FTM lenses

[GrayShade]

I keep seeing people talking about how great being able to manually focus a lens without disengaging auto-focus is, but I can't really understand why. I assume that this is mostly used to fine tune the focus distance chosen by the camera.

But is it really possible to do this? My camera has a pentamirror viewfinder and I don't have a split focusing screen and I doubt anyone would be able to do this kind of tuning without using Live View; and if you care to switch the camera to the magnified Live View mode, flicking the AF/MF switch doesn't seem to be such a hassle.

So what am I missing? Do better viewfinders help that much or is it something else?

 

[JamesRL]

I have some manual lenses for my Nikons.

I can get pretty close by eye most of the time, in broad daylight, I can focus without any other assistance. But Nikon also has a focus indicator in the form of a green light. It flickers when you are close and is solid when you are dead on.

 

[Doug Pardee]

Speaking for myself: I keep my Canon DSLR in back-button AF mode, and my lens in AF. I use a split-screen viewfinder and typically manually focus using FT-M. Sometimes I need/want to autofocus, either totally or just as a quick starting point for manual focus, and to do that I simply press the AF button on the back of the camera. No switching necessary between MF and AF.

 

[Hugowolf]

My most common use of FTM is when the camera chooses to AF on some part of the subject and I want to focus on something else. This happens particularly often with ultra wide angle lenses when shooting indoors. It is much faster for me to refocus than to shift the AF pattern.

For example, I’m shooting an event. Floral arrangement in the foreground, people behind the flowers. The AF picks up the flowers and I want the people in focus. I refocus on the people, one or more of the AF points over the people illuminates to show that they are indeed in focus, then I shoot.

I also use FTM with close ups and macro. At high magnifications the depth of field is paper thin at best and often the part that I want in focus isn’t the one chosen by the AF mechanism.

Brian A.

 

[GrayShade]

Thanks for you responses.

My Canon has a focus indicator light, too, but I didn't find it to be really precise and sometimes it doesn't even light up at all. I'd love to play with a split-screen viewfinder, but I might try MF again in the mean time .

 

[Deleted1929]

What you're describing can't be done with all lenses. In fact switching to and from manual with some lenses is convoluted.

You'd want to do it because you don't want to waste time switching to and from AF, but AF doesn't always pick what you want - AF areas are relatively large and the AF system can pick anything it likes in those areas.

Personally I'm either in MF or AF and I don't have a problem with either. I don't have a split focus screen either. MF does take practice and it's never going to be 100%. If your eyesight isn't good you're going to have problems with MF. For example, I wear glasses and keep them on when shooting.

--
StephenG

Pentax K100D
Fuji S3 Pro
Fuji S9600

 

[JamesRL]

In the old days we had diopters to slip on the eye piece to correct our vision. Now my D200 has one built into the camera. But since I wear contacts I don't use it.

 

[Guidenet]

I rarely have to override the AF. I either am using a single point or multi with tracking. I can quickly aim at the obvious subject, half press the shutter and hold the focus while I recompose. Rarely is there an issue.

If using a macro lens or a manual focus lens, you just manually focus of course.
--
Cheers, Craig

Equipment in Plan via Profile

 

[GrayShade]

That's something I never heard of before. How convoluted can switching between AF and MF can be?

 

[JamesRL]

Well in Nikonland, that I'm familiar with, it depends on the lens.

Most AF common AF lenses, you have to turn the lens AF off and then turn the camera AF off, then you can freely turn the lens on the manual ring.

Some AF lenses however, you can turn the manual focus ring without doing anything else first.