[Joetitch]

Jumping to conclusions is the only exercise I get🤪

[Gary H Perth]

Hello.
I have to offer my most humble apology for my ridiculous thread and I do feel somewhat embarrassed I have to say.
There is nothing wrong with the plastic lens mount. The black specks are coming from the worn Pentax strap. The inside of the strap is made of some sort of velveteen material which is quietly falling apart.
So I guess what my thread should have said was " worn Pentax straps should be replaced as soon as possible".
That is unless someone has a good idea to treat the strap in some way to clear the muck. It's just as important to be careful when changing any lens really that this muck does not get inside the camera.

PS Is there any way to either remove this thread or at least change the title please administrator?

Well spotted, friend. I have had problems over the years with dirt in my sensor arising from both the Pentax Strap backing layer starting to fall apart, and from foam in the lens cases. In both cases, the detritus was sticky and didn't move easily with a blower, sounds like you were more fortunate, since I ended up paying for sensor cleans both times.

Welcome to the forum of helpful and interested Pentaxians. Great to hear that you have no problems with lens or camera bodies.

[marty-0750]

Ok so here's the thing.
There is nothing wrong with plastic lens mounts right ? Well I beg to differ after my recent experience.
About three years ago I bought the penta da 50ml f1.8 with plastic lens mount. At the time I thought nothing of it. It didn't turn out to be a particularly useful lens so I haven't used it much at all.
This year I have noticed Pentax used DSLR cameras are selling cheaply so I decided to buy more cameras, and started to use the da 50 a bit more.
Also I got a bit more confident with changing lenses which was something I had avoided doing too much because I wanted to keep the sensor clean. In fact I've never needed a professional sensor clean because the in built system is quite well designed. So I have plucked up more courage and I'm using all my lenses more frequently which means I am enjoying the fun of photography much more than before.
Occasionally I have noticed quite a few black specks appearing on my dining table where I carefully change lenses. I didn't really think about their origin until one day after cleaning the table and then swapping lenses the black specks appeared again. I had just removed the da 50 from my camera.
So every time I remove this lens from a camera, the black specs appear. So I then thought, what if these black specs are getting into the camera as well ?
So I have had to methodically check all my cameras using a blower first in the mirror box ( which found and removed a fair few black specks and in one case having to raise the mirror to use the blower in the sensor area as well. I don't think any specks had got into the sensor area but there was a tiny thread which was removed.
So is it really sensible to use plastic mounts for lenses?

I have two DAL 18-55mm Pentax. One with metal mount, the other plastic. Find that either way still need the same periodic dust cleaning off the sensor. BTW the one with the plastic mount has better optical quality. Notice this in astrophotography. For the metal mounted, stars never really sharp with uneven focus across the field, while the plastic mount stars are crisp across the field.


Marty