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08-09-2016, 12:03 PM - 1 Like   #1
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SLR Weather Seals: Pentax LX vs. Rain Forest

I cringed throughout this video...



Steve

08-09-2016, 12:11 PM   #2
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Help me understand the LX's weather sealing- how can it pull this off when there's no gasket around the lens mount?

Adam
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08-09-2016, 12:28 PM   #3
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A little part of me died when I watched this...
08-09-2016, 12:37 PM   #4
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QuoteOriginally posted by Adam Quote
Help me understand the LX's weather sealing- how can it pull this off when there's no gasket around the lens mount?
Good question. To be honest, in my 45 years of shooting manual focus M42 and K-mount film SLRs under various challenging conditions (rain, spray, snow, cold), I have never had water incursion at the mount face despite exposure at that point. Tolerances are typically tight enough to resist both light and water. The greater fear among my photographer peers here in the Pacific Northwest with non-digital cameras has generally been condensation on the internals as temperatures drop.

Edit: My experience noted above was with standard K-mount, not KA

I know this is contrary to current doctrine, but things were different then in terms of how both cameras and lenses were constructed.


Steve

(...owns NO sealed lenses at present...)


Last edited by stevebrot; 08-09-2016 at 01:39 PM.
08-09-2016, 12:49 PM   #5
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I was wondering about this the other day -- it would seem possible to use a modern WR lens on the LX, but in practice it look like the lens mount plate is wider on digital WR cameras such that the rubber lens gasket is sort of "around" the LX lens mount, rather than pressing against it, and not really providing any WR function. Does this seem accurate? (I didn't do any sort of water test.)

---------- Post added 08-09-16 at 12:56 PM ----------

QuoteOriginally posted by Adam Quote
Help me understand the LX's weather sealing- how can it pull this off when there's no gasket around the lens mount?
It didn't *completely* pull it off, given that it got wet in the battery compartment and shorted out the battery (?).

In general the application of the water was pretty light, like a mist, as opposed to anything providing a lot of pressure that would force the water into the lens. It basically just ran down off it, but not iton it.
08-09-2016, 01:12 PM   #6
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there is a couple of reasons why water migration did not occur.

1: the camera was sitting in an upright position. It was not being handled and moved around at various angles. For the water to get into the battery compartment, water would have to defy gravity over and beyond the capillary action within the threads of the battery compartment door. Also air pressure within the camera itself may inhibit the migration of water into the camera.

2: the lens was not being refocused every few minutes. This in fact changes the air pressure in the camera, acting as a pump, pushing air out and pulling it back in. Where air can go, water may follow. This is a major problem for some of the so-called water sealed lenses on the market. If the front element moves in and out when focusing/zooming, it will act as a pump. This is an issue that has been discussed before.

Besides, There is a big difference between a digital camera and a film camera. Film cameras may use mechanical timers and shutters and have very little in the way of electronics. Although this is not necessarily the case in all film cameras. Mechanical mechanisms are not necessarily affected as much by water. Although it can increase the resistance of the timing mechanism. Corrosion is another problem with any camera. Just because the camera works right after it gets wet, doesn't mean it'll work a week later. Corrosion takes time. And once something starts to corrode, it is very difficult to permanently stop. That is why all cars within the United States are considered totaled if a significant amount of water migrates into the passenger compartment. It is almost impossible to guarantee that the electrical connections within that car will not fail at some point in time. Water migration is something to avoid, in any camera.
08-09-2016, 01:50 PM   #7
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QuoteOriginally posted by leekil Quote
In general the application of the water was pretty light, like a mist, as opposed to anything providing a lot of pressure that would force the water into the lens. It basically just ran down off it, but not iton it.
Time and pressure...given enough of either and all seals/gaskets will fail. The test was 24 hours. I would have expected failure at the rewind axle, wind lever, shutter dial, bottom plate, and/or film door. When they said it was the battery cover, that did not surprise me since that part of the camera is designed to vent to the outside and may normally have drained through the vent hole had the camera base not been in standing water.

As a footnote, comments on the video indicate that after a couple of days drying out, the LX came back to life.


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08-09-2016, 01:59 PM   #8
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They are the same guys, if I am not mistaken, that left a LX (prolly this same unit) in a freezer for 24 hr. See their other video(s) in YouTube. Cheers

08-09-2016, 01:59 PM   #9
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QuoteOriginally posted by promacjoe Quote
For the water to get into the battery compartment, water would have to defy gravity over and beyond the capillary action within the threads of the battery compartment door.
Water did defeat the battery compartment. It is not sealed and actually has a vent hole. The camera base was sitting in a centimeter or more of standing water by the end of the 24 hours.

QuoteOriginally posted by promacjoe Quote
2: the lens was not being refocused every few minutes. This in fact changes the air pressure in the camera, acting as a pump, pushing air out and pulling it back in.
Not so much with most manual focus designs. The lenses are fairly well ventilated. Whatever resistance they have to water is in the form of the same baffles that make the barrel light-tight and the threads of the focus helicoid itself.


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08-09-2016, 02:36 PM   #10
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Just for perspective, here is the flagship Nikon F4 and Cosina-made Nikon FM10 in the same test:


Unfortunately, they did not do forensics on the FM10 to see where the water was and how it got in. Strangely, there was water on the mount face on the FM10 and none on the F4.


Steve
08-09-2016, 04:45 PM   #11
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QuoteOriginally posted by stevebrot Quote
I cringed throughout this video...

Pentax Lx rainforest durability test - YouTube


Steve
Great find. Not bad for a used - unknown, condition still maintaining it's weather sealing as I expect it to be. I also just watched their frozen test and will check out the others.

QuoteOriginally posted by leekil Quote
It didn't *completely* pull it off, given that it got wet in the battery compartment and shorted out the battery (?).
It did as originally intended - weather sealed but not submersible. On the ground with standing water means part of the body will be submerged as opposed to actively using it in hand above water. In production, random samples are subjected to severe downpour.
08-09-2016, 05:47 PM - 1 Like   #12
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I was a bit surprised but it does make sense. The vented battery compartment would be susceptible to water incursion. I have used mine a number of times in the rain and never experienced a problem. But, it obviously was not left to sit in a puddle.

The F4 test was also extremely interesting. The Nikon professional F series cameras are certainly impressive.
08-09-2016, 06:08 PM   #13
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QuoteOriginally posted by Pioneer Quote
The F4 test was also extremely interesting. The Nikon professional F series cameras are certainly impressive.
I don't know about the F4 and later models but know that the F, F2 and F3 are not weather sealed. Neither are the Canons Canonflex, F-1 and New F-1. I am also not aware of any of the other fixed prism variety to be weather sealed. I suppose unless stated otherwise, they are all not weather sealed.
08-09-2016, 09:59 PM   #14
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From the factory LX covers are put on with black silicone seal around the edges of the covers. The battery door has a black rubbery piece blocking direct air going in and there are seals everywhere. The seals around the back use closed cell foam etc. The lens mount issue has bothered me too, however. When I managed a camera store in Pacific Grove, CA we had a customer who used LX cameras for taking pictures of wildlife in Big Sur triggered by IR or remotely and was very happy with his results. My guess is that he had them in a blind of some sort and the seals were a second layer of safety. Nevertheless, he found the seals necessary.
08-12-2016, 08:06 AM   #15
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I'm sure this LX will be on Fleabay next week, advertised in mint condition.

Glenn
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