Comments on: Panasonic Pancake Dissections

By: Michael Jelks

Michael Jelks — Tue, 30 Oct 2012 17:36:33 +0000

This is what happens when reading articles on an iPhone screen. It’s hard to keep the entire article in context.

By: Roger Cicala

Roger Cicala — Tue, 30 Oct 2012 13:27:09 +0000

Michael, that’s the thread that started all this . . . .

By: Michael Jelks

Michael Jelks — Tue, 30 Oct 2012 08:02:23 +0000

There was a thread recently on DPReview in the micro 4/3 forum that seemed to suggest the banding goes away after the lens has had a chance to “warm up”. Noise and/or electrical interference was a possibility as well.

http://forums.dpreview.com/forums/thread/3285963

By: tmei

tmei — Tue, 30 Oct 2012 04:13:41 +0000

The spring is probably to eliminate mechanical backlash, so that the movement of the lens when focusing does not depend on previous direction of travel. Very thoughtful design!

By: David

David — Tue, 30 Oct 2012 03:52:05 +0000

Those ribbon cable connectors are conveniently close to the rear lens mount. I’m curious if you could disconnect one (say to the focus motor) and test the lens for banding, or if this would just give you a lens error. Not as much fun as dissecting a lens, but this kind of troubleshooting can be fun too if you have the patience and equipment (would need an oscilloscope). I agree with A that the motor could be the cause, bet it is powered during focus lock. The motor would be easier to isolate than a component on the PC board, if you have the patience to try it out Lend me an OM-D and I’ll help you out!

As an aside, I once had (still have actually) a turntable that developed a bad rumble (low frequency hum), and it turned out to be a ribbon cable was the culprit. I fixed it using shielded wires jammed manually into the connectors at both ends ( couldn’t get a replacement cable). I thought this was a bogus place to use a ribbon cable, especially given the premium paid for the turntable, which was programmable and allowed random play of songs on an LP.

By: questionlp

questionlp — Mon, 29 Oct 2012 20:16:33 +0000

Nice to see these lens teardown articles.

NB: The link to DPReview is broken.

By: A

Mon, 29 Oct 2012 18:17:06 +0000

Actually I’d say the motor could very well be the source – a poorly chosen/constructed motor can kick out a fair amount of noise on a whole host of frequencies… Banding basically *is* noise.

As a matter of interest, is the “mirror(less) box” on the OMD any wider than other similar m43rds cameras which don’t exhibit banding? Or does it have more plastic where there’s metal in the front of the body.

Also, I wonder whether a lens (or camera) gets FCC tested in isolation, or when used with a particular camera/lens?

By: Sean Esopenko

Sean Esopenko — Mon, 29 Oct 2012 17:46:13 +0000

I noticed the COPAL stamp on one of the AF motors. Do you guys see that stamp on camera parts often? I have view camera lenses with “Copal” shutters. Is there a correlation?

By: Joachim

Joachim — Mon, 29 Oct 2012 05:26:27 +0000

To me, the spring looks like an antenna. If the camera is set into continuos or automatic decision whether focus method to use, it could be the motor is powered, although not moving. You can use a motor as a brake as well. this kind of waves are difficult to measure, especially in a small device like a camera. Does banding happen with all focus- and ISO-settings? Higher ISO is an amplification of the sensor’s signals. And light is also just a kind of waves in a different spectrum. Interesting to see how much electronics and mom-optical stuff they packed into a small volume.