Focus lock

[Nathaniel]

I am aware of the principles of focus lock i.e to lock the focus on a subject by placing the focus point exactly where you want to and then depress the shutter slightly to hold it steady. But I find that after I use focus lock and try to re-compose the picture,all the time keeping my finger depressed slightly on the shutter,the image is soft; it is never sharp. What am I doing wrong?
I have read through the instruction manual, and an old EOS camera guide and still don't get it right. Any advice?

[colin C]

Re: Focus lock

Hmmm, bearing in mind that Sunday is almost upon us and it could be a number of things, how about:

• Focus on the subjects eyes.
• Switch lens to manual focus.
• Re-compose for the group.
• Take the shot.
• Switch lens to auto for next shot and repeat steps above.

That is the failsafe plan of last resort, without re-jigging your camera for back button focus. However, try the following:

• Set up the focus points for centre point only. It is much more sensitive, which is what you want in low light applications.
• Ensure that your finger is keeping first pressure on the shutter button after you press focus lock - it is so easy to relax pressure slightly in the heat of the moment and as soon as you do, focus lock is lost.
• If using flash to light the subject, check that focus assist beam is on - check the manual for the right settings.

Good luck and don't worry .......... it'll be fine.

Colin

[djguk47]

Re: Focus lock

without re-jigging your camera for back button focus

I don't know as all Nathaniel has to do is plant his thumb on the back button, watch the centre focus point light up forget about the shutter button, recompose the shot, then hit that shutter button with his finger.
On Saturday spend a couple of hours just photographing anything that is in sight using the back button function to get used to it.
Back button is easy... but then again as you say, Sunday is getting close

[Nathaniel]

Re: Focus lock

Hi!, I wasn't thinking of focus lock for this coming sunday as I am quite sure I can have the subjects in my sights and take the photo all in one go.I have been to the site more than once and even tonight I will be in church for choir practice and I will double check that everything is OK My question was for my future use of focus lock esp as my over seas travel arrangements are coming up -although here I will have good daylight to contend with, apart from th Oberamagama Passion Play which is in the afternoon and night. Also I won't be under any STRESS.

Yes, I am aware of the back button which I will try out after this Sunday.

[NickJ]

Re: Focus lock

I'm sure i've read somewhere that focus lock and then recompose can sometimes lead to a slightly out of focus shot if you inadvertantly move the camera forwards or backwards (I assume) whilst recomposing. Is it not beeter to select the autofocus point instead? I have to say it is sometimes a pain and easier to use the centre point.

[Nathaniel]

Re: Focus lock

Thats exactly the problem I seem to be having. So I will use the centre point for important,once in way, shots and play around with focus lock at mhy leisure.

[Canon-Fodder!]

Re: Focus lock

One other thing to bear in mind when using AF and focus-lock is that it's rare for most lenses to acquire precise focus at the first attempt!

If I'm using AF, single-shot, I almost always focus twice; once to get the lens in the right general arena; and the second half-press generally locks on precisely. You can always hear the USM on the lens correcting itself on the second focus!

[colin C]

Re: Focus lock

Hmmm, interesting observation. I must try that.

Colin

[EOS_Jim]

Re: Focus lock

I do that too - although usually three times (I saw a pro do that and just followed the same logic CF mentioned).

I use the back button for focus and I've had good results with focus recompose except at larger apertures than f4 - Can be ok at 2.8 depending on distance to subject and focal length but at f2.8 and larger - you need to be precice generally.