Out damn spot, out!

[Ron Evers]

Anybody know for sure the affect two dust spots in this lens will have on pics?

[m3photo]

Originally Posted by Ron Evers

Anybody know for sure the affect two dust spots in this lens will have on pics?

Oh no! Take it back to the shop! Ask for an immediate refund!

Seriously though, unless you shoot straight into the light and then hunt for a drop in contrast at 100% near the offending area I doubt you'll see anything much wrong with images taken with it. Some of us here I'm sure have even taken pictures with the odd completely-ridden-with-fungus lens and have just had to crank the contrast up afterwards. Another thing of course is using less than perfect glass for critical landscape work ...

[Ibeti]

Take a look here: http://kurtmunger.com/dirty_lens_articleid35.html (there are other good examples as well - conclusion - I think you are ok (although it is hard to see where its at from the photo - if it is on one of the not-front-or-back elements it might have a larger effect).

[lattiboy]

Ha! Ibeti, I was about to link to that same article because it should eliminate any fear people have about "cleaning marks" or dust in the lens. Unless you're shooting blue sky at f/22 you'll probably never see a single bit of dust, even if your lens looks like an old kitchen cabinet.

Your sensor on the other hand is a real PITA to keep clean. I'm amazed at the anti-dust system of M43! Both the Panny and Olympus have totally exposed sensors whenever a lens is off and I've yet to see so much as a speck on my sensor. It's unreal when you think about what a problem it is on many dSLRs.


PS Kurt actually bought some stuff from me he ended up testing on his site. He's essentially doing the gruntwork DPReview and others make money off of. He also does it better, IMO.

[Ron Evers]

Thanks Guys, that is reassuring.

[Tullio]

I think it's hard to tell. I believe in most shooting conditions you might not be able to see anything caused by it. However, it may show its effects on shots of blue sky and scenes where the background has a smooth light color with no objects that could potentially mask the effect caused by the speck. Just give it a try. If there's blue sky above, point the camera to it, increase exposure to +0.7 or +1.0, keep the aperture wide open and shoot.

[Ron Evers]

Originally Posted by Tullio

I think it's hard to tell. I believe in most shooting conditions you might not be able to see anything caused by it. However, it may show its effects on shots of blue sky and scenes where the background has a smooth light color with no objects that could potentially mask the effect caused by the speck. Just give it a try. If there's blue sky above, point the camera to it, increase exposure to +0.7 or +1.0, keep the aperture wide open and shoot.

I did as recommended. The lens is a Vivitar series 1, version 2, 70-210 f 3.5. This shot of the sky has +1.0 exposure.






Here is another shot with this lens wide open @ FL 210mm hand held. The water tower is 4 km away.






I do not see any influence of the dust specks do you?

[bronney]

I can clearly see the dust and it made the lens ultra inferior. In picture one you can see how the dust is diffused into 4/5 of the picture and made the sky "less blue" and in picture two, the dust obviously made the branches blur.

Therefore, you should send your legendary Series-1 to me to fix. lol.. ok joking. Seriously if the dust isn't on your sensor and you aren't stopping it down beyond f/16, you shouldn't see the dust. Even if it's sitting on the last element. I rarely notice any dust in my shots if the dust isn't directly on the sensor. Now it's time to test out some Takumar bubbles

[pellicle]

Hi

Originally Posted by lattiboy

Unless you're shooting blue sky at f/22 you'll probably never see a single bit of dust, even if your lens looks like an old kitchen cabinet.

well, as you can see the dust speck is showing up black, essentially this means (and it is on an inner element too) that it will be adding some effect to the transmission of light ... just as your lens iris does. It might reduce the T-Stop of your lens by as much as 1/20th of a stop. So when you've selected f2.8 you may be actually getting f2.81 or something a bit darker.

Haze which uniformly covers the lens is of course quite different ... smear vaseline over your lens and see how you go (David Hamilton anyone?)

Dust on the sensor? Gee ... haven't seen any since I bought my G1

:-)

[bronney]

smear vaseline..

lol I almost fell for that one!! When I was small I gel up my hair with that stuff and my mom still talks about it occasionally. She said it took her 2 hours to clean it off. Wait, are we talking cameras here?

[Tullio]

I honestly can't see it on either picture.

[pellicle]

I think I misunderstood Tullio's post

[pellicle]

Originally Posted by bronney

lol I almost fell for that one!!

but it works! though I recommend using a filter to sacrifice ... as it happens I have a old Canon EF35-70 lens which seems to have come with this effect as part of its optical design



BTW, if you've never seen David Hamiton's work how else would you describe it?

Wait, are we talking cameras here?

LOL ... yes, of course ... or the ones on ones rose coloured glasses (where are mine?)