Auto Focus Vs Manual Focus

[BCordeiroPhotography]

can someone please help me out here should i be auto focusing or manual focus in engagement session weddings etc or should i auto focus. please let me know thank you all.

 

[Derrel]

With an AF camera, and an AF lens, you should almost always use the AF system to drive the lens to the correct focus. My experience is that the focus should be established on every shot, not focused once, then "locked", which can result in focus errors if everything is not 100% perfectly executed. People often move a little bit, or re-position themselves, so I think it helps to focus each and every shot.

Many AF lenses have very hair-trigger focusing ring throws at distances beyond about 5 feet, so manually moving the ring, and using human eyesight to determine the focus accuracy, is VERY tricky with a d-slr, because the focusing screens in digital SLRs are not optimized for human visual focusing, and they show MORE depth of field than the lens's maximum aperture. One Canon model shows the DOF of a lens at about f/4.8, according to Canon's former ombudsman, Chuck Westfall. That means that the "in" and the "out" focus points are badly compromised, making focusing by human hand and eye a very sketchy deal.

If you want to do a lot of manual focusing with a d-slr, you want a replacement viewfinder screen installed, AND you most likely want a manual focus lens, with a long-throw, precision, helicoid focusing system, and NOT the loosey-goosey, short-throw of a typical autofocus lens. The replacement screens from KatzEye are the most popular, but not every d-slr model can accept one.

I know you're pretty new at d-slr shooting, so I would say, stick with the AF system and the AF lenses, and use them with the best possible practices.

 

[imagemaker46]

I agree with Derrel, the autofocus systems are tough to focus manually until you really get used to the lenses. There have been times when I thought I was spot on focus and then looked at the image and wasn't even close.

I use my manual focus 400 2.8 from time to time, just to practice and play around, it's easier to focus with that the auto lenses.

 

[astroNikon]

Modern lenses don't seem to have the "throw" that old manual lenses have and are more difficult to use MF. ie, a AF lens will take half a turn from one extreme to another whereas an old MF lens will take several revolutions it seems. Thus helps AF system focus faster (less distance to go)

I was practicing MF my 80-200 and it was a pain as just minute movements brings it in focus or out of focus.
On an older lens the rotation is much greater and much easier to bring something in focus.

So .. just use AF.

 

[astroNikon]

I think you have a d7000, if so Katzeey does have a MF screen replacement. I nearly bought one when I got my d7000 until I tended to like the AF system alot

Nikon apparently doesn't sell the screen anymore so Katzeye can't get them for newer models.
==> Nikon DSLRs - KatzEye Optics

 

[BCordeiroPhotography]

thanks everyone i was using a d7000 some images came out super sharp and overs i thought were in focus was out of focus and a friend of mine that is a photography told me to start shooting in manual mode. i figure i will post it here and get some information on what you guys think i rented a nikon 24-70 f2.8 i was pretty upset because the shots i really loved were out of focus and i was using AF mode on it. what a bummer i want to become better with this focusing so i can nail every shot i take i hope everyone has some good tips to help me out here.

 

[minicoop1985]

My rule of thumb is AF camera, AF. MF camera, MF. AF cameras are hard to manually focus, as covered by Derrel. Hell, MF cameras can be hard to manually focus.

 

[astroNikon]

My rule of thumb is AF camera, AF. MF camera, MF. AF cameras are hard to manually focus, as covered by Derrel. Hell, MF cameras can be hard to manually focus.

you should try a telescope. makes MF cameras simple by comparison. 'cept the subjects aren't going anywhere anytime soon .... so you have more time.

 

[minicoop1985]

you should try a telescope. makes MF cameras simple by comparison. 'cept the subjects aren't going anywhere anytime soon .... so you have more time.

I need an adapter for mine. I have a telescope that I wanna use. Focusing without the camera on it's enough of a pain...

 

[mrs.hankIII]

The only time I switch my lens to manual is either on a macro shot (and I normally bomb it) or when I'm just goofing off with it. I'm still fairly new at this as well, and if I were trying to manually focus in on everything, I would miss A LOT of shots.

 

[JerryVenz]

thanks everyone i was using a d7000 some images came out super sharp and overs i thought were in focus was out of focus and a friend of mine that is a photography told me to start shooting in manual mode. i figure i will post it here and get some information on what you guys think i rented a nikon 24-70 f2.8 i was pretty upset because the shots i really loved were out of focus and i was using AF mode on it. what a bummer i want to become better with this focusing so i can nail every shot i take i hope everyone has some good tips to help me out here.

I would NEVER use a rental lens on a paying job without first checking it's ZERO on MY camera body using my SPYDER LENSCAL--focus checker.
However you first must own a camera body that has MICRO-FOCUS ADJUSTABILITY--as a full-time professional I will not own a camera without this feature!

With that said I use auto-focus for virtually everything ( since I check all my lenses' focus zero every couple of months ). The only exception would be MACRO work when I'm on a tripod.

 

[BCordeiroPhotography]

JerryVenz i own a d7000 i will be purchasing a SPYDER LENSCAL first thing in the morning.

 

[astroNikon]

I would NEVER use a rental lens on a paying job without first checking it's ZERO on MY camera body using my SPYDER LENSCAL--focus checker.
However you first must own a camera body that has MICRO-FOCUS ADJUSTABILITY--as a full-time professional I will not own a camera without this feature!

With that said I use auto-focus for virtually everything ( since I check all my lenses' focus zero every couple of months ). The only exception would be MACRO work when I'm on a tripod.

Thanks
I was looking for a good method to test focus.

 

[KmH]

Use AF when you can. Use manual when it is advantageous to.

There are several fairly common situations where AF won't work very well.
In the D7000 user's manual (page 93) Nikon describes those situations.
Canon user manuals have a similar section in them somewhere.

Since AF is not a be all to end all when it comes to focusing the lens we really should be skilled at doing both manual focus and auto focus.

Nikon AF mods can be release priority or focus priority.
By default AF-S (single focus) is focus priority
By default AF-C (continuous focus) is release priority but can be changed to focus priority in the Custom Settings menu - a1.

If you are using a manual focus lens, or an AF lens in manual focus mode, the D7000 has the Electronic Rangefinder manual focusing aid that will light the in-focus indicator in the viewfinder when focus has been manually achieved. See page 100 of the D7000 user manual.
And it may be useful to review pages the entire Focus section of the manual that starts on page 91.

An additional key part of focus is knowing how to control depth-of-field (DoF) to your advantage.
Several factors determine how deep or how shallow DoF is.
Point of focus (PoF) distance has a big effect. The closer you are the shorter the PoF and the shallower the DoF.
Wide lens apertures contribute to a shallow DoF IF the closer the PoF is to the camera. In other words if the PoF is far from the camera the DoF contribution of a wide lens aperture as far a shallow DoF is concerned diminishes.

A common misconception is that longer focal lengths deliver shallower DoF. Longer focal lengths require increasing the PoF distance to maintain subject scale in the frame. With subject scale the same in the frame, longer focal lengths deliver the same DoF at the same lens aperture as the shorter focal length lens.
What does change is the field of view (FoV) and how much background elements are magnified (background compression) using a longer focal length. As lens focal length increases FoV gets narrower and back ground elements are larger (magnified). If the magnified background elements are blurred by a shallow DoF many interpret that as shallower DoF, but it is the background compression


Understanding Camera Autofocus
Understanding Depth of Field in Photography
Tutorials - Sharpness

 

[bratkinson]

Why have a highly sophisticated camera with sophisticated AF capabilities and an AF lens to go with it and not use it?

Perhaps the only time I've used manual focusing while shooting live action is when the lens couldn't achieve focus automatically because it was too dark. So I basically 'bracketed' my focusing and hoped to get lucky. I've set my camera to stop trying to AF if it can't achieve focus, and not to shoot if focus hasn't been achieved (menu settings). So if it doesn't shoot when I press the shutter, I know I have to aim somewhere else, achieve focus, lock focus, and recompose.

I 'played around with' manual focusing several years ago with my camera on a tripod and taking equipment photos for insurance purposes. Even with live view, it was difficult to really nail the focus. I strongly considered getting a Katz Eye focusing screen for my camera at that time. The 'split ring' focus screen that was commonplace on film SLRs was what I was accustomed to using. I never did get the Katz Eye. Instead, I honed my skills at knowing what the AF will choose to focus upon and getting the shot I want. It's a whole lot easier than trying to manually focus everything.