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a7iii makes shots with a dark spot at sunny day and apeture > F11

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I am a total newbie in the photography world.

I bought a Sony Alpha 7 iii this spring.

This is my first camera which is better than the builtin smartphone one.

I need help to understand where the problem lies. Is it about my hands or hardware ;)

After some time I noticed a strange thing - sometimes in a bright environment and aperture greater than F11.

Greater aperture => more dark spot gets. I tried changing lenses (Sony 28-70mm / Sony OSS 70mm-200mm) / filters  - the issue persists, but it is not reproduced 100% times.

So genuine  nature is unclear for me. I suspect the matrix. The camera matrix looks okay with bare eyes (no scratches).

What could it be? How to reproduce it 100%? Reproducing must be vital for warranty justification, doesn't it?


I attached a few samples from White Sands Park and USS Alabama.





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100% either a spot of dust on your lens or on the sensor - probably your lens. This does happen and really can't be avoided and so get used to having to clean them. There are plenty of YouTube videos showing you how to clean both - a particularly good one for sensor cleaning is here: https://youtu.be/b-7ciRxh6s8



Edited by alasdairmac
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Yep, looks like a dust spot. I reckon it's on the sensor, because it's in the same place on each image.  

Sony alphas of this vintage are prone to gather sensor dust when changing lenses (latest models close the shutter when changing lenses, to keep the dust out).

Don't be scared to clean the sensor - as long as you follow the advice (Alasdairmac's link).

If you still find dust spots on your images it is possible to erase them when editing. I use Luminar Neo which clears most dust spots at the push of a button and replaces with the appropriate background

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I'm thinking something's on the lens, not the sensor. Been my experience gunk on the sensor are sharper, more defined. Gook on a lens is fuzzier as it's further away from the sensor so I'm hanging my hat on debris on the rear element of the lens. If swapping lenses makes no difference then it's the sensor. Gone tells you it's the lens.

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It's easy to check if it's dust on the lens or on the sensor. Dust on the sensor becomes more defined if you close down the aperture, and gives a dark spot in 1 area of the image only. Best to be seen if focussed on infinity on a clear blue sky. Light rays hit the dust speck very parallel this way, casting a clearly defined shadow on the sensor. Dust on or in the lens on the other hand is usually invisible at small apertures and becomes more defined if you open up the aperture. Lens dust shows up in all the bokeh balls, so focus closely with a wide aperture and specular highlights in the background to spot it best.

Remember that the projection on your sensor is inverted. If there is a dark spot at the top of your image, the dust speck is at the bottom of your sensor.

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Sorry, I missed Daniil's comment in his original post that the spot persisted after he had changed lenses.  That tells that the dust spot IS on the sensor. A good cleaning mode vibration and/or a blower should sort it and if not then it will be a job for a sensor cleaning kit.

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On 6/30/2022 at 10:36 PM, XKAES said:

Dan (OP) has already said he changed lenses with the same result -- and that it happens with small apertures.

I know, but I live by the adagium:

'Give a man a fish and you'll feed him for a day. Teach a man to fish and you'll feed him for a lifetime.'

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