K5 sensor overheating/on way out?

Sorry, sensor hasn't seen a rocket blower, let alone a wet clean.

Photome will show you the sensor temperature on the original file.

Afraid you were going to say that.

Oh well ...I may have to eat my words, the streaks do appear to brighter at one edge fading off across the frame, while the streaks seem mostly parallel the broader centre band appears off ...very strange.

Guess it's a process of elimination to exclude reflections as the cause first. It may well be a fault, I have not seen anything similar in mine and it has had quite a few very testing exposures.

Hope you get to the bottom the problem soon!

Mike

Exif is intact - I can see 'camera temp' listed, warmer than ambient but under 20 degrees?

Cheers Mike - sadly the Mrs came down with a viral infection last night so I'm on nurse duty for now, but itching to run some tests and get to the bottom of this. Hopefully just me being dumb and panicky!

Ok, so the sensor isn't overheating then.

I think alig is pointing in the right direction.

Not been able to get out and test further though can't reproduce it indoors, so beginning to think the PU common sense wagon is right.

Could be a design difference with the K7/5 body as I've been utterly careless with respect to covering the K-x viewfinder before now with no ill effects.

Will update as soon as I get chance to head out with the camera again.

Sorry to dig up an old thread but it has been found in a web search and posted elsewhere, so thought I should add a definitive (and happy) conclusion.

After more testing it appears these streaks are, as suggested in the thread, light leaks through the viewfinder. The simple bit of fabric that had worked so well for me using the K10 and kx wasn't cutting it on the K-5.

Since switching to the 'proper' Pentax eyepiece cap I'm happy to report there have been no further problems and my sensor is performing exactly as Pentax intended

Unfortunately I missed this thread, I could have diagnosed that immediately. One of my useful photo accessories is a lump of blue tac to stick over the viewfinder to prevent this light leakage with long exposures.

Does nobody use the Eyepiece M designed for the purpose?

It's also worth noting that if we use the 2 second delayed action, not only is the mirror locked up before exposure (reducung vibration) but also the exposure is locked, so at that point we can take our eye away from the viewfinder.

John the problem here was stray light through the viewfinder showing up on the image. The 2 second delay is of no help here. I have used the proper eyepiece cover, but it's fiddly & easily lost so I usually leave it at home & just use my hand as a shade.

I suspect the reason the problem is being seen with the K5 & K7 but not the K-x is down to the pentaprism being brighter than the pentamirror. More light will get through in the reverse dirrection as well.

I understand, perhaps I don't experience this as a problem because I'm still stood behind the camera, so it's in shadow anyway.

On the face of it, to have so long and exposure in light bright enough to cause a problem, seems like quite an extreme situation, so is this happening when very dark ND filters are being used?

Light leakage in cameras has always existed, but usually the exposure is so short it's not obvious and usually it affects the metering more than anything else. I would have expected the flipped up mirror to seal off any leakage from the prism area.

I've just been back & read the whole thread (usually a good idea before commenting)
The problem occurs with a Cokin ND110, and appears to be still present (but improved) with the eyepiece covered.
One other possibilty is light getting on the back of the Cokin filter. Their filter holders are not ideal for very dark filters - I tried one with welding glass & stray light was horendous, I had to shade the back of the filter to get anything else on some shots.

Yes this thread is about the 10stop ND. I use the screw-in B&W, so all the light leakeage is viewfinder. Of the squares I know the Lee has a foam seal and I'd like one eventually as the blue cast seems easier to deal with than the B&W purple. But they seem just about impossible to find, they seem to be traded at more than cost. Don't know about the Cokin.

In the meantime I'm sticking with the bluetac, does the job.

LOL - I use the same thing.