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A rainbow of shots on a Panasonic 20mm f/1.7 (1st version)

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#1 KarlBlessing

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Posted 16 June 2021 - 05:02

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The UV shot does show there's a little bit of a hot spot of sort in some situations.

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And yes the Breakthrough Photography X4 Circular Polarizer does reduce a lot of UV below 400nm (though it's not a total blackout when paired with the LUV U II, it's still -3.0 even at ISO 128,000 despite a discernable image on the screen).

Found that for my own personal fun use, using the BG3 with the CPL yeilds a nice image out of the camera, giving me a little bit of control in the visible range.

Didn't bother to use the CPL on the RG850 because like with the UV pass, it isn't much use. Above 700nm or so the CPL has no visual impact in any angle.

Those were all handheld since I didn't have my tripod handy before the place closed for the night, and also the Panny 20/1.7 was the only lens I had on hand (will try the same with my vintage lens later).

Two handheld shots with the EM5ii and Panasonic 20/1.7 (noticing this particular model body does a fair bit of banding at ISO 3200, not sure if that's the case unmodified).

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And two unfiltered full spectrum shots on the lens

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Edit: Regarding the banding at high ISO shown in the two UV shots. It appears there's a specific problem with the Panasonic 20mm f/1.7 (H-H020) and the PL25 and some of the Olympus bodies, wasn't an issue on the first generation (E-M5 mk1, E-M1 Mk1) that I have but is to the EM5ii. So it's a lens+sensor specific issue and not particularly a UV+Sensor+ISO issue. I'll try to replicate it with my other lens to verify.

Edited by KarlBlessing, 16 June 2021 - 05:45.


#2 dabateman

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Posted 16 June 2021 - 05:22

Are you sure that the UV images are with a BG3 filter?
That filter normally lets through mostly blue and some green.

http://www.photoir.n...-of-bg3-images/

Edited by dabateman, 16 June 2021 - 05:27.


#3 KarlBlessing

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Posted 16 June 2021 - 05:44

View Postdabateman, on 16 June 2021 - 05:22, said:

Are you sure that the UV images are with a BG3 filter?
That filter normally lets through mostly blue and some green.

http://www.photoir.n...-of-bg3-images/

That's a typo in the picture due to copying and pasting the text.

The "UV" (not UV+IR) is with the LUV U II made by uviroptics on ebay

#4 dabateman

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Posted 16 June 2021 - 08:02

I didn't know about the Sony IMX109 banding problem with the Panasonic 20mm until you posted this.
People reported that its not a problem with the EM1MK1 (Panasonic MN34230 sensor) and most don't see it with the Pen-f (IMX269 sensor).
I wonder if it was ever figured out. The fix for some is to use only manual focusing. The fix for others was to use only electronic shutter.

Really weird. I may need to test my lens out.

#5 Andrea B.

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Posted 17 June 2021 - 22:59

The first composite is cool. I always enjoy those for quickly seeing how filters perform.
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#6 KarlBlessing

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Posted 18 June 2021 - 05:15

Well guess I have a different problem unrelated to the lens combination, though it's hardly noticible below say f/11, but you slap a last cut 2mm pinhole on, and my suspicion was confirmed.

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It appears to be under the clear glass and it's the sensor as the dust moves with the image stabalization when I watch it on the LCD.

Edit: F/22 on a Panasonic 42.5/1.7 (since pinholes will always exagerate, it's still pretty distinct on a non-pinhole).

Posted Image

Edited by KarlBlessing, 18 June 2021 - 05:38.


#7 Andrea B.

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Posted 18 June 2021 - 06:26

What the heck is that?
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#8 KarlBlessing

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Posted 18 June 2021 - 06:36

View PostAndrea B., on 18 June 2021 - 06:26, said:

What the heck is that?

Dust in between the sensor and replacement glass.

#9 dabateman

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Posted 18 June 2021 - 06:38

Well you have to decide if that dust will drive you nuts and need to return the camera.
Or collect a flat and dark with every image and subtract it out.

The newest update to Photo Affinity now supports an Astrophotography module for doing just that. Quite interesting. It sort of also handles my fits files from my Lodestar camera. Its in version 9.1.2

#10 KarlBlessing

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Posted 18 June 2021 - 07:03

View Postdabateman, on 18 June 2021 - 06:38, said:

Well you have to decide if that dust will drive you nuts and need to return the camera.
Or collect a flat and dark with every image and subtract it out.

The newest update to Photo Affinity now supports an Astrophotography module for doing just that. Quite interesting. It sort of also handles my fits files from my Lodestar camera. Its in version 9.1.2

For the most part below f/11 doesn't seem like it's there (course now I'm noticing just because I know where they are now, in terms of faint dark areas). Sucks that I'll flying out of the state in a couple days or I would attempt to do a return or re-do, but just looking at the above "All conversions are carried out on a Class 100 Clean Bench to eliminate sensor contamination." this statement seems false.

#11 dabateman

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Posted 18 June 2021 - 12:57

View PostKarlBlessing, on 18 June 2021 - 07:03, said:



For the most part below f/11 doesn't seem like it's there (course now I'm noticing just because I know where they are now, in terms of faint dark areas). Sucks that I'll flying out of the state in a couple days or I would attempt to do a return or re-do, but just looking at the above "All conversions are carried out on a Class 100 Clean Bench to eliminate sensor contamination." this statement seems false.

I am concerned that the sentence says on not in. Is the bench off on its side and he uses it?

But you also should be clear on what class 100 actually means. Class 100 = ISO 5 and this presentation is quite good at explaining things:

https://www.pda.org/...vrsn=1bf5838e_6

See page 11 for the size and number of allowed particles. To give you perspective computer chips are typically manufactured using ISO 1. Our sensors having really small photosites would be sensitive to the allowed particles of ISO 5 and his bench may still be compliant.


For some reason I can download the ISO standard here 14644-1:

https://zoser.com.co...sion%202015.pdf

Usually you have to pay for this document.

Edited by dabateman, 18 June 2021 - 13:12.


#12 UlfW

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Posted 18 June 2021 - 13:54

There are also very strict procedures to avoid contamination when working in such controlled environments.

Normally one works in zones with increasing demand of cleanliness, where a clean bench is placed in a cleanroom with worse class.
To enter a cleanroom you normally dress upp in special cleanroom clothing and pass an airlock, to keep the dirt out.
https://www.cleanenv...ign-principles/

If you are not working with the correct procedures a clean bench is meaningless.

I think a ISO 5 environment would be quite OK if it really was that clean when working there and all used parts and tools were cleaned properly.
832 or less particles per m3, ≤1µm is actually rather clean for working with our type of sensors.

I have actually designed a special workbench for sample preparation that had a ISO 5 clean bench function.
I have also worked many hours in different cleanrooms, even if it never was in any ISO 1 rooms.
All optical media was produced in cleanrooms in the beginning.

Edited by UlfW, 18 June 2021 - 14:03.

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#13 dabateman

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Posted 18 June 2021 - 16:38

Yes,
To buy a hood. Sit down and sit your arms in with a camera and screwdriver, isn't enough. Who knows how he does it. But there have been many complaints.
Good to know to avoid.

#14 KarlBlessing

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Posted 18 June 2021 - 16:45

Very informative, and a very good point about procedure. Having the equipment isn't much if you're a chain smoker, you bring all that in with you.

#15 UlfW

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Posted 18 June 2021 - 17:05

It is not just smoking.

In the normal world the air is full of all sorts of particles, vey many of them in one m3.
It is dust from alls sorts of sources, pollen, smoke, shredded skin cells, very fine sand...

That is why clean room personel is using these special cleanroom suits, to insulate their bodies from the clean environment.
The suits has to be washed in special washing machines specially modified with particle filtered water.

Edited by UlfW, 18 June 2021 - 17:07.

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#16 Andrea B.

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Posted 19 June 2021 - 05:51

Not the first time we have seen a dust complaint about that particular Ebay converter!
You just got the converted camera. It shouldn't have that much dust already.
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#17 KarlBlessing

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Posted 19 June 2021 - 13:47

View PostAndrea B., on 19 June 2021 - 05:51, said:

Not the first time we have seen a dust complaint about that particular Ebay converter!
You just got the converted camera. It shouldn't have that much dust already.

Was my thought, his initial response was :

"Thanks for letting me know! Do you see the dust on the sensor? I'm happy to have a look and get it better. My process minimizes dust some amount in nearly inevitable. From your pictures I see 6-7 specs but I cant enlarge or download them attached to ebay messaging."

So I linked back a full resolution image of one of the examples : https://i.imgur.com/txpLoEY.jpg
More like 50+ with easily a dozen being more easily picked out at a wider aperture (f/8~11). And I know it's not the lens because nothing moves when rotating it (only time they move is when the image stabalization is engaged).

Edited by KarlBlessing, 19 June 2021 - 13:48.


#18 Andy Perrin

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Posted 19 June 2021 - 14:53

View PostAndrea B., on 19 June 2021 - 05:51, said:

Not the first time we have seen a dust complaint about that particular Ebay converter!
You just got the converted camera. It shouldn't have that much dust already.
...did I miss something? What converter did his conversion?

#19 KarlBlessing

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Posted 19 June 2021 - 15:42

View PostAndy Perrin, on 19 June 2021 - 14:53, said:


...did I miss something? What converter did his conversion?

Eeassa (they recall from another thread), I didn't know his history among some of the members until after I placed an order and then started looking up UV information with that model and then saw admin notes about him in some threads about the replacement glass he uses. That thread was from back in 2014, guessing the trend holds and he hasn't improved from it.

Not sure what the usual rate would be on an em5ii that's being sold used and was converted, so may just be a matter of living with it for the cost if 95% of what I shoot at remains below f/8 with faint splotches that only show in open areas since I don't like dealing with returns and because looking around the same model with a more reputable history done would still easily end up 400 more. But I guess that's what he's banking on.

#20 Andy Perrin

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Posted 19 June 2021 - 16:06

Haha, yes, you saw MY threads! He converted my NEX-7. I also got a dusty camera but no dust under the glass thank heavens so I just cleaned it myself. But I can’t say I’m surprised.

I didn’t have trouble with the replacement glass, though. Alex told me I might but it never became a real issue.

Edited by Andy Perrin, 19 June 2021 - 16:07.