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Who would have guessed that this Leica gear could record UV? Not me!

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#21 Cadmium

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Posted 15 October 2018 - 06:20

Thing is about lenses...
Let's take the Nikon 18mm f/4, maybe the best 18mm lens for UV, yet it doesn't transmit UV all that well, but it will produce a UV pattern, like from a Rudbeckia, or such.
I think it cuts off to absolute 0 at 360nm, and is 50% at 395nm.
The 18/4 is not what I would call a good UV transmitting lens, but it works. I am sure there are worse newer lenses of any focal length to use for UV, but a lot of lenses will work,
and I might add that monochrome eliminates the false color range, which is another difference we would see between lenses in false color Bayer UV shots.

Edited by Cadmium, 15 October 2018 - 06:21.


#22 Andrea B.

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Posted 15 October 2018 - 14:37

Cadminum: If the sun ever returns (I keep having to say that!), then I will try the 340/10 filter on that Summicron. Just for grins. :D

David: No, unfortunately I don't currently have any M-mount adapters. That is easily remedied however. B)
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#23 Cadmium

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Posted 15 October 2018 - 21:43

Also try a few IR filters of different cut off.

#24 A Stranger In The Wind

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Posted 17 October 2018 - 16:30

View PostAndy Perrin, on 14 October 2018 - 02:37, said:

Wait, what do you mean by that? Is it only the Leica that has this problem? Normally we get plenty of light with the B+W093 and similar?

With the Leica they had issues with the M8 recording too much IR in their images and many users mentioned there was too much red in the images. Leica came out with filters to lessen the impact of UV and IR wavelengths. With the M9 Leica subdued the IR wavelengths at the sensor.

Leica uses the same sensor in the MM243 as the M9 and the MM246 as the M240.

The images I tried with the 093 attached were very muddy, little to no contrast and had extremely long exposure times. I didn't bother testing the 093 any further just switched to 092 which gave pleasing results.
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#25 Andrea B.

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Posted 18 October 2018 - 15:28

That is to say, the internal UV/IR blocker was very weak in initial digital Leica M bodies. The strength of the filter was increased in subsequent Leica M bodies.
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#26 Andy Perrin

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Posted 18 October 2018 - 15:51

View PostAndrea B., on 18 October 2018 - 15:28, said:

That is to say, the internal UV/IR blocker was very weak in initial digital Leica M bodies. The strength of the filter was increased in subsequent Leica M bodies.
Yeah, it did sound weird to me to claim they changed the sensor when all they had to do was change the internal blocker!

Edited by Andy Perrin, 18 October 2018 - 15:52.


#27 A Stranger In The Wind

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Posted 18 October 2018 - 16:47

View PostAndy Perrin, on 18 October 2018 - 15:51, said:

Yeah, it did sound weird to me to claim they changed the sensor when all they had to do was change the internal blocker!

Never claimed in the original post that they changed the sensor for the IR Blocking, I stated the sensor did not record any useful information. Which it didn't as it had flat, muddy images. I did state in the above post that they changed the sensor in going from M9/M243 to the M240/MM246 models as it was CCD in the M9/M243 and CMOS in M240/MM246.
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#28 Andy Perrin

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Posted 18 October 2018 - 17:04

We were discussing your last comment, not the original post. This one:

Quote

With the M9 Leica subdued the IR wavelengths at the sensor.

I don't think changing from CCD to CMOS would have had such a dramatic effect on the IR. As far as I know, both types of sensor record quite a bit of IR.

#29 A Stranger In The Wind

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Posted 18 October 2018 - 17:42

Again it doesn't state anything about the sensor change is just says subdued at the sensor, which can have many meanings. All I said is the amount of IR wavelengths reaching the sensor is subdued with the M9.

To clarify so everyone understands the Leica had an issues with excess red (or magenta cast) in images taken with the original M8. Leica's initial solution was to provide registered owners with a set of filters. My understanding later M8s did not come with the filters which makes the original M8 an item in demand. Exactly what Leica did I do not know. My first Leica was the M243. The M243 was the 1st Monochrom released based on the M9, same sensor and blocker without the color array. This was a CCD sensor, When the 246 was released it was based on the M240 which was a CMOS sensor because Leica wished to include video, again the same setup and color array removed.

Where your interpretation came from that I claimed they changed the sensor to fix the IR/UV issue I do not know, maybe misread or misinterpreted what I wrote. Going back to the original post and the subsequent one it was just to info passing on about the Monochrom that I found using a B+W 093 did not give good results in IR, though your responses are saying I claimed something I did not.

I would agree with you both sensors likely record a lot of IR but Leica did something be it in the IR blocker or something else to eliminate the issue with the result less IR gets through.
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#30 Andy Perrin

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Posted 18 October 2018 - 17:50

I think the issue is now clear. The problem was the IR blocker. The business about changing sensors or changing things AT the sensor (or whatever) was a distraction.

You spoke extremely vaguely, and then continued to add more vague statements on top of that, so I did the best I could to understand what you were talking about.

Edited by Andy Perrin, 18 October 2018 - 17:51.


#31 Andrea B.

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Posted 18 October 2018 - 22:31

Leica digital M history is easily Googled.

To briefly review:
In the M8, the filter over the sensor was too thin and thus too much IR was transmitted. Certain IR reflecting, visible dark subjects were contaminated with the "washout" effect. Leica offered IR blocking filters to M8 buyers.

In the M9 and other M bodies before the M10 (such as the Monochroms) Leica used a thicker S8612 glass successfuly as an IR blocker but apparently failed to coat it. (Added: Or failed to coat it properly.) The S8612 glass naturally began to oxidize and the deterioration showed up as spots in the photos. So those cameras had to be recalled for filter glass replacement.

Eventually Leica got it right after those M8 and M9 snafus. While Leica lenses may be impeccably built, apparently Leica was not quite so knowlegeable about filter glass when they started out?


Edit: Added short phrase about S8612 coating to make statement clearer.
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#32 Andrea B.

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Posted 03 November 2018 - 18:36

I went out to calibrate the UV correction for the Leica MM-Gen1, but got sidetracked because I couldn't make exposure compensation work in aperture mode. Not sure what I'm missing there.

Here are some SOOC JPG photos anyway of three Labsphere standards against a Spectralon slab.
From left to right they have 50%, 99% and 2% reflectivity, respectively.

ISO 800 was too high for the visible photo because camera only goes to 1/4000".

The UV photos, made with 5 different UV-pass options look pretty good. Next time I promise I'll get that calibration done! Metering seemed to work quite well for the UV-pass filtration.

The Summicron may have some mild center hotspotting. No problem as it was not meant to be used for UV work. The Cron certainly is a sharp lens though! Wow!

The results here have convinced me to spend some money on an F-mount to Leica adapter so that I can try out the UV-Nikkor and CO60 in the MM1.

Further details on the U340: I stacked one 4mm U340 and one 1mm U340 for a total of 5mm.

Attached Image: leicaMM_cron50_vis_sunlight_f4_iso800_2018110301.jpg

The UV-pass photos are presented in alphabetical order.

Attached Image: leicaMM_cron50_uvBaader_sunlight_f4_iso800_2018110301.jpg

Attached Image: leicaMM_cron50_uvKolari_sunlight_f4_iso800_2018110301.jpg

Attached Image: leicaMM_cron50_uvLaLa_sunlight_f4_iso800_2018110301.jpg

Attached Image: leicaMM_cron50_uvSeu2_sunlight_f4_iso800_2018110301.jpg

Attached Image: leicaMM_cron50_uv340x5mm_sunlight_f4_iso800_2018110301.jpg

Attached Image: leicaMM_cron50_uv340x5mm_sunlight_f11_iso800_2018110301.jpg
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#33 Andrea B.

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Posted 03 November 2018 - 19:19

And here is one IR effort. Again a SOOC JPG.

I found that in Aperture mode the MM1 will not meter through the Schott 830 filter, so I needed to switch to Manual mode. Interestingly this f/4 ISO-800 photo in IR took so much longer than any of the UV photos in the immediately preceding post. And all of those UV shots were made with MM1 supplied metering while in Aperture mode.

Thus I suspect that I've run into an internal IR-blocking filter. But isn't it funny that the MM1 internal filtration is so strong in IR and not at all strong (apparently) in UV?

Leica MM1 + Summicron 50/2 + Schott 830 (2mm) + Sunlight
f/4 for 1" @ ISO-800
It was very windy. The leaves were really moving, as you can no doubt see. The sky seems acceptably dark for an IR830 photo. This is not the fairest of tests, because it is 3PM here and sunlight intensity is dropping. I will try again some other day.

Attached Image: L100018701.jpg
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#34 Andy Perrin

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Posted 03 November 2018 - 19:26

I am really getting the impression from this thread that Leica does not understand digital very well.

#35 Andrea B.

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Posted 03 November 2018 - 19:34

Added: I'm such a nitwit with this MM1. I didn't know I had the toning set to Sepia/Strong for the last two posts. Or maybe forever. These Leica Ms barely have any menu system at all, so you'd think I'd notice the settings. Oh well.

I still can't get exposure compensation to work in Aperture mode.
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#36 Andrea B.

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Posted 03 November 2018 - 19:37

I am really getting the impression from this thread that Leica does not understand digital very well.

Andy, it's probably toss-up at this point as to who is dumber, Leica or Andrea? Prolly me. I need to sit down and figure out this cam. I keep looking for things it doesn't have.
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#37 Andrea B.

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Posted 03 November 2018 - 19:48

Well this is rather a vast difference. Geez!
Is this a no-brainer or should I actually consider the Novoflex adapter?

Attached Image: Screen Shot 2018-11-03 at 3.46.25 PM.jpg

Attached Image: Screen Shot 2018-11-03 at 3.46.38 PM.jpg
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#38 dabateman

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Posted 05 November 2018 - 19:21

I would say to get a cheap china adapter off ebay for even less. I have had no luck what so ever with Fotodiox adapters. The Pentacon 6 ones I have would not focus to infinity and the Nikon F to Canon EF mount one was just too wide and would not fit the EF mount. I need to sand it down slightly to work. And that was a "Pro" adapter that I paid $60. The cheap $10 china one works flawlessly.

#39 Andy Perrin

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Posted 05 November 2018 - 21:43

My Fotodiox adapters (plural) all work great and have held up for years.