Quickest, cheapest lens repair ever

[Tannin]

This week my new mega-expensive Canon 600/4 II arrived. For a short while yesterday (only an hour or so stolen from other duties) and today (most of the day) I got to try it out.

I wasn't anticipating much of the difficulty one has adjusting to new gear because it is, when all is said and done, not terribly different to the 500/4 I've had for years. Nor was I anticipating any problems. My experience with Canon equipment is that it is always beautifully presented and their QC people are top notch - you can count on your new lens or camera working perfectly straight out of the box.

All seemed to go well at first (other than the usual difficulty of finding interesting birds to point it at). I put it on the 7D II (which is also quite new to me, I've only had it for a month or so) and went for a drive, looking for those open grassland birds I am so fond of: pippits, Singing Bushlarks, songlarks, and so on. My usual technique with these grassland birds is to stay in the car no matter what. Even in the car they won't let you get close to them, but if you get out you are lucky to get within 50 or 100 metres.

But every now and then, for no reason I could see, the 600/4 refused to auto focus! Complete non-cooperation! Ouch! Eventually I realised (or thought I did) that the neoprene Lenscoat (not a Canon product) was at fault. The Mark II primes have a much larger manual focus ring than the Mark Is had, so the matching Lenscoat includes an extra cylinder to cover it (it was not thought necessary to cover the slim black focus ring on the Mark Is). I decided that the Lenscoat cover was slightly too long and thus fouling the focus ring such that it was too stiff for the AF motor to rotate, and therefore removed the cover.

(This was a completely stupid thing to think, as the whole point of a USM focus motor is that the manual focus ring does not rotate during AF. It's not as if I haven't known that for many years, I just had the stupids, which is strange. I mean, I had the stupids when I was young, same as I had the chicken pox. Seeing as I've already had it, I am now immune to chiicken pox. Why aren't I immune to the stupids?)

Before too long, the problem was back. Ouch! A very expensive lens, brand new, randomly not focusing at all is serious stuff. Yes, it is under warranty, but it costs hundreds to ship it (as you have to have insurance) and would be a major inconvenience. Besides, was it the lens? Or the 1.4 teleconverter? (Itself almost new.) Or the camera? Or something to do with the combination of all three?

I battled on, fiddling around, turning the camera off and on again, pointing it at object close and far, turning the manual focus ring by hand. There seemed no pattern to it. Sooner or later - sometimes after the bird had flown away - it would suddenly work perfectly. Then, two minutes or 20 minutes later, the problem would come back. I've saved up for years and years to buy this lens and it doesn't work! Not a good day.



(Evidence for the prosecution: rather blurry Richard's Pippit, manual focus at 840mm if you don't mind. Damnit, the last time I had to use manual focus on a bird it was 2004 and I was digiscoping.)


Eventually I found the problem. It was caused by the modern mania for adding useless damn live view and video functions to perfectly innocent DSLRs. I better explain.

On the back of Canon DSLRs, there is a button marked "AF-ON". Out of the box, it simply starts the auto-focus system, which is a bit pointless since a shutter half-press does that anyway. Lots of sport and wildlife shooters disable the half-shutter AF and focus only with the AF-ON button. It's called back button focus. This is a good idea because it gives you more control over when the cameras focuses and (in particular) the ability to force it to stop auto-focusing, which can be very handy. On the other hand, it makes shooting rather counter-intuitive and awkward, especially if you are hand-holding a heavy lens, and imposes a different way of shooting all the time even though you only actually need to take over control of the AF once in a while. This is why I prefer reverse back button focus where the AF ON button STOPS auto-focus instead of starting it. You can use the camera normally for everything, but when something odd crops up and you want the camera not to auto-focus, just press and hold the AF-ON button. Easy! Works like a charm. I've done it for years.

So where is my problem with the 600/4, and what has it got to do with live view and/or video?

Everything. When Canon designed the 7D II, they included that useless damn extra button immediately right of the viewfinder. It's just clutter, and a right PITA until you go into custom functions and disable it to stop the mirror clacking up and live starting every time you bump it. Now the 7D II is far from the first camera to have that extra button. From memory, even the venerable 50D had it, but on the 7D, for some reason, there is less space between that button and the AF ON button. Worse, the ridge you rest your right thumb against is much smaller and shallower than it is on (for example) my old 20D.

Result? If you have medium-large hands, when you hand-hold a 7D II with a heavy lens, you tend to depress the AF ON button without realising it. With more than 4kg of camera and lens to hold up, the tiny amount of force required to press AF ON goes unnoticed.

The cure: Mr Lens Technician Tannin went into custom controls and disabled the AF ON button: pressing it now does nothing. I reassigned the AF STOP function to the next button to the right, formerly AE lock, and haven't bothered assigning anything else to AE lock because I never use it. (When it is required, I just use more EC, or go to manual exposure. This is almost as quick and saves using up brain cells. As you can see from the tale above, I urgently need to conserve brain cells.)

Anyway, lens is now "fixed". I dare say I'll have to tweak the 5D IV in similar fashion as it has a similar design.

[arthurking83]

Boy o Boy!!
I couldn't live with myself without the AF-On feature. I'd have to give it all away.

Lucky for me I'm not you!

So the way I'm reading that story(about the location of the liveview/movie switch) .. it's more to do with the location of the switch .. not the feature itself.

Nikon's answer is to locate the Liveview/movie feature enabler swtich down the bottom of the rear face of the camera.
Still easily reached by thumb when needed(rarely).

[Tannin]

But of course I have the AF ON feature. I just have it organised more efficiently. (You have to press an extra button to use it - i.e., 99 shots out of 100 - whereas I only have to press that same extra button 1 time in 100 when I don't want to use it.)

Looking at a couple of random pictures of the backs of recent Nikons, they do look considerably less crowded and more pleasant, largely because the second wheel is so much smaller. But then I wouldn't trade the big, thumb-friendly Canon-style back dial for a moment - i.e., I want to have my cake and eat it. Don't we all?

Edit for clarity: when I disabled the AF ON button, I didn't lose any functionality: I simply shifted it one button to the right, onto the button marked * which wasn't doing anything else important, is still easy to reach, and difficult to press and hold by accident.

[Cage]

That was a fair challenge you set for yourself Tony, manual focusing at 840mm.

[arthurking83]

My biggest issue with not using the AF-On feature, and therefore forced to use the half shutter press, is when doing landscapes.
For sports, action, birding, etc, type shooting style .. I can totally understand your point of view with the AF-On system.
Having tried to use my old 300/2.8 manual focus and holding AF-On at the same time(to get the focus indicator working) .. is hard in terms of ergonomics. ie. not having a full grip on the grip side of the camera.

But I'm regularly going from one style of photography to another(ie. try a bit of bird chasing, then settle down to landscapes after the miserable effort with birds!) .. and doing landscapes, the type of control I prefer for landscapes is that I enable it(as opposed to your setup of disabling it).

To do that, you need to decouple AF from the shutter to start with and the only way to do that is to use the AF-On button to activate the AF system.

For landscapes, deliberately done, on a tripod, time taken to compose, wait for a particular moment(light) or whatever ... you don't actually want to refocus for every shot and have the shutter locked until you do AF again!
Many times I'll quickly slip into live view, either AF or manually focus on a section I'd like in focus .. maybe away from a focus point in the viewfinder .. and have focus just 'locked' there at that point.

So a decoupled AF system from shutter is better for landscapes.

[Tannin]

^ Makes perfect sense to me, Arthur. For your uses, I can see clear advantages to standard BBF over reverse BBF. Indeed, you practically talked me into it, as it would be just the thing for my landscape work. But that would mess me up for long lens work.

Landscaping, I usually start by simply trying to find an AF point over some suitable object in the scene, which is why the 5D II with its tiny little diamond of AF points drives all squashed into the centre makes me mutter and froth at the mouth.

Or I sometimes AF and recompose, slipping the AF/MF switch on the lens to off. But by the time I've done that, unless I'm using a prime, the lens will have magically changed its focal length - both the 24-105 and the 100-400 suffer from droop - and I have to fiddle about to correct things. By the time I've done that, the sun has gone behind a cloud or I've forgotten what brilliant compositional idea I had in the first place. It's all a bit of a muddle.

Recent model Canons have a remarkably flexible set of possible button reassignments and user modes but (without checking), while I think it is possible to reassign AF from half-press to various other places (such as the AF ON button), I don't think that is only possible on a global basis. You also have three user modes. I usually set them up for time exposure tripod shots. I.e, I'll set User 3 to mirror lock-up, f/11, ISO 100, five second timer delay (hopefully soon to be replaced by IR triggering), and so on: everything I want if I'm shooting something like a slo-mo waterfall. (Not that I do slo-mo waterfalls. Honest!) But I don't think you can reassign the AF buttons ONLY for User 3. Just the same, I'll look into it.

For birding, mechanical difficulty of holding a 4 kilogram lens aside, you have to be really, really fast, and if you are taking more than a couple of seconds over a shot you are probably about to bring home a perfectly focused picture of an empty branch. So reverse BBF is best for that.

I mostly use different bodies for different jobs, so I could set the 7D II (which only ever does birds) for R-BBF as usual, and the 5D II for standard BBF (as it only does landscapes), but I'd soon start getting mixed up between them and press the wrong button half the time. And both of the Mark IVs do both types of photography. So I'll probably just have to muddle on as-is.

Nevertheless, your thoughts have been valuable and may yet stimulate a minor brainwave.

- - - Updated - - -

That was a fair challenge you set for yourself Tony, manual focusing at 840mm.

It looked good in the viewfinder, Kev. NQR on the big screen though.

[Tannin]

An update on BBF. I've been giving this some thought lately. My 16-35/4 has finally arrived, and been partnered with the 5D II. (I seem to have a habit of assigning my least-liked or least-capable camera to wide-angle duty - I did the same with the 50D, and a 40D before that, and probably a 20D, and certainly a 450D back in the day.) But wide-angle duty is a perfect use for the 5D II: it has a wonderful sensor to resolve all that detail, and landscapes don't fly away on you so you have the extra moment to fiddle around with focus.

Alas, the 5D II AF system has this tiny little diamond of AF points in the centre, and if there is one sort of lens with which you nearly always want an AF point not near the centre, it's an ultra-wide. I really wasn't looking forward to the combination.

So after thinking over what you said in a post earlier about how well orthodox back button focus works for landscapes, Arthur, I decided to give it a try. Not for all the other cameras, just for the 5D II and the 5D II only. Is my mind flexible enough to manage using opposite AF start/stop methods on different cameras? Only one way to find out! Sop I did.

Early days yet, but I got used to it very quickly, and it works like a dream! The only trouble I had was forgetting to focus at all (because I'm still expecting the shutter button to do it for me): an unfocused shot isn't always obvious at 16mm the way it would be with a 70-200. But I think I can overcome that with a little practice. Best of all, I had not the slightest difficulty switching back to reverse BBF on other bodies.

So thanks Arthur. Good tip!