Mirroring Autumn

The title today is deliberately ambiguous. Maybe you were hoping to find some carefully crafted autumn mirror reflections. If so, sorry: you guessed wrong. This post is about a Mirror you look through – a 500mm Mirror lens.

In an earlier post – ‘Microscapes of Autumn’ – I explained what I meant by the word ‘Microscape’ and how I liked to focus in on the detail in landscapes (particularly in Autumn and Spring) rather than seeking out the wide views.

Smoke Bush (Cotinus coggygria) - click to enlarge

It may sound ridiculous, but sometimes I use a Mirror lens to do that. I can almost hear the scratching of heads out there! A Mirror lens to focus in on the Microscape – sounds crazy? Well, it can be done, and all the images of Autumn leaves in this post are the proof. With patience you can acquire images that will have some distinctive qualities – but you do need a tripod! A 500mm lens on a DX camera body equates to about 750mm of Telephoto. That is a very long lens!

If you wanted to cart around a 600mm telephoto lens you would need a trunk and a new mortgage (think Sports photographers with their massive lenses). Compare that with my 500mm Tamron Mirror: it weighs in at 650gms (almost exactly the weight of my D80 body), is compact (not much bigger than my 24-85 Nikkor), and in the UK you can pick one up for under 200 pounds sterling (Nikon versions will cost 400-500 pounds). Those are figures worth thinking about.

Mirror lenses generate trademark doughnut-ring out of focus highlights – or Bokeh as they are known. People tend to either love them or hate them. They can be intrusive, but if they are subtle then that intrusiveness can be channeled into a more impressionistic embellishment. For a further technical note about Mirror Lenses see the footnote at the end of this post.

The last leaf of Autumn - click to enlarge

The image immediately above is fairly obviously taken with a Mirror – the highlights give it away but they are subtle and for me acceptable. This is one of my favourite shots of Autumn.  The first image in this post may not at first glance appear to be taken with a Mirror but if you enlarge and look closely at the top middle of the image you will see fine beading and ‘lining’ along a highlit branch – this can be a more obtrusive problem.

Low level branch – click to enlarge

In the image above, this beading and lining of out of focus grasses is much more visible. But because it is subdued, personally I find it adds rather than distracts – but that is an arguable point of view with which you may disagree.

Acer leaves - click to enlarge

Because of the narrowness of the depth of field, it helps to select objects that are at 90degrees to your line of sight. This is what I deliberately did in the image above.

In isolation - click to enlarge

My plan when working with a Mirror is to search out a subject that I can separate as much as possible from a diffused background.  The length of the lens allows me to stand back and alter the shooting angle – shooting more across than up. To go back to the first image: my original intention was to shoot that with a much shorter lens but if I did that I found that I would be shooting up into the sky. By standing back I got the same leaf framed – but against the largely dark wood in the distance.

Finally, below is another image of the Smoke Bush at our front gate.

Smoke Bush (Cotinus corrygria) - click to enlarge

This large shrub is a delight in Autumn. Here I have tried to use the characteristics of the Mirror lens to add something extra to the image without being too distracting.

I hope this post may prompt some of you reading this to be more interested in the potential of a Mirror lens – a lens that is not in common use.

Footnote on Mirror Lenses

Mirror lenses are called ‘catadioptric’ or reflex. They combine refraction and reflection of the light entering the lens – actually folding the pathway of light.

On the plus side they are lighter, smaller and cheaper than refractive lenses and chromatic aberration is almost eliminated.

There are downsides. Optical compromises common to Mirror lenses are that images tend to be slightly soft and lacking contrast compared with refractive lenses of similar length. There is no adjustable diaphragm, meaning the F-number is fixed (typically F8) and all, with the exception of the Sony version, are manual focus. Your camera will need to be set to Manual, and you will need to decide how to meter your intended subject.

Finally due to the central obstructive mirror inherent in their design, out-of-focus highlights, or Bokeh, are displayed as doughnut-shaped rings.  These can be subtle or dramatic depending on the brightness of the highlights.

Sony is the only lens manufacturer that currently produces a Mirror lens. Second hand versions of the Nikkor, Canon, and Tamron Mirrors are often available on eBay. And in the UK, Grays (the specialist Nikon dealer) often has secondhand lenses listed. There are other Mirrors to be found on the market but not all are of equivalent quality. Naturally with a lens of this length the depth of field is very narrow and focussing can be difficult and needs to be precise. As the lens aperture is fixed, then remember WYSIWYG. Aim for a shutter speed of 1/1000^th or faster and adjust the ISO accordingly. A cable release or remote helps to eliminate blur.

This is not a lens for action photography but it is a cheap way to acquire a long lens that would otherwise be beyond the pocket of many amateurs. Teleconverters of course are an alternative. I regard my Mirror lens as a ‘fun’ lens that I occasionally carry but because it involves carrying a sturdy tripod and has limited application it’s not something that is in my bag unless I am going out with the firm intention of using it.

Click here for an in-depth article comparing a Tamron 500mm Mirror with a Canon EF500mm lens.