AF or MF?

[leefhall]

I hope to get some feed back on the best method for focusing?

Sometimes when using AF my lens is all over the place by the time my subject is focused its gone.

I have been a little quicker using MF, but as I wear glasses I don't quite trust my self. (i have focused the eye piece). Shots seem to be ok.

Can people suggest when to use which method, or have a prefered method which I should practice.

Your help and suggestions appreciated Thank you Lee

[big bill]

Hello Lee firstly what camera do you have?
Myself I use both depending on circumstances,I have the Canon400D and have selected the center focus point for use, and this is focus point I use all the time I also set the focus to A1 servo so if the subject is moving slightly the focus keeps locked onto it.
The manual focus I will use if the subject is in the trees and there is a chance that I may inadvertently focus on a branch in front of it ,in this case I wouold use manual to ensure I get correct focus on the bird other than a branch.
But the majority of the time its on AF and A1 servo and I have no problems
I also wear glassesand do not find this to be a problem .

[Geoff F]

. . . and the same here. AF for flying birds but MF for macro or questionable backgrounds.

Slightly different glasses problem. Only need reading glasses but have to put them on to find macro subjects then take them off to get a sharp manual focus. Trouble is what to do with the glasses when they aren't on my nose. In a trouser pocket they get bent as I don't want to keep opening and closing a case. Too often I just put them on the ground and step on them or they fall into the undergrowth and I can't find them again. Tucking into my collar works best but they can still fall out when I bend over. Only take cheapie specs with me now!

But back to AF/MF. I find that while AI servo works fine for flying birds it can tend to keep 'hunting' when used on closer depth of field work so I switch to One Shot then. Variable focus problems can be common when using Converters.

For close work a tripod makes all the difference, and subjects blowing around in the wind can be problematic.

Poor contrast in the background can also cause problems.

[Maccattack1]

Hi Lee , I also wear glasses , some of my shots come out ok .Manual focus is great for static stuff , you keep total control of the focus , macro subjects focus faster manually in general .For moving things auto is a help but as implied above you need to think about the settings beforehand. If you have a "continuous" focus set ,this may jump around a bit and can only improve with practice , it may be easier to use "fixed" autofocus first so the focus stays put, if your subject isnt moving around too much.The speed of focussing will depend on your set up ,some cameras and lenses move a lot slower than others .
I found practicing on subjects like seagulls or pigeons a great help.

Details of your set up may help

Malcolm

[Cellarman]

Originally Posted by big bill

Hello Lee firstly what camera do you have?
Myself I use both depending on circumstances,I have the Canon400D and have selected the center focus point for use, and this is focus point I use all the time I also set the focus to A1 servo so if the subject is moving slightly the focus keeps locked onto it.
The manual focus I will use if the subject is in the trees and there is a chance that I may inadvertently focus on a branch in front of it ,in this case I wouold use manual to ensure I get correct focus on the bird other than a branch.
But the majority of the time its on AF and A1 servo and I have no problems
I also wear glassesand do not find this to be a problem .

I do exactly the same with my 400D. I've recently bought a 450D and use the "live view" when taking macro shots - I can use 5x or 10x mag on the live view sceen, which enables critical focussing, also allows me to watch for the moment when the plant stops moving, so I can press the remore release.

[leefhall]

Thank you for the responce. I'm using a Canon 1000D along with a 75mm 300mm Lens, and I do have a 2 x converter and have experienced the focus hunting with that attached.

I do have the middle focus light set up only, and its set up for salvo. I don't understand what A1 Salvo is???

The valid points you are all mentioning I am experiencing, wind, movement, 2 x converter. By the sound of it I should think a lot more about what i'm trying to do. My guess is that will dictate what method to use.

Once again thank you, your responces do help. Lee

[Geoff F]

I'm afraid all I can say is 'throw the converter away'. You need a really good quality lens to successfully take a x2 and, sorry to say, the 75-300 just isn't up to it. I did manage to use a 1.4x on the newer 70-300 but I wasn't totally happy with the quality of my photos so I gave up with it.

AI (artificial intelligence) Servo automatically locks onto a moving subject and holds the focus by automatically adjusting itself by continually refocusing. It works fine on distant subjects where there is a fair bit of spare depth of field distance but struggles to hold focus where the depth of field is shallow.

Alternatively AI Focus focuses on a still subject but then switches to AI Servo mode if the subject (or photographer) starts to move.

For best results, from static subjects under the right conditions, I always prefer the One Shot setting as there is no chance of the camera deciding to try to alter focus.

So experiment with the other focusing options then choose the best one for each photo.

When you have sorted out this little problem, have a think and experiment about the different exposure alternatives. Nowadays I mostly use the spot or partial metering option and often once I have worked out the best settings (subject to operator error) I use the manual controls. Never the Full Auto controls!

[wrogers]

I only manually focus (as big bill does) when branches or grass are in the way... however my Sigma 150-500 OS does nearly always lock on and very quickly...
I have only had to switch to MF with tiny objects that even a 800mm + 2x tc would struggle with (I only tried this to test the lens)
the other problem is with my dog running, but she is the 3rd fastest breed (smooth collie)
and MF on a running dog at over 30Mph is pretty impossible!!!

unfortunately the 75-300 isn't the best lens at AF and the 400D ain't much better...
however some of us can't afford a 1Dmk3 and 600mm F/4!!!
try the 55-250 IS... at £200 it is a reasonable lens that does work very well for £200... It seems more like a £300-£400 lens!!

[Markulous]

AF where the light/contrast is good (I use a 350D/30D/40D) and smallish movement. MF by preference, if subject is still or if in poor light/complex movement

I use the supplementary button (*) on 30/40D for focus so choosing AF/MF is just a question of using or not using the button - quite often will AF initially and then fine adjust manually

[galanthus]

I too tend to use central focus point only, with AF and on one-shot unless taking moving subject shots. If I'm snapping a group together or a landscape shot i use all focus points and one-shot but again AF. I use MF usually only for macro shots or birds mid-tree same as others who have posted.

....and in defence of the 400d I use it and it's fantastic, I have some stunning shots with it. Lenses, good composition and a steady hand or good tripod make more of a difference to your work.