What is this on my sensor?

[rhythmworx]

Here's a 100% crop @ f22 there are speckles in the photo they are only pretty much central on the frame/sensor, it appears no matter what lens I put on.

It is not dust and I can not see any oil on the sensor even under magnification.

I bought the cam 2nd hand and the only thing I have used on the sensor is a blower, never touched it.

Could it be remnants of the previous user dabbing a lenspen on the sensor?

Could it be spores of mould between the sensor and filter?

I'm getting it cleaned this week I hope it solves the problem, but for the time being anyone got any ideas what it could be?

[vaultdweller0013]

Probably just dust on the sensor; this is to be expected when shooting as such small aperatures. If you clean it, it may go away, but as soon as you change the lens, more dust will likely get in are cause the problem to reappear. Hard to explain whats happening without drawing a diagram... basically, at a wide aperature, you have light coming in at different angles relative to the sensor, so the dust doesn't cast a noticable shadow; however, at small aperatures, the light is coming in as a more narrow beam, so even a very small spec of dust may cast a shadow.

You are also probably running into the diffraction limit of the optical system, which can cause some unusal artifacts as well. (for fun, try using a lens that goes to f32 with a 2x teleconverer, give an effective aperature of f64, this produces a very poor quality picture with some interesting artifacts from such a small aperature)

If you are stoppng down to f22 for DOF (which you really probably don't need to do; after f11 or so, you probably wouldn't notice much of a difference most of the time), there's not much to be done (or at least nothing I am aware of; would love to learn if there is away around this)

If you are stopping down because you want a slower shutter speed (for example, to introduce intentional blur), then you should concider using a ND filter to allow you to shoot at the slower shutter speed at a largeraperature.

[rhythmworx]

No it's not dust as already said.

f22 = sunstars

[fimgirl]

I think you may have a problem there. The pattern is just too uniform to be anything other than infestation.

I hope I'm wrong.

[sunshine51]

I have to agree with fimgirl...kinda looks like spores....hope

the cleaning works good for you.

[rhythmworx]

Maybe it's time to buy that D7000 and 85/1.8G I wanted.

[MJP]

Could be oil spots.

[Tywais]

I have to agree with fimgirl...kinda looks like spores....hope

the cleaning works good for you.

And agree with both of the above. Looks like fungi due to the very regular separation. Dust I would expect more random density distribution. But as mentioned, f/22 can be problematic aperture.

//Edit - Actually MJP's comment on oil spots is also a good observation due to the translucency and smoothness of them but how did it get there and so well distributed? T

[Tywais]

If you look at these Google Images, the top row far right likes very similar at a single spot level. But it does look like splatter or growth on the OPs sensor rather than random dust.

//edit - the OP didn't mention which camera he got but the Nikon D600 has a known problem of this coming from within the camera.

[neverdie]

If you look at these Google Images, the top row far right likes very similar at a single spot level. But it does look like splatter or growth on the OPs sensor rather than random dust.

//edit - the OP didn't mention which camera he got but the Nikon D600 has a known problem of this coming from within the camera.

and not just the d600 either, there were early reports of some d800 and d4 owners as well.

[sunshine51]

^^^ Yes it seems that Nik has been having this problem with

many of their models of late. So far all I have read off the

Nik website is that they will fix the problem for D600 owners

for free regardless of warranty & wotnot. Nik hasn't mentioned

anything about doing this for D4 & D800 owners if they have

the problem...not yet anyway.

The reason I mentioned a possible fungus infestation is due

to my old F4 having a similar problem on the mirror & it looked

almost exactly like what is on the OP's sensor. I had the mirror

R & R'd and never had the problem again.

NB....It is a worthwhile investment to purchase a drybox/cabinet

for the climate we have out here...or anywhere for that matter.

Dryboxes are cheap compared to lens or sensor repair/replacement.

I recommend Aipo...and there are others just as good and easily

available in LOS.