A friend recently emailed me to ask how I was getting on with my Canon EOS R, which I've had for a year or so now. This was my reply.

The EOS R is the most frustrating and annoying camera I have ever owned, particularly insofar as it has some notable strengths which tempt me into forgiving it just when I've decided to chuck it into the nearest river.

On the positive side, it takes a lovely picture. In theory it should be equal to the 5D IV and almost identical - it's pretty much the same sensor and the exact same lenses after all. However it often seems to me to produce even better picture quality straight out of the camera. It's a subtle difference, but nevertheless real, I think, and I ascribe it to the newer generation in-camera processing - in other words, it's something that new model SLRs will have in equal measure when they eventually arrive.

On the negative side, a laundry list. In no particular order:

* The autofocus system is unpredictable. It's excellent when it works well, which is most of the time during typical use, and is if anything even faster and possibly even more accurate than the SLR systems. When it works. But quite often it just doesn't. It mulishly refuses to do anything, even when faced with what seems to me to be a perfectly reasonable scene, and a scene which I'd have no difficulty getting focus with using any of my SLRs except possibly the 5D II, which is a very, very old model notorious for its primitive AF system even when it was new. These EOS R stop-work meeting things happen often enough to make the thing unusable for many subjects. More than 90% of the time (with normal everyday subjects) it's very good. But the failure mode it goes into makes it unsuitable for anything that moves or offers only fleeting opportunities.

* The autofocus system lacks the ability to select a small point. All Canon SLRs have had this ability since ... er ... since at least the 1D III and the 7D Mark 1 a decade or more ago ... but the EOS R does not. For wildlife it is critical. If you can't say "I want you to AF on the bird's eye and ignore that stick" the camera is just about useless. There are people who use an EOS R for birds, and some of them even say they like it. I think they are insane.

* The autofocus system lacks a viable way to select an exact focus point in a timely manner. (I.e., while the bird is still in the same postcode.) It does have a nifty touch screen system, but that is impractical (for reasons detailed below) and is in any case rather inexact. The alternative is a very low-rent arrangement of four clumsy little arrow buttons - something I haven't seen on a non-toy Canon camera since the very cheap little 400D I owned in ... er ... about 2007. On the 400D, it had to control a choice of maybe a dozen AF points and worked adequately. On the EOS R, it has many hundreds of points to select from and, being able only to step through them one at a time, delivers the desired result around about as rapidly as Australia Post. (Compare with the fast and accurate joystick system on all the better SLRs.)

* The touch screen AF selection method I mentioned above would work very well indeed if you habitually work in Live View, particularly with a tripod. So it's good for video. Although rather vague, it's probably precise enough for most things, possibly even for bird work. However, to use it you have to have the flippy screen facing out and switched on (which does terrible things to your battery life), and you have to take your eye away from the viewfinder, especially if (like me) you are left eyed. (And don't even think about it if you wear reading glasses.) By the time you've done all that and got back on the subject, the subject is gone. You also need to have the screen flipped out to the left (beyond the body) because if you have it tucked in neatly on the back like an ordinary non-flippy screen you keep getting nose-focus. (It might be OK on the back if you are right-eyed.) Summary of touch-focus: hopeless. I don't even try to use it.

* Flash. Although it focuses very well in quite low light, when the light gets really low it drops its bundle because it is unable to use the AF assist function provided by flashguns. (This limitation applies to all current mirrorless cameras, which are unable to detect the IR emitted by AF assist lights because they focus using the main sensor instead of a dedicated AF sensor.)

* Battery life is poor through to very poor, depending on your options and usage.

Nearly all of the other EOS R issues are to do with the ergonomic design, which is an equal mixture of poor and dreadful.

* First, it's too small for anyone with average sized hands, especially so if you are using big lenses. These require that you support some of the lens weight with your right hand. With (for example) a 7D you can do that comfortably and still reach all of the common controls with your fingers. Canon have decades worth of experience designing simple, logical camera controls that work well with the average human hand, and that experience and attention to detail is obvious when you use any of their SLRs - especially so with the 1 Series professional models which are a joy to hold in hand, but we see it with the lesser models too. For reasons unclear to me, Canon comprehensively failed to apply their own skills to the EOS R.

* It lacks controls. Too many functions are squashed onto too few buttons, resulting in annoying and time-consuming fiddling about trying to set a particular dial or button to a particular function, all the while praying that the sun doesn't go behind a cloud and that the subject doesn't go away. The EOS R is a very bad thing to be holding and trying to set up quickly when a one-time event is about to happen. For example, suppose you see that a train is about to go over the bridge you are interested in. You have five seconds to be ready and you have to compose, frame, select an aperture and shutter speed, possibly change your ISO, possibly apply appropriate exposure compensation, and possibly change your focus mode and/or focus point. With a 5D or a 1D or a 7D, no problem. I do that (typically with a bird, but regardless of subject) pretty much as routine. With the R, either it's set right in the first place (aperture and exposure compensation aside) or you miss the shot. Everything else just takes too long.

*Customisation is partially crippled. You can move functions around in the firmware to try to make the most of the limited selection of controls you do have, and that helps, but there are weird and apparently senseless restrictions which you have to try to work around.

* The controls it does have are badly placed. In particular, the second dial is a shocker. Instead of being a flat wheel on the back of the camera where it is instantly accessible at all times and easy to reach, it sits way up high where you can't reach it without changing your grip - and if you are using a heavy lens like a 600/4 (or even a 100-400), that is a big deal. It takes time, and in the process you lose alignment and may have to reaquire the subject, which takes more time. Other controls are also hard to reach and not as easy to find without looking as they should be.

* Some of the controls are pretty much useless. The ill-thought-out rocker/slide thing up near the viewfinder is the worst example. I can think of several practical uses for it, but the crippled customisation scheme doesn't allow any of them.

* The AF ON is another example. It sits exactly where you put your thumb when you hold the camera, especially with a big lens. As with many of the R's other problems, this is a consequence of making the body too small. (The 7D II has a similar problem, but it is easy to reprogram the AF ON button to do nothing and the fairly useless button next to it to do AF ON. You can't do that on the R because it only has the one button and nothing to replace it with.)

* The viewfinder sucks. It's quite clear under good circumstances, but is not to be spoken of in the same breath as a really good optical finder (any of the 5D, 6D, and 1D models) or even a medium-good one (7Ds and the 20D to 90D series). It's not really good enough to compose with the way you can with (say) a 5D. You need to compose in your head and only then lift the camera to your eye.

* The viewfinder is unusable under some lighting conditions. Strong sidelight is the worst.

* The viewfinder has an annoying lag before it switches on.

* The viewfinder can't be used for any length of time for observation because of the picture quality (which is poor relative to an SLR), because of the eye-strain which becomes apparent after a while, and because it chews through the battery. For wildlife photography, which involves long periods of waiting for the magic moment, this is a showstopper.

* The viewfinder suffers from unacceptable lag. It is unusable for serious wildlife or sport photography. Note that Canon's new professional level camera is an SLR, presumably mainly for this reason.

* The fancy-dancy electronic level is huge and clumsy - so big that it obscures the view of the scene you are trying to photograph - but nevertheless somewhat difficult to read, and in any case unreliable. What is the point of an electronic level which can't tell the difference between level and tilted? (Compare with the plain Jane electronic levels in the SLRs, which are small, boring, easy to read, and actually know when the camera is straight.)

* General firmware and design weirdness, often poorly documented. For example, the electronic level turns off and disappears completely if you have eye-controlled AF on. It took hours of head scratching to discover this stupidity hidden deep in an apparently irrelevant section of the manual.

* Badly designed settings menus. The parts simply copied from the time-tested SLRs work as flawlessly as you would expect. Some of the new-for-mirrorless parts are borderline incomprehensible. Pretty much everything is there ... somewhere. Good luck finding it.

Apart from those things (and whichever others I forgot to mention) it is fine.

Despite all that, I use it regularly. As you know, I have the usual bird photographer's fetish about never being caught with the wrong lens mounted - you never know when some mega-rarity will pop up and if you are not ready, you miss out - so I carry multiple cameras as routine. Usually, I have the best two wildlife cameras (5D IV and 7D II) on the two long lenses, which leaves a choice of three for general-purpose use - mostly landscapes - nearly always with the 24-105/4.

The ancient 5D II is adequate but annoying. It lacks an electronic level (something I really struggle without) and has a very primitive AF system. I usually consign it to wide-angle duties with the 16-35/4, where focus isn't much of an issue.

That leaves the R and the elderly 1D IV, which has a weird but not unpleasant crop factor and only modest resolution, but is an utter joy to use. (Analogies are always suspect, but think of a really fine musical instrument, or of driving a well-sorted Italian sports car.) I much prefer using the 1D IV. The lowish resolution is nevertheless sufficient, and because the controls are so well sorted you pretty much forget about the mechanics of driving it and just think about the pictures you are taking. It's a no-brainer.

.... Except that it isn't.

It is much larger than the other cameras, and rather heavy, and it doesn't fit comfortably into even my biggest camera bag if there is already another camera in it. I can fit any two cameras and reach either one without taking the bag off - except the 1D IV. So, despite its obvious charms, it tends not to get used unless I'm working from the car rather than on foot, and the unlovely R gets the job by default: it's a more manageable size than the huge 1D IV, more capable than the ancient 5D II, and more available for general duty than the superior 7D II and 5D IV.

I have never hated a camera more than I hate this one. I sometimes wish it was bad all over instead of just in places so I could justify throwing it away.

Now some people say that those issues above are things you can work around if you try hard enough. Sure you can. And if you haven't got a horse, you can ride a goat. It's slower and less practical, but it works. Sort of. But why would you want to ride a goat if you can afford a horse?

The new R5, when it comes out, looks set to deal with about two-thirds of the long, long list of EOS R faults, albeit at vast expense. I'd rather one of those than an R, but not at the likely price. Instead I plan to wait for a 5D V, and if Canon don't bother making one, I'll eventually sell my stuff up and switch to Nikon. But I reckon they will - there are a lot of people like me, and the sport and wildlife markets are huge. They can't ignore a market of that size.

At that point, I'll have a spare modern SLR to replace the R with, and I'll presumably consign the R to the dishonourable semi-retirement of wide-angle duty, replacing the 5D II. Will I miss it? Not in the least.