Opticallimits

A perennial subject!



I just read in another thread a suggestion to change lenses in a plastic bag. This is certainly sound and sensible advice, but I'm wondering what the real consequences are if you don't.



I've used a couple of DSLRs and never once cleaned the sensor except for the occasional blast with a rubber bellows. On my current 5D, I'm changing (most prime) lenses all the time, in all types of situations, and I haven't noticed any image degradation over the last year. Being more of a hands-on photographer, I don't have the time or patience to treat a camera like a museum exhibit - I just want to use the darned thing! <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='' />



So the questions are: Does dust really inhibit image quality, or is it just visible to pixel-peepers? What are the long-term effects of dust, and will these problems realistically occur within the useful life of the camera?

Different people have different needs and paranoia levels.



Personally I don't worry about dust until it starts having a visible impact in my photos. If you shoot mostly at wider than say f/8 or so, then you need a fairly large speck of dust to become visible. I also do macro where I might be working at f/16 or smaller for DoF, never mind diffraction, and in that case, dust is much easier to become visible.



So to me, I clean when I need to clean. I don't do preventative cleaning - if I can't see it, it is not a problem! A blower is my first stop, and if that doesn't work I do a wet clean. I'm very casual about changing lenses in the field as I mostly do nature and wildlife. I often have lens rears and mirror boxes exposed in any weather condition and still don't find dust to be a problem. I do a wet clean on average maybe 2 or 3 times a year.

[quote name='Pinhole' timestamp='1280249785' post='1341']

A perennial subject!



I just read in another thread a suggestion to change lenses in a plastic bag. This is certainly sound and sensible advice, but I'm wondering what the real consequences are if you don't.



I've used a couple of DSLRs and never once cleaned the sensor except for the occasional blast with a rubber bellows. On my current 5D, I'm changing (most prime) lenses all the time, in all types of situations, and I haven't noticed any image degradation over the last year. Being more of a hands-on photographer, I don't have the time or patience to treat a camera like a museum exhibit - I just want to use the darned thing! <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='' />



So the questions are: Does dust really inhibit image quality, or is it just visible to pixel-peepers? What are the long-term effects of dust, and will these problems realistically occur within the useful life of the camera?

[/quote]If you photograph a lot with small apertures, and have dust (enough to be visible), it will be a problem as you keep having to remove the dust spots in raw conversion or in other software like Photoshop as you will see it on many images. If you e.g. photograph lots of portraits and use big apertures, you might not notice a problem at all, ever.



I have a feel things tend to get more stuck over time though, so when you do notice it, try to remove it when you can to avoid it getting more stuck over time.

I don't know whether you were referring to my post on changing lenses in a bag in dusty conditions, but if so, this is actually a practice used a lot even by professional photographers when shooting, e.g., in a desert or in safari type conditions, where dust is really a problem.



This not only because of dust on the sensor, but also anywhere on moving parts and on electronics. Dust has an impact on AF, f.e., on the shutter mechanism, on the aperture mechanism of lenses if the lenses aren't entirely dustproof, etc., and most of this dust generally enters lenses from the camera or lens mount.



I have read a few horror stories on photographers working in the desert with neither a camera or nor lens left to shoot with after a couple of days of dusty consitions, basically because their gear wouldn't even work anymore because of this dust.



So far this side of the dust issue.



The other side is dust spoiling images. I find it quite interesting, provided you use a 5D classic, that you haven't had any problems with dust on that large, non-dustprotected sensor of that camera. I found I had to clean it every 1000 shots or less, because it became too much work to get rid of dust spots in landscapes or macro photographs, especially in middle light to light areas. That is the only aspect of the 5D classic I really hated.



The 5D Mark II is a different story alltogether: the dust shaker seems very effecive. So far, and I have that camera for well over a year now, I have never had to remove any dust. The same is true for the 1D Mark III, but then, I only have that for a couple of months.



BTW , I do believe you have to use your camera, otherwise why even bother having one (or more as may be the case), and your lenses. This weekend I went out for a few hours, shot about 120 images, and changed on average my lenses every two to three shots <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />. Ok, I do shoot primes with the exception of 1 zoom, but even so, they do all get a workout. This particular instance was a little extreme, but generally I rarely shoot more than 10 exposures with the same lens before a lens change, unless I am doing macrophotography or studio work.



Kind regards, Wim

Hi Wim,

Yes I did refer to your post. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='' />



I'm using a 5D MK II, so maybe that helps. I also do a lot of portrait and theatre shoots so I'm not usually using small apertures in my work.



Having said that, I recently used a 'Subjektiv' pinhole adapter (review coming sometime!!) and man, there were spots all over the place! It's about a f124 or something, so this is probably to be expected.



I guess I'd be a little unhappy about getting sand in one of my Zeiss lenses, but the camera body doesn't bother me that much. I usually calculate the value depreciation on a body so it pays for itself in 2-3 years. The lenses are a longer-term investment, so I hope they stay in good shape for many, many years.

[quote name='Pinhole' timestamp='1280270038' post='1353']

I'm using a 5D MK II, so maybe that helps.[/quote]



Absolutely. The 5D Mark II has sensor cleaning built in.



Cameras that do not (like the D3x) will collect dust spots easily and, as already mentioned, these can be visible in the image, especially when stopped down and with wide angles. Honestly: not having sensor cleaning in the camera is a major pain with both the D3x as well as the M9.



To give you an impression, this is what I got out of the D3x after a few weeks without cleaning:







And yes, it looks even worse with a pinhole cap, even after excessive cleaning <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='' />



When in use, I clean both camera usually once a week.



-- Markus

Just a question Markus:



Is that really all sensor dirt? I've never seen a hair look so defined if its lying on a sensor, nor dust spots. On my camera, it just produce an undefined dark 'blob' unless it's on the lens somewhere.

That much visible at f/11?



I have a 300D still in active use, and have owned the 5D1, both of which don't have built in sensor cleaning. I don't have a dust problem with them even with my care free lens changing method. But in both cases I rarely use them smaller than f/8. Specifically on the 5D1, I would have thought its relatively massive pixels would help make any dirt insignificant for longer.

[quote name='Pinhole' timestamp='1280270038' post='1353']

Hi Wim,

Yes I did refer to your post. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='' />

[/quote]

I thought so <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' /> <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='' />.

Quote:I'm using a 5D MK II, so maybe that helps. I also do a lot of portrait and theatre shoots so I'm not usually using small apertures in my work.

Yes, that does help, and it seems to work impressively well. Also, due the new coatings on the sensor and AA-filter assembly and the dust shaker it seems to trap dust a lot less. It is actually a lot better than on my old 40D, which I think is truly amazing, considering the size of the sensor.



Even so, changing lenses in a dusty environment as mentioned in my earlier reply is a definite no-no without any protection at all <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />.

Quote:Having said that, I recently used a 'Subjektiv' pinhole adapter (review coming sometime!!) and man, there were spots all over the place! It's about a f124 or something, so this is probably to be expected.



I guess I'd be a little unhappy about getting sand in one of my Zeiss lenses, but the camera body doesn't bother me that much. I usually calculate the value depreciation on a body so it pays for itself in 2-3 years. The lenses are a longer-term investment, so I hope they stay in good shape for many, many years.

Well, as an amteur photographer i am less worried about depreciation <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />, although I'd hate to have to replace anything because of sand or dust entering my equipment - I don't think I could afford to right now ... <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />



Kind regards, Wim

[quote name='mst' timestamp='1280311104' post='1358']

Absolutely. The 5D Mark II has sensor cleaning built in.



Cameras that do not (like the D3x) will collect dust spots easily and, as already mentioned, these can be visible in the image, especially when stopped down and with wide angles. Honestly: not having sensor cleaning in the camera is a major pain with both the D3x as well as the M9.



To give you an impression, this is what I got out of the D3x after a few weeks without cleaning:







And yes, it looks even worse with a pinhole cap, even after excessive cleaning <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='' />



When in use, I clean both camera usually once a week.



-- Markus

[/quote]

Ouch!



I'd really hate that to happen. I do hope both Leitz and Nikon will come up with a solution for this.



Kind regards, Wim