I have recently noticed an artifact appearing in the bottom center of my pictures.

 

1. This only happens at smaller apertures F8 - F22. It is not dust as it forms almost a perfect 1/2 ring.
2. I have swapped out lenses so it is not on the lens.
3. I have done the self cleaning, as much as that does.
4. I even looked at the sensor, I figured something this big would be visible, but the sensor appear clean.
5. Given its size and shape I am not sure that a cleaning of the sensor would be helpful

 

I have included 2 pictures. One is a blown up view of the artifact and the other is the full picture. You can see the artifact about 1/3 of the way in from the left and 1/3 of the way up from the bottom. The camera is still under warranty and I was looking for any advice before I have to pack it up and send it away for a few days or weeks depending on the speed Sony's warranty service.

 

I would like any advice on how I should proceed.

 

Thanks

I forgot to mention that it was an A7RII purchased about 10 months ago.

I would carefully clean the sensor first, it almost looks like a minute moisture drop that dried leaving the ring.  It's location as you look at the sensor would be upper left center I believe.  Did you inspect with a loupe?  Also, if you have another camera with macro capability, a detailed photo of the sensor might reveal what your eye cannot see.

This is probably something that will not just blow away. Since it is under warranty is this something that is safe since air is the only 'authorized' cleaning method. I have investigated the cleaning solutions and there are two methods. One is using a gel stick after the sensor is locked down and the other is a wet cleaning. I have read in several places that a wet cleaning could impact the coating on the sensor. Any suggestions on how the best cleaning if it is a water drop.

 

Also, I've always been careful when changing the lenses (i.e. sensor down, never in the rain, usually inside) could this be a condensation drop of some sort? I live in Virginia and the humidity can get pretty high.

Just an additional note, I have performed a "wet" cleaning twice in five years without incident and with total resolution of the problem that wouldn't blow away.  There are useful guides on youtube to demonstrate the technique.  You just have to be careful.  Cleaning a mirrorless camera is obviously easier than one where you have to expose the sensor by locking up the mirror.

If it is any help, due to ambiguities regarding whether Eclipse fluid is safe or not (I think there are two versions) I opted to use Dust Patrol Gamma Optical Cleaning fluid on my A7RII. Beware however to simply use a couple of drops on the full frame sized sensor cleaning pad as too much fluid will leave you with more drops or smears than you started with - I did this with the sensor locked down in cleaning mode [and got smears so had to go again] with minimal fluid on the pad.

 

I have also used Dust Aid Platinum silicon stick with Cleaning Strips to great effect on this camera. Regarding violating the warranty I think this is an unfortunate stance taken by Sony and is probably their way of covering their proverbial in case some fool pours cleaning fluid into their camera - I'm sure Sony will use both wet cleans and silicon gel sticks to clean your camera but I wouldn't assume it would be free. Maybe start with the Dust-Aid [or some equivalent product] but be prepared to go wet if necessary.

 

The A7RII sensor does get really dirty IMO regardless of how careful I am. I get by fine not seeing much until I'm at smaller apertures [f11 and higher e.g. when taking landscape shots] - might I suggest you take a shot of a clear blue sky at f22 as a pre-clean reference image to see  just how much dirt / other marks there is now on your sensor and again after cleaning to make sure you haven't smeared it with cleaning fluid due to using too much.

I will post this once again. "The best way to clean a sensor".

For your sensor problem I would first use a sensor pen only and

then see if it has had any effect. These pens work wonders on

oil and water spots but do leave behind fine particles, the gel

stick is a perfect tool to clean up after using the pen. Do not

use any liquid cleaner.

 

Thank you everyone. My biggest worry was that there was an issue with the sensor in that the area was so large and mostly circular but @tinplater had a very reasonable explanation.

 

Being a wuss, I am taking it to the local reputable (they have been around since 1938 and have done good work for me before) camera shop for a cleaning.

 

Thanks again.

Svilla, get back to us and update the outcome...

Just got it back. I was able to see it in the view finder, but now it is gone completely. I think it is fixed. Gonna snap a shot and bring it into Lightroom tonight to get a closer inspection. But so far B-E-A-utiful.

 

Thanks again for your help.