Help what is wrong with me lens?

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Without having seen your gear, I
can not blame your lens as some
fault may come from a dirty sensor.
 
Its not dirt on your lens it is more likely dirt on your sensor.

Your top shot was shot at F32 so will show the dirt in great detail. The second shot was at F10 so the dirt starts to look diffused. Shoot your lens wide open and you probably won't even see it.

notwithstanding that its evident you need a sensor clean!
 
As above, due to the way optics work, I'd bet next years salary it's a dirty sensor.

Look up sensor cleaning, either DIY or letting a shop do it for you.
 
Sensor by the look of it.

Annoying isn't it?

If that's the lens you should be able to see the hairs and dirt when looking through it.

Does it happen with another lens? If so it's the sensor.

Just don't take it to Jessops unless you want it worse than when it went in!!!
 
Phil V said:
As above, due to the way optics work, I'd bet next years salary it's a dirty sensor.

Look up sensor cleaning, either DIY or letting a shop do it for you.
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Me too.

Clean the sensor, and avoid high f/numbers that will show up every spec of dirt. It's pretty much impossible to keep a sensor 100% clean, but if you shoot at lower f/numbers then dirt will usually be invisible. Also, lenses do not perform well at highest f/numbers, due to a thing called diffraction that all lenses suffer from, regardless of quality or cost. Try to go no higher than f/11 unless you really need to.
 
HoppyUK said:
Me too.

Clean the sensor, and avoid high f/numbers that will show up every spec of dirt. It's pretty much impossible to keep a sensor 100% clean, but if you shoot at lower f/numbers then dirt will usually be invisible. Also, lenses do not perform well at highest f/numbers, due to a thing called diffraction that all lenses suffer from, regardless of quality or cost. Try to go no higher than f/11 unless you really need to.
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I usually find f8 to be the "sweet" spot for most lenses and try to use it when possible - unless you have a high MP count ( above 30MP) - when diffraction can really start to make a difference and wider apertures may be needed.

I am undecided on whether it has the same effect at macro distances where it seems to me the very large sensor images would obviate the diffraction effect.
 
petersmart said:
I usually find f8 to be the "sweet" spot for most lenses and try to use it when possible - unless you have a high MP count ( above 30MP) - when diffraction can really start to make a difference and wider apertures may be needed.

I am undecided on whether it has the same effect at macro distances where it seems to me the very large sensor images would obviate the diffraction effect.
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I've always thought the lens 'sweet spot' to be nothing more than trivia.

I tend to use the aperture required for the shot I want. I'm clearly doing it wrong. :(
 
Phil V said:
I've always thought the lens 'sweet spot' to be nothing more than trivia.

I tend to use the aperture required for the shot I want. I'm clearly doing it wrong. :(
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I'm pretty sure you know this but I'll say it anyway for anyone who thinks you're being serious :D ... lenses have usually produced their technically better performance when stopped down a bit... back in the film days it was common for lenses to be relatively rather rubbish wide open but to improve on stopping down and produce their best results somewhere between for example f5.6 and even as small an aperture as f10 or there abouts, give or take.

These days I'm sure some more modern lenses produce their best at much wider apertures and Googling lens test results from years ago and comparing them to modern digital era lenses might me interesting and might show that some lenses are indeed at their best at wider apertures than year ago... or it may just be my suspicion.

Like you though I just use the aperture I want.

Shukat... it's almost certainly contamination on your sensor but don't worry too much.

What I suggest you do and assuming you're using a camera with a removable lens... Watch some YouTube videos about cleaning sensors or take it in somewhere and have it professionally cleaned. Personally I like to do it myself and I'd start with buying a Rocket blower and giving that ago. After cleaning shoot s series of out of focus shots of a white door or blue sky at small apertures to wider ones and check the results. If a Rocket doesn't clean it sufficiently a wet clean may be needed but the main thing is don't panic, contamination on the sensor is just an annoying fact of life with cameras.
 
Phil V said:
I tend to use the aperture required for the shot I want. I'm clearly doing it wrong.
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Absolutely not, Phil!

Aperture is just another corner to the triangle and
it has, like the other two, some choices of options.

It is all a matter of compromise. One may chose
smaller aperture for better DoF but to the price of
less sharpness due to diffraction.

Diffraction is a physic phenomenon where the ED
type of glasses I use may help in this matter but is
not a miracle cure.

I feel free to go to higher or lower ƒ stops when ever
I need except in some 3 areas: architecture, macro,
and wildlife where ƒ8 is the MUST measure for me.
 
Kodiak Qc said:
Absolutely not, Phil!
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To me the final image is King and diffraction may not be visible in it or if it is may not be too destructive or it may not even be noticed by most people or indeed any normal people :D As always I think it's best to start with thinking about the final image and working back from there to decide the settings and kit you're going to use but it's dangerous talking about stuff like this as it's only a matter of time before Phil goes off on one and tells you/me that all this is nothing to do with the original post :D
 
Kodiak Qc said:
<snip>

Diffraction is a physic phenomenon where the ED
type of glasses I use may help in this matter but is
not a miracle cure.

<snip>
Click to expand...

Diffraction is indeed a fact of physics, but it is not helped by exotic glass* or lens design or cost - they're all the same.

The f/number at which diffraction becomes visible varies by sensor size, and smaller sensors are effected sooner. Compacts and phone-cams get hit at surprisingly low f/numbers but for our purposes I would suggesting not going above f/8 on M4/3, f/11 on APS-C, and f/16 on full-frame. At these apertures any decent lens will be well past it's best (at least in the centre) and easily visible in controlled testing, but in practise there are so many other things that effect sharpness it's probably not worth worrying about.

*The better the lens, and the higher the peak sharpness, the sooner the effects of diffraction become visible as the f/number is raised. The very best lenses these days deliver peak sharpness around f/4 on full-frame! But when it gets to f/11 and f/16, they're all the same.
 
petersmart said:
I am undecided on whether it has the same effect at macro distances where it seems to me the very large sensor images would obviate the diffraction effect.
Click to expand...
Diffraction affects small/fine details first... Because you are magnifying the small details so much in macro work, they are not small/fine anymore (as delivered on the sensor), and therefore they are less affected by diffraction. IMO, the increase in DOF w/ small apertures usually far outweighs losses due to diffraction. It is the even finer details that may potentially be lost, but that makes little difference if nothing much is acceptably sharp.

It does make a difference, but you have to be pretty serious (crazy?) in order to avoid it... i.e. stacking a few hundred f/4 images.
 
As the others have said... I consider a bulb ("rocket") blower essential kit that every camera owner should have/use. Beyond that, you may want to pay a professional to do the cleaning (I would suggest taking a reference image prior to having it serviced).
 
Wow, it looks like you've been changing lenses in a dust and lint factory with the fans on full pelt!

Have to ask though, why would you shoot anything at f/32 :/ ?
 
Last edited:
GreenNinja67 said:
To check your sensor for dust bunnies only I'd have said. Or to produce sunstars if your aperture blades are conducive to them.
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Normally I'd agree, but the sunset shot the OP posted was shot at f/32 which is why I asked. Didn't look like a test shot as this was before the OP asked the question, and doesn't seem to be aware of the dust bunny issue until now.

F/32 on a crop (or FF for that matter) will cause all sorts of diffraction issues.
 
I'm gonna guess auto mode chose f/32
 
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