GH2 w/ 20 mm Polarizer problem

[Christopher Sanderson]

My Panny GH2 goes into complete non-function when I add a polarizer to the Panny 20mm pancake lens.

The firmware within the lens and camera lockup; both manual & auto focus are impossible. The camera ceases to respond to any adjustment.

The only way out is to power off, remove the polarizer & lens; then re-attach lens without filter and power on. Other lenses work fine with the pola.

I am using a step-up ring which moves the filter about 2 or 3mm further out than normal - so this may be the cause.

Has anyone else had similar problems with this lens?

[fredjeang]

Yes, it seems to me that it is the center of the question. I don't see the reason why the step-up ring could cause a disfunction.

IMO, you could have trouble with a linear. But it would be exposure issue, and maybe the sensitive electronics is "seeing" that something's wrong somewhere, basically a metering issue. You need to have enough light entering to make that sort of lens work properly.  (more exactly, you need the light to be distributed the same way and not having a "zone of shade". If you got a linear, try with a circular to isolate the issue.

If you have that prob with a circular, I surrender. It should work, there's not reason it shouldn't work.

Ps barking line: why in 2000 bloody 11 we still have to put-up with those gadgets filters?

[Christopher Sanderson]

Yes, I should have mentioned that crucial piece of info: it is in fact, a circular polarizer...

[fredjeang]

Yes, I should have mentioned that crucial piece of info: it is in fact, a circular polarizer...

Well...have you seen the exorcism? I think that someone jalous has send you bad vibes in your 20mm.

Remedy: a good crucify, some garlic and a holly book of your choice (it could be the GH2 user manual by the way...the holly bible of the mess), would do the job.

But wait, could it be that the use of the  step-up ring actually affects the circular pola and you end having trouble with it as it was a linear? I suspect, that you tried with and without already.

I surrender and good luck.

[grzybu]

Please be aware that this pancake when focusing is moving whole lens module.
If you block this movement you may destroy lens.
Maybe your step ring is blocking this movement somehow?

[Christopher Sanderson]

The lens works fine without the filter & ring. So I have ordered the proper sized polaz - Panny branded yet. I'll post my results when I get the filter.

[Gary Brown]

This probably isn't directly related, but FWIW, another idea you could try, Home made stand off ring:

“A stand off extension ring is a ring for attachment to the filter threads of a lens, and allows for mounting something further away from the lens. It has the same diameter threads on the outside as on the inside.

“This kind of ring has many uses. One can be to offset an attachment to the Panasonic Lumix 20mm f/1.7 pancake lens. Mounting a step up ring to the Lumix 20mm is not advisable, since it will cause the lens to jam when powering down. The front lens assembly is withdrawn into the chassis when powering down, which will cause anything wider than a normal filter to jam. But using a stand off ring between the lens and step up ring solves this problem.”

(goes on to talk about using a cheap UV filter for the purpose)

[Christopher Sanderson]

Thanks Gary - that link was most useful. And thanks 'grzybu'. I had not realized that the front element housing retracts very slightly on power down. This was undoubtedly the cause of the problem.

It remains to be seen if the Panny Polarizer that I have ordered has an outside diameter that will accommodate that movement.

[fredjeang]

Very usefull informations indeed from Gary and grzybu. I was thinking of buying this lens and those are the kind of things we want to know. It's the first time I see such a behaviour on a lens when power!
Mmm...it does not give me a lot of confidence to be honest, such a little delicate peice of glass...is it good really?

[Christopher Sanderson]

Light, sharp, small & fast - but obviously a couple of quirks for the unwary!

[Christopher Sanderson]

Update: The lens works fine with the Panny 46mm Pola. The filter has an outside diameter of 48.5 mm - small enough not to impede the movement of the front element assembly.

[grzybu]

I have retractable rubber lens hood permanently mounted on my 20/1.7 and there are no problems with blocking movements. It moves with lens while focusing or enablig power. You just have to be careful with mounting heavy lens hoods, etc. on this lens.