70-200mm VR 1st generation making strange artefacts

Hi, all

A few days ago, I was photographing in the fog with my D750 and 70-200 f/2.8 VR (generation 1, about 15 years old). I shot raw. When I processed the photos, I noticed some weird 'artefacts' as you can see in the pictures. The vignetting in the corners is no surprise, but the black circle in the central part sure is.

First photo was only opened and processed in ACR (Auto setting); the second photo was also processed by Nik (tone mapping) to exaggerate the effect. The third one was processed in ACR, lens profile used and then tone mapping applied.

Can please someone explain the reason for the black circle?

Settings: D750, Nikkor 70-200 f/2.8 VR (generation 1) at f/4, ISO 125.

PS: It also seems to me the lens is stronger vignetting in the bottom two corners.

Thanks for your help, Miha.

Photo 2:

Photo 3:

Photo 1:

Sorry,I can't get the photos in the correct order :-(

That looks almost like darkening through a central condensation patch.

If you shine a torch into the wide end, can you see any misting?

Pop the lens off, raise the mirror etc as if for cleaning and look at the sensor surface, all OK?

What was the view through the v.finder like? Same with LV?

Is this the only lens this dark area appears with?

...... and you have a shed-load of big crap on your sensor for a shot at f4!

.......and they look very round, like oil or somesuch.

Question, was there a filter placed on the lens ?

Forme it looks like a "fogged-up' or wet (UV?) filter which was "wiped clean" ..also because ogt he lighter ring around the dark area

Hi,

there was no filter on the lens. The view through the viewfinder is OK. Lens seems ok, I just see some minor dust particles.

I got hold on a Sigma 70-200 f/2.8, i got similar results, but not so pronounced. Other lenses did not produce this effect.

I think it may be the effect of the software filter.

I will clean the sensor.

Thanks.

I got hold on a Sigma 70-200 f/2.8, i got similar results, but not so pronounced.

If two 70-200mm lenses produce similar results @200mm, it sounds like a camera problem at the max focal range of 200mm?

As Mary says, if it happens with 2 different lenses, it's the camera. I don't think it can be 'created' by corrupted software, unless it's a kinda reverse vignette removal feature!

I suppose you could turn OFF vignette correction and see if it still looks the same.

Having taken the filter stack off a couple of Nikon DX and FX cameras (for IR conversions) there's a rubber/silicon seal between the sensor surface and the AA/IR glass. I guess if moisture gets in that void and condenses you might get a damp central spot.

Why you should see it worse at 200mm I don't know, but I guess it would look worse at small apertures.

Oh, and what does:-

"I think it may be the effect of the software filter."

mean??

Hi,

I found some time to retest the lens and the camera.

This time i tried the ACR and the Nikon Capture NX-D. No such effect as in my original post. So I conclude it was some condensation effect reinforced by the applied Lens correction profile. I'm happy the problem is gone.

"I think it may be the effect of the software filter".

mean??

I was referring to the ACR option > lens corrections > Enable Lens Profile Corrections which in my oppinion has similar function as Photoshop > Filter > Lens correction > Auto correction. So in Photoshop it is a 'software filter'.

Regards, Miha.