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The 35mm f/2 AF is great

Just a quick note about my test with Nikon D700 and the Nikon 35mm f/2 AF. This could become my new favorite lens – sharp, no fringing, no hotspots. That’s how it should be. In general, the first thing to do is to use Liveview – especially at close range. Secondly, it can also be advantageous to shoot in M mode and turn to “infinity” especially for objects that are medium-distance away.

X1-Orange “Aerochrome” filter:
Objects at a great distance and the edges of the image are sharp from from f/13, better 14.
Temperature: 2800. Tint: 67.
Blues -30, Greens -20

 
35mm f/2 AF

 
720nm:
Objects at a great distance and the edges of the image are sharp from f/8, better 9.

 
35mm f/2 AF

Limitations of a self-converted camera

It’s nice when you can build your own IR camera. But it has limitations. This has become clear in my test of wide-angle lenses with my Nikon D700.

If you just remove the IR cut filter, then of course you are missing a layer of glass in front of the sensor. That in turn affects the focusing. Here it gets complicated, because it strongly depends on the lens and the filter (!), with which minimum f-number you can generate a sharp image.

And please note: We are not talking about objects that are a few centimeters or even meters away – these come out sharp, even at f/4 or f/5. I am talking about 50, 100 or 1000 meters, of mountain ranges or distant buildings. These come out sharp only at f/11 or even 13, depending on the lens and filter.

 
self-converted camera

 
This creates a problem. Primarily with old fixed focal length lenses that have to be operated manually. But also with AF lenses, for example in the 35mm or 50mm range, you have to set the f-number high to get distant objects into focus.

Professional IR retrofitters like Life Pixel or Kolari Vision replace the hot mirror with a piece of glass that lets the full spectrum through. This is a service that is worthwhile and also justifies a higher purchase price.

This replacement is the real challenge in IR conversion. The problem is dust or scratches. If dust gets between the sensor and the hot mirror replacement, you can see it very well. In fact, you can see every minimal speck of dust or scratch because the glass is so close to the sensor and therefore at the “plane of focus”. Therefore, hats off to the professionals who manage to install such a filter in an absolutely sterile environment.

What does that mean now? Does it mean that a self-converted camera that “just” has the IR cut filter removed doesn’t work or shouldn’t be bought? No. You just have to pay a little more attention. The following points should be noted:

1. strong IR filters are not a problem. Whether 720nm or 850nm, these filters work fine with a self-converted camera, usually from aperture 7.1 or 9. The problem is those that let through large portions of the visible and areas of the IR spectrum, for example my Aerochrome combo. There, on average, aperture 11 or even 13 is necessary.

2. zoom lenses work very well on average. For example, the Nikon 28-80mm – a dirt cheap but fantastic lens, goes very well. There you can easily shoot with relatively low f-stop even with false color filters.

3. in general, the wider angle and fixed, the more difficult.

4. pay attention to Liveview. Always use it if possible. But this applies to IR photography in general.

I tested the following lenses with the D700:

– Nikon 35mm f/2 AF
– Nikon 28mm f/2.8 AI-s
– NIKKOR-N Auto 24mm f/2.8

Conclusion: The 28mm and 35mm generally generate excellent sharpness and also perform well with the X1-Orange combination. With both lenses, the optimum sharpness (sharp from corner to corner) is f/11 at 720nm and f/13 at X1-Orange. The 24mm has severe corner blur at both 720nm and X1-Orange that you can’t get rid of even with a high f-number, and fringing and strange colors with X1-Orange.

I will probably test later with the Nikon D7200 converted from Life Pixel to Full Spectrum. This has a hot mirror replacement filter built in – and I’m convinced that you can “focus” distant objects there with a smaller f-number. But once you’ve used an FX camera, especially the D700, you don’t want to go back to a DX. I don’t know. Especially the X1-Orange combo just works much better with an FX.

TB550/660/850 plus Tiffen 16

Sometimes it’s like a jinx: You want to test new gear or have good ideas for experiments and the weather doesn’t play along. That’s what’s happening these days. I need sun! Unfortunately, a thick blanket of high fog hangs over me, indeed over all of Europe, it seems, from the Pyrenees over France and Germany to Finland, as SRF Meteo writes. Well. It’s good enough for a first small test.

I took out my TB550/660/850 filter again to see how it performs in combination with the Tiffen 16 Orange filter (which I use for my usual Aerochrome emulation with X1). The ultimate goal is to capture “Aerochrome-like” videos in a simple and fast way, without much post-processing.

And that is only possible to a limited extent with X1 and Orange, since you have to make changes in the raw converter as well as swapping channels. It works well with photos and Photoshop, but videos and Premiere are another story. Ideally, I would be able to set the white balance in-camera so that it matches and then just feed the video into the channel mixer in Premiere.

The problem with the TB550/660/850 filter, which actually works on the same principle as the Aerochrome film (registers only green, red and infrared), is that the vegetation comes out too orange and even more post-processing is needed than with the X1-Orange combination. It seems that the IR contamination of the red and green channel is too strong. Paradoxically, processing a video with this filter is easier. The reason is primarily that you can set the correct white balance in-camera.

So maybe a complementary orange filter could help get better colors in-camera.

Here is the result – on the left without Tiffen 16, on the right with Tiffen 16. It seems to be better. The pale pink-orange becomes a richer pink. But what matters is how it will look in the sunshine. I hope the tenacious blanket of fog dissipates in the coming days.

 
TB550/660/850 plus Tiffen 16

TB550/660/850 plus Tiffen 16

Going pre-AI: The NIKKOR-N 24mm

I am looking for the best wide-angle lens for my Nikon D700. It should perform very well in infrared, both in combination with 720nm filters and with the Aerochrome combo (green-orange). Well, it’s not that simple, unfortunately. Photographer Edward Noble has compiled a helpful list of lenses that have good IR performance.

Based on the recommendations, I recently bought the ancient manual lens NIKKOR-N Auto 1:2.8 f=24mm and tried it out briefly for the first time today. Conclusion: Thumbs up for 720nm, thumbs rather down for Aerochrome combination. In general: no hotspots, which is great. Sharpness from f/11 and Infinity at distant objects, which is OK. Needs more testing. Would also like to make a comparison with the Nikon 28mm f/2.8 AI-s. Which is sharper, which has better IR performance?

What’s great is that I didn’t have to convert the lens (as I feared). Because normally you have to grind off the aperture ring or replace it with another ring to use the lens with modern cameras. But here it has already been done, probably by Nikon itself, in a service that no longer exists.

 
NIKKOR-N 24mm

NIKKOR-N 24mm

NIKKOR-N 24mm

NIKKOR-N 24mm

NIKKOR-N 24mm

NIKKOR-N 24mm

NIKKOR-N 24mm

Autumn Aerochrome

I was finally able to photograph autumn vegetation with a converted Nikon D700 and the Aerochrome combo. This time with an older 50mm lens (f/2 AI). So far the best lens for Aerochrome emulation with Hoya X1 and Tiffen Orange 16.

The settings in the raw converter in Photoshop:

Temperature: 2800
Tint: 53
In Color Mixer the following:
Blues: -30
Greens: -20

 
Autumn Aerochrome

Autumn Aerochrome

Autumn Aerochrome

Autumn Aerochrome