This may not be just a fling - SD15

Roger wrote:

[...]

The 3 things I dislike about the SD15 are:

2. No AF adjustment

The AF (and MF) on the SD15 is adjustable. I did the adjustment myself. There are two hex-head screws inside the mirror cave. One adjust the resting point of the mirror, and hence affects manual & automatic focus.  The other adjust the resting point for the AF mirror. It affects AF only.  They can be reached by removing the dust protector and then locking the mirror up - so adjustment is cumbersome.

It goes like this: Adjust Manual focus first - or check if is correct already.  This must be first, because it will also affect AF!  Use preferably a large-aperture wide-angle lens - those will show focus errors the most. I used a 20mm f/1.8

Take a picture of a ruler set at 45 degrees (or a better focus test target). Place it near the camera, for minimum depth sharpness.  You should be able to focus manually easily. Then take a picture, see if the viewfinder matches the sensor. If not, turn the adjustment screw a little. Take a new picture, see if it gets better or worse. Keep trying till it gets good. These attempts take time, as you need to take off the lens & dust protector each time. Don't leave out the dust protector, as focusing will be different without it.

When manual focus is good, time to adjust/check AF. Let the lens focus automatically. You may verify by looking at the now correct viewfinder, but actually taking a picture is better. (The viewfinder could still be a tiny bit off).  Take several verification pictures for each attempt, move the lens out of focus so AF has to work every time. This because AF isn't equally good each time - but you can find out what is typical.

If AF is off, adjust the other screw a tiny bit and try again til it is good.

I do not remember exactly where these screws are (somewhere in the side of the mirror well.) The mirror can only rest on one of them, that would be the MF one.

You have to experiment turning the screws. The screw heads are off-center, so the full range of adjustment is within a half turn. Use smaller steps than that. This also means that the direction for closer focus depends on how the screw sits at the moment - closer is not always the same way.

There is an illustrated article about such adjustment on the net. Search for it, for more details and explanations of how AF works.

Be warned that this adjustment only works for one focus point (and any other points at the same height.) Lower/higher points could still be off .  Still, it is the best DIY procedure available without taking the camera body apart.

Note that there not enough room to turn the allen key 60 degrees. So you may need two keys - e.g. a straight one and a bent one.

Also note that the camera won't lock the mirror up for long. A solution is to lock the mirror up, and then remove the battery. The mirror is then stuck up while you turn the screw. It comes down when you re-insert the battery.