fullspectrum Monochrome Full Spectrum - UV - VIS - IR - someone modified it

[ph0toni]

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Analogue full spectrum - with 6x6 photographic film - Rollei Infrared - from deep UV to IR 720 nm

(I'm still looking for a good 246 at a good price to do the modification)

 

 

[ph0toni]

I went crazy and got an M246
I knew it wasn’t the perfect camera for my research, but I got some interesting results - all F8 - auto iso - Garda Lake from Desenzano (ovest to nord)

with a UV filter (range 370>400 nm) 1/45 - 3200 iso

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.
with an orange filter to remove the haze (range 530>700 nm) 1/2000 - 320 iso

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with a dark red filter (range 670>700 nm) 1/30 -1250 iso

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with a 720 nm IR filter (range over 720 nm) 1/30" - 12500iso

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P.S.

I read that the M9M is the best for IR photos, I wonder how it is possible to make a precise focus (it does not have live view).

Thanks

Toni

Edited May 15 by ph0toni

[fotomas]

Maybe off interest (if you not already know).

[ph0toni]

4 hours ago, fotomas said:

Maybe off interest (if you not already know).

@fotomas Thanks for the link, I had no feedback on the various IR filters with M246, this post is clear!
... but it was complicated to translate from German to Italian
.
I have a Sony A7 full spectrum, I understood well the differences in speed (+12 stops) and file quality (much sharper). If I can't modify the M246, I will have to give up UV and IR
Maybe UV + visible ... similar to orthochromatic film is easy, but the wood effect of the foliage can only be obtained with the help of a tripod.
I took an M246 because I believe that only a mono sensor can be translated into grayscale with color filters. I tried many color filters with my standard Nikon Z7, the raw does not have a clear and logical response, if it is converted to black and white.
Thanks

-

[fotomas]

With BW-colorfilters with digital color-cameras never worked for me. Better to do the BW conversion in the post. Can't tell for a full-spectrum camera.

But with an monochrome camera it's possible and you have to use them. Another comparison with contrast filters here. Could be I have posted the link before in one of your threads.

Since you can push the ISO on the M 246 up to 10.000 (at least for me with acceptable IQ) it could even be possible without a tripod in bright light, but in general a tripod helps a lot.

Unfortunately my Italian is rather basic😥

[ph0toni]

On 5/24/2025 at 10:30 PM, fotomas said:

With BW-colorfilters with digital color-cameras never worked for me. Better to do the BW conversion in the post. Can't tell for a full-spectrum camera.

But with an monochrome camera it's possible and you have to use them. Another comparison with contrast filters here. Could be I have posted the link before in one of your threads.

Since you can push the ISO on the M 246 up to 10.000 (at least for me with acceptable IQ) it could even be possible without a tripod in bright light, but in general a tripod helps a lot.

Unfortunately my Italian is rather basic😥

I have been asking persistently if it is possible to modify the M series, the answer is that they all have the hot-pass filter glued in... and it is not possible.
So I will use my M246 with near UV and near IR filters
This is a comparison with a similar 24 Mpx RGB sensor

Thanks . Toni

.

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[ph0toni]

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M246  - Voigt 35 f 1,5

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with the UV filter it is not sharp, the infinity focus is wrong

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[lawman]

1 hour ago, ph0toni said:

M246  - Voigt 35 f 1,5

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with the UV filter it is not sharp, the infinity focus is wrong

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Thanks for these postings - very clear results - especially the Lake Garda set.  I don't understand why the UV here is not in focus.  The focal point should change with infra red, but I would think not with the visible spectrum filters?

[ph0toni]

18 minutes ago, lawman said:

Thanks for these postings - very clear results - especially the Lake Garda set.  I don't understand why the UV here is not in focus.  The focal point should change with infra red, but I would think not with the visible spectrum filters?

Voigt isn't "apo"; it has a noticeable shift in UV and IR. There are older lenses that have better apochromatic correction; generally, stopping down to f/8/11 doesn't cause any problems.
With the M246, you have to keep the aperture wide open; it's 4x less sensitive in UV and 10 stops less sensitive in IR than the full spectrum.

[Stephen.s1]

Fascinating reading.  Many thanks for your post.

[jaapv]

On 5/15/2025 at 10:05 PM, ph0toni said:

I went crazy and got an M246
I knew it wasn’t the perfect camera for my research, but I got some interesting results - all F8 - auto iso - Garda Lake from Desenzano (ovest to nord)

with a UV filter (range 370>400 nm) 1/45 - 3200 iso

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

.
with an orange filter to remove the haze (range 530>700 nm) 1/2000 - 320 iso

.
with a dark red filter (range 670>700 nm) 1/30 -1250 iso

.
with a 720 nm IR filter (range over 720 nm) 1/30" - 12500iso

.

P.S.

I read that the M9M is the best for IR photos, I wonder how it is possible to make a precise focus (it does not have live view).

Thanks

Toni

That is not correct. The M9 M is about 20% less sensitive than the M8 and 10% less sensitive than the M 246. Kolari might be able to convert your M246 camera to full spectrum. After all, they can replace the IR filter on the M9.A full spectrum conversion on a M9 costs 1229 $. Just buy a corroded one for peanuts and have it converted. 
M cameras are ideal for IR and UV photography as the viewfinder is not affected by the filter. 
For UV photography I recommend the Summarit 50/1.5. 

[frame-it]

On 5/25/2025 at 12:14 AM, fotomas said:

Maybe off interest (if you not already know).

and

 

[frame-it]

On 8/31/2024 at 5:24 AM, ph0toni said:

I think I will give up this dream, it is too expensive, I am retired, I do not work for a museum or the scientific criminal police

this might help you

https://www.ultravioletphotography.com/content/index.php?/topic/1654-sticky-uv-capable-lenses/

 

[ph0toni]

On 12/6/2025 at 9:07 AM, frame-it said:

this might help you

https://www.ultravioletphotography.com/content/index.php?/topic/1654-sticky-uv-capable-lenses/

 

Yes I know UVP well, my nickname is photoni, on the site I have 1.1K posts, this is my last one. Thancks

https://www.ultravioletphotography.com/content/index.php?/topic/6571-leica-m246-monochrom-sony-a7-fs/

[ph0toni]

On 12/6/2025 at 3:21 AM, jaapv said:

That is not correct. The M9 M is about 20% less sensitive than the M8 and 10% less sensitive than the M 246. Kolari might be able to convert your M246 camera to full spectrum. After all, they can replace the IR filter on the M9.A full spectrum conversion on a M9 costs 1229 $. Just buy a corroded one for peanuts and have it converted. 
M cameras are ideal for IR and UV photography as the viewfinder is not affected by the filter. 
For UV photography I recommend the Summarit 50/1.5. 

I'm not familiar with the Summarit, but it probably works well, like my 1954 Elmar 50 f/3.5 that I tested on the Sony full-spectrum with UV filters
I'm new to the digital M world.
I'm only interested in the Leica's BW sensor.
I was curious about its sensitivity, but its performance in the UV and IR ranges is very POOR. 
The difference is that the M9 mono had an "open window" in IR... but I didn't buy it because it doesn't have live view for precise and accurate focusing.

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I asked Kolari Europe, and they offered me a discount (the list price is €1814.98).
It's still too high. The IR range above 760 nm is all black and white, whether with an RGB or mono sensor. The UV range with the black and white sensor is very flat. An RGB sensor is better.

Edited Tuesday at 02:27 PM by ph0toni

[jaapv]

The sensor is identical between the aM9 colour and M9M. The only difference is that the Bayer filter was replaced by plain glass. Both have an IR filter which is stronger than the M8.