Back Button Focus

One of the more controversial subjects in photography, at least for me, is the use of back button focus.

The premise is that, on cameras that allow this level of configuration, you can separate the ‘focus’ and ‘shoot’ operations, so one button under the thumb on the back of the camera becomes the ‘focus’ button, and the half-press of the shutter button no-longer changes the AF setting.

I’ve tried it, admittedly fairly briefly, and I can’t see the point. I don’t want the camera focussed on something that isn’t what I’m taking a picture of.  My two most used cameras have 49 and 65 autofocus points.  Recompose and shoot doesn’t happen very often, and I’m usually working with moving subjects, so the camera is permanently in AI-Servo mode.  Why would I NOT want to focus at the same time as taking the shot?

Shooting with the 7Dii, I’m usually steering the autofocus point in use as I’m shooting (and using a single AF point), so my thumb is busy elsewhere.  I’m still learning the finer points of the M6, and usually I’m using the touch shutter if I want to take more control over where the camera focusses. With the EVF, you can at least see where it’s aiming so can correct if needed. 

However, the thing that really, really winds me up is the assertion made that BBF will improve your photography, or even worse that you’re somehow not a ‘proper’ photographer if you don’t use it.  By all means give it a try.  If it works for you, the carry on.  But please don’t suggest I’m not as good a photographer just because I don’t use it.   Thanks.


Nest V3 Installation (UK)

For anyone thinking of doing a DIY installation of a Nest Thermostat in the UK, it’s not so difficult.

Obviously, it requires a level of understanding of electrical wiring and confidence in what you’re doing, but the reality is pretty simple.

For most UK installations you’re likely to have a junction box, though I beat the wiring doesn’t look as neat as this diagram.   This is a “Y plan” system where a 3 position valve controls whether the heating, hot water or both has a flow of hot water from the boiler.




Before doing any of this make sure you’ve killed power to the heating system.   If you need help doing that, you should be paying someone to install the system for you.

The nest heat link is pretty much a drop in replacement for the existing programmer, but with the wiring in a different order.

You’ll need to jumper terminals 2 and 4 to the live feed to the programmer, and swap the terminals as below.

Existing Terminal
Hive Terminal
Not used
2, 5
Jumper to Live IN

Once this is done, the next step is to identify the wires from the junction box going to the room thermostat.    Confusingly in my system these are different colours in the junction box to those in the thermostat housing, so theres obviously a link somewhere along the way.

To identify these, I basically had someone to twiddle the ‘stat up and down while I held a multimeter across the terminals I suspected, and when it jumped from open to zero resistance and back I new I had the right connections.

Once I knew what wires were what, what I did was to replace the room thermostat with a link (between points 4 and 5 in the diagram above) to minimise the amount of wiring I actually touched (and to make it simple to revert if needed).  Then I took the existing wiring to the thermostat and linked it to the 12V feeds from the Nest Heat Link.

For safety I did the 12V join in a separate, new junction box so it’s not in danger of touching any 12V circuitry.

As a final check I powered up the system without the Nest thermostat attached, and checked for 12V across the terminals in the thermostat wall mount.

If you plan on using the provided USB power to relocate the thermostat then you can just short out the existing one and you’re done.

It’s now in learning mode – it remains to be seen how good it is – watch this space.

Update: I’ve corrected the wiring terminals since I originally wrote this.  Please use a professional installer if you’re not 100% confident in what you’re doing.

Dear Apple

1TB is the biggest SSD I can get in a MacBook Pro?

I mean it’s lovely and fast and all that, but I’ve got 600GB of images, 350GB of music and video in iTunes, and a metric shedload of documents in Evernote and elsewhere to sync.

Let me know when I can have 10TB plus in a laptop and not have to hang and external SSD off the side just for music and films. 

Canon 24-105 f/4 L IS USM Lens Repair

After looking for some information on line about how to repair this lens, I didn’t find a good disassembly guide, so I thought I’d write some instructions.  Apologies for the standard of the photos – if you take some better ones, please share them with me and I’ll update the article.
This lens is designed with a deliberate weak point at the rear of the lens which is designed to break off to prevent more expensive damage.  The one I got from eBay had been bodged after this had happened and was sold as new (scumbag!)  You can see the the 4 plastic lugs around the circuit board in the pictures – these are designed to break off if damaged, and the front of the lens will partly separate from the rear if this happens.   The replacement part is about £90 and I was quoted £120 for fitting.  Since by this point I’d already stripped the thing down, I opted for them to ship me the part.   The replacement fixed barrel assembly includes the switch pack and the zoom ring (see notes at the end on removing the zoom ring if you are going down the ’spares for repair’ route).
Tools needed: #00 philips screwdriver.   Two very small straight screwdrivers
Blunt ended tweezers
Soft plastic pick
A rubber band.  No, really.
Before you start, a word of warning.  Some of these screws will be very small and very tight.  You will need a precision screwdriver and even with that you run the risk of rounding off the heads.  If this starts to happen, you can use this tip to try and get the screws out.  If that doesn’t work, give up, send it off, and know you will pay extra for getting the damaged screws out. 
I also strongly recommend working in some kind of tray, and in bright light.  The tray is in case you drop a screw!
1) Put the lens cap on the front.  You’re not going there, and you don’t want to damage anything.   
2) Before you go anywhere, check the heads of the 4 screws.  If they are damaged at all, order some new screws when you order the assembly.  Extend the lens and pull out the rectangular cover in the centre by hooking a finger behind and pulling.  It will seem to need inordinate force, but does just pull out.  The body contacts will remain in place.  This is shown with the green circle below.
3) Remove the two tiny screws holding the contacts in place.  These really, really are tiny.  
Lens small
Don’t drop them.
4) Undo the 4 screws through the mount and remove the mount, water seal, and rear cover.   These are shown in red on the top image. 
This is what you will see. 
5) Work your way around the connectors.  There are three types:   Flip up catch, pull out catch, and one that’s a push fit, best done with a couple of small screwdrivers.   The flip up catches are highlighted above.   For these gently flip up the coloured piece and the cable will lift clear.   For the ribbon cable top right you will need to push against the tabs on the table to pull it out of the socket.  This is the only one that should have any resistance.  The final ones need you to pull forward the clips at the side very gently to release the cable. 
6) Remove the 1 screw holding the circuit board in place (orange arrow). You can then lift it clear. 
7) There are 4 screws holding the rear fixed barrel to the lens.  Remove all 4 noting positions, and also that one of them holds one of the ribbon connectors in place.  Do not touch the screws on the inner most ring of the assembly. 
8) Carefully slide off the rear barrel making sure you don’t trap any of the ribbon cables.   Note alignment to main lens body.
To reassemble, you will need to line things up – it’s not quite the reverse of disassembly, but isn’t far off. 
1) Gently pull the front of the lens out to 105mm, and set the zoom ring on the new barrel to 105mm.  
2) Check the ribbon cables on the new barrel are routed the same as the old one, then lower into place, lining up the window in the barrel with the focus distance scale. Use a plastic hook of some sort to make sure all eight ribbon cables come up into the rear of the lens. Be gentle. As the barrel drops into place, you need to engage the mechanism to drive the zoom, and with a little juggling of the zoom ring and the lens itself, the barrel should drop fully into place.    Make sure all ribbon cables are clear and not being crushed, then replace the 4 screws holding the barrel in place. 
3) The next trick is to get the circuit board back in the right place. All 8 ribbon cables go around the outside, so if this isn’t the case you’ve routed something wrong.  Look at the image above. 
4) Line up the biggest connector (at the top in the diagram above) and screw the board into place.
5) Refit all the other cables with reference to the fastener mechanisms.  They will pretty naturally fall in the right place apart from the two new ones which will point up more.  This is now a good point to get all the greasy finger prints off the rear element. 
6) Separate the rear cover, mount ring and weather seal.  The rear cover will go on in two orientations, but only one will leave the screw holes in the right place to re-attach the camera connector.   The words “image stabilizer” should line up with the 24 number on the zoom ring with the lens at 24mm (or 105 at full extension).
Lens rear cover
7) Place the weather seal on the rear cover, and sit the mount on top, being careful to line things up so you don’t have to rotate it to get the screws in.  If you rotate them the seal will get caught up and not sit right.
8) Insert the 4 screws holding the cover and the two tiny ones to locate the camera connector.  Make sure all 4 main screws are in tight and not sitting proud or they will foul on the camera mount when you attach the lens.  I’d test at this point.
9) Replace the inner cover (just snaps into place)
Further disassembly of the old barrel:
1) Carefully prise away the ribbon cable leading to the switch unit where it’s held to the inside of the barrel.  Undo the screw on the outside and prise off.
2) Undo the two screws holding on the level that engages in the zoom mechanism.  Twist past the end stop and lift off the zoom ring.  Note alignment for refit.
The zoom ring is hard to get in place without damaging the spring contacts.  I suggest putting a piece of plastic (like flash gel) over the contacts as you slide it back together,  then pull the plastic out.  I’d already damaged the contacts on my old barrel before I figured out how fragile they are. 
Usual caveats apply.  I am not a qualified Canon service engineer and this will definitely void your warranty.  But I figured this out in a couple of hours and saved myself a £120 service cost.
Part Number for the rear barrel is…

Mushroom Curry, twice

I got asked for my mushroom curry recipe recently.  Here’s two variations. The first is a more hearty curry, the second is higher and more suited to a side dish in my view.

 Andy’s Mushroom Curry.

1 onion, finely chopped
2 cloves garlic, finely chopped
chunk of root ginger (about as big as the garlic), finely chopped
1 finely chopped chilli pepper, or chilli powder to taste
1 tsp ground cumin
1/2 tsp ground turmeric
2 tsp garam masala
1 tin chopped tomatoes (1/2 tin will do, but I like it saucy!)
400g mushrooms (button ones work best, or quartered larger ones)
Fresh Coriander (Cilantro) to garnish

Serves 4 as a side dish or 2 as a main course.

Spray a frying pan with fry-lite, or paint with a thin coating of oil.

Add the onion, garlic, chilli, ginger, cumin and fry under a medium heat until the onions soften.  (You could add a chopped bell pepper as well for a main course dish).

Towards the end of this cooking, add the turmeric, but don’t let it get too hot/dry or the turmeric will burn and it will be nasty – add some water if necessary to stop it from sticking and burning.

Add the chopped tomatoes and turn up the heat until it boils.  Stir in the garam masala and mushrooms and simmer, uncovered,  for 10-15 minutes until the mushrooms cook through.  You may need a fairly high eat to stop it getting too mushy.

Add the coriander just before serving.  You could also stir in some yoghurt once it’s off the heat for a creamier curry.

Serve with plain rice for super healthy, or chapatti (or cheat and use pitta) if you prefer.


Zarrin Zardari’s Mushroom and Coriander Curry as modified by Andy
From Madjur Jaffrey’s “Curry Bible”

1 tbsp oil
1 stick cinnamon
2 small onions (or 1 large)  – very finely chopped
3 fresh green chillies, finely chopped
250ml natural yoghurt (low fat will curdle but still taste OK)
pinch of salt
900g button mushrooms
1/4 teaspoon ground cloves
1/4 teaspoon ground cardamom seeds
60g fresh coriander leaves

Heat the oil, add the Cinnamon, stir once and then quickly add the onions and chillies.  Stir fry for 5-7 minutes until onions start to brown.  Take the pan off the heat and add the yoghurt and salt.

Return to the heat for a few minutes, and add the mushrooms, cloves, cardamom and coriander.
Stir, reduce the heat to low and cover and simmer for 10-15 minutes.
Remove the lid and turn up the heat to reduce excess liquid.

I decided it looked a bit insipid, so stirred in a tin of chopped tomatoes with the mushrooms, and left it uncovered to remove excess liquid from the start.



Biryotto – you heard it here first.

So, when the Biryotto graces the menu of the finest restaurants, you heard it here first.

What’s a Biryottto?  It’s a fusion (and portmanteau) of Biryani and Risotto.  Indian spices in the base, then add arborio rice and slowly add stock for a risotto like creamy finish.

This isn’t so much a recipe as a guideline.  Feel free to play with quantities.  You could also do a veggie version with butternut squash (cut into chunks and roast with cumin then add instead of the chicken and mushrooms), or use lamb or whatever you like.  

1 onion

2 cloves garlic
1″ cube of ginger
2 chicken breasts (or 4 boned thighs if you prefer)
150g arborio rice
5 or 6 decent mushrooms 
1/2 tsp turmeric
1 tsp cumin powder
1 tbsp garam masala
1 tbsp medium curry power
a good squirt of tomato puree
chilli powder to taste – or a finely chopped chilli 
500ml chicken stock – if done from a cube it’ll be all the salt you need
a good grind of black pepper.
at least a tablespoon of chopped coriander
2 tsp oil, or a good spray of fry lite to keep the fat down.
100g of frozen peas
Chop the onion, garlic and ginger as finely as you can.  Add oil or fry-lite to the pan, and when it’s hot add them and turn the heat down and stir occasionally until the onion goes translucent.  
Add the chicken, turn up the heat, and stir-fry until the chicken starts to colour.  Add a splash of water if necessary to keep it from sticking and burning.   Add the black pepper.
Add the spices, the rice, and mushrooms, and the tomato puree and stir until all evenly coloured.  
Start to add the stock and let it simmer and reduce like a normal risotto.  Keep adding stock and simmering until the rice is tender.  As the rice is close to being cooked, stir in the frozen peas.
Once the rice is ready, stir in the coriander.
Serve as is to be healthy, or with a pitta bread, roti or naan bread if you’re really hungry.

Google Glass: I think I’ve found the killer app

I’ve been watching the fuss around Google Glass with a bit of an air of detachment. In a world where you feel like a geek for wearing a bluetooth headset for your phone, wearable computing has got a way to go.

But the application for Google Glass I’d love is a super version of Evernote Hello – tracking the people you know.

Combine facial recognition with background information – when my boss walks into view it reminds me I need to get him to approve my holiday request. When I meet someone new (they stay in shot for more than 30 seconds) it automatically adds their photo to the “people I met today” where I can add name, contact details etc. If I haven’t seem them for a while it pops up their name and where we met and any other notes. Also tracking context “This is Fred Smith from Fubar computing. Last met at Fubar user conference in Barcelona.”

Pebbles, Google Glass, and all that

At work this week a colleague had a pebble watch. t’s really, really neat. 

Apart from one small thing:  it’s … one tenth of what it could be.

And all the fuss around Google glass  – again, it’s not even starting to get there.

If I’m going to wear a bit of technology, it needs some useful features.

Facial recognition: if I walk up to someone I haven’t seen for a while it should tell me who they are, when I last met them, and anything else relevant.

Navigation: if you’re heading for the pub you arranged to meet the guys at, you need to turn right here.

Money: when I look at a menu, remind me I’ve already overspent on dining out this month and to go for a cheaper option.

Seriously, guys, you can do better with this technology than recording everyone bullshitting their mates in the pub and putting it on YouTube.  

How much technology to play a song?

So, I’m sat here with my laptop, and I decided it would be nice to listen to some music for a few minutes.  I grab a bluetooth speaker, fire up iTurnes, and play some playlists from the library on my desktop.  Took all of 10 seconds, 8 of which was ferreting in my bag for the speaker.

But let’s think about this.  The computer upstairs is pulling a data stream off its local hard drive, sending it down a wire to the wireless access point, which sends it over the air to my laptop, which then sends it via a different radio format to the speaker sat next to me.  I’m not just amazed that I have superb quality audio being played to me right now, with that lot of technology in the way, I’m amazed that it’s not only possible, but affordable.e