NIR Response of Nikon Z7 Converted to Full Spectrum

[Tom Lewis]

I’m looking for the NIR response of the Nikon Z7 after it has been converted to full spectrum. I haven’t been able to find this yet. 
 

I have found this for other Nikon cameras, and for other brands. But I can’t find for the Z7. 
 

Does anyone have any suggestions for where I might be able to find these curves?

 

Thanks!

Tom

[dabateman]

The same Imx309 sensor is used in the Nikon D850, z7 and z7ii.

If you have found the response for any one of those cameras,  it will be the same for the other 2.

[Tom Lewis]

Good to know. I didn’t notice those either when I was searching yesterday. 
 

I asked Kolari if they could test my camera after the conversion is complete.  I mentioned that I would share the result here if they provide. 

[colinbm]

https://www.dpreview.com/forums/post/63595614

 

[Tom Lewis]

Bingo. Thanks both. 

[Tom Lewis]

Oh, I just noticed this is only for the human visible spectrum. 

[Andrea B.]

So far, almost every full spectrum Bayer conversion has been able to make images between 700 - 1000 nm.

 

You also must consider the light source. If sunlight, then, of course, the amount of IR declines a bit between 700 - 1000 nm. (The decrease is not at all as strong as the decrease of UV from 400 nm to 300 nm.) So an IR photo with a 1000 nm filter will take a bit longer than an IR photo made with a 830 nm filter.Biological UV in low light condition.

 

Sunlight irradiance depends on altitude, cloud cover, "atmospherics" (wind is blowing dust or other particulate matter), time of day, time of year and......(whatever factor I have forgotten). But the general slope of all solar irradiance charts is similar.

[ulf]

57 minutes ago, Andrea B. said:

So far, almost every full spectrum Bayer conversion has been able to make images between 700 - 1000 nm.

 

You also must consider the light source. If sunlight, then, of course, the amount of IR declines a bit between 700 - 1000 nm. (The decrease is not at all as strong as the decrease of UV from 400 nm to 300 nm.) So an IR photo with a 1000 nm filter will take a bit longer than an IR photo made with a 830 nm filter.Biological UV in low light condition.

 

Sunlight irradiance depends on altitude, cloud cover, "atmospherics" (wind is blowing dust or other particulate matter), time of day, time of year and......(whatever factor I have forgotten). But the general slope of all solar irradiance charts is similar.

It also depends on latitude and time of the year. At 6 AM the sun is not up yet here in early March.

[Andrea B.]

I knew I was forgetting something -- latitude !!    (I had time of year.) 

 

It has been interesting here in the Santa Fe area to see how much UV there is in winter at 7000 ft (2133 meters). My UVA/UVB reader* has shown values between 3 - 4 mW/cm² on clear sunny winter days. Those are the typical values I used to get at sea level in New Jersey in the summer.

 

* from solarmeter.com

 

 

 

[Andy Perrin]

Haha, I love that you moved to a place that is blessed with plentiful UV, Andrea! It's like UV photographer-heaven!

[Tom Lewis]

Thanks for the irradiance graph and insight, Andrea.  Not that I’ll run out and get one, but what model SolarMeter are you using?
 

Alas, Kolari responded that they don't currently have the right equipment to create an accurate measurement of the CFA in my Z7.

 

I’ll confess here that the reason I want the NIR response of the CFA in my full spectrum converted camera (or, say, the D850) is to find the slope of the red filter response in that range.  Then I was hoping to look for a filter I could buy that would compensate for that response.  And if I took only the red CFA channel output that was filtered by that external filter, then I would have a linear monochrome camera in the NIR.

[Andy Perrin]

Better to just get a monochrome camera as previously discussed. Either the Leica that I mentioned in the other thread, or an astro camera like Lou suggested. Particularly the monochrome astro cameras will have a well-documented response curve (quantum efficiency) and for lab work will be fine. Trying to linearize a bayer camera is futile unless you do the measurements yourself (as Jonathan did once) and get a custom filter made (expensive and probably dichroic, which has its own issues). You will not find an off-the-shelf filter that will linearize the response. 

[Tom Lewis]

Sigh 

[Tom Lewis]

17 hours ago, Andy Perrin said:

 (as Jonathan did once)

@Andy Perrin, who is Jonathan?

[Andy Perrin]

JMC. One of our members! I highly recommend reading all his threads. 

1 hour ago, Tom Lewis said:

@Andy Perrin, who is Jonathan

[Tom Lewis]

Thx

[Andrea B.]

IF the Pentax Monochrome is convertible via removal of any internal UV/IR-blocking filter, then it might be a less expensive way to get a Mono for UV work?

 

The solar meter I have is an earlier version* of Solarmeter Model 5.0 Standard UVA+B Meter for outdoor use. I had fun with it during the last partial eclipse when I took readings every 10 minutes or so. I can't say that I really need a Solarmeter, but I have enjoyed having it and do make regular use of it.

 

* Mine is a Model 5, but looks different from what is currently displayed. 

[Tom Lewis]

3 hours ago, Andrea B. said:

I can't say that I really need a Solarmeter

I can’t say I really need a full spectrum infrared camera, but I’ll have one early next week!  How boring life would be if we only bought what we really need.  I will say that we have a snake, so I think I do need a Solarmeter. 
 

It’s nice to see that the number of options for monochrome imagers is increasing, gradually at least.