Focusing and Eye correction?

[aprisa]

Can't get this right in my head (too much room!)

I am a little dissapointed with some of the fucusing on my latest shots with the 20D, I have the eyepiece correction set to roughly the same as my Prescription for my right eye (-1.25) should thios mean that when prefocusing for sporting shots that It will be correct for the focal distance and show clear in the viewfinder? If you have to use correction does it really need to be bang on and require a corrective eyepiece?

I need to start using manual focus a lot more as especially with Horses the auto is just on the wrong spot for what I want.

Any advice?

Nick

[beano500]

Hmm?! Dunno specifically, but I imagine a little way out means you won't get perfect focus.

Possibilities include the tricks I use:

1) let the camera focus on auto, then switch autofocus off (damn trick doesn't work on manual lenses though )
2) use autofocus indicator in viewfinder (PITA in bright light though )
3) pick a smaller aperture so it's not so critical

>> Edited by beano500 on Friday 23 September 12:28

[aprisa]

Thanks for that, part problem is that I need a fast shutter speed to freeze such things as the horse jumping but want a reasonably shallow depth of field to blur out the crap backgrounds. As I'm centralising the rider the horse's head tends to be blurred on auto, when in manual its seems to be variable probably down to user error!

Nick

[beano500]

(My Dad used to have the problem that he couldn't focus an SLR without his glasses, so I know the problem.)

I'm a significantly higher correction than you (and I use my left eye, just to be awkward), but why don't you just use your normal prescription lenses and have no adjustment at all?

[simpo two]

Stick a telephoto on and look at the brickwork of a house 100 yards away. If you can't get it sharp in the viewfinder regardless of how you twist the focus ring, then the viewfinder correction is insufficient - crank a bit more in. Or zero it and wear glasses/CLs.

But why not use AF with focus tracking? Then it doesn't matter if you can see it clearly or not!

aprisa said:

As I'm centralising the rider the horse's head tends to be blurred on auto, when in manual its seems to be variable probably down to user error!

Is the blur caused by focus error or movement? If it's focus then your DOF is too shallow. If it's smovement then your shutter speed is too slow.

>> Edited by simpo two on Friday 23 September 13:23

[elderly]

It has just been reported in the trade press that Canon may have a quality control issue with the lens flange on its 10D, 20D and 350D cameras which can
give an unsharp appearance.

Canon have not yet given a response.

[fergusd]

The lens will focus on the sensor/film or the focus screen depending on where the mirror is . . .

The eyepiece will focus on the focus screen . . .

They are two seperate systems, and eyesight correction on the eyepiece will not effect the main lens focus . . .

If it's not sharp it's nothing to do with your focus correction . . . ;-)

Fd