THE UNDEFINED CONVERTED NIKON Z5 FOR LIGHTPAINTING, INFRARED AND ASTROPHOTOGRAPHY
THE IDEA
So far I have mainly used two cameras. The Nikon D750 for my light painting pictures, shots of the starry sky at night and photos in daylight. A few years ago I converted the Nikon D300 in an undefined way, i.e. I removed the hot mirror filter, which blocks most of the ultraviolet and infrared radiation. I used the D300 to take infrared photos in daylight. With long exposure times and high ISO values, the camera, which is now 17 years old, does not cut a good figure. The image noise is almost impossible to get under control. In addition, the sensor of the D300 is not very sensitive in the infrared range. False colour photos with infrared pass filters with 630 nm or even 550 nm are only possible to a very limited extent and only in bright sunshine and temperatures above 25° C. So I have been looking for a better solution for a few years now, one that at least has the characteristics of the Nikon D750 and can also take good infrared photos. In addition, the camera should also be used for astrophotography with appropriate filters.
THE CAMERA
The first option would be to remove the hot mirror filter from the Nikon D750, or rather have it removed. This would enable the camera to take infrared photos. For images in the visible spectrum of light, a UV/IR cut filter is attached in front of the lens. And that brought me to the first problem. The Laowa 12/2.8, which I use very frequently, has no filter thread. Square 100 mm filters can only be attached to the Laowa with a special filter holder. UV/IR cut filters are not available in this size, at least I have not found any despite intensive searches. Filters for astrophotography are usually attached as clip filters directly in front of the sensor. This is very fiddly with an SLR camera and there is always the risk of damaging the mirror or the mechanical shutter. Clip filters cannot be stacked either, so you can only use one filter at a time and therefore have to change it more frequently. The biggest advantage of this solution would be that I wouldn’t have to buy a new camera. The sensor of the Nikon D750 is perfect for long exposure times and high ISO values. The image noise is very low. The dynamic range is large. Here is an example. I took the following picture with ISO 4000 and an exposure time of 30 seconds.
The better solution would be to use a camera without a mirror and mechanical shutter. On the one hand, all conceivable lenses can be adapted more easily than on the DSLR due to the smaller flange focal distance, and on the other hand, working with clip filters is easier and less dangerous. Until now, I have stubbornly refused to buy a mirrorless camera. The main reason for this is the pricing policy of the manufacturers. A very similar camera with almost identical imaging performance is built without the mechanically complex mirror and shutter and then the savings in production are not passed on to the customer? The list price of the Nikon D780 is 2259 €, that of the Nikon Z 6II is 2139 €. For the Z 6II I would need the FTZ adapter to be able to use the old lenses. This would cost another €200.
But then there’s the Nikon Z5. The sensor of the Z5 is identical to that of the Nikon D750. The imaging performance should therefore also be identical. The list price of the Z5 is €1629. Nikon is currently offering a €300 – €500 instant discount on many products. After some research I found an offer for just under 1000 €. I think that’s a very reasonable price compared to the D780. My only criticism at this point is the body. It is not made entirely of a magnesium-aluminium alloy, as is the case with the D750, D780, Z6 or Z7. Some housing parts are made of plastic. It remains to be seen whether this will actually have any effect in reality. But perhaps I will manage to prevent the camera from falling to the ground or something similar. However, the D750 has already had to withstand several falls from a height of 2 metres onto hard concrete. And it has.
The advantage is that the batteries of the D750 also fit in the Z5 and the connection for the remote release is the same.
THE ADAPTER
Since I’ve been shooting exclusively with Nikon cameras since 1992, I’ve added a few lenses to the mix. To be able to use the lenses on the Z5, I need an adapter. The FTZ (F to Z) mentioned above is apparently the only adapter available with an electrical connection from camera to lens. So if you want to use lenses without an aperture ring or autofocus, there is no way around the FTZ adapter. All my lenses have an aperture ring. Autofocus is permanently switched off on my D750, and most of my lenses don’t have autofocus at all. So a purely mechanical adapter for 40 – 50 € would be completely sufficient for me.
The adapter compensates for the difference in flange focal distance between Nikon Z (16 mm) and Nikon F (46.5 mm). I had the idea that it would be very cool if filters could be accommodated in the adapter. 1.25″ or 2″ screw-in filters come into consideration. These are usually used in telescopes and, due to their small size, are cheaper than large screw-in filters for the filter thread of the lens or clip-on filters. Unfortunately, there is no such adapter available to buy. After some research, I found a solution to build such an adapter myself. I bought an adapter from Nikon Z (camera side) to T-2 (telescope connection) and a second adapter from T-2 to Nikon F (lens side). This adapter has a thread inside to attach 1.25″ filters. The T-2 adapter for the camera side is 8.3 mm thick, the adapter for the lens side is 21 mm. This means that 1.2 mm is missing to correctly compensate for the flange focal distance. So I ordered some T-2 levelling rings. Unfortunately, these are not available individually, but only as a set (15 pieces in different thicknesses). The set includes rings with the 1.2 mm, so I didn’t have to combine several of the rings to get the correct dimension.
I found another adapter from Nikon F to T-2, or M 52, from the company ZWO. However, at 29 mm, this is too thick for my project. With the missing 1.5 mm thickness, it will probably not be possible to find a counterpart for the connection to the camera.
THE CONVERSION
To get the camera into the desired undefined state, the hot mirror filter had to be removed and replaced with clear glass. For a brief moment, I considered doing this work myself. I quickly discarded this idea. In the case of the Nikon Z5 and almost all other current cameras, this is anything but easy. So I sent the camera to IRreCams.de and had the desired conversion carried out there. After two weeks I had the converted camera back in my hands. The conversion meant that the automatic sensor cleaning function no longer worked. All other functions, such as optical image stabilisation and autofocus, remain intact. I don’t need any of these functions, but it doesn’t hurt if they still work.
NORMAL PHOTOS AND LIGHT PAINTING
I use a UV/IR cut filter to ensure that the camera works as it did before the conversion. This blocks ultraviolet and infrared radiation, ideally in the same way as the removed hot mirror filter. One possibility now is to attach a 1.25″ filter in the adapter. The second option would be to attach the filter in front of the lens. As mentioned above, some of my lenses do not have a filter thread, so I screw the UV/IR cut filter into the adapter. In this state, the camera only captures light from the visible spectrum. If necessary, I can then attach a screw-in filter to the lens with other lenses, for example colour or ND filters.
INFRARED PHOTOGRAPHY IN DAYLIGHT
To take infrared photos in daylight, I remove the UV/IR cut filter from the adapter and attach an IR pass filter in front of the lens or again as a 1.25″ version in the adapter. Unfortunately, the selection of IR pass filters in this size is not very large. So far I have only found variants with 645 and 830 nm. The latter delivers monochrome results. False colour photos are also possible with 645 nm. I mostly use the Nikkor 17-35/2.8 for infrared photography. I can then also screw filters with other wavelengths (550, 580, 630 or 720 nm) onto the 77 mm filter thread. IR pass filters block almost all the light below the specified wavelength and have a high transmission in the range above this wavelength.
FULL SPECTRUM LIGHTPAINTING
Light painting with the full light spectrum is quite simple if there is no ambient light at the shooting location, for example in an unlit basement. In this case, the camera can be used without a filter. All the light is then painted into the picture with artificial light. You can use infrared torches, UV torches and normal torches. The camera then only “sees” the respective light. All wavelengths can theoretically be combined in a single exposure. In practice, however, this is quite difficult because the white balance cannot be set appropriately for all wavelengths. Either the value for infrared light, visible light or UV light is correct. This can be seen clearly in the example image. I had set the white balance to infrared light (4780 K). I illuminated the tube with an 850 nm torch. The image result for this part is therefore monochrome. I painted the light figure in the centre with a Convoy S2 with an orange LED. Due to the “wrong” white balance, this is green in the finished light painting. The picture was taken in a single exposure and, apart from sharpening and denoising, was not processed on the computer.
To avoid having to work “blind”, as you can’t see anything at all when working with the IR torch, I screwed a 720 nm IR pass filter in front of the lens. As this blocks visible light, I was able to illuminate the room with a green torch without this being visible in the image. Green LED light has no infrared component. I then used a UV/IR cut filter for the light figure so as not to pick up any additional infrared light. I’m not sure whether the orange LED emits infrared radiation. Screw-in filters in front of the lens are easier to change during the exposure than the 1.25″ filters in the adapter.
ASTROPHOTOGRAPHY
The starry sky at night shines in both the visible and invisible spectrum. In order to record the radiation from distant nebulae, for example, a conversion to the full light spectrum or an astro conversion with a defined filter is necessary because the nebulae mainly shine in the infrared range. In the latter case, however, the camera would no longer be usable for the tasks mentioned above. I use an astro filter as a clip filter. Test shots with a 1.25″ filter in the adapter were not satisfactory. Particularly with short focal lengths, the sharpness of the image decreased visibly.
There is often a lot of light pollution at the shooting location and it is necessary to attenuate this by using appropriate filters or, ideally, to eliminate it completely. Narrow-band pass filters are used to amplify faint celestial bodies, which only allow the radiation of the celestial bodies, especially nebulae, to pass through and block all other wavelengths. These interference filters are usually very effective, but also very expensive, especially if they cover two or even three radiation bands (H alpha, H beta, OII, SII). Such filters are rarely available as screw-in filters for the standard filter threads of lenses and are very expensive. Furthermore, the filter effect is often better if they are placed between the lens and the sensor and not in front of the light entry opening. Due to the high costs, I have not yet purchased any of these filters. So I can’t say anything about the quality and effect of these filters.
I took this panorama in two rows of eight panels each. Each panel consists of 15 images with an exposure time of 15 seconds each at ISO 3200. I had set the aperture on the Soligor 25/2.8 to 4. In addition to the 270 individual images, I took 15 dark frames and 11 flat frames. First I stacked the individual images in Sequator, in the second step I used Hugin to stitch the stacked panels into a panorama and in the last step I processed the image with Darktable (white balance, sharpening, denoising, contrast etc.).
Conclusion
I still need to gain some experience, especially in the field of astrophotography. As you are very dependent on the weather, the phase of the moon and the light pollution at the shooting location, it will probably be a while before I can show really good pictures. Apart from that, the converted Nikon Z5 fulfils all my requirements so far. I wouldn’t want to be without the simple adaptation of the various lenses, whether Nikon F, M42 or Canon. The results in infrared photography are very good. As usual with Nikon, the operation is good.
Sven Gerard, Jahrgang 1969, geboren und aufgewachsen in Berlin. Er fotografiert seit frühester Jugend mit großer Leidenschaft. Neben dem fotografischen Erkunden zahlreicher beeindruckender verlassener Orte, widmet er sich seit mittlerweile 10 Jahren intensiv dem Lightpainting. Sein umfangreiches Wissen teilt er auf seinem Blog „Lichtkunstfoto.de“, weiteren Publikationen und in seinen Workshops. Darüber hinaus organisiert er Veranstaltungen zum Thema Lightpainting, wie „Light Up Berlin“. Gerard lebt gemeinsam mit seiner Lebensgefährtin in Berlin und hat einen erwachsenen Sohn.
Sven Gerard was born in 1969 and grew up in Berlin. He has been a passionate photographer since his early youth. In addition to photographically exploring numerous impressive abandoned places, he has been intensively involved in light painting for 10 years now. He shares his extensive knowledge on his blog ‘Lichtkunstfoto.de’, other publications and in his workshops. He also organises events on the subject of light painting, such as ‘Light Up Berlin’. Gerard lives in Berlin with his partner and has a grown-up son.