Manual Focusing

[olivia]

What do you think about the value of manual focusing over auto focusing?

I like the concept of manual exposure, but wonder whether manual focusing is enough better than auto to make it worthwhile. My lens 24-105 f/4L does a good job focusing on my 20D. Occasionally it picks up a leaf instead of the center of the flower, but....

What do you think....overall is it worth fooling with?

[KCMO Al]

Problem with manual focusing is that some, perhaps most AF cameras are not set up for critical focusing. Their view screens are too small in some cases and the plain matte screens are difficult to critically focus on. Back in the film days, many cameras came with split-image screens that were precise and easy to use. Some cameras offer focus confirmation but that can be off as well. Having said that, manual focus is necessary to use in close macro (true macro) shooting, and for me, at airshows using my 100-400.

[chauncey]

The very delicate "throw" of AF lenses, necessary because of AF motors, makes manual focusing difficult.

[yogestee]

What do you think about the value of manual focusing over auto focusing?


Try it and see..Costs you nothing..

Back in the film days, many cameras came with split-image screens that were precise and easy to use.

I've been a Nikon film user since 1975.. Whenever I bought a new Nikon, I would always buy a matte focusing screen for it.. Much easier to use that the split screen.. I disliked the way half of the split would black out when using depth of field preview..

[Pmolan]

I've always been tempted to pick up a Katz Eye screen, but there seems to be many exposure drawbacks with it.

[KCMO Al]

Chauncey, another point I forgot to mention. Fast AF=short throw, but difficult precision for manual. Years ago Alpa of Switzerland made a macro lens that took three full rotations to focus from infinity to macro.
Yogustee, yes, you are correct. I recall that phenomenon, but still feel the split image finders were very precise. Don't forget, if you look at my sig, I also use a Leica.

[PhotosGuy]

My lens 24-105 f/4L does a good job focusing on my 20D. Occasionally it picks up a leaf instead of the center of the flower, but.... Sometime the subject moves & sometime you move, especially with flower close-ups. If you switch your 20D's Custom Function 13-1 to put point selection on the Multicontroller (Joystick), life with AI Servo becomes a lot easier. It only takes a fraction of a second to set the point you need.

[440roadrunner]

There is no way in hell to get accurate focus on crop camera viewfinders consistently. Doubt it? Just borrow a 40D or other camera with a larger than the older viewfinder and live view. Magnified live view will quickly show you that there is room for improvement.

Somewhere around here is a REAL handy chart of viewfinder comparisons, I believe the "standard" of comparison is an old OLY OM. It matters not, all film bodies in that era had viewfinders that were MUCH larger than our current crop of DSLR crop bodies.

Here ya go:

http://photography-on-the.net/forum/attachment.php?attachmentid=396728&d=1254274513

Notice that even the 40D, which I use, is MUCH smaller than the old OM-1, typical of bodies of the day. Add to that the mirror robs light because it's semi-transparent

Even some pro's with large format view cameras use magnifier loupe's to check critical focus

[yogestee]

Here ya go:



Notice that even the 40D, which I use, is MUCH smaller than the old OM-1, typical of bodies of the day. Add to that the mirror robs light because it's semi-transparent



The Olympus OM series of cameras had an unusually large view finder even for its day.. A colleague used to shoot with OM1 and OM2 cameras and compared to my Nikons of the day the OM view finders were huge..

But I do agree with you,,35mm film camera are heaps easier to manually focus than a crop sensor DSLR.. Not saying it's impossible,,it just takes practice..

[DStanic]

I never manual focus. On a crop body the viewfinder is just too small. If I had live view, then I'd probably try it anyways. It *might* be okay on a 7D with a Katz eye screen but still nothing compared to my film SLRs.

[neilwood32]

As Jurgen says, give it a try - it will cost you nothing but time.

There are situations where AF just isnt right such as landscapes (hyperfocal distances)

[Tallking]

Problem with manual focusing is that some, perhaps most AF cameras are not set up for critical focusing. Their view screens are too small in some cases and the plain matte screens are difficult to critically focus on. Back in the film days, many cameras came with split-image screens that were precise and easy to use. Some cameras offer focus confirmation but that can be off as well. Having said that, manual focus is necessary to use in close macro (true macro) shooting, and for me, at airshows using my 100-400.


The very delicate "throw" of AF lenses, necessary because of AF motors, makes manual focusing difficult.

It's interesting (to me anyway...) that this question came up now. Yesterday I was lamenting the failings of AF systems. I know, they're pretty good compared to the first ones, but I still see enough focusing errors, a little off here, a little off there; that I'm getting fed up.

I'd like to see the return of proper manual focus rings on the AF lenses so you can be comfortable when MF is appropriate, Also, what harm would it do to leave in the classic split image focusing screen. MF or AF, the latter would allow positive confirmation of good focus.

[E-K]

Also, what harm would it do to leave in the classic split image focusing screen. MF or AF, the latter would allow positive confirmation of good focus.

It impacts the metering and obstructs the view in some cases. That being said, I do use one in my XT.

e-k

[SkipD]

I frequently focus manually with my 20D and the "L" zoom lenses that I have and don't find it to be problematic at all. The "kit" lenses that I have handled in stores suck wind for manual focusing, though, because the tiniest movement of the focusing control ring on the lens makes a huge change in the focus. My lenses (original version 16-35 f/2.8L, 24-70 f/2.8L, and 70-200 f/2.8L IS) are all fairly easy to use for manual focusing.

I do use a "trick" that some folks may not have tried. I first auto focus (using the * button on the back of the camera) to get roughly in focus and then I will rotate the focusing control ring back and forth a little bit. I try to go equally far past the "in focus" point when cycling the control ring back and forth. With only a couple of cycles, I get a good feel for how far past "in focus" I've travelled each direction, and then I simply split the difference. It may be surprising to some how accurate I can get.

When I need to be really precise, I may use my Angle Finder C with it adjusted for the 2.5X magnification. Then, it's super-easy to tweak for precision focus. This is best done on a tripod, though.

[zincozinco]

What do you think about the value of manual focusing over auto focusing?

I like the concept of manual exposure, but wonder whether manual focusing is enough better than auto to make it worthwhile. My lens 24-105 f/4L does a good job focusing on my 20D. Occasionally it picks up a leaf instead of the center of the flower, but....

What do you think....overall is it worth fooling with?

Its well worth it in many cases, the whole focus/recompose can in sometimes put the focus plane OOF for ex.

Also it slows you down a bit and many times I find myself re composing as a part of it.

you might also want to try with a MF lens as they are a lot smoother and not so big and heavy as the AF.

go for it!! :)

[20droger]

We use a Katz-Eye split-prism screen with a 30D. We love it.

Since a majority of our shots are either macro shots or shots of birds/critters, autofocus is often all but useless. Manual focus is always dead on with a split prism.

We also love our Sigma 150mm f/2.8 macro. Not only is it razor sharp, it has a nice long manual focus throw, making it easy to get precise focus. And, it's fast enough to use with a 1.4× TC as a general-purpose long telephoto (same field of view as a 330mm on a FF camera).

[440roadrunner]

One warning to ya'all about split prism glass. THE ACCURACY is affected by the diopter setting on the viewfinder, so take the time to set things up on a tripod and check. This situation becomes obvious if you have a "live view" capable camera

[20droger]

One warning to ya'all about split prism glass. THE ACCURACY is affected by the diopter setting on the viewfinder, so take the time to set things up on a tripod and check. This situation becomes obvious if you have a "live view" capable camera
Not my experience.

Neither did errors occur during experimentation this morning over the full range of diopter settings on our 30D.

And neither would such inaccuracy be explained by the theory of split prism focusing, nor by how diopter setting work.

Split-prism focus screens and diopter settings were often found on cameras in the good old days. I cannot remember anyone ever complaining about split prism inaccuracies due to diopter setting.

[yogestee]

Split-prism focus screens and diopter settings were often found on cameras in the good old days. I cannot remember anyone ever complaining about split prism inaccuracies due to diopter setting.

This is true.. There is no physical connection between focus screens and diopters..

[440roadrunner]

This is true.. There is no physical connection between focus screens and diopters..

I can assure you all that YOU ARE INCORRECT. I've done careful checking on this with a split prism screen in my 40D Here's the setup:


Using my 100-400L as well as a couple of other lenses, I set up a flat, high contrast target outdoors in bright light on a tripod.

I first focused AF, then switched to MF to lock the lens. I then went to live view and checked the focus, going back and forth several times to check AF/ live view.

When I had satisfied that area, I paid attention to the split image. I found that the diopter adjustment WOULD MOVE THE SPLIT IMAGE. Even though I thought I had accurately set the diopter, I found that if I FIRST focused manualy in magnified live view, then went back and set the diopter so that the split image was spot on, that the viewfinder was still absolutely sharp.

Further testing revealed that:

With the camera on a solid tripod, the lens in MF, and ONLY changing the diopter setting, the split image would "move" in/ out and "on" the focus point

I CAN ASSURE YOU that I've done careful testing and that the above is correct.