White balance test

[photoni]

During the winter solstice, there is no sun and UV, and few flowers.

I decided to test various types of media useful for white balancing in the studio,

with the few flowers in my garden and the lights at my disposal.

 

Flash light (Elinchrom 1000W clear quartz tube)
Cold neon fluorescent 6500°K
Nemo 365 nm
WOOD neon fluorescent

 

Sony A7 fs + Meritar 50 f2.9
Capture One software + photoshop

test image with artificial light ~ 3000°K with QB39 filter with 1,5 mm thickness, similar to BG39.

TSN 575 + ZWB2 stack (2mm thickness) is similar to BG39 + UG1 (U-360).

QB29 is similar to BG25.

 

If you want to check with other software, I can provide you with the 9 Raws with Wetransfer, send me an e-mail photoni@tiscali.it

 

Thank you
Toni

 

.

 

[colinbm]

How was the WB done & on what please ?

[photoni]

3 hours ago, colinbm said:

How was the WB done & on what please ?

Each image has a different white balance point. the right side of the Teflon panel is always overexposed.

I used the middle or left side
using different point... aluminum, metal, Kodak gray, there are noticeable, but not destructive deviations.

Therefore nothing fits everything, overexposed or underexposed images or with different lights need a balance that only a good monitor and a good eye can do.

P.S. I am amazed at the lack of color with the light from the Nemo flashlight, 365nm.

[Andy Perrin]

Torches are narrowband sources. You should not have been surprised. Can’t get much color when the source is pretty monochrome. 

[Wayne Harridge]

How does the spectral output of the flash compare with sunlight?  Does flash or sunlight have any spikes in the UV-A region?

 

[nfoto]

12 minutes ago, Wayne Harridge said:

How does the spectral output of the flash compare with sunlight?  Does flash or sunlight have any spikes in the UV-A region?

 

Xenon tubes decline quite gracefully in the UV region. No spikes but more a slight plateau around 360-350nm like sunlight. There are lots of narrow spikes in the IR band, however.

[photoni]

I don't have lab tools but with a simple diffraction grating

 

I think it shows that my Sony A7, with a simple three-lens lens like the Meritar 50 f 2.9

with flash light he sees well beyond 365 nm

[photoni]

LINK

[photoni]

@aphalo measured filter combination    LINK

 

 

the limits for the cheap TSN 575 + ZWB2 ones are 354 nm

a Baader-U filter works best up to 325

 

but maybe we "humans" ... don't care to go so deep.

specifically I'm more interested in the "near" UV that emulates the orthochromatic black and white film, wet collodion, bee vision.

 

it seems to me that the deeper you go into the deep UV and deep IR the colors are few and questionable

 

[lukaszgryglicki]

I actually "do care" about deeper than 325nm. My recent images are from around 310-330 nm with sunlight.

I'm very interested in how deep can I go with sunlight... this is because I prefer to do landscapes and outside non-marco photos, something like 300nm seem to be my current limit, and I actually don't have much hope to go deeper than 300nm with sunlight.... 

UV-C is another story - I'm also struggling with this, decided to focus solely on mercury 254nm light...

 

[ulf]

2 hours ago, photoni said:

the limits for the cheap TSN 575 + ZWB2 ones are 354 nm

a Baader-U filter works best up to 325

 

but maybe we "humans" ... don't care to go so deep.

it seems to me that the deeper you go into the deep UV and deep IR the colors are few and questionable

I think Tony meant humans that are not using monochrome converted cameras and/or not illuminating macro scenes with monochrome LED or line light sources.

[photoni]

@lukaszgryglicki Luka you are not part of us "humans" that is 99.99% of those who read UVP :-)))
I read with curiosity and admiration what you do with your fantastic equipment.
technically I understand what you want to do but visually I don't understand where you want to go.

Like many, I have basic equipment; two years ago to understand this world, I bought a Sony A7 for €150

(with electrical problems, scratched sensor, etc.) then I added some Chinese UV filters to the classic BW.
What I would like in the future is to modify my Nikon Z5 or take an A7 equal to mine (without all its problems)

and find a cheap way to remove the Bayer filter from this scratched one.

´Does anyone of you have an idea?`

 

@ulf

[Andy Perrin]

1 hour ago, photoni said:

cheap way to remove the Bayer filter

If anyone had such a method, they would be converting cameras and making lots of money now. 

[lukaszgryglicki]

One of my first mono-converted Nikons (D600) had mechanically or chemically removed Bayer filter. Herra Kuulapaa did that and sold that Nikon to me for a quite normal money (PM me if you want to know the cost). That amateur conversion is my "signature" ... :P

[photoni]

I forgot.... I asked Santa for a 350mm f4 , but I wasn't a good boy in 2022

 

@Andy Perrin unfortunately it is complicated
a Leica M10 with the oxidized S8612 filter, to be modified F.S. costs too much for my curiosity.

 

@lukaszgryglicki I am writing to you, I can risk failure with this A7 . thanks

[lukaszgryglicki]

I never used any Sony camera, so I cannot make recommendations. I don't modify cameras myself, I either buy them, or modify locally in Poland, or, i mono-case, dan from maxmax did that for me.

 

[photoni]

@lukaszgryglicki I meant that it's not worth spending more than 1000 euros for a mono conversion of an A7 with various problems

if I find someone  in Europe who tries to scratch the Bayer empirically ... I would risk

[Yves W]

Tony,
I don't have a solution for your sensor.
For the Z5 : 
-    Sensor Cleaning ist lost ;
-    Problem Internal Infrared LED.

 

I may buy a Sony A7 III which retains the Sensor Cleaning after modification. Sven Lamprecht can keep it but not on the Fuji X-T4. The Sony A7 II has the LED problem.

The Sony A7 III has Interval Timer Shooting but not the Sony A7 II.

The camera is a little expensive and the modification too …530€.

I'll wait. My Fuji X-T2 and X-T20 are very good and ergonomic.

[Andrea B.]

I don't understand what is the "cold neon 6500°K" lighting?

It appears to be outputting UV light? But then why is it labeled 6500°K?

Is it an actual neon tube light or did you mean a fluorescent tube?

 

 

 

[photoni]

16 hours ago, Andrea B. said:

I don't understand what is the "cold neon 6500°K" lighting?

It appears to be outputting UV light? But then why is it labeled 6500°K?

Is it an actual neon tube light or did you mean a fluorescent tube?

 

 

 

Excuse me @Andrea B. in the last year I've always made a mistake ... I wrote "neon" in many posts but I meant "fluorescent light"

.

They are the old lights that have been banned for a few years because they contain mercury; in fact they emit a luminous peak at 365 nm.

[photoni]

On 1/6/2023 at 4:26 PM, Yves W said:

Tony,
I don't have a solution for your sensor.
For the Z5 : 
-    Sensor Cleaning ist lost ;
-    Problem Internal Infrared LED.

 

I may buy a Sony A7 III which retains the Sensor Cleaning after modification. Sven Lamprecht can keep it but not on the Fuji X-T4. The Sony A7 II has the LED problem.

The Sony A7 III has Interval Timer Shooting but not the Sony A7 II.

The camera is a little expensive and the modification too …530€.

I'll wait. My Fuji X-T2 and X-T20 are very good and ergonomic.

@Yves W

I found the cheap solution
I took a used Sony A7 equal to mine (but without the scratched sensor and without electrical defects)

it has 4k shots for only 400€
Now the Sony repair shop near my house is converting it to full spectrum (150€)
I lose infinity focus, but I don't have Sony lenses I have M42 lenses & helicoid :)

 

I have asked many repairmen to remove the Bayer filter from the old A7 with the scratches, but nobody in Italy does it.
I could ask some nerd to do it, even if the risk is great...
Do you know someone ?

[Yves W]

Thank you Toni,

Very good solution

550€ for a camera Full Spectrum.

 

Sven Lamprecht asks 460€ for the conversion of an A7.

info@IRreCams.de

www.IRreCams.de

 

I don't know anyone else

[photoni]

9 hours ago, Yves W said:

Thank you Toni,

Very good solution

550€ for a camera Full Spectrum.

 

Sven Lamprecht asks 460€ for the conversion of an A7.

info@IRreCams.de

www.IRreCams.de

 

I don't know anyone else

 

now in Italy there are many astro laboratories that make the modification, with or without an internal filter
...... even private individuals who do it for €50 !!!!

this is good:
https://www.astrohobby.it/categoria-prodotto/laboratorio-astronomia/modifiche/modifiche-reflex/modifiche-per-sony/modifiche-per-full-spectrum-sony/
makes changes to 179€ "naked" and 279 with Clear filter with anti-reflection treatment (bandwidth >300nm).

I preferred to go to the Sony repair shop near my house.

 

but no one does Debayering :(

[photoni]

@Ming  I will try to buy the GRAY tape you mention
.
Teflon PTFE furniture glides (middle) are not reliable.
.
high QB39 (1.5 mm t) ~BG39
medium TSN + QB29 (2 mm t)
under TSN+ZWB2