this in the raw file as well?
I pulled the picture from LR and took a screenshot. I only shoot in RAW and it doesn't appear to move. is it possible that would only happen with one lens?
01-21-2019, 08:14 PM   #6
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If you don't see anything unusual in the lens I think it is the sensor. Try with other lenses at different apertures as Just1MoreDave suggested.
01-21-2019, 08:15 PM   #7
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QuoteOriginally posted by Just1MoreDave Quote
Stuff on the sensor is not really visible at f4 but is easy to see at f16 or a higher f number. It just keeps getting sharper as you stop down. So it could be that you use one lens pretty stopped down and the rest at wider apertures.

But it's also in different spots in each example, and doesn't look like dust.
Its always in the same place. it just looks weird because I did a screen capture and it wasn't even. The smaller spec was taken with f14 the larger one f9. what's the chance of getting a speck of dust inside the lens? If do that would be a bummer I just got it in July of last year. =(

01-21-2019, 08:19 PM   #8
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QuoteOriginally posted by Bethor Quote
Its always in the same place. it just looks weird because I did a screen capture and it wasn't even. The smaller spec was taken with f14 the larger one f9. what's the chance of getting a speck of dust inside the lens? If do that would be a bummer I just got it in July of last year. =(
A speck of dust inside the lens will not create an imperfection in the image. I have many very old lenses with a lot of dust inside and you never see it inside.

My thoughts are it is on the sensor.
01-21-2019, 09:51 PM   #9
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sensor spot or fungal spore on the camera lens?
set the camera for cleaning of sensor and use a flashlight to look at sensor
use a flashlight, and look through the lens with the light pointing at the other end, then reverse the lens,, with the aperature fully open in all cases, and no filter on the lens.
Hope that helps.
01-21-2019, 10:19 PM   #10
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Please clarify - do you have another lens to verify if this is caused by the lens or the camera? My money is on a sensor dustbunny or similar (a whopper).
01-21-2019, 11:33 PM   #11
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QuoteOriginally posted by UncleVanya Quote
My money is on a sensor dustbunny or similar
Same here, only under extremely rare circumstances have I ever seen a defect in a lens cause an artifact like that.
01-22-2019, 01:27 AM   #12
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QuoteOriginally posted by Bethor Quote
Hey all, I recently noticed something on all my pictures taken with my 18-135mm that has me stumped.
...
*This does not appear on any other lens that I use.

Thank you in advanced.
You've already stated the most important fact: it appears with one lens, not with others. Therefore, the defect is in that lens, as the title of your thread states.
Take the lens off the camera (subsitite a lens or use the cover that came with the camera to keep other dust out, of course) and use a good magnifying glass (like, 8x or 10x) and carefully examine both the front objective lens as well as the rear. I use a hobby magnifier to do cleaning, one of those head-band things with built-in LED illumination and multiple lenses so I can not only see well with both eyes, but use both hands while I'm looking.

In my experience, crud on the sensor makes a glob on the images that won't go away, doesn't move, and doesn't change according to variations of the lens settings.
Bits on the lens or filter will expand or contract depending on focus, and will go from visible to invisible depending on the use of the zoom function.
01-22-2019, 03:21 AM   #13
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Dust spots or stains on the sensor preferentially show up when the lens is stopped down a lot, say f/9 or f/16. If you tested other lenses at say f/4, you probably wouldn't see anything. Since the problematic images were taken at f/14 and f/9, it could be sensor.

Another possibility is the rear element of the lens rather than the front. But be careful cleaning that; the coating is softer than it is on the front element.

It doesn't look like dust. Perhaps a drop of dried liquid? A blower would not remove that.
01-22-2019, 06:52 AM - 2 Likes   #14
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From your profile, it looks like you have a KP? It has composition adjustment. You could crank the sensor all the way to the left, take a photo with the lens stopped down, then crank it to the right and retake the photo. If the blob is on the sensor, the blob won't move between photos. If the blob is caused by something on the lens, the blob will move.
01-22-2019, 09:59 AM   #15
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QuoteOriginally posted by twilhelm Quote
A speck of dust inside the lens will not create an imperfection in the image. I have many very old lenses with a lot of dust inside and you never see it inside.

My thoughts are it is on the sensor.
Agreed.

Also, I wouldn't worry about it being on the filter. Any dust or marks on a filter merely diffuse the image, and possibly cause flare. You're not going to get that precise a mark from a filter smudge or mark.

It's got to be on the sensor (some sort of dried droplet?), and as stated above, you're only noticing it with that lens because of how you use that lens.

Take your other lens out, set it to minimum aperture (f16, f22 or so) and photograph a clear blue sky (or a blank wall) and you're bound to see it there too.
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