Why manual focus

[Dao]

I got home late. So I can only tried it at home. Here is the result. Hand held shots
1/200, f/2, ISO100, flashed(of camera), 50mm and hand held.

AF center point only to the the text on the lens paper. Straight out jpeg from the camera. (only resize on the 1st one and crop and resize on the 2nd one)

I point the center point to the text and the push the AF button, then the camera just beep once (confirm focus).

I may try it outdoor and see with a telephoto lens as well if weather is good.

 

[Ron Evers]

It will be more difficult with long glass where your target is very small in comparison to the field of view. Try to get a small subject with much clutter in front & behind & see if you can isolate it in auto focus & I will be impressed. A bird deep in a tree where you are looking between foreground branches is such a situation. Easier now with the leaves off.

 

[Robin Usagani]

thats why I love USM

 

[Dao]

It will be more difficult with long glass where your target is very small in comparison to the field of view. Try to get a small subject with much clutter in front & behind & see if you can isolate it in auto focus & I will be impressed. A bird deep in a tree where you are looking between foreground branches is such a situation. Easier now with the leaves off.

I will try that once the I got a chance. Ron, by the way, I am not trying to proof you wrong. Since I believe the AF should work in those situations, that is why I try to see that is the case or not.

By the way, you got some great shots there. And after all, the end result is all that matters! Manual or Auto, right?

 

[Ron Evers]

Dao

And after all, the end result is all that matters! Manual or Auto, right?

Exactly!

 

[BuS_RiDeR]

Nice shots Ron. Although I feel that in your 1st one. My eye is drawn away from the butterfly to that leaf... I assume that the butterfly is the subject here...

 

[rocdoc]

I would love to be able to manually focus more. On a DX body though, especially with AF lenses, it's not easy. I got one of those eye piece magnifiers on my D90 which helps minimally, but it's still tough on far subjects, especially with wider lenses I find. It works very well with my Tokina 100mm macro, the focus ring is excellent. Not so good with my 35mm M35 Pro Tokina, definitely not with the Tammy 28-75. A split-screen would come in handy I guess. This keeps me from buying a lens I wanted for a long time, the Voigtlander 40mm Ultron, a nice manual focus lens - I'm worried I would get frustrated getting the manual focus, with the small magnification.
Those are excellent shots btw. I agree that for the first one, of the bird buried in the branches, AF would have missed 9 times out of 10.

 

[shaunly]

although I do agree that MF is fun to use and great skill to have, AF system these days are so accurate and fast that you almost never need to MF anymore. All those image provided are great but like other have said, none are hard to achieve with single point AF system. I am a long time Nikon shooter so my experience is all from Nikon AF system. And yes I do have a few old AiS MF Nikkor lens, which I love btw. The only time I use MF is when I'm shooting in extremely low light with very little contrast.

 

[Overread35]

USM/HSM (all the time manual focus) + backbuttong AF control (getting the AF activation off the shutter button) + single central point AF (or you can use surrounding single points if you've more than one cross type AF sensor in your camera) + continues AF mode = happy days


I agree with Ron - in the cases of shots 2 and 5 and maybe shot 3, there is significant content in the foreground. Even with a single point of AF shooting into a complex scene where the surroundings are close to or might even cross over the subject even with single point AF control there is a good chance that the AF might catch the branch, reeds, bars at the zoo etc...

It won't always happen, but when it does being able to instantly shift into using manual focus is essential - even with wildlife there are times when you will need to use manual focusing.

 

[Ron Evers]

Overread has understood my argument & cited frames 2, 5 & possibly 3. I expect because I had not cropped out the all the foreground clutter as in the other frames. In retrospect, perhaps my post would have been better understood if I had only posted these three shots. I did say they were cropped shots in a previous post but I can see that this may have been easily overlooked.

Long glass, small subject = big crops.

 

[shaunly]

Overread has understood my argument & cited frames 2, 5 & possibly 3. I expect because I had not cropped out the all the foreground clutter as in the other frames. In retrospect, perhaps my post would have been better understood if I had only posted these three shots. I did say they were cropped shots in a previous post but I can see that this may have been easily overlooked.

Long glass, small subject = big crops.

What were the equipment used here?

 

[Chamelion 6]

Seems to me there is no right way to focus a shot, but plenty of wrong ways. As with most things it's a matter of choosing the right tool for the job and the real secret to that is understanding the limitations of each system. The better you know the things that mess with the various AF settings on your camera the better you can choose the right setting to get what you want. And the better you'll know when is the time to focus it manually.

I feel the same about AE and programmed modes. The better you understand each and their limitations the more options you have at your disposal, and the more flexible the camera itself becomes. There's nothing magical about "M," it's just another means to an end.

 

[GooniesNeverSayDie11]

To each his own. If you like using manual, then I say go for it. I will agree though that with a good AF system and a good lens you shouldn't have too much trouble unless the ambient light is pretty low ( or you aren't using the correct AF or AF points ). I think backbutton focusing helps me a lot. It wasn't available on my T1i but the 7D has it ( along with a much better AF system which doesn't hurt ). Also, a cheap lens takes for ever if it starts to chase focus at all and also if you have a better lens with full time Manual Focus ( like Canons L lenses and most USM lenses ) it makes it much easier to manual focus if need be and not miss a shot.

 

[Overread35]

Here's a good (if slightly extreme in some ways) example of when AF can fail.

Single, middle AF point being used with continuous AF mode active:

Shot 1:

Shot 2 (yes I changed the orientation, but that won't affect cross type AF - and as far as I know shouldn't affect AF at all - plus I was getting this problem through the whole series of shots on the lynx)

Shot 3

Shot 4

As you can see because there is enough distance between me and the bars that the AF can get a lock, and because the bars have sufficient contrast the AF was able to lock onto them - even in single AF point mode the AF is always trying to get a lock on the closest point of contrast difference it can find. So in this case it picked up on the bars - even though the previous shot was focused much further into the scene.

This is the same as you'd get for reeds, leaves, branches etc.. - if they are in front or very close to the subject and if they themselves hold enough contrast then the AF can pick up on them and focus on them rather than the subject itself.
This is why I like to use lenses with the fulltime manual focusing along with backbutton AF - the backbutton AF only changes when AF is activated - in a case like the above I can simple flick my finger off the backbutton AF control and readjust the focus quickly and manually with my hand on the focus ring -(the USM meaning that I don't have to first flick the lens in to manual mode - I can just jump right in) - and then because the shutter button no longer engages the AF I can take the shot with the focus hopefully sharp.

 

[Canon AE-1]

I got to say i really love the manual focus on my AE-1 and T-70 (soon to come A-1) compared to AF. I have a couple of digitals with no manual override and i hate that AF loop focus dance they do on some complex shots. In the future as digitals progress and still have lens interchangeability and MF, perhaps i will get a high end unit one day, till then, it's the tried and true old school for me.