K-1 ‘breathing’ query.


Benz3ne

Link Posted 01/03/2020 - 13:43
After owning the K-1 almost a couple of months, and the D-FA 28-105 for a short while, I’ve gotten around to putting the latter on the former. I’m aware both are WR, so wondered if this was normal or typical.

When zooming from wide to zoom, the K-1 breathes in. When zooming from zoom to wide, the K-1 breathes out, through the rear dial and towards my face. I assumed that, given it WR, it should be sealed to some degree. What that degree is, however, I’m not sure.

Anyone else seen this or is it a quirk of a slightly older camera who’s seals aren’t what they used to be?

LennyBloke

Link Posted 01/03/2020 - 14:16
Interesting to hear this - I don't have the D-FA 28-105 but have been considering getting it to replace my D-FA 24-70 (too heavy for general use), I don't think I've noticed this "feature" with any lens!
LennyBloke

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pschlute

Link Posted 01/03/2020 - 14:27
I have never noticed this before but it is worth noting that any zoom lens where the volume inside changes as you zoom needs to breathe somehow, otherwise you physically would not be able to zoom. With a weather resistant lens it makes sense that the most likely place is going to be at the mount end into the camera body.

Again if the body was not able to breathe you would have the same problem.

ps zoom lenses are often referred to as having focus-breathing properties, where the focal length can reduce, usually when close focussed. This is entirely separate from what you are describing and I add this just for the sake of clarity.
Peter



My Flickr page

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HarisF1

Link Posted 01/03/2020 - 16:01
This is weird but normal behaviour for the 28-105 and 18-135 lenses from what I've seen. It's due to the weather sealing.

I first noticed it on the K-3/18-135 combo after a quick zoom motion popped the rubber mic cover open. If you open up one of the rubber covers it should probably be easier to zoom.

Edit: I'll test with mine and report back with details on where the air escapes
Last Edited by HarisF1 on 01/03/2020 - 16:02

HarisF1

Link Posted 01/03/2020 - 18:39
I've tested the same kit and I couldn't pinpoint any specific spot for the air leakage when all rubber covers were closed. When one cover was opened then the air whooshed in and out clearly.

It's probably still within normal operation, but might indicate wearing of a seal or even possible previous repair, most likely a 'mode dial' repair if it's an early model.

Have a chat about it with the seller and see if they have any history/info to share.

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Benz3ne

Link Posted 03/03/2020 - 12:50
I've spoken to the supplier this morning and they've agreed with my concerns surrounding dust and water ingress considering it is a weather-sealed camera. They've offered me a postage label to return for inspection and if they find the fault (or at least agree that it's a fault upon inspection) it'll be sent for repair. 3-4 weeks typically for repair so potentially a while without the camera, but I'd suggest a worthwhile repair considering I live in rainy ol' Wales! I'd rather the peace of mind than a camera that's potentially accumulating dust where it shouldn't be!
Last Edited by Benz3ne on 03/03/2020 - 12:52

HarisF1

Link Posted 03/03/2020 - 15:16
That's actually a very good resolution, worthwhile if it sorts out the issue. Might have been worth sending the lens with it to ensure they replicate the issue. But that might be a bit of a risk considering it's brand new.

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Benz3ne

Link Posted 03/03/2020 - 15:22
HarisF1 wrote:
That's actually a very good resolution, worthwhile if it sorts out the issue. Might have been worth sending the lens with it to ensure they replicate the issue. But that might be a bit of a risk considering it's brand new.

I would have thought they have demo Pentax lenses considering they stock Pentax stuffs anyway, so hopefully they can chuck one on the front and replicate it. I wouldn't have thought it was specific to my lens and camera. I've let them know that it does only appear to be present with the WR zoom as I'd never noticed it on my A 70-210mm f/4. Hopefully it'll mean a camera that doesn't blow in my face (steady on!) when I use it in 3-4 weeks time!
Unfortunately that means a likelihood of no DSLR when I visit Tenby towards the end of the month but I'll take a film camera anyway for funsies.
Last Edited by Benz3ne on 03/03/2020 - 15:25

bforbes

Link Posted 03/03/2020 - 15:55
Has anyone said where it should blow from? Looking at the change in size of the 150-450 it needs to move around 300cc of air between the 150 and 450 ends
Barrie
Too Old To Die Young

http://www.pentaxphotogallery.com/artists/barrieforbes
Last Edited by bforbes on 03/03/2020 - 16:11

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Benz3ne

Link Posted 03/03/2020 - 16:28
bforbes wrote:
Has anyone said where it should blow from? Looking at the change in size of the 150-450 it needs to move around 300cc of air between the 150 and 450 ends

Not really, but again no one aside from myself has reported the rear dial being an exit/entry point for air. It's quite notable too, there's a definite 'whoosh' of air in and out. I say notable as I can feel it on my face with the camera to my eye, and Mabel (doggo) was doing some tilty head at it yesterday when I was taking some practice shots of her from about a m or so away.

I'm not denying the air has to go somewhere, I'm just surprised at how easily it sucks/blows through that rear dial.

bforbes

Link Posted 03/03/2020 - 18:34
I can't remember where I read, or even if it was relating to Pentax, but it's in the back of my mind that the vent was through one of the rubber terminal covers. Like the remote or HDMI.
Barrie
Too Old To Die Young

http://www.pentaxphotogallery.com/artists/barrieforbes

HarisF1

Link Posted 03/03/2020 - 19:52
When any of the other rubber seals are opened the air clearly rushes out from that point. You also feel a difference in the resistance when the lens is zoomed in and out.

With the seals closed I could not pinpoint any specific point where air was moving out of the body.

Cayman

Link Posted 04/03/2020 - 16:17
This is normal. On Nikons the air comes out of the eyepiece. I image Pentax designers have also developed an engineering solution to this problem

"Eyeblow

As the 24-70 2.8 is zoomed in and out, some air pumps in and out, and you may have some air blow out of the eyepiece into your eye.

I couldn't feel anything at a camera's viewfinder, even though some air does pump in and out of the back of the lens."

https://www.kenrockwell.com/nikon/24-70mm.htm

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Benz3ne

Link Posted 04/03/2020 - 18:20
Cayman wrote:
This is normal. On Nikons the air comes out of the eyepiece. I image Pentax designers have also developed an engineering solution to this problem

"Eyeblow

As the 24-70 2.8 is zoomed in and out, some air pumps in and out, and you may have some air blow out of the eyepiece into your eye.

I couldn't feel anything at a camera's viewfinder, even though some air does pump in and out of the back of the lens."

https://www.kenrockwell.com/nikon/24-70mm.htm

Is the Nikon in question weather sealed like the Pentax though? Note also I’m yet to find anyone else who has reported air blowing from the rear dial. Similarly I never had anything like this with either the K-70 or K-S2 before it.

Benz3ne

Link Posted 04/03/2020 - 19:28
Managed to upload a video to Flickr that I took yesterday.
https://www.flickr.com/gp/benz3ne/1070d6

I think it highlights the extent at which the air is travelling in and out of the camera.
As I said to Haris when I sent it to him, please ignore my long thumbnail - I play guitar and they're handy.
Last Edited by Benz3ne on 04/03/2020 - 19:29
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