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Photography Question 
Kathy L. Pollick
BetterPhoto Member Since: 7/14/2005
 

Autofocus vs. Manual Shooting


My camera is an autofocus and/or manual. This might sound like a real amature question, but if I use my manual settings, do I want to keep the camera on AF or do I want to use the Manual focus mode? Also, if the camera is smart enough to know what the best settings are for the pix I am taking, WHY would I want to use the manual settings at all? Oh, how I wish you guys lived closer to me, so I could get some hands-on training ... I feel so dumb. Thanks much.


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8/11/2005 6:15:33 AM

 
Jon Close
BetterPhoto Member Since: 5/18/2000
  Focus is a separate issue from exposure. If you want, you can autofocus while setting exposure manually, or vice-versa.
The camera's meter does not always give the best exposure, or necessarily the exposure the photographer wants. It is calibrated to a midtone 18-percent gray and so tends to underexpose light/white subjects and overexpose dark/black subjects. But it's close enough for general use, especially with print film which is very forgiving of exposure errors.


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8/11/2005 6:27:54 AM

 
Kerry L. Walker   Jon is correct, as usual. For the vast majority of the photos taken, the meter will operate properly and give you an excellent exposure. However, in some instances, like a snow scene, it will read the whites as gray so you need to switch to manual. Also, for a backlit scene, you will need to switch to manual and meter off the subject, set your exposure, recompose and shoot. The use of manual focus or autofocus is optional. Manual focus works best when you are shooting scenics where you want to use hyperfocal distance focusing. Again, for most shots, AF works fine.


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8/11/2005 6:39:56 AM

 
Kathy L. Pollick
BetterPhoto Member Since: 7/14/2005
  OMG Kerry, I have no clue what you just said!!! AAGH!!

"meter off the subject, set your exposure, recompose and shoot.".... you're talking to a real amature here. I don't know what any of that means except the work SHOOT.

"want to use hyperfocal distance focusing.".... again, what does that mean?

I was playing with the camera last night, trying to learn how to use the manual settings & discovered by accident that I could use the Manual focus or NOT... when I pushed the button down half way to focus & realized it didn't stop at half way, it took a very blurry pix.... I guess that's how I learn!!!


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8/11/2005 6:47:36 AM

 
doug Nelson
DougNelsonPhoto.com
  As you learn more about exposure, it will be helpful to know what part of your viewfinder screen is being read by the meter. Center-weighted means the whole scene is being read, with emphasis on the center. See your camera's manual for what they mean by "center". If you set the meter on "Partial", my preference, you know exactly what part of the scene is being measured.
Light meters give us an accurate reading nearly all the time, because all the shades in the area being measured average out to the middle gray Jon tells us about. Center-weighted usually works.
It may not work in the black-cat-on-a pile-of-coal, or bridal gown against a white wall situations. At times like these, we have to outthink the camera and keep the light meter from deceiving us. Estimate how many stops the subject deviates from a middle gray and adjust accordingly. In the bridal gown situation, that white is maybe two stops brighter than the way the meter reads it, so you open up two stops. (Then shoot another one three stops over, and another 2 1/2 over, and another a stop brighter).

Autofocus is useful if you're losing your ability to fine focus because of failing eyesight, like me. For sports and wildlife, AF may well be essential. The better systems work quite well. Trouble is, in low-contrast situations, AF just doesn't work, but hunts back and forth to find the correct focusing point. Or it may put out an infrared beam, scaring your subject. When this happens, just focus manually. This is also necessary in fine macro work. The better Canon EF (and probably other makers' better lenses) allow you to do this.


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8/11/2005 6:55:22 AM

 
Kerry L. Walker   LOL. We all learn more from our mistakes than our successes. Here is an example of how to meter a backlit scene. It also works at times when you know the meter (which averages all the light it reads) will be fooled. I used this technique on Man of God by the Light of God in my gallery. I had to because I knew the meter would read too much light coming through the window and overexpose the subject.
1. Set your camera to manual and walk up to your subject. Get close enough that the part of the subject you want to expose correctly fills the viewfinder (in my case, his face.)
2. Set the shutter speed and aperture so that the exposure is correct (you may have LEDs or match needle metering, whichever).
3. Back up to where you want to shoot from and re-compose your picture and focus - manual or AF, doesn't mater.
4. Shoot.

Hyperfocal distance - The smaller your aperture, the greater the depth of field (area of acceptable focus). When shooting a something like a landscape shot, you can use the DOF to your advantage, assuming you have a distance scale on your lens.
1. Compose you picture (decide what you want to shoot).
2. Set your aperture to a small aperture (f/16 or f/22).
3. With your camera in manual focus, set the infinity mark on your lens to coincide with the aperture you have chosen. Everything from the shortest distance (where your aperture mark is on the other side of the distance scale) to infinity will be in acceptable focus.
4. Shoot.
Believe me, it is quicker and easier to do this than the time it takes to read what I just wrote. Also, note that hyperfocal distance focusing should be used judiciously. You don't always want everything in focus. Sometimes you want to intentionally blurr the foreground, for example.


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8/11/2005 7:02:59 AM

 
Kathy L. Pollick
BetterPhoto Member Since: 7/14/2005
  Thanks. I sure hope I catch on to this lingo soon. It's the most frustrating part for me.


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8/11/2005 7:03:43 AM

 
doug Nelson
DougNelsonPhoto.com
  Kathy, don't let it frustrate you; just enjoy taking pictures. Your light meter and exposure system will work, most of the time, except for the unusual situations mentioned. I have an article on exposure that may help you. I'll send it along when I get home. Believe me, you'll find photographers willing to help you, and willing to distill this lingo to understandable terms. If you want to learn serious photography, there's a course on exposure here at BetterPhoto. The instructor has also written a book on it.

Editor's Note: "Understanding Exposure" is the name of Bryan Peterson's online course and his how-to book.


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8/11/2005 7:19:00 AM

 
Kathy L. Pollick
BetterPhoto Member Since: 7/14/2005
  I ordered the book Understanding Exposure by that Peterson/Peterman... whatever his name is. I haven't received it yet, but I've heard it's pretty good & very easy to understand!!

It IS frustrating to me as I feel I'm a pretty intelligent person (at least with computers I am). And WHY I can't seem to understand this is driving me crazy.


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8/11/2005 7:23:58 AM

 
Kerry L. Walker   I have never read Brian's book but I understand it is very good. I do know that he is a GREAT photographer and knows his stuff. It should help a lot.


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8/11/2005 7:40:34 AM

 
Robert Staniewicz
BetterPhoto Member Since: 1/20/2004
  Kathy, I know how you feel. I am in the same boat as you. I am glad you asked the question on "why use manual setting." In my experimenting with the different modes, I found myself wondering the same thing. Thanks everyone for answering this and helping us new people get a better grasp on things.


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8/12/2005 12:56:41 PM

 
Deborah Bettencourt   I'd like to insert another question into this one... Kerry Walker mentions using hyperfocus if the lens has a distance scale. What do you use if it doesn't? I'm using a Nikon N80 with a Nikkor 28-80mm lens and it has no markings. Sorry if I shouldn't send a question off into another direction but couldn't find another way to tack onto Kerry's reply.

Thanks!


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8/16/2005 10:24:07 AM

 
Maria Melnyk   Kathy, I think that part of your question wasn't answered. If you were asking if you should leave the camera on AF to focus manually, don't do this. If you manually focus, you need to set the camera to Manual Focus; you don't want to mess up your camera's AF motor.


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8/16/2005 10:48:40 AM

 
Jon Close
BetterPhoto Member Since: 5/18/2000
  If your lens does not have a focus distance scale, then all you can do is guesstimate. You can look up the hyperfocal distance based on the focal length and aperture set from a chart (see http://www.dofmaster.com/charts.html), then focus your lens on something about that far away.


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8/16/2005 10:51:19 AM

 
Bill Lewis   Kathy, you have received some good advice in answer to your question. Let me add another twist to the discussion. I use manual focus to control my depth of field sharpness. I may want to place my plane of sharpness (or sharp focus) in the middle of my image. Autofocus does not always find the particular spot in the image that you want sharp. If you are using a zoom lens then zoom all the in make the image as large as you can in your view finder. Focus manully on what you want to be sharp in your image. Zoom out to recompose the image and shoot away knowning that you have placed your focal point exactly where you want it to be.


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8/16/2005 6:06:24 PM

 
Maria Melnyk   Hi, Bill. Your "zoom in, focus, zoom out" technique won't work with all lenses. With my Canons, as soon as you change the focal length you have to refocus.


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8/16/2005 9:23:38 PM

 
Bill Lewis   Maria,
I shoot minolta. I can only speak for the camera that I shoot. It seems odd that Canon does not have a manual focus feature that does not require refocus when you zoom.


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8/17/2005 6:19:54 PM

 
Maria Melnyk   Yea, Bill, it's somewhat irritating when I decide to change my focal length at the last minute, or when I want to do two photos in rapid succession; one zoomed out and one zoomed in.


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8/17/2005 6:40:55 PM

 
Jon Close
BetterPhoto Member Since: 5/18/2000
  There are two types of zoom lens designs - parfocal will hold focus throughout the zoom range, and varifocal will change focus with zoom.

While it was common for manual focus lenses to be parfocal design, this is much more difficult with autofocus. With Canon and Nikon I know that most of their pro-level zooms are parfocal, but most of their entry-level zooms are varifocal. I'd assume the same for Minolta, but I could be wrong.


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8/18/2005 5:51:21 AM

 
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