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UltravioletPhotography

Was is the function of this pane?


baffe

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Today I was converting my Olympus E-PL1 MFT cam to full spectrum.

 

After disassembling the cam and removing the sensor unit i found a pane in front of the filter stack. There are some electric contacts, each 2 connections going from the electronic to components glued onto the pane.

 

http://up.picr.de/20267627eo.jpg

 

http://up.picr.de/20267628do.jpg

 

I didn't want to destroy another cam so I left the pane with the electric parts in place.

 

The cam is ok, it works well, even with uv:

 

http://up.picr.de/20267853qa.jpg

 

But under certain conditions there are horrible reflexes on pictures:

 

http://up.picr.de/20267855iv.jpg

 

http://up.picr.de/20267858ts.jpg

 

So I think I have to remove the pane and simulate the electric components to the electronics. What are they for:

 

Heating to avoid condensation?

Sensor to detect condensation?

Sensor to detect accelleration for is?

Something different?

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Removing the pane did improve performance. Now nothing is connected to the electronics instead of "the pane".

 

http://up.picr.de/20269323mx.jpg

 

http://up.picr.de/20269324ac.jpg

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Expected as much. Even thin layers of glass can adversely impact UV response if the glass itself has strong UV attenuation or coating that reflects UV.
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Finding a block with several layers of glass and an additional pane in front of a sensor inside a cam makes me feel a little strange. When I count the number of surfaces (and add those inside a zoomlens) light has to pass...
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The ICF is pretty thick so in comparison the dust shaker is very thin. But supposedly all adds up. Do remember the digital camera is designed with the presence of the ICF filter pack in mind.
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Thanks for this Stefan

Did you disconnect the flat cable to the dust shaker or were you able to just cut it off ?

The removal of all this glass in the path will actually be better for the performance of the M42 type lenses, that were designed for no other glass in the path to the film/sensor plane.

Cheers

Col

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Just ripped it off... carefully

 

In my opinion it will be better for any lenses. It's impossible to compensate stray light in lens design, just change the angle light beams arrive.

 

We are told that that angle is almost orthogonal in MFT designed lenses. Using M42 lenses with a big flange focus distance of about 45mm makes the same on MFT cams. As we have a small sensor.

 

The pane? I still don't know its purpose. But I didn't try to switch to image stabilizer or lens cleaning.

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Would have said dust cleaning filter too. Canon cameras have a film over the sensor that is vibrated using piezoelectric motors whenever the camera is switched on or off (depending on settings).
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First checked conductance => no conductance

=>heating

=>temp. probe

 

Then I applied 5Vss 3.5kHz and the pane begins to "sing"!

 

So you are right, it is the dust shaker. The two elements are piezo actuators.

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No Problems with reflections, WB easy to use (much easier than on Sd10).

 

Use of M39/M42 no problem at all.

 

MFT and adapted QBM lenses are not to focus on infinity. This is bad because I intended to use my Rollei and Zeiss lenses with the cam.

 

I have to measure and meditate a little to find out if I leave the cam like it is or modify the bajonet.

 

To day I'm too exhausted.

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Made my decision and did some metalworking. Voila a M42 full spectrum digital mirrorless system cam. Possibly the first:

 

http://up.picr.de/20285980hr.jpg

 

Wih 60W incandescent lamp 720nm Filter on Cam, Pentacon 29mm f2.8:

 

http://up.picr.de/20285981ks.jpg

 

No filter on Cam, UG11 on flash, same lens:

 

http://up.picr.de/20285982tg.jpg

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I have a Panasonic GF-1 likewise equipped. A nice alternative to stacking adapters as many potentially useful lenses come with M42 threads.
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Bjørn I like M42 lenses because I can use the same lens and equipment on different brands of cams.

 

Any M42 lens fits perfect to the cam with a 20mm ring. That is ok so far.

 

The "troublemakers" are not M42 but M39 lenses adapted to M42.

 

Colin my "Pentax Auto Bellows M" goes down to 33.5mm. Without PK adapters. It's big enough in Diameter to set the lens intended for uv * a little into it.

 

I don't like helicoids...

 

Someone in germany offers me a similar or the same helicoid colin.

 

I have to think it over. And I have to measure. A ring with 18mm is too much to reach infinity. 11mm is not enough. So possibly the 17mm is too long for me.

 

 

* D.O. Industries 50mm f4,5

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Why are "The "troublemakers" are not M42 but M39 lenses adapted to M42." ?

The M42 mount looks neatly done, have you just screwed the M42 mount ring on top of the Oly mount ring, with longer screws ?

Col

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The M42 are ok. When I fix 20mm ring to the cam then I have a half mm less than the original flange focus distance.

 

But the M39 are different and not all the same flange focus distance. Leica uses 28,8mm.

 

So calculating:

 

M42 ffd - nexessary ring = cameras ffd

 

46,46 - 20 = 26,46 [mm]

 

So the Leica lenses work with the helix. Not perfect but ok.

 

But the D.O. lens needs a ring of something less than 18mm and more than 12mm. And I couldn't check if the 17mm are ok yet. Because it is something close to 17mm. Maybe a little more (ok). Maybe a little less and then the 17-31mm heli is not suitable for infinity.

 

I didn't even use longer screws to avoid potential damages to the inside of cam. The ring is just drilled and bolted onto the bajonet with the bajonets screws which are really long. Also the screws are not the common 1.6mm but 2mm screws.

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Thanks Stefan

The focusing heliciods come in many sizes, 12-17mm, 15-26mm, 25-55mm, 17-31mm, 35-90mm........

Some have m4/3 mounts & C-mounts & L39 mounts......all sorts....

Col

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