[UncleVanya]

Before Bluestringer's response:
Yet when I go back to conventional photography — capturing a distant image with the 135 mm lens alone — I'm fine.

Just for grins please try intentionally making an out of focus shot with the 135, say focus at infinity and point at your shoe.

[mrNewt]

Before Bluestringer's response:
Catch-in-focus already was disabled. Now I have tried setting the reversed lens to the brightest aperture and stopping down the lens on the camera.
Answering Mr. Newt's 1:29 p.m.question: The lenses are connected with a filter ring.
I have been using a bright LED array to supplement the lighting, and I see an image on Live View but am failing to capture anything — not even a black frame.
Yet when I go back to conventional photography — capturing a distant image with the 135 mm lens alone — I'm fine.

I am truly out of ideas to be honest...

[smf]

Update:
Thanks very much to everyone who responded to my requests for help!
Applying suggestions from several of the posts above, I moments ago managed to capture several images. Because my method wasn't scientific, I can't report what step(s) made the difference. But I finally succeeded after changing the shutter speed and the source of light and using the viewfinder rather than live view.
The successful source of light was sunlight coming through a large window (sliding glass door) which was extremely close to my subject.

[old4570]

For extreme close-up photography with my K-x, I reversed a 1:3.5/28 Super Takumar on an SMC Pentax M 1:3.5 135mm. The 135's aperture is set between 3.4 and 5.6. The 28 mm is set at f/16 (and previously at a larger aperture.) I chose the M setting and set the shutter at 2 second delay. I am shooting on a focusing rail mounted on a tripod, and I use an LED light to supplement room lighting. Although I can see my subject when using Live View, I am failing to capture an image. When I attempt to view in the LCD the "image" I attempted to capture, I instead see the last image I captured (a snowy landscape) before I mounted the combination of the 135 mm lens and the 28 mm lens.

In other unsuccessful attempts on a previous day, I used other aperture settings and the Auto Pict and AV settings.

I do hear a shutter sound.

I will be grateful for suggestions.

Thanks very much.

Leave the aperture wide open on the stacked lens ( Please )
If your not using a flash (?) start the aperture wide open on the lens in the body .... 28mm to 135mm 4.82:1 That's a lot of Macro , I tried 3:1 and it was small ..
Never mind ..


FOCUS is critical , one mm one way or the other and you might be out of focus .. ( Bare this in mind )
You need light , unfortunately your playing with a M lens ..
So fully manual .. I would try a timed shutter 3 seconds maybe as camera shake will also be critical .. ( Maybe 12 seconds )


Your at such an extreme level of macro , that everything is critical ...
As for shutter speed ? , I would maybe start around 1/10 ...
Whats bad is if its black = No light ...
If your getting light , then its one of several other issues ..


Focus - Seriously critical
Camera shake - Oh boy is it bad at this level
DOF - almost non existent at low F-stop


What I would do :
Stacked lens left wide open
Lens in body , max F-stop what ever it might be
Flash , where is the POF ( point of focus ) how many mm in front of the lens ? You need to get a lot of light here ...
Securely mount the camera ( Tripod ) for minimum camera shake ... Just the mirror lifting could induce too much movement
So I would use the shutter timer - it lifts the mirror right away and then counts down and takes the image without inducing further vibration ..


And after that its trial and error :


If your saying the camera stops capturing an image ?
Pull out the card and see whats on it ..
If its a bunch of black images your simply not getting the light you need ..

[smf]

Thanks very much, Old4570 and all who responded earlier.

[T Evergreen]

Another possibility for not being able to take a picture is that you're unable to release the shutter when the subject isn't in focus. This is the default setting of the camera and, unless you are in focus, you can't release the shutter. You can fix this issue by going to item 12 in the C Menu and set the value to "2" -- Release Priority, which will allow you to release the shutter even if the camera isn't in focus.

What I posted above relates to the K-50, not the K-x. Sorry of any inconvenience

[smf]

Thanks very much, T Evergreen. Please see the PM I sent to you moments ago.