Micro-Nikkor 105/2.8 AF-D

[lukaszgryglicki]

This is how Micro Nikkor 105/2.8 AF-D behaves on Nikon D600 full spectrum converted and debayered (white balance makes no sense at all in this case). The filter is 4mm U-340 Hoya.

 

All handheld, just first trials, I would say that 50mm/1.8 has some "chromatic" aberrations in UV, so that makes its images dreamy (by chromatic I mean just different wavelengths inside UV-A range). Less than 50/1.8 AF-D I *think*

 

 

Some leaves in UV:

1/100s, f=2.8, ISO, 4000:

 

1/30s, f=2.8, ISO 1600:

 

IR 760+ nm for comparision 1/250s, f=4, ISO 100:

[lukaszgryglicki]

BTW: you can see how the Bayer filter was "physically" removed from the sensor, see edges... you can see how much light is stolen by the Bayer matrix/CFA in UV.

[nfoto]

Nikon designates these lenses 'Micro-Nikkor', to differentiate them to the true Macro-Nikkor line-up.

 

I would off the bat say the "UV" images here mainly are influenced by little UV and a healthy amount of IR contamination.

[lukaszgryglicki]

Ohh sorry for the typo, I'll fix.

I will have one more filter soon (Kolari one for UV), I was thinking that there is not that much IR here (besides the last one which is in IR 760)... anyway - this is just a first test. My actual "first try" into UV.

[dabateman]

Yes those leaves don't look dark. I think 4mm U340 on its own still lets in too much IR.

Do you have a IR blocking filter, like S8612, BG39 or even bg38?

[lukaszgryglicki]

Nope, Kolari UV is on its way fro m US - will take maybe a week or month, who knows...

[ulf]

Ohh sorry for the typo, I'll fix.

I will have one more filter soon (Kolari one for UV), I was thinking that there is not that much IR here (besides the last one which is in IR 760)... anyway - this is just a first test. My actual "first try" into UV.

Due to the huge difference in light sensitivity between UV and IR you must have a very strong attenuation of the IR spectra.

All U-types of filter glass has a secondary peak at around 700nm.

For a really good, not IR contaminated UV image with such a filter glass, the IR peak must be suppressed.

 

Compared to the UV peak the IR-peak must be 10 000 lower (OD4) for a converted camera with the Bayer-array intact.

Your de-Bayered monochrome camera change the need for attenuation lower.

 

A lens that is not very good at transmitting UV even more attenuation of the IR is needed.

 

I think the Micro Nikkor 105/2.8 AF-D UV-transmission is lens is not that good at transmitting UV.

The improvements gained from de-Bayering might be lost by using this lens.

 

Normally foliage is black in a proper UV-only image, except for any specular reflections.

[Cadmium]

Lukaszgryglicki, I really like that last photo, the IR, it is great.

 

U-340 4mm is thick, but you would need to use 8mm to block all the IR, therefore your photos that use U-340 4mm are mostly IR, not UV, and why the foliage is white, rather than black.

It only takes a very small amount of IR to be prominent and show no UV.

Also, I would not use BG38 for any kind of UV stacking, you should use S8612 (preferably), or BG39 (which suppresses IR the same).

 

[ulf]

Lukaszgryglicki, I really like that last photo, the IR, it is great.

 

U-340 4mm is thick, but you would need to use 8mm to block all the IR, therefore your photos that use U-340 4mm are mostly IR, not UV, and why the foliage is white, rather than black.

It only takes a very small amount of IR to be prominent and show no UV.

Also, I would not use BG38 for any kind of UV stacking, you should use S8612 (preferably), or BG39 (which suppresses IR the same).

 

1mm S8612 is a good thickness for U-430 4mm, but if you would like a filter that can be working well in other filter stacks too, I would recommend 2mm thickness instead.

[colinbm]

The Baader U filter is very good for UVA photography.

[lukaszgryglicki]

OK, I need to find that filter then...

This one: https://www.ebay.pl/...iQAAOSw~sJgBLPr will be OK?

 

BTW: can this "dreamy look" be due to IR leak? I imagine that UV is, say, quite free of "chromatic" aberration (in 350-400 nm range) but then IR leak comes around 720 nm (quite far away from UV-A) and is not sharp (compared tom UV part) and contributes to dreamy look, or worse, IR leak is in focus and UV contributes to unsharpness and dreamy effect?

 

But then - debayering remainings are sharp - which looks like UV is focused, in IR photos DeBayering artifacts are barely visible.

[colinbm]

Baader is in Germany.

[lukaszgryglicki]

OK, but it won't "fix" the U-340 problem, it is just a "standalone" filter for UV, right? And if I buy S8612 2mm I can "fix" the U-340 and also have a UV-Vis filter alone (no idea if S8612 is any useful alone?)

[colinbm]

Baader U is a single filter used by a lot of people here, It is the best by far for UVA with no leaks, & it is a dichroic coated both sides & doesn't get affected like the phosphorous filters.

[lukaszgryglicki]

OK, will consider, the "problem" (or not?) is that I've already ordered Kolari UV which is on it way to me... so I will hold on a bit and see what that Kolari can do...

[ulf]

OK, I need to find that filter then...

This one: https://www.ebay.pl/...iQAAOSw~sJgBLPr will be OK?

 

BTW: can this "dreamy look" be due to IR leak? I imagine that UV is, say, quite free of "chromatic" aberration (in 350-400 nm range) but then IR leak comes around 720 nm (quite far away from UV-A) and is not sharp (compared tom UV part) and contributes to dreamy look, or worse, IR leak is in focus and UV contributes to unsharpness and dreamy effect?

 

But then - debayering remainings are sharp - which looks like UV is focused, in IR photos DeBayering artifacts are barely visible.

That is a good source for a S8612, 2mm.

Be aware of that this filter material is sensitive to humidity, especially if stored at higher temperatures. then it eventually corrode at the surface.

With proper care it is not a problem.

 

As your camera cannot show any colours experimenting with different filter stacks might be less interesting.

Then the Baader U might be a better alternative for you https://www.ebay.pl/itm/124506250509?hash=item1cfd269d0d:g:SzMAAOSwQqZgAZy1

[dabateman]

Yes that 2mm S8612 will fix your IR problem and work with other filters. Since you have a monochrome camera you may also want to get a U330 filter.

1.5mm or 2mm U330 with 2mm S8612 is a very fast UV filter. Its gives you green UV patterns with a full spectrum converted camera, but your monochrome camera it would give you the typically dark UV signatures.

Also would be at least 3 stops faster than your 4mm U340 filter stack.

[ulf]

The Baader U is designed for astronomy with at rather parallell light path.

Then the dichroic design is not a problem.

 

Dichroic filters are changing their transmission properties depending in the light incidence angle and that can be a problem when used on wide angle lenses.

With your monochrome camera there is less demand for a high OD, if using a lens with better UV-transmission.

 

I have in a few cases seen some traces of IR-leakage with a good lens using my Baader U. The U-360 S8612 2 + 2mm stack did not have that problem.

The problem, I think , was caused by a bad UV/IR ratio i the light together with the camera sensor sensitivity with a bayer array.

 

Colin lives in a humid place with much UV in the sunlight.

The Baader U is ideal for UV photography there.

 

He has seen much problem with corroding S8612.

I live in a cooler dryer climate and have much less problem with that.

 

The truth changes with environment and location.

[colinbm]

Baader U

https://www.baader-planetarium.com/en/filters/dual-use-(visual-/-photographic)/baader-u-filter-(venus-and-uv---350nm).html

[lukaszgryglicki]

I also have other full spectrum cameras (but not monochrome): another D600 and D3200 (crop 1.5 sensor Dx).

[ulf]

The advantage with working with different stacks is that you can have peaks with different wavelengths in the UV-A range, or as David suggests a creative fast filter stack that includes some visual and with your camera still looks like an UV image.

 

I have a set of tree filters for different UV:

• A stack of two U-340, 4mm + 4mm (no BG-glass) for shorter UV-A
  
• A stack of U-360 2mm + S8612 2mm for a more typical UV-a Image, similar to the Baader U, but with better IR-rejection
  
• A StraightEdgeU 3 for the UV-A spectrum close to 400nm http://www.uvroptics.com/index.php?PrecisionU
  

[lukaszgryglicki]

The "only" problem here is that every single filter from all those stacks costs around $200 or more :P

[ulf]

I also have other full spectrum cameras (but not monochrome): another D600 and D3200 (crop 1.5 sensor Dx).

Then it would definitely be interesting to explore different filter stacks.

 

I must admit I need my Baader U very seldom.

[ulf]

The "only" problem here is that every single filter from all those stacks costs around $200 or more :P

No they do not. https://www.ebay.pl/str/uviroptics?_trksid=p2047675.l2563

The dichroic filters like the SEU3 and Baader U do, but not the others.

You can buy a S8612 2mm and a U-360 2mm for less than the cost of either of the others.

When you have one S8612, 2mm you can combine it with many different other filters, temporarily making a stack.

By reusing the S8612 2mm or even a BG39 2mm you can create many different stacks.

 

The filter collection can grow step by step while you explore.

[ulf]

I have standardised my UV-filter collection dimension to 52mm filter rings.

That is one of the most common dimension used.