Sony a6400 - Tiny colourful dots in photos + circle dark corners

[Med]

Hi all,

I've got a a6400 with 18-135mm lens kit. Although I am a bit dispointed with the sharpness of this lens, I faced 2 new problems today (separately) while taking pictures:

1- Seeing tiny little dots (kind of pixels) both in high and low ISO (64000 and 1600 tested).

2- A Strange circle crop in black coulor over the corners only.

Any idea what could be the reason (am I using a specific setting that does this... Maybe a pb with the sensor...?). I wanted to upload the pictures that you could see it, but too heavy (24 MB, and can't downsize it!).

I really appreciate your feedback/help, in advance.

Cheers

Med

[Olaf W.]

Welcome!
 

1600 ISO isn‘t „low“. Sensor noise will be visible up from about 400 ISO, depending on other factors like shutter speed and light conditions.

Regarding the circle crop - do you use the lens hood and is it attached properly?

[Bjurheim]

The dark corners will happen when your shutter speed is set too fast. If you use lightroom it'll compensate for it automatically.

[Pieter]

Dark corners may also be caused by some lenses if you disable distortion compensation in camera or process RAW files without distortion correction. This also applies to the 18-135 lens at the wide end. Easily fixed by enabling distortion correction in-camera or fixing it in post.

Like @Olaf W. said: ISO 1600+ is quite high ISO, with ISO 6400 barely considered usable by most. ISO 64000 (no typo?) shouldn't be used at all. If you're disappointed with the results, this is likely the cause. Don't blame camera or lens for wrong settings or expectations.

[Med]

Thanks to all of you gent for these insights. Really appreciated

@ Pieter: I don't blame the camera, but I wasn't expecting to have the best sharpness when I was going to take 18-135 (we can have a perfect lens!).

I guess I got a bit confused because I used to work with a DSLR (Canon EOS) and didn't really get why Sony had that wide range of ISO option! I will try to change the settings as you suggest.

Thanks again.

Cheers

[Med]

8 hours ago, Olaf W. said:

Welcome!
 

1600 ISO isn‘t „low“. Sensor noise will be visible up from about 400 ISO, depending on other factors like shutter speed and light conditions.

Regarding the circle crop - do you use the lens hood and is it attached properly?

Thanks Olaf.

No I don't use hood.

[Pieter]

These extreme ISO-settings don't make sense at all, it's just marketing nonsense.

I don't own the 18-135 but from what reviews I read / watched it should be decently sharp. Considering you're using such high ISO-values, I assume you're shooting under dim lighting conditions. Are you sure the unsharpness isn't caused by motion blur? Take some test shots during daylight to assess the quality of the lens again. Unsharp photo's can be caused by a plethora of things. With modern lenses, lens (un)sharpness usually isn't the primary reason unless you're very experienced with perfect understanding of all your camera/lens settings.