2010-12-06

Winter Cycling III: Riding Tips

Riding in the winter can be a challenge no matter how well prepared you may be.  If riding in icy or snowy conditions I would recommend that you should already be confident on a bike in slippery conditions.  If you don't know what to do when a bike slides out you should probably get some practice in more benign conditions.

That being said, there are a few simple techniques you can use to keep you out of trouble when riding in bad conditions:

Rough ice
When riding on icy back roads you will often find that the surface has been churned up and re-frozen.  The general rule is to stay loose on the bike.  Most of the time if you have reasonable momentum the bike will find its way out of trouble without too much input from the rider.

The exception to this is riding through the ruts left by vehicles (tractors and farm machinery seem particularly bad for creating ruts).  You have two choices.  You try to ride the rut.  If it's wide enough and smooth enough this can be a good thing to do.  Be careful that you don't hit the side of the rut as the bike will try to climb out and may throw you out of control.  The other option is to cross the rut.  I approach this in the same way as crossing tramlines or wet tree roots.  Cross the rut as close to 90 degrees as possible.  While crossing the rut use only minimal input to the bike, no brakes, no steering, no power, stay loose.

Deep snow
Once the snow gets above about 20cm deep my bike starts to struggle.  I can find grip, but the weight of the snow being moved aside becomes too much for forward progress.  If you have ultra-wide tyres you can float across the deeper stuff without the same problems.

When I have no choice but to get through the deep stuff I try to carry as much momentum as possible.  I pick a low gear, get a good spin going and try to maintain speed throughout the deep snow.  Shifting your weight back a little bit also helps.  It will give you a bit more traction on the rear wheel and allow the front to float slightly.

Controlling a slide
Even with the best prepared bike you can find yourself in a slide.  The nemesis for my bike seems to be unconsolidated loose slush - everything else is fine.  Once you're in a slide you have to decide quickly if it's recoverable.  Most of the time you can get control back by shifting your weight to counteract the slide and possibly dropping a foot off the pedal (flat pedals are handy here!).  Again, stay loose and go with the slide.

If the slide is terminal you need to decide how to crash.  If possible lay the bike down flat and push it away from you.  If you're heading for a ditch or hedgerow again try to get the bike away from you and if possible aim for something soft!

Other traffic
When road riding in winter you should be acutely aware that most other road users won't have nearly as much grip as you have with your spiked tyres.  It's all too easy for a car to slide wide on a hill or corner.  My general rule is if I see a car on a piece of road that could possible cause problems I will stop, get off the bike and get off the road.  It's not worth the risk of getting squished by a sliding car.

2010-12-04

Winter Cycling II: Clothing

The correct clothing is just as important as the correct bike when riding in winter.  I've found that the key is to ride with a set of carefully chosen layers.  This will allow you to fine-tune your clothes as your ride progresses.  My typical winter riding gear is:
  • Wicking base layer to remove cold sweat from your skin
  • Wicking thermal mid-layer to provide insulation.  I usually go for a lightweight fleece as a mid-layer.
  • Breathable windproof / showerproof top layer.  I don't ride in a full waterproof as they usually aren't breathable enough for cycling, so a windproof to keep the elements away is better.
  • Full pack-away waterproof.  This is a last resort when it gets really wet.  It will be uncomfortable to ride in but will stop you getting completely soaked.
Different people experience different problems riding in cold weather.  I find my hands and feet can get very cold.  To reduce this problem I wear either fleecy gloves in good, cold conditions or waterproof fleece-lined gloves in wetter conditions.  These reduce the feel you've got for the controls on the bike, but as with everything it's a matter of compromise.

To keep my feet warm I typically wear Sealskinz waterproof socks.  These have a neoprene layer integrated into the fabric which do a reasonable job of keeping your feet dry.  Even when they fail and your feet become wet they do a good job of keeping the water warm!

Finally I will wear some good quality riding shoes.  When riding on the road I typically wear my walking boots.  I figure if my bike goes wrong there's a good chance I will have a long walk ahead of me, so I should be comfortable.  On the mountain bike I favour Five Ten shoes.  They aren't very waterproof, but they are warm and the soft rubber means you've got reasonable grip on frozen ground.

2010-12-02

Winter Cycling I: Bike Preparation

This year I decided not to get caught out by the Scottish winter and to be properly prepared for a winter's worth of cycling.  I am going to post up a few articles that cover the basic of cycling in the winter.  These are all based upon my own experiences of what works and what doesn't.

The bike I will be using over winter is my Cotic Roadrat.  In its usual guise I have it set up as a fast tourer with tough, but fast rolling tyres, racks and panniers.  In this first post I will go through some of the changes I made to the bike in order to get it to work in the winter.
Roadrat in usual fast-touring guise
Tyres
The first thing to address are the tyres.  Normal road-biased tyres will very quickly reach the limit of grip once the roads get icy.  Luckily there are a few options.  MTB style chunky tyres can be found in 700c sizes and will give a lot more grip in slushy and snowy conditions, especially if you choose some with a soft rubber compound.

Unfortunately, even chunky tyres will be useless once the roads get icy.  Once this happens the only option is to use studded tyres.  These are usually a combination of chunky tread for snow and a number of steel studs embedded in the rubber which bite into the ice.  I use Continental Nordic Spike 240 tyres which have 240 spikes in each tyre.  They're quite expensive, but as this is only way I get to cycle at this time of year, they're well worth it.  On sheet ice these tyres feel like you're riding on dry tarmac.

Drivetrain
My Roadrat is equipped with an 8-speed Shimano Alfine gear hub.  So far this winter it has been faultless.  There's a barely perceptible increase in drag, but no more than you get with most hubs at this time of year.

Gear hubs tend to cope a little better than the alternative derailleur system as they are less prone to icing up and jamming.  Some people advocate, how do I phrase this... "micturating" on your rear derailleur once it gets frozen.  I'm sure this would work as a temporary fix, but in most conditions would re-freeze quite quickly.  A better option I use on my mountain bikes is to make sure all the moving parts are very well oiled.  This seems to do a reasonable job of keeping the water, and so the ice, from jamming up the mechanism.  Of course, even this will start to fail after a number of hours in snowy sub-zero conditions.

Other tweaks
A few other minor tweaks can be made to your bike to make it more comfortable in the winter:

  • Fit flat pedals so that you can wear warm boots.
  • Drop your saddle a bit for when the bike starts squirming around in the icy ruts.
  • Make sure you have plenty of lighting.  Winter conditions can change quickly so I run my usual Blackburn lights along with the USE Exposure lights I usually use on the mountain bike.
  • If fitted, raise your mudguards as high as possible.  Your tyres can get clogged with snow and jam under the guards, so try to get as much clearance as possible.
The end result
Once you've made these changes your bike should be in good shape for some winter riding.  I find my setup works well on icy roads, slushy conditions and snow up to about 15-20cm.  If you're riding in deeper snow you probably need to float on top of the snow rather than digging through it.  In which case you probably need something more specialised like the Surly Pugsley.

I'll be adding a few more posts on this topic in the next week or so.

Roadrat with spiked tyres

Winter riding!

2010-10-11

DIY Macro Photography IV: On-Board Flash Diffuser

As I get more into macro photography it has become clear that lighting is absolutely critical for good results   The best way to achieve good lighting appears to be one or two external flashes mounted on a bracket.  This allows you to have loads of control over the light sources.

However, in the truest bodging spirit I decided to see what I could do with just a few bits of rubbish I had lying around.  Obviously this rules out using external flashes and brackets.  Despite this I thought I could probably do a bit better than just using the on-board flash on my camera.  The plan was to build a snoot / diffuser to direct and soften the built-in flash in a way that fitted my macro set up.


Ingredients
  • Cardboard tube
  • Aluminium foil
  • Duct tape
  • Kitchen roll


Construction
The first step is to cut down the tube to size.  I wanted the tube to reach the end of my macro lens, but also to have a bit of a an angle at the end.  I used my mitre saw to chop the tube down to the angle I wanted:



I also decided to cut a small notch in the opposite end of the tube to make it fit slightly better against the built-in flash on my camera:





Once this was done I did a quick test fit to ensure all the dimensions were as I wanted:


I decided that lining the tube with aluminium foil would be a good idea.  I imagine this will help minimise light loss.  As the flash on the 7D is a bit weedy I need all the light output I can manage.  I cut some foil to size allowing enough for double thickness when rolled up and also a good edge for securing the foil to the tube:



Fitting the foil to the inside of the tube proved tricky until I realised that the fuel bottle for my camping stove was a perfect fit inside the cardboard tube.  This allowed me to use it as a blank around which I could wrap the foil and insert it into the cardboard tube:







Once the foil was inside the cardboard tube I cut tabs into the ends to allow it to be folded back and secured to the tube:



To make the diffuser a bit more robust I decided to wrap the whole thing in duct tape (bodge tool #1).  I paid particular attention to the ends of the tube where the foil was folded back.  The foil is not very robust, so some protection here is a good idea:


Once the foil lining was in good shape I fitted a diffusing element to the business end.  I used some kitchen roll, but any translucent material would be suitable:


One final feature I decided to add was a foil-covered cap for the camera end of the tube.  This simply hinges on a piece of duct tape and sits behind the flash head.  Again the idea is to try to direct as much flash energy forwards as possible.  I'm not sure if this makes any difference, but it does reduce the bounce-back you get when using the camera.




Once construction is complete it's a simple matter to fit the tube to your camera with some strategically placed rubber bands:


Results
Overall this modification works very well.  The snoot directs the flash quite nicely and really pours light on the subject.  I still have a few issues in my macro setup with vignetting, but that's a lens issue that I will address some time in the future.  Here's a few test shots:
SD card contacts

Zippo flint

Dead fly

2010-10-09

DIY Macro Photography III: Extra Stuff

Macro photography can be a tricky and frustrating experience. By investing some time (and some money) in a few bits of extra equipment you can make life a lot easier. There are plenty of other websites around which offer comprehensive tutorials on building a macro setup, this page just details the bits and bobs that I use.

Lighting
Macro photography is almost always easier when you have plenty of light available. I currently use a single 50W halogen desk lamp as my light source. Ideally, a second lamp would also be used to throw even more light onto the subject. To compensate for the colour cast from the lamp, I always shoot a grey/white card before starting to take real pictures.

Light diffusing box
If you simply douse your subject with light directly from a desk lamp you will end up with very bright highlights and very deep shadows. Sometimes this is what you want. I find that slightly softer lighting works well for macro pictures, so I built a light box to diffuse my light sources.


The basic construction is very simple: take a cardboard box, line it with white paper, cut holes in the side and cover the holes with tracing paper. The tracing paper on the sides of the box diffuses the light evenly inside the light box. There's a good tutorial on how to build this box somewhere on t'Internet - just use The Goggle to find it. My lightbox is very rough and ready as it's only designed for macro subjects. If you are photographing larger objects, take more care with lining the inside of the box to avoid ugly seams.

Tripod setup / focus rails
When using very high magnifications it is almost essential to have a good stable tripod. I use a Benro tripod with a fairly sturdy ball-head. Cheap tripods may seem tempting, but they are usually a false economy - you'll get annoyed like I did and end up buying something decent in the end.

With macro photography, focussing is both critical and very difficult. The optical properties of a macro setup leave you with a very shallow depth of field. It is almost always better to control the focussing in a macro setup manually. Autofocus usually doesn't work very well (of course, you may have better luck than me).

After a bit of experimentation and research, I found that the easiest way to focus is to use a set of adjustable rails in between your camera and the tripod. These are typically geared racks which allow very precise control of the fore/aft position of the camera.

Focussing racks can be purchased for around £30 on eBay, or about £50-£70 in a camera shop. I decided to spend a bit extra and purchased a Novoflex Castel-Q rack. This rack is very well built and has absolutely no play in the mechanism. Another nice feature is the Arca-Swiss compatible mounts which allows it to work with other bits of equipment (such as my Benro tripod).

DIY Macro Photography II: Reversed Lenses

Ingredients
  • Canon FD manual lenses (28mm f2.8 and 50mm f1.8).
  • 77mm-77mm reversing ring.
  • 77mm-55mm and 77mm-52mm step-up rings.
  • Canon FD rear lens cap.
Construction
Most of this approach is very simple to put together. All you need to do is reverse mount one of the manual lenses onto the front filter thread of one of your digital camera lenses. This is done using two adapters in my case. I have some L-series Canon lenses, so chose a 77mm reversing ring for maximum flexibility. In order to use this ring on the manual lenses, a step-up adapter is needed (55mm thread for the 50mm lens, 52mm thread for the 28mm lens).


The one stumbling block I found was stopping down the FD lenses. The FD design has a number of catches and levers on the rear face of the lens. Unless particular pins are pressed in, the lens will not stop down. You can work around this by poking the pins and levers with a screwdriver, then gluing them in place.

Instead of fiddling around with a screwdriver I decided to modify an FD rear lens cap to fool the lens into thinking it was mounted on a camera body. This hack is easy to do:

  • First, cut the central section of the lens cap away. I cut the cap right back to the edge so that there would not be any bits poking into the image frame.

    • Next remove the stop tab on the edge of the cap. Normally this prevents the lens cap from rotating all the way round. This normally allows the lens to distinguish between and lens cap and a camera body. By removing the tab we can rotate the cap all the way around and fool the lens.

    • Mount the cap and depress the stop-down lever on the lens. The lens is now stopped down, the lens cap also doubles as a handy lens hood.



    Once this is done, simply use the appropriate reversing and step-up rings to mount the manual lens onto the front of one of your digital lenses. The picture below shows my complete setup with the 50mm lens mounted onto my 100-400L.



    Use
    I found the following method worked best for me:
    • Set both lenses to manual focus, set focus to infinity.
    • Leave the manual lens aperture wide open (f1.8 on the 50mm lens).
    • Frame the image and set focus using focus rails.
    • Set the main lens to stop all the way down (f40 on the 400mm lens).
    • Take the image.

    Results and conclusions
    As expected, the 28mm lens gives greatest magnification, but results in a large amount of vignetting. Combining the 28mm lens with the 400mm lens gives about 7-8x magnification. I found that the 50mm lens combined with 300mm on the main lens gives the most useful magnification (somewhere around 5x).

    Image quality is reasonably good. The main issues are a lot of cyan/red chromatic aberration which can be partially corrected during raw processing. The other difficulty is the extreme limited depth of field, however this is just an aspect of macro photography

    Some example images below:









    2010-10-08

    DIY Macro Photography I: The Enlarger Lens Bodge

    A simple way to make a DIY macro lens is to build one from an old enlarger lens and a set of extension tubes.

    Ingredients

    • M42 to EOS adapter.
    • Two sets of M42 extension tubes.
    • 50mm enlarger lens (a Durst Neonon f/2.8 in this case).
    • Hot glue gun.

    Construction
    I picked up most of my ingredients from eBay, I think in total I paid about £20 for the whole lot.

    The first thing to do is to mount the enlarger lens to one of the extension tubes. The lens can be mounted either way around, but reverse mounting gives higher magnification.

    This bit can be a bit tricky - you should try to get the lens mounted as straight as possible with no gaps between it and the extension tube. I held the enlarger lens against the tube and put a small blob of hot glue on the joint to hold it in place. Once the glue had cooled it was easy to finish the job by running a line of hot glue all the way around the seam.

    Don't worry if you don't get this right first time, just let the glue cool, then peel it off and start again.
    That's the fiddly bit done, now you just need to assemble the extension tubes, screw on the M42-EOS adapter and mount it on the camera.


    Use
    Once you have the lens mounted up it's time to take some piccies. Enlarger lenses are completely manual which means you will need to set the aperture manually and also devise a way to set the focus. My process was as follows:

    • Set the lens aperture wide open (f/2.8).
    • Frame the image.
    • Set the focus. I used my focus rails to do this. If you don't have access to rails, you can move the subject a bit or maybe take advantage of any play in your tripod head. Note: at f/2.8 the depth-of-field with be wafer thin (mint), this will improve once the lens is stopped down.
    • Stop down the lens to f/16 to achieve reasonable depth-of-field.
    • With the camera on full manual, take pictures of varying exposure durations until the exposure looks good on the histogram.

    Results and Conclusions
    Here's a picture from this setup:


    What a disappointment. It is fairly clear what has happened. As the Durst lens elements aren't coated this leads to an internal reflection causing a huge amount of flare. This is a particular problem on digital cameras as the digital sensor is shinier than film. The original enlarger-bodge macro I used had a Nikon enlarger lens with coated elements - this reduced flare a great deal and resulted in some nice images.

    The problem of flare can be reduced a bit by placing your subject onto a dark background and by under exposing the image slightly. This reduces flare, but also brings up more noise in the image when the exposure is corrected. Below is the best image I managed to produce using this setup:


    So, lesson learnt: if you are going to take this route, make sure you buy an enlarger lens with some sort of anti-reflective coating on the elements. I decided to move on and try something different... stay tuned for a different approach to DIY macro...