Pixiq

The title says it my current favorite… and it’s true, I love both the Sigma 15mm f2.8 and the 10mm f2.8  rectangular fisheyes. But things might change, who knows?

Maybe it’s a personality defect but I guess a heck of a lot of photographers, nature photographers in particular, are sufferers. You set yourself a goal (eg rainbow reflections in the eyes of a living horsefly) or a particular shot of a rare plant, an insect or some aspect of behaviour ...endless challenges and delights, why nature photography possesses me.

So, you try, you fail; wounds get metaphorically licked and you try again. Success yes, but does it bring lasting satisfaction? No way - you think of something else; another hill to climb, river to swim… Holy Grail to grasp at and gasp as it slips out of reach…

So why I am now using rectangular fisheye lens for ‘in your face’ wide-angle macro photography? Simple answer they get you much closer and with a bigger magnification than a conventional ultra-wide. Designers can be more generous with close focus since they do not have to eliminate edge distortion...and they are affordable.

What exactly is a rectangular or diagonal fisheye?

Many people associate fisheye lenses with the circular 180° coverage – fun for a while but the gimmick soon palls. Didn't you just lurv those shots of people looking down through glass-topped tables?

Rectangular or diagonal fisheye lenses do not offer a true 180º horizontal panorama - this is the measure along the diagonal (hence the name). Of course, if you fancy a bit of 3D trigonometry you can calculate that horizontal angle of view - its enough that it is less.

These lenses will render lines near the centre as horizontal when leveled at a horizon but tilt them up or down and straight lines show barrel distortion and begin to curve. DX format sensors take the central portion of the image circle and so a 15mm rectangular fisheye meant for FX produces very little distortion in this central portion taken by a DX sensor. It’s now a very close-focusing ultrawide: the way I use it. 

Sigma’s 10mm f2.8 lens is designed for DX and with this you do get considerable distortion which as an occasional is very effective.

Background story…About 2 years ago I began to get frustrated using existing wide-angles I had and the thinnest Nikon extension tube I could find the 8mm mentioned which was not thin enough…

So I did what any self-confessed, recovering optics nerd would do and started reading lens specs from 30 year old Zeiss Flektagons onward. I thought that to do what I wanted was going to mean my dismantling the rear end of a lens…and fit thin shims of 1-2mm as others have done. I have a technical background and will do stuff when away on assignment and there is no choice…but something has happened to my once-precise hands after five years working on the Italian building site we call home. Yep, I can now work stone, wood and even stucco…but not hold those tiny screws, no way.

So, how far could one realistically go at the ultra-wide end? I started looking at diagonal (or rectilinear) fish-eyes. Long ago, when filming, I played with things like circular fish-eye lenses, endoscopes and borescopes inspired by the legendary Lennart Nilson (http://www.lennartnilsson.com)

Sigma (UK) kindly lent me a pair of their rectangular fisheye lenses to evaluate. Some people claim on-line to have had ‘issues’ with Sigma quality - in 15 years I have not (in fact, I have had more with Nikon…including 3 ‘soft’ 105mm f/2.8 AF macro lenses and a D300 body that failed after three days… ). I think it's more to do with the fact that ‘critics’ feel the need to justify spending a fortune on marque lens other than vanity...I just want the shots regardless.

Which is how I come to have been using a 15mm/ f/2.8 EX DG an FX rectangular fisheye and a 10mm /f/2.8 EX DG for DX. I eventually chose to purchase one of them…but which?

Let me say that quality of both these lenses is superb – they are incredibly sharp (optimum achieved at f/8-f/11) and images even at 200% look astonishing with much hidden detail. The front element of such lenses protrudes and a knock would be a disaster so Sigma provide slide on, tube-like lens hoods.

The close-focus capability

 They both have excellent close focus: the 15mm goes to 15cm (from the sensor) and has a reproduction ratio of 1:3.9 while the 10mm achieves a reproduction ratio of 1:3.3 at 13.5cm. With the 10mm I can get down on the ground and create a bug’s eye view of leaves and such like. Edges are dramatically curved – the central portion not.

On a DX camera the 15mm barely distorts since one is using the central image portion and is equivalent to a 22.5mm (or wide-angle (crop factor 1.5) whilst the 10mm is equivalent to a 15mm lens…The 15mm has a 'real' click-stop diaphragm, with the 10mm it is electronic, set from the camera.

When using them  for close-ups although the 10mm actually gives a slightly greater degree of enlargement at closest focus the subject is just 18 millimetres from the front lens element. In comparison, the 15mm can focus on a subject at about 7cm, still very close, but that bit more room with which to work.

Lighting

This is your continual challenge when dealing with rectangular fisheyes and other ultra-wides up close… when you go Kodak and keep the sun over the left shoulder your lens front casts a shadow. So you move and get that right and now there is too sky with bright patches which can fool even a sophisticated exposure system.

• Easiest to achieve are close-ups photographed from slightly below - eg. insects above on flowers with blue skies behind offer the ideal conditions. So, you see a lot of these from photographers who shoot ultra-wide close-ups.
• Shadows creep into corners where you don’t notice until you have got it wrong a few times and when you try to use reflectors with ultra-wides/ fisheyes they can sneak into the edges of your frame (as can toes and fingers….)
• First try to keep white patches of sky out of frame – you can break them up with trees but they are still way outside the latitude of exposure.
• As long as those patches are not too over-exposed you can do some neat fixing in Lightroom with that incredible graduated filter- I use this a lot.
• So who not try a mix of natural light (photograph against the sky – hard to avoid this anyway) and light the foreground with a touch of ‘flash’.
• This can work well but then you run the risk of properly exposed sky, foreground and a mid band of shadow…There is no panacea for this each case has to be solved on merit.

I often use the Nikon R1C1 lighting set-up but with the two small diffusers and their associated lenses fitted. I have used my SB900 flash gun off camera with a diffuser and it works well You have to experiment a bit to get a good balance between foreground and background light.  My previous 3 posts on flash in macro photography - The Art & Craft of Macro Photography with Flash cover this approach in detail. Click each link below

Part 1       :    Part 2      :   Part 3

 In the FINAL part of this post  I will have some lens specs and how to build a lighting unit for wide-angle macro….