Circular Quay

I mentioned a couple of weeks ago that before I headed for Sydney I had two photos that I wanted to come home with (and I more or less achieved this), but there was a third photo on my list too, and it was the reason that I packed my fisheye lens.  Needing to pack my hand luggage within a 7kg limit, and already bringing a relatively heavy D700 and 24-70mm lens, weight (and space) was at a premium, so the decision of whether or not to bring the fisheye lens was a carefully considered one.

The reason it needed consideration was due to the fact that it is what is known as a DX world, and lately I’ve been living in an FX world.  If you’re not familiar with that Nikon-specific terminology, let me explain.

My first digital SLR – a Nikon D50 – was (like all Nikon digital SLRs at the time) what is called a DX camera – the D being, I presume, for digital and in this context referring to the fact that the sensor in the camera is not the size of a 35mm frame, but a special smaller size (2/3rds of a full 35mm frame) which was specially designed for digital SLR cameras.  The reason manufacturers designed smaller sensors for their first digital SLRs was multi-faceted.  A smaller sensor means less bits of data to process, and so faster image processing.  It means a smaller form factor, and lower power consumption.  Most importantly of all though, it allows them to design cheaper lenses.  This is because they can optimize lenses to give good image quality over a smaller area.  The ability to make lenses cheaper means they are more accessible to photo enthusiasts, and in turn will encourage more people to invest in equipment.

My next digital SLR was a Nikon D300 – also a DX camera (the DX sensor is also known as a crop sensor, due to it effectively being a crop of the center of a full 35mm frame).  By then I was seeking out better quality lenses, but again these were almost always DX lenses, mainly for reasons of cost.  And as I was seeking out better quality lenses, other photographers with bigger budgets were seeking out better quality cameras – and particular ones with better noise performance.  Bigger sensors would allow for bigger “pixels” (they’re not really pixels at the sensor level, but conceptually they are), and bigger pixels would have a better signal-to-noise ratio. All a bit techy, but suffice to say a bigger sensor would have better low light performance.

And so Nikon brought out its first FX cameras – the F standing for full-frame.  (Incidentally, Canon progressed through a similar path and has a range of crop sensor and full frame cameras also, but it is Nikon which I know best).   The D3 and the D700 (and more recently the D3s and D3x) have 35mm sensors, the same size as traditional film, and not only better low light performance but also better image quality.

But there’s a catch.  Those cheaper lenses that work on the crop sensors aren’t so good on the full frame ones.  They may not even project the image onto the entire sensor.

So it is with my DX fisheye lens and my FX D700 camera.

Thankfully, Nikon built in a DX mode into its FX cameras, and the camera can automatically detect a DX lens is present and will switch the camera to operate like a DX camera – so only the centre 2/3rds of the sensor is used to capture the image.

This works reasonably well, but at a price – firstly and most annoyingly, the viewfinder is now only 2/3rds as relevant as it was, and you have to pay very close attention to framing images in DX mode, as the edge of the viewfinder is no longer the edge of your image.  It takes getting used to, is non-intuitive, and generally a recipe for disaster (as I’ve found out in the past).  Secondly, only 2/3rds of the pixels are used, so your image is smaller and lower resolution.  Against these negative aspects is the fact that you can continue to use your selection of previously purchased DX lenses, and that is a good thing – at least until you can afford to upgrade to FX lenses (not a cheap upgrade path).

So…. with all that in mind, my initial thought when I went to pack my fisheye lens was to pack my DX Nikon D300 with it so as to avoid the DX-on-FX issues I’ve mentioned.  But my hand luggage wouldn’t allow me bring two bodies, and so I almost left it behind.  Until, that is, I remembered Circular Quay.  What better place to capture a picture with a fisheye lens, and all its circular distortion, than a place called Circular Quay.  With that thought, the lens with in the bag, and off to Australia I went.

Skip forward a few days, and I’m at Circular Quay, having photographed my favourite building in the world, and I decide to put the fisheye into use.  Framing is difficult due to the DX viewfinder problem, and also because I need to have the camera low for the shot I am  trying to get, so it takes a few attempts – and those attempts require me to leave the camera about 10 feet away from me in the middle of a relatively busy thoroughfare so that the 180 degree field of view does not have me in the frame.

But I get the shot.  A 0.6 second exposure is determined by the camera in aperture-priority mode.  I’ve previously set the aperture to be a few stops away from its widest so as to keep some depth of field (though the fisheye is particularly forgiving in this respect) and I’ve bumped up the ISO as this is a night time shot and I want to keep the shutter speed reasonable.  And that ISO of 1600 isn’t a problem thanks to that bigger sensor.

Whether this one photo justifies carting a fisheye lens to the other side of the world and back is debatable, but the circular format and the circular subject suit each other.  And it seems an appropriate subject to illustrate a post about how camera technology, going from 35mm film to crop digital sensors to 35mm full frame sensors, has gone full circle.