Nikon Z6/Z7 as a UV/IR Conversion: the Bad News

[dabateman]

The art of 2020 will be interesting. Many different forms of inspiration and emotion from various people.

 

[nfoto]

I had the briefest of opportunities to try the Z6 with my 21mm f/4 Panagor for UV photography, the subject being the classic spring flower in my region, Tussilasgo farfara. A member of the vast Asteraceae, T. farfara has a very well known UV appearance.I shot the flowering specimens with ISO 200 and the lens stopped down to f/11. Exposures varied between 2 and 4 sec. (this was afternoon shooting).

 

Here is my "reward",

 

 

As shown by this 100% crop, the 21mm f/4 Panagor actually is quite sharp for UV work. In common with so many wide-angles lenses, its bokeh quality isn't going to make it famous. Besides, it flares easily and the rear filter box occasionally leaks a little light too, if not shielded carefully. Both factors lead to my cropping the composition quite a bit before I was satisfied.

 

 

All the expected UV details were clearly exhibited by the Panagor..

 

As I did shoot at a fairly low ISO, the dreaded "striping" phenomenon of the modified Z6 was plainly visible, but Topaz DeNoise handled it fairly well so only the weakest vestiges were present afterwards.

[Bill De Jager]

The 35cm f/4.5 lenses were customised to be used on high-speed film cameras, used for documenting nuclear tests etc.

 

I have three of these lenses, two with the Photo-sonic mount and one (shown here) in the original Nikon(RF) mount. I managed to fit one of the two converted lenses to a bellows device, thus knew this lens could do UV, but the rig was a little on the awkward side for field use. Thus I had no hesitations acquiring a third, complete lens, and as far as I recall, asking price was very modest as well. Shipping was more than the lens itself. I already had several of the N-F Tube adapters linking long-focal rangefinder lenses to F-mount in my possession.

 

Birna, I'm having my lens modified with an F mount and an internal filter. Two locations are possible, both to the rear of the last element: right in front of the diaphragm, or right in front of the mount. Are there any optical or other technical reasons to prefer one over the other, assuming both are equally accessible when the lens is in use? (The front assembly containing the elements unscrews allowing easy access to the diaphragm area.) The diameter of the diaphragm is ~49mm wide open so there should be no vignetting at smaller apertures.

[nfoto]

I would opt for the 'right in front of the mount' approach.

 

In my case, vignetting was caused by the first version of my rear filter box, which hailed from the m43 period.

[Bill De Jager]

Thank you, Birna.

[Andrea B.]

Tussilago !!!! I love those crazy little flowers.

 

Birna, do you remember when I spotted a yellow flower from Ruth's balcony? We eventually went down to look and found it was a very late-blooming tussilago.

[nfoto]

Another example that the love-hate relationship with the Z6 actually ends up in useful images.

 

Kissed by the Fierce Spring Sun

 

 

Kyoei 35mm f/3. Baader U, modified Z6 (camera on M, see below)

 

The main point of interest her is that despite the massive overexposure of the solar disc itself, from using 1/10 sec exposure at f/16 and ISO 1600, did still leave rather soft contours and details around the overexposed area. This tells at lot about the dynamic range of the Z6 sensor.

 

I couldn't get the little Tussilago properly in focus whilst keeping the silhouette of the dead tree in the background reasonably delineated, thus opted for a "deconstructed reality" rendition instead.

 

The final output was massaged by Topaz Denoise, however some residual striping survived the plugin. Not very important for this photo, though.

[nfoto]

An example of a field of application the modified Z6 does pretty well. That is, with the caveat one should be careful using native Z-mount lenses as they tend to give uneven illumination and colour shifts of the frame. My guess is the rear elements of these new-designed lenses sit quite close to the sensor surface and there are reflections involved.

 

Not a problem, though, as many older lenses can work their magic even with the Z system. One of these is the vintage 200-400mm f/4 ED Nikkor AIS (non-IF) which always has been a favourite of mine for landscape work. Here is a recent example taken with that combination.

 

 

We are looking across the inland delta of Nordre Øyern, the largest in Northern Europe, and the background houses are 4-5 km away. Birches just entered first stages of leafing across the delta islands. The depth feeling appears very compressed and perspective flattened here.

 

This is a stack of 10 frames processed through Photo Ninja and subsequently in Zerene. False-colour IE emulation using Nikon O56 filter. It was a windy day and lots of movement in the trees, but in the end the sequence panned out well.

[nfoto]

Another false-colour IE emulation with the Z6 and Fisheye-Nikkor 16mm f/3.5 lens.

 

 

Interestingly, the native Z lenses tend to cause uneven illumination and colour shifts across the frame when used with dense filters. Or even worse, they exhibit nasty hot spots for false-colour or IR work. Time to press the proven old-timers into service.

[Andrea B.]

Once again Birna finds Scenes from an Alien Planet right here on earth!

[Alaun]

A little update on the small, recently purchased (directly from Baader) Baader U.

The pictures were taken with the Z6 and the UV-Nikkor

all at F11 and ISO3200

Each picture developed with 3 WB-settings done with PhotoNinja

Each row one WB setting

Filters:

1.Line: Only Baader-U (0.25s)

2.Line: Baader-U & S8692 2mm (0.5s)

3. to 5. Line: Baader-U & S8692 2mm & old Marumi Pol (3s, 2.5s, 3s rotated)

 

[nfoto]

A quick assessment indicates, to me at least, that the S8612 is required to give a resemblance of the U 2" rendition.

[Alaun]

I agree.

 

A quick simple visual comparison with bare eye looking through both Baader-U filters (small with greenish surface and large with golden surface) on to a brightly by sun lit concrete surface: With the golden surface everything is dark, with the greenish I can see structures, some colors, mostly into the red.

[Andy Perrin]

What is going on here? It seems like this brand new Baader U has a significant leak? Or is this somehow related to the Z6, which I thought was the main purpose of this thread?

[Alaun]

It is a response to #245

[nfoto]

A tangential development, sparked by my positive experience with some wide lenses that could or should work with a small rear-mounted filter. The Z system in general allows rear filtration due to its very short register distance. I did order a 1.25" Baader that turned out to be a disaster. Question was whether this was old or new stock.

[Andy Perrin]

It is a response to #245

A tangential development, sparked by my positive experience with some wide lenses that could or should work with a small rear-mounted filter. The Z system in general allows rear filtration due to its very short register distance. I did order a 1.25" Baader that turned out to be a disaster. Question was whether this was old or new stock.

Ah, I see, this thread is getting so long that I'm losing track of the tangents!

[dabateman]

Yes more tangents. The thread I would title "Birna's current thought part 1".

"Birna's thoughts part 2" is the Sony monochrome thread.

Easier to keep them straight in my mind that way.

[nfoto]

I did test my modified Z6 for internal flare with the Z 35mm f/1.8. With the lens capped and everything well hidden under a thick blanket in the dark, horrible flare developed already after 30 sec exposures. A similar experiment with the PrimaLuce Z5 did not show anything expect total blackness.

 

This observation, and the UV striping grievances I experienced with the Z6, finally made me to consider resetting the Z6 to stock conditions and selling it off. This goes against all my principles but frankly, the modified Z6 simply cannot be relied upon. Any company now offering Z6 modifications is potentially ripping off their customers. (this applies to the original Z6, I have no data on the Z6 Mk.II on the internal leak issue).

 

I might ask my friendly Nikon tech to keep the coverglass from my modified Z6 to put on the Z5, as I strongly suspect it will allow deeper UV.

 

So the painful experience of the Z6 finally has reached its end point. To paraphrase our Admin-in-chief, "Oh well".

[dabateman]

Yes Nikon looks to have fixed most issues with the budget Z5. Amazing, seems to be the Z-mount camera to get.

[otoien]

I came across this filter drawer solution in an Astro forum available for z-mount, not sure if it has been mentioned here before. Perhaps it could be of use for those who do not want a home-brewed construction:

https://astrohutech.store/product/mirrorless-camera-filter-drawers/

[dabateman]

Yes Birna has a drawer kind of like that.

The m43rds one to EF-mount only work on cameras without the hump, as it collides with it. Unless you machine it down. I think I read that Johan did that or is trying it.

[Andy Perrin]

Was there any major reason to prefer the Z6 over the Z5 as a camera to begin with? What did they change?

[nfoto]

I decided upon the Z6 at a time well before Z5 was launched.

 

At the time I already had Z7 (for studio work) and a Z6 for general use, so was familiar with the Z system.

[Andrea B.]

And so I'm not surprised you are restoring the Z6 and giving it a new home. You stuck with that Z6 conversion far longer than I could have tolerated !