Dust in prime lenses? 50mm 1.8, is it common?

[brian_yeung]

<p>I just noticed my 50mm 1.8 which I didn't use much and bought 2 months ago, has quite a bit of dust inside all elements of lens. Behind the front, middle, even at the rear element. </p>

<p>What gives? Should I get this replace via "nikon warranty" or what should I do or is it normal?</p>

<p>I thought Prime lenses sealed pretty well so there's no movement compared to zooms...</p>

[Ian Rance]

<p>Brian, dust gets in via the aperture mechanism - but that much dust is not normal. Was it there when you purchaced it (machining dust)?</p>

[Michael R Freeman]

<p>What is quite a bit of dust? If you can count the specks and not reach 100, you do not have "quite a bit".</p>

<p>The front and rear lens cells are essentially "sealed" assemblies in this lens. But the area between the front and rear cells, where the aperture is located, is open to the air via the stopdown mechanisms and can accumulate dust.</p>

<p>A lot of photographers are way too anal over a little bit of dust inside lenses. If they knew how much was between their subject and the camera, they would know a few bits of dust inside a lens is completely inconsequential. Dust inside a lens can't resolve as spots in a photo, and it takes a lot to cause any effects at all.</p>

 

<blockquote>

<p><em>"... so there's no movement compared to zooms"</em></p>

</blockquote>

<p>Comparatively less, but there is still movement, and more importantly, a change in volume. Watch your 50mm as it focuses from infinity to 0.45m ... you'll see the lens changes size, and each time it focuses it has to suck and blow air. The same air that is between you and your subject that is full of dust.</p>

<p>Completely normal, very common, stop fussing about it, and go take some pictures. :-)</p>

[brian_yeung]

<p>I'm not sure if it was there when I bought it, I never looked that closely. As for counting to 100, not sure either, there are small specs and big ones. It just seems my 17-55 that is 5 years old has less than this 50mm that's 2 months old....</p>

[gary_watson]

<p>It takes a wanking amount of debris to affect image quality, OK? I bought a Mamiya 90/3.8C last summer with a few specks on its otherwise pristine glass. Impact of the specks on this big-ass lens's ability to resolve? Nada. Nothing. Agree fully with Michael--get out,shoot, and leave the OCD at home.</p>

[shuo_zhao]

<p>The 50 f/1.8's AF mechanism rely on moving the entire optical design back and forth, so it's a rather "open" design. It's also a AF-D lens with a aperture ring that lacks a rear rubber seal. So overall, it's probably not all that hard for dust to get in. </p>

<p>If the presence of dust is affecting the lens' performance/image quality, then you should definitely get it replaced. </p>

[bourboncowboy]

<p>I don't know what a "wanking amount" is, but I generally agree. If you want to test this, get a sticky note, tear off a piece of it about the size of a pencil eraser. Put it anywhere on the front element of the lens and take a few test shots. I'll be willing to bet that you won't notice that much of a difference between those shots and shots taken without the obstruction.</p>

[aaron l]

<p>My 85mm f1.4 has sucked in several specs of dust into the back element. It's disconcerting but I haven't come across a situation where the dust appears in the image. Yet.</p>