[pavpen]

Am I missing something? The bad aperture mechanism (in lens) should only introduce the evenly underexposed pictures. Here I see that something is blocking the sensor. Something like slow mirror.

Cheers

[Dr.Pentaxian]

Thanks for the feedback. I tried a few things based on what you suggested. I completely charged the original battery and mounted the DA-L 18-55mm AL wide open (f3.5). The setting was P mode (Tv hyper). Same thing happened again al 1/5000 and 1/6000 (see image). I'm guessing it's a mirror problem. Since we don't have Pentax Service around here I'll just will have to avoid higher speeds...

[stevebrot]

Oh well, the OP apparently has disappeared...I guess we will never know!!!


Steve

[altopiet]

Steve, he hasn't been gone that long... some of us do have to work for a living

About Dr.Pentaxian
Country
Chile
Pentax Cameras
K-30
Photographic Equipment
SMC Pentax-DA L 18-55mm F3.5-5.6 AL
Occupation
M.D.

[stevebrot]

Am I missing something? The bad aperture mechanism (in lens) should only introduce the evenly underexposed pictures. Here I see that something is blocking the sensor. Something like slow mirror.

Cheers

Remember that at speeds faster than the X-sync speed, the shutter operates as a moving slit. If the light intensity changes as the slit moves, you will get a gradient effect.

As for the mirror...it has been my understanding that most shutter systems are integrated into the mirror box such that the shutter travel does not start until after the mirror is confirmed in the up position. Conversely, the mirror does not fall until after the following curtain finishes its travel. At least that is how they used to make them. Things may be different now with the requirement for high FPS drive rates.

A good check would be to use the 2s delay or self-timer mechanism to take the mirror out of the loop.


Steve

[SteveB]

If it helps, I just tried my K-30 with a few old lenses, K55/1.8, A50/1.7, M135/3.5, Vivitar 28/2.8 in M, Av modes at f8 and wide open and couldn't see any issues at all at 1/6000sec.

[Dr.Pentaxian]

A good check would be to use the 2s delay or self-timer mechanism to take the mirror out of the loop.

Thanks Steve, I'll try it and post the results.

[Dr.Pentaxian]

I followed Steve's suggestion and tried it with the 2s delay. Mode M, M-50mm lens wide open (f1.7) at 1/5000s. This is what I got...

[stevebrot]

I followed Steve's suggestion and tried it with the 2s delay. Mode M, M-50mm lens wide open (f1.7) at 1/5000s. This is what I got...

Well, there you go. Wide open, M-mode, mirror up, nothing left to blame but the shutter.

Hello, Pentax? We have a problem...

It is still on warranty, I hope



Steve

[Sagitta]

Did you try a different battery?

My same issue cleared up when I tossed the lousy batteries I was using and reverted to the kit battery and better quality AA's.

[apentacitis]

Hey, did anyone ever find a solution to this, I currently have a Pentax K-x that is exhibiting the same problem. Seems fine at 1/4000 but once you switch to 1/5000 you get about a quarter of the top screen blacked out. When switching to the highest speed of 1/6000, you get about 1/3-/12 of the screen blacked out. Not the hugest problem in the world as those shutter speeds rarely are a necessity but I feel more comfortable knowing all the gremlins that my camera currently has. If anyone ever figured this out or has any ideas, feel free to give me an update. Thanks.