purple spot in centre of OOF shots ....

[Yardbent]

any ideas..?

been taking a few f22 OOF sensor shots prior to cleaning when my swab kit arrives

at 100% and some PP to clarify the dust spots - I see this. ( it's dead centre on all the images.)



I'll do some with another lens tomorrow...................any thoughts.......
.

 

[Bobsyeruncle]

Is the lens coating damaged?

 

[woof woof]

I've seen similar but only when doing a dust bunny test of a white door at very small apertures, in normal real world shooting you may not see this.

 

[Yardbent]

Is the lens coating damaged?

under a white LED torch and a magnifying glass, it all looks fine

however I have a sensor loupe arriving next week ( so I can get a closer look)

but I am somewhat relieved to read Alan (above) has seen similar

 

[GHP]

It's possibly something like the result of the massive focus shift and diffraction messing with the light.
Unless you shoot everything at f22, and completely out of focus, I would ignore it.

 

[woof woof]

Whenever I do an out of focus dust bunny test at min aperture I also shoot a more normal aperture and in focus shot... and if this does nothing else it convinces me that my camera can actually take in focus pictures

It might be worth adding a normal shot to the routine as a confidence restorer after a shot like this and of course the next time you get the chance you can shoot at f22 just to make sure that the camera performs well enough in real world conditions and although this test shot looks rather worrying I think all will be ok with real world shots.

 

[Yardbent]

Whenever I do an out of focus dust bunny test at min aperture I also shoot a more normal aperture and in focus shot........

Actually I spent the afternoon with 3 x 50mm primes and 2 x zooms set at 50mm
took f22 and f8 with each - the f8 images didn't show much at all - binned
then compared all 5...some showing dust that others didn't depending on my PP

strangely no sign of the purple blob - maybe was the sun angle that day - as @GHP suggests
when the loupe and Swabs arrive, I'll have a DIY sensor clean...fingers crossed, my first attempt at this

I took a few garden landscapes too - jpeg and RAW --- all OK...

EDIT ,, do you view at 100% or go higher searching for spots..?

 

[woof woof]

EDIT ,, do you view at 100% or go higher searching for spots..?

No, I don't bother, I just look at the whole image on screen but the cameras I have now (Sony A7 and Panasonic CSC's) are a lot better than the Canon DSLR's I used to use and hardly ever require cleaning. I used to check the DSLR's at 100% and scan across the screen, move the image up and scan across etc until I'd scanned the whole sensor but only now and again but these days with my new cameras it just isn't necessary.

One thing I have done in the past is shoot a series of shots from minimum aperture to something like f4 or 5 or so and if any dust bunnies were visible at extremely small apertures but then vanished and were not visible at the apertures I'd be shooting at I sometimes didn't bother cleaning the sensor that day.

 

[Yardbent]

@woof woof

Alan
thanks for the info