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07-04-2013, 09:16 AM   #1
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questions about the effect of humidity on image quality

I was trying my new copy of DA*200 and found the images to be a little soft but at close range they seemed ok. They also seemed to have more noise than usual. At this time of year it is very humid in Japan so I was wondering if this is what is causing it.

Also when i turn the focus ring quite quickly there is a loud squeaking noise.

Any comments would be Helpful

07-04-2013, 09:36 AM   #2
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A sample image would be helpful, but without seeing one I would guess atmospheric haze due to the humidity.
07-04-2013, 10:03 AM   #3
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I think it could be. To me it becomes apparent when photographing on a hot day over a water body like a lake or the sea, and then photos look like they have noise (or rather, confused details) even in bright parts. Its a combination of air rising and swirling due to heat and water vapour causing a haze and tiny reflections. When I used the same lens in a different environment (winter time mountains) it didn't have that effect.
Also, check your camera settings, things like NR turned off, enabled shadow correction or highlight correction can affect the noise. And if the lens has problems, I doubt it would show up as noise. You are more likely to get decentering or misfocusing than a complicated mistake. But it would be great if you could try the lens in some different place at long range, a place with different environmental factors. Like in a mall maybe?

QuoteOriginally posted by everydaylife Quote
Also when i turn the focus ring quite quickly there is a loud squeaking noise.
How loud and squeaky? People sometimes hear "odd" noises when paying close attention in a quiet room, but those noises are actually normal and cannot be heard in regular ambient. But I can't say for this particular lens.

Last edited by Na Horuk; 07-04-2013 at 10:09 AM.
07-04-2013, 08:35 PM   #4
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QuoteOriginally posted by Na Horuk Quote
I think it could be. To me it becomes apparent when photographing on a hot day over a water body like a lake or the sea, and then photos look like they have noise (or rather, confused details) even in bright parts. Its a combination of air rising and swirling due to heat and water vapour causing a haze and tiny reflections. When I used the same lens in a different environment (winter time mountains) it didn't have that effect
Thanks for your interest.
My question is really a general question. Posting an image would not provide an answer as the images were taken handheld so many other factors come into the equation. I was just wondering if humidity could be another factor.

I am aware of the effect of heat haze I have many mirage like image, but if high humidity does have an effect I doubt it is the same as heat haze and would have thought it would cause a more general softening of the image.

Regarding the squeaking it is more like a screeching banshee. I do not remember any of the several other copies I have used being as stiff to turn or making an obvious noise.

07-05-2013, 04:23 AM   #5
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QuoteOriginally posted by everydaylife Quote
My question is really a general question. Posting an image would not provide an answer as the images were taken handheld so many other factors come into the equation. I was just wondering if humidity could be another factor.

I am aware of the effect of heat haze I have many mirage like image, but if high humidity does have an effect I doubt it is the same as heat haze and would have thought it would cause a more general softening of the image.
Well, I guess we'll never know for sure since you're unwilling to provide a sample image showing us precisely what you are seeing that prompted you to ask the question in the first place.
07-05-2013, 10:48 AM   #6
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Humidity should have zero impact on image quality nor on AF capabilities.

The squeak is a more of a concern. A seal may have torn. I'd get a lens of that value properly serviced.
07-05-2013, 11:20 AM   #7
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Very common on summer days here I'll take a shot of an aircraft and find the hazy humid day has made the subject soft. On winter days they're sharp. It's just atmospheric haze making the image soft. Other images the same day from closer subjects - also at infinity at full zoom do not show this. It's too bad, too, because some interesting aircraft fly over our area fairly frequently.
07-05-2013, 12:46 PM   #8
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Hum-diddy certainly DOES have an effect on IQ! When I'm drippin' with sweat, wiping it out of my eyes, and my shirt is stickin' to my ribs I have no patience for the effort needed to make the best possible shot!

In a technical sense, humidity lowers air density, which microscopically affects its optical properties, and it usually adds some degree of haze to the atmosphere. Anything from being practically unnoticeable to human vision (but not necessarily to some digital sensors or film - and the same may be said for UV incidentally) to pea soup fog. Haze scatters light and reduces contrast which may affect AF in some circumstances. A poor excuse - but, hey, it's there if you need it, eh?

OTOH, there's not much you can do about it in a practical sense, so just make the best shot possible.

H2

07-06-2013, 02:57 AM   #9
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QuoteOriginally posted by Aristophanes Quote
Humidity should have zero impact on image quality nor on AF capabilities.

The squeak is a more of a concern. A seal may have torn. I'd get a lens of that value properly serviced.
I got it a week ago so I returned to the place of purchase to see if they thought it was problem. They did and exchanged it. Unfortunately the lens they have given me in exchange has dust and also the lens cap looks faded in parts as if bleached by the sun. I suspect it is not new and is an ex demo or a return.
07-06-2013, 03:16 AM   #10
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My country of origin is not humid so at the moment in Japan within five minutes of stepping out the door

QuoteOriginally posted by pacerr Quote
I'm drippin' with sweat, wiping it out of my eyes, and my shirt is stickin' to my ribs
Interesting that you should mention contrast as that is quite low in the images I had taken.
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