Variants of IR with the Nikon Z5

[nfoto]

This is a sketchpad-like thread to show some of the work I've conducted with the full-spectrum modified Nikon Z5. The camera is the common denominator while the lenses will vary.

 

I start with a most unusual optic, the heavyweight Rodenstock TV-Heligon 50mm f/0.75. once maligned as 'crap' lenses, they have seen a new spring with the new cameras of today. Read here https://nikongear.net/revival/index.php?topic=10627.0, in which the story is elaborated more in depth.

 

The entire projected image circle is approx. 23mm diam., but the core of the sharpness zone is smaller. How large is dictated by the focused distance and at first glance it's confusing that the core zone is at its largest, and the total image circle at its smallest, when the lens goes to infinity focus. In contrast, the image circle increases and the zone of core sharpness shrinks when the lens is brought to closer focus. Concomitantly spherical aberrations increase dramatically.

 

For the examples below, I did shoot  a typical Nordic blue-hour scene at 22 PM hand-held, ISO 100, with the full-spectrum Nikon Z5. With the ultrafast lens 'speed', shutter speeds were more than adequate for hand-held shooting even as the dusk deepened.

 

IR 720nm filter, b/w rendition,

 

 

 

Next, filtration set up to emulate false-colour infrared film, IE 2443, often (and in my opinion, potentially misleading) designated 'Aerochrome' rendition, the latter tends to lack the delicate differentiation of red, yellow, and green hues typical for the old film developed in E-4.

 

Using Nikon O56 filter, I got this result;

 

The lens continues to surprise me with its performance. Once it was maligned as a crap optic ... food for thought indeed. Depth-of-field at f/0.75 definitely is restricted, but for scenes ~100m away one can get most of it into passable focus.

 

 

[nfoto]

Another useful lens for IR is of course extreme wide-angle  designs. The Laowa 11mm f/4.5 fills the bill admirably with its huge 122 degree field of view and offering a nice and convenient 62mm filter thread. The lens can be had for different camera systems  and my sample is in native Z mount.

 

The Laowa is very sharp over most of its view, apart from the extreme corners unless the lens is stopped all the way down and even then the corners are a bit lack-lustre compared to the centre of the frame. However, given the manner in which wide lenses are used  the slight degradation in the corners is of little practical importance. More serious is the tendency to flare and a diffuse central hot spot at the smallest aperture settings. Thus the lens  demands a slow and meticulous approach to deliver the best imagery, which by the way is beneficial in other contexts as well.

 

An abandoned '70s Chevy Camero (1976?) shows off the typical exaggerated 'wide' look, often false claimed as being a 'wide-angle perspective' but in reality is a manifestation of a rectilinear optical design, a wide field of view, and a very short distance to the subject.

 

 

Decrepit rural buildings are a perfect subject for using a wide lens, and  few lens would be better than the Laowa 11mm !!

 

 

In the case above, i opted to hide the bright sun behind the building. Despite the immense motif contrast, the shadows came out quite bright thanks to the diffuse cloud layer present. The cracks and structures of the old wooden walls are rendered with breathtaking detail.

 

Now, if I had shot directly into the sun, all the illness inherent in using a lens + filte with ineffective coatings in the NIR will appear. Perhaps once in a while even these reflections can make a motif all of their own?

 

 

(the old dilapidated building is just discernable in the image centre, by the way)

[lukaszgryglicki]

Wow, fantastic photos, I love them!

 

[nfoto]

Another very interesting optic for digital IR is the vintage 5cm f/1.1 Nikkor-N from the mid '50s. Wide open images whether IR or visible-light are soft and dream-like, whilst they tend to sharpen up dramatically if the lens is stopped further down. This change in lens characteristic allows the photographer to play around with the manifestation she wishes to achieve. Unfortunately, the lens is quite rare, commands a high price, and uses the obsolete Nikon S rangefinder mount. Two versions exist and only the last one, using external mount attachment, is suitable for modern cameras. The 5cm lens takes 62mm filters and like virtually all lenses from the rangefinder era, does not focus very close.

 

Here is a typical example what the 5cm f/1.1 can do for IR,

 

 

The  dreamlike appearance is very visible, and to my eyes, very pleasing in this image. The same holds for the alternate view of the abandoned farm building already presented by the 11mm Laowa, again taken at f/1.1;

 

 

As the sky was overcast it is rendered bright not dark as one might expect. Remember I'm shooting into the sun here.

 

Here is another example at f/2 this time, so sharpness  extends further to the off-centre parts;

 

 

 

There will be a diffuse hot spot when the lens is stopped well down, but as the next example indicates, even at f/11 the issue is not very serious. The advantage of stopping the lens down is that it is very very sharp, in fact surprisingly sharp given the lens is nearly 70(!) years old;

 

 

Even a modern optic would be hard pressed to deliver something better ....

[lukaszgryglicki]

I love images at full aperture in daylight - everybody says this is "stupid" because its better to close it down for optimal sharpness, etc. - but fully open aperture shows each lens "soul" and adds that exact dreamy look which is something that I sometimes want.

 

[nfoto]

I'll round off the report on the 5cm f/1.1 Nikkor with some additional examples. Apparently I tend to use either the lens wide open, at f/1.1, or around f/11. to explore the changes in its rendition efficiently.

 

At f/11, it is really sharp, as witnessed by this small crop showing a modern modern more focused on her mobile than her child. Sigh. (focus is placed further back in the scene so she is not perfectly focussed - she just walked into the frame as I was shooting)

 

 

 

The appearance of its bokeh is quite different in front of, and rear of, the focused plane. The front bokeh can be quite sharply outlined and a little harsh at times, in particular if combined with bright out-of-focus details,

 

 

In contrast, the rear bokeh is very smooth and soft, as seen in this image of a vandalised birch tree remaining on a forest clearing,

 

 

The rangefinder 5cm lens was designed for an era in which black-and-white film reigned supreme and colour correction being less sophisticated took a second position. Thus is not surprising that using the 5cm f/1.1 for false-colour emulated infrared is fraught with problems. However, I have used lenses even worse off in this regard. A capture of my "standard" test scene shows a passable result at f/1.1, but I probably will prefer alternate optics for such applications.

 

 

If the hunt for an exotic vintage 5cm Nikkor fails, there are modern alternatives. Unfortunately IR hot-spot issues are rampant with modern lenses for the Z system, but given some care as to the manner in which an image is captured and/or processed, good results can be obtained. I'll deal with some of these candidates later.

[nfoto]

Another 'veteran' optic of interest is the Zoom-Nikkor 180-600mm f/8ED. Again, we're talking about an elusive item, but as I own a sample, why not use it? This beefy zoom lens is special by the fact it has no IR refocusing marks. Thus it is a joy to use for IR colour emulations.

 

Nature is warming up -- literally -- to bring this year's delayed spring development to a more normal state. Still lots of deciduous trees in early leafing or flowering stages, though, thus colour IR is a suitable approach these days.

 

A typical example from today shows the varied stages of verdure development at present,

 

 

 

This is shot with the 180-600 ED at f11, ISO 100 on the Z5.  The scene is made up of approx. 25 individual frames run through PtGUI, so heaps of details not possible to render here on UVP.

[nfoto]

Another example of what the Zoom-Nikkor 180-600 ED can deliver on the Z5. This is a winter scene just after a fresh snowfall. In fact, I took the picture while the snow still was falling.

 

 

The lens was set to approx. 250mm and f/11. The Z5 contributed 1/30 sec at ISO 200 for this image.

[lukaszgryglicki]

Lookin' great!

 

[Andrea B.]

Birna, your photos are magnificent!

And as you might guess, I am crazy about the 3rd photo in the 2nd set. I want a print of it!!