Sunday, 8 June 2014

Lens Review - Nikkor 85mm f/1.4 AF-D

I'm making these lens reviews to illustrate their capability at capturing infra-red images. The Sony A7 platform is great for displaying almost any 35mm lens' full potential on digital (via adapters), so I'm now capable of testing nearly any lens I can get my hands on. These review won't be exhaustive or hugely technical, they'll concentrate on real world samples and experiences. Mostly it will help point out the ones to avoid when choosing a lens to shoot in infra-red.

I hope to build a good library of reviews by borrowing lots of new and old lenses from friends, but I have a few to start me off and also have my eye on a few to buy, so hopefully this section will grow quite quickly.

The 85mm Nikkor lens has been one of my favourite lenses to shoot with for the last 3 years or so. Although it's a little niche when used normally, since shooting a lot of panoramas it has opened up the possibilities to shoot wider angles and it works in pretty much any lighting conditions too. It has almost replaced the 50mm as my top choice when going out for a days shooting (I tend to choose only one lens).

    IR Issues
This is the most important factor when choosing a lens to use for infra-red photography. I can happily confirm that the Nikon 85mm f/1.4 AF-D does not suffer from the infamous hot-spot issue. I have tested it at various apertures (which would effect the size/intensity of hot-spots if they showed up) and I've seen no hint of it here. Flaring remains as controlled with IR as it does with visible light. It's capable of producing some great clarity and contrast, as long as you keep direct sunlight off the front element, but that's true of all lenses. The included metal lens hood helps a lot in this regard, so despite making it even bigger I advise leaving it on as much as you can.

Note: Corner quality is difficult to quantify with infra-red for a host of reasons, but I will do my best to review around these issues.

The 77mm filter thread is common for many professional, large aperture lenses. High quality infra-red filters of this size will cost you a hefty sum, but on the up side you can step them down to most other filter sizes. If you have other high end lenses they'll probably share the filter size anyway. Lenses like:

  • 17-35mm f/2.8
  • 24-70mm f/2.8
  • 70-200mm f/2.8

As for which infra-red filters to choose - I've narrowed the ones I need down to a minimum. 77mm filters can be really expensive so this will be an important consideration for some.

  • When using a full-spectrum camera I really like the pure black & white B+W 093 (about 850nm). For colour IR anything between 680-720nm just doesn't provide enough colour to cope with the huge amount of IR light that gets captured, so I use a plain old red filter. Some people like orange, but I find that red gives me plenty of options with different processing techniques. 
  • When choosing an infra-red filter to be installed on the sensor itself, if converting to IR only (ie. you aren't interested in shooting UV or colour) then I'd suggest somethning similar to red. 650-665nm IR filters let in plenty of colour too. This way you can shoot colour IR with no filter and then simply add a more aggresive IR filter for more moody shots. The higher you go the less colour comes. Colour pretty much stops at 750nm so after that it's black&white or split-tone all the way.
  • On a non-converted camera this balance is very different and there I would recommend a 695-720nm IR filter for colour, but this depends greatly on how aggressive your cameras IR blocking filter is, so a bit of trial and error may be needed. Much lower than this and you'll have too much colour information, which drowns out the small amount of IR light captured. Much higher than this and it will be all IR anyway. I haven't tried the orange filter with this lens on the full-spectrum camera yet and that could be interesting, but I get such good results out of the red I don't see a lot of point - yet.

    Handling / Physicality
This is a pretty big and heavy lens if you're used to a 50mm prime, or a cheap zoom. There's a lot of metal and glass here, but that's why it's so great. Here's a picture of it next to the 35mm f/2.0 lens (reviewed previously) for scale reference. This 35mm is also about the same size as the 50mm f/1.8 or f/1.4 from the same range.

On an SLR the 85mm lens is a little heavy but no big deal at all. I've used it with a Nikon D3 and D600 and both feel very well weighted. Adapting this lens to a mirrorless camera is a much different story. Apart from the annoyance of loosing autofocus the weight distrobusion is odd, although mostly in looks. As long as you hold the camera with both hands and support the lens' weight it's actually quite comfortable to use. Considering you'll have to shoot this way to continuously adjust focusing anyway it's not a particularly awkward experience.
When not shooting and holding the camera one handed I recommend to holding it by the lens and not the camera grip. There's just too much weight, too far forward to safely hang off of the A7's mount.

Although Nikon used to make a couple of manual focus lenses that went as wide as f/1.2, they've never done it with an 85mm. This lenses maximum aperture is the widest you'll get from any modern autofocus prime lens from Nikon right now. I hope that changes one day, but I doubt it given their new seriously high-end 58mm lens is also f/1.4 as well. The aperture control ring, like all AF-D era lenses, is horribly plastic, nasty to turn and has an annoying locking mechanism (which must be on for use on electronic Nikon cameras). There is nothing nice about the dial, but thankfully the widest aperture gives some really quite beautiful and large bokeh. This is one of my favourite lenses for shallow depth-of-field work and as you'll see from the sample pictures at the bottom of this page, I don't just use it for portraits.

There's been a newer AF-S version of this lens out for a few years, although optically it's largely unchanged from this one. It has a silent motor, full-time focusing and nano crystal glass, but it will cost more than this one and is bigger. Although this older AF-D lens has come down in price a bit over the years there's also more competition now. If you don't mind forgoing autofocus entirely then Samyang offer a very compelling version of this lens for a fraction of the price. I'm very curious to see how well the Samyang deals with infra-red and I hope to test it out really soon, so I will report back as soon as I've had a go.

With all this glass you didn't expect this to be quick did you? Good because it's not, although it's not exactly horrific either and I expected it to be noisier too, given it's not a hypersonic lens (AF-S). Actually the focusing is OK here until you want to switch it from autofocus to manual. It feels preceise and it's not easily knocked (like the smaller AF-D lenses), but when you switch it to manual the button on the lens will leave you with a nasty feeling. The press and rotate mechanism is awkward and feels fragile. I've had this system break on a Nikon 80-200mm lens and it's not cheap to fix. Quite what's wrong with a simple button I don't know. Unfortunately you'll have no choice but to use this switch if you want to use manual focus because otherwise the focus ring is locked (you can't just use the switch on your camera body instead).

The sharpness of any super wide-aperture lens will never be as good as a version with a less wide-aperture. This lenses considerably cheaper sister - the Nikkor 85mm f/1.8 AF-D will provide slightly better sharpness (as well as less aberrations etc.). So you buy a lens like this for it's wide aperture and the relative sharpness it gives at that aperture. They are not for pixel-peeping statistics monkeys as they will always look worse on paper / in tests. What they excel at is producing shallow depth-of-field and hopefully produce some pretty bokeh. These things are very hard to quantify so you generally just have to look for some nice samples somewhere, but the good thing is that these aspects should jump out at you from even a small sample picture.

All that said - that the relative sharpness of this lens I find to be fantastic. If you don't need the shallow depth-of field (subject isolation) then you can avoid almost all of the lens aberrations from about f/2.8, although if that's all you ever want to shoot then you should buy the f/1.8 version.

This aspect is this lenses main feature for me. The quality of the blurred backgrounds (or foregrounds) is really pretty, but don't take my word for it, take a look at the samples below that are taken on the widest apertures. If you would like to see some of the colour images I've taken with this lens wide open click here, here, here & here (there are more examples on my Flickr gallery).

    IR Samples
Here are some images that I've taken with the Nikkor 85mm AF-D on the converted Sony A7 camera:

▲▲  Full Spectrum @ f/1.4 ▲▲

▲▲  Hoya #25 (Red) @ f/1.4 ▲▲

▲▲  B+W 093 (850nm IR) @ f/8 ▲▲

▲▲  Hoya #25 (Red) @ f/8 ▲▲

▲▲  Hoya #25 (Red) @ f/1.4 ▲▲

▲▲  B+W 093 (850nm IR) @ f/1.4 ▲▲

▲▲  Hoya #25 (Red) @ f/1.4 ▲▲

    Bokeh Panoramas
Here are a couple of bokeh panoramas that I've taken in infra-red. This technique involves taking a bank of photos @ f/1.4, while rotating the camera on the lenses entrance pupil. These are then stitched together to make a larger, wider angle photo with shallow depth-of-field. On average I take about 40 images for each panorama and the results are roughly equivalent to a single shot taken with a 28mm f/0.8 lens (on the full-frame format). If it existed a lens like this would be too large, heavy and expensive to warrant using/buying. It would also be extremely difficult to make it perform to the same quality.

The down side to this technique comes from the multiple images. They restrict you to rather static subjects and lighting, can cause stitch errors and give a pretty distorted perspective most of the time. The latter two issues can be fixed/corrected in Photoshop, but the most difficult element is visualising the final result and getting it to work. Despite all this I do still feel that the technique has a lot of potential, so if you like experimenting I recommend giving it a try. You can see my colour examples here, here, here & here (plus there are more examples on my Flickr gallery).

▲▲  Hoya #25 (Red) @ f/1.4 ▲▲

▲▲  B+W 093 (850nm IR) @ f/1.4 ▲▲

▲▲  B+W 093 (850nm IR) @ f/1.4 ▲▲

This is almost certainly my favourite lens (so far), but this is heavily influenced by personal preference. I'm a prime lens nut, I love shallow depth-of-field and pretty bokeh and at that this lens is one of the best. Let me this another way - if I had to choose a lens to be stuck on a desert island with it would be this one, not the 50mm, not even an autofocus f/1.2 50mm. No, for me it's the 85mm that's king. There's just something about the lack of distortion, the sharpness and bokeh on this lens that is better, cleaner, prettier.

On a manual focus platform like the Sony A7 this 85mm lens is much harder to recommend. This is especially true when something like the Samyang equivalent is out there, but I've yet to try that lens myself, so I've no idea how well it copes with infra-red either. I will be testing it soon though, so, if you're curious, watch this space.

IR Clarity (lack of issues): 10/10
Sharpness (Middle): 9/10
Sharpness (Edges - FF): 8/10
Sharpness (@ f/1.4) - 7.5/10
Bokeh quality: 9.5/10
Bokeh amount: 9/10
Size & weight: 6/10
Lens Markings: 9/10
Versatility: 8/10
Value (used): 6/10
Value (new): 5/10

Overall Score (Colour): 9/10
Overall Score (Infra-red): 9/10
Very Highly Recommended

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