Full Manual Focus

[GovtLawyer]

After some not-so-spectacular shots with my Sigma 18-200, due to photographer error and some auto-focus issues, I decided to take a look at some Canon Lenses. I realized that I really like manual focus, as I am used to it from 30 years of film photography, and I do not really trust the auto focus to be right all of the time. I went to Adorama and tried the 17-85 & the 70-200 F4 L. Both have full manual focus, whcih means you can manually focus while in auto mode.

I have some questions about the whens and whys of "full manual focus" on these lenses. I tried both lenses in manual and in auto with manual override; a fairly strange way of focusing. So, the following questions arise from my test.

Why would a person use manual override on auto as opposed to simply starting in manual?

If you press half way down, and feel you wish to tweak the focus manually, would you have to keep the shutter half depressed?

If you let go of the shutter and then focused manually, would the camera refocus automatically when you pressed the shutter?

What would the operating procedure be if you remapped the autofocus to the * button?

Would you focus manually and then use the * button for auto, all the while in auto mode?

While I'm on the remapping to * area; what happens to continuous shooting, and/or auto/servo ifocus f you remap it? Do you need to keep your finger on the * button at the same time you are holding down the shutter; in effect, needing two fingers to shoot? If so, what is the advantage of this remapping which so many people seem to do?

[Hellashot]

A main point of full-time manual focus allows a user to do a manual focus without the need to switch the lens to manual - for a quick shot when time is of the essence. It's not something someone would use all day long.

I'm not sure what camera you have, but my Drebel has a small viewfinder. When I first got it I only did manual focusing. But I've realized that most of the time AF is going to get it right. When I have a lot of time and have a somewhat close subject I'll use MF, but usually it's a lot of back and forth to get the right focus and often people and wildlife don't like to sit still for more than a few moments. :)

Have you posted some of your problem images and asked for help in here?

[FScott]

I use manual focus quite a lot. So much that I'm thinking of getting a replacement focus screen:

http://photography-on-the.net/forum/showthread.php?t=83084&page=1&pp=20&highlight=focus+screen+20D

If I have a still shot I almost always check the focus by flipping into manual mode. I usually start with autofocus because that is the way I store the camera but after the first focus I flip into manual mode and rock the focus back and forth to make sure what I intend to be in sharp focus is in fact correct. As far as how the half-shutter press works, if you tweak the focus on a USM lens like the 70-200 f4L then press the shutter it will refocus. Remapping to the * key I believe fixes this. Now if you are in autofocus mode and the camera doesn't get focus confirmation you can't take the picture. I'm not sure if remapping to * means the camera doesn't check or what. I would like the answer to that one too. Maybe this afternoon I'll play with it and see what happens.

-- Scott.

After some not-so-spectacular shots with my Sigma 18-200, due to photographer error and some auto-focus issues, I decided to take a look at some Canon Lenses. I realized that I really like manual focus, as I am used to it from 30 years of film photography, and I do not really trust the auto focus to be right all of the time. I went to Adorama and tried the 17-85 & the 70-200 F4 L. Both have full manual focus, whcih means you can manually focus while in auto mode.

I have some questions about the whens and whys of "full manual focus" on these lenses. I tried both lenses in manual and in auto with manual override; a fairly strange way of focusing. So, the following questions arise from my test.

Why would a person use manual override on auto as opposed to simply starting in manual?

If you press half way down, and feel you wish to tweak the focus manually, would you have to keep the shutter half depressed?

If you let go of the shutter and then focused manually, would the camera refocus automatically when you pressed the shutter?

What would the operating procedure be if you remapped the autofocus to the * button?

Would you focus manually and then use the * button for auto, all the while in auto mode?

While I'm on the remapping to * area; what happens to continuous shooting, and/or auto/servo ifocus f you remap it? Do you need to keep your finger on the * button at the same time you are holding down the shutter; in effect, needing two fingers to shoot? If so, what is the advantage of this remapping which so many people seem to do?

[CorruptedPhotographer]

that split image screen for the 20D by Houahda looks interesting.

[Tapeman]

If you set custom function #4 to 4-1 you can focus by pressing the * button and then manually adjust focus. When you press the shutter release the focus will not change.

[CorruptedPhotographer]

Tapema, good point, that is a fantastic feature. I utilize it a lot when photographing wildlife, yes sure AF is great and sharp, but its not 100% accurate all of the time.