Pixels

[skiking]

I was playing around with a lens today to see if some specs of dust beneath the outer lens have an effect on IQ. I stopped the lens down to f22 and snapped away. On loading onto computer and zooming in I was reasonably happy although there are a couple of blotches. The main problem was that there were a number of coloured crosses appearing that I assume are pixel related ? First question, is this a normal thing of pixels dying ? and is there anything I can do to fix this other than PP and how do I clean the inner elements of dust ? How did they get there in the first place ?

 

[HoppyUK]

What you are seeing is dust on the sensor. Dust specs on the lens or in the lens are way too out of focus. Dust on the sensor becomes more obvious at high f/numbers in areas of plain tone - most of the time you'll not notice it.

Dead pixels or hot pixels are not uncommon, but don't worry about them unless they're spoiling your pictures.

 

[Capt_Crash]

i have a couple of those same hot/dead pixel 'X's on my sensor. To be honest i never notice it unless it happens to be in a certain coloured area of the photo, or if i blow it up to 500-1000%. They are more noticable on long exposures though (they seem to get 'hotter', obviously) still not too much of a concern.


So, unless it noticeable at a 'normal' size, dont worry about it. its super quick to fix in PP if its ever an issue anyhow

The dust, thats another issue!

 

[skiking]

Cheers for the comments. I am reassured about the pixels.

The dust....I take it there is no way to clean this other than to take the lens apart ? How feasible is that ? - I think I know the answer but I thought I'd ask!

 

[Scarecrow]

As Hoppy has already said, if you are seeing blobs in your images, it's more likely to be dust on your sensor rather than dust in your lens, and your sensor is a lot easier to clean (no dismantling required.)

 

[HoppyUK]

Cheers for the comments. I am reassured about the pixels.

The dust....I take it there is no way to clean this other than to take the lens apart ? How feasible is that ? - I think I know the answer but I thought I'd ask!

I wouldn't worry about a few specs in the lens - makes zero difference. But if you do want rid of them, some lenses are very easy to remove the front element section which is where the dust usually lodges (some dust is inevitable with lenses that extend when zooming, sucking in air). Google and there are a few guides on the web - Canon 17-55 is a common one, and that's very easy.

Or you can send it away of course.