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Old Jan 29, 2008, 6:29 PM   #11
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Hello fellow members,

Thank you (so far) for your posts. I've nowlearned thatmultipoint focusis dependent on contrast rather than an average of focus points. I also nowunderstand that multiple focus points are more appropriate for dymanic situations, i.e., multipoint focus allows for quicker composure of the photo.

I think Iunderstand what has been said, however when coupled with the objective of focusing ona face that is typically in the upper part of the framerather than a body in the middle of the frame, the photog has to pick either a single autofocus point in that area of the frame or several points in that area of the frame - correct? Since the scene is dynamic, does the photog then have to wait for the subject to move into the position of the chosen points? If not, how fast can these points be "re-chosen"? It appears that in the act of choosing certain focus points one defeats the purpose of instantaneouslycapturingan in-focus, properly composed photo in a dynamic situation. Or possibly (probably) I'm just as confused as I was. lol

I typically shoot static situations which is probably why I don't truly understand the nuances of multipoint focus. I also just installed a Katz Eye focusing screen to aid manual focus - and it helps tremendously. Because of these two facts, I tend to agree with emes and mtngal'sfocus philosophy - focus and recompose. YOMD

(TCav, I enjoy your posts and learn a lot from them. Possibly I can educate you in a minor way. The E-510 can be set to allow picture taking without focus lock while in auto-focus mode. It's called "Release Priority" and can be set for either single frame or continuous frame shooting.)

Thanks again for the responses.

Dennis

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Old Jan 29, 2008, 6:51 PM   #12
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Greg Chappell wrote:
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Wow...it's wonder anything shot with a 400mm f2.8 prior to, say, 2001 was ever in focus....
wow, it's a wonder people got from A to B riding a horse and buggy. And yet for some reason they choose not to anymore. Truly amazing!

But hey, why use plain old common sense? Just take a poll of any 400mm 2.8 users shooting action and see how many of them prefer manual focus. Please let us know the results of your poll - I'm sure it will be enlightening.
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Old Jan 29, 2008, 6:58 PM   #13
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erutcip wrote:
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however when coupled with the objective of focusing ona face that is typically in the upper part of the framerather than a body in the middle of the frame, the photog has to pick either a single autofocus point in that area of the frame or several points in that area of the frame - correct? Since the scene is dynamic, does the photog then have to wait for the subject to move into the position of the chosen points?
Dennis,

Think of it this way - if you know you are taking a photo of a person and you want their whole body in the frame you know the face will be in the upper portion of the frame the whole time (assuming the person isn't crouching down or diving or whatever). So even a dynamic situation like most sports - saybasketball or baseball - the human is very often upright soyou can count on wanting the face in the upper part of the frame. So, just like Gregg, I use a single focus point - but I choose a NON Center focus point - a point higher up in the frame.

Look, number of focus points, precision of them, autofocus algorithms are just components of the tool. To some jobsand some users they're more criticalcompoents than to others. Photography isn't a one size fits all thing. Everything is a trade-off. The key is to understand, for the style of photography you want to pursue, what features will help you be more successful. Then choose the camera and system that's the best match.
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Old Jan 29, 2008, 7:40 PM   #14
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erutcip wrote:
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(TCav, I enjoy your posts and learn a lot from them. Possibly I can educate you in a minor way. The E-510 can be set to allow picture taking without focus lock while in auto-focus mode. It's called "Release Priority" and can be set for either single frame or continuous frame shooting.)
Thank you for your kind remark. And, yes. Thank you for pointing that out. I believe that most cameras have a similar feature, but switching it on when it's needed and off when it isn't would probably negate any speed advantageone might have with manual focus, if indeed there was one.
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Old Jan 29, 2008, 9:45 PM   #15
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To all posters in this thread, thanks for clearing up a subject that has been confessing me since I unwrapped my 40D Christmas morning. Coming from manual focus SLR's this has been giving me some trouble but with this new information I should be able to work the mulit focus points in short order with a little practice.

Hi Dennis,

Nice to know I'm not the only one out here in the desert taking pictures.

Craig


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Old Jan 30, 2008, 1:49 AM   #16
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The standard screens in DSLRs are not designed for accurate MF, and also most AF lenses are not geared in such a way that MF is necessarily very easy. MF lenses typically have a much longer gearing, but AF lenses want fast AF so have a shorter gearing so that the motor only has to move the focus ring a shorter distance.

However having said all that, it is possible on some (many? most?) DSLRs to change out your normal focus screen for one which is better for MF and switch your AF lenses to MF mode.

In fact I have a special focus screen on my 5D which allows me to use MF more accurately. Sometimes even my 9+6 AF points on the 5D don't allow me to accurately focus where I want, and in a dynamic situation I often do find it quicker to focus manually than switch between AF points. I have to say however that (perhaps partially because I'm using AF lenses in MF mode) I cannot generally focus as accurately as the AF system on the camera. So when using MF I often get shots that I would otherwise miss, but a greater percentage are OOF.

As to switching AF points - camera ergonomics differ and I think this is a fairly important feature. I only have experience with the Canon DSLRs, but before getting another brand I would personally make sure that it allowed me to switch AF points as easily and quickly. This feature is one that is important to my style of shooting, but may be irellevant for others. Using a wheel to scroll through AF points for example (which is another option on the Canon) strikes me as ergonomically inferior and is certainly slower.

On the Canon you can set it so that the little "joystick" nub on the back controls AF point selection. So it's push a button, then select the AF point. Easy to do with your eye to the viewfinder with a little bit of practice. Takes perhaps only a second or two, more practice makes you quicker.

P.S. Do you remember in the 1980s when AF was first introduced how controversial it was? Lots of pundits thought it would never catch on.


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Old Jan 30, 2008, 10:08 AM   #17
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Hi, Dennis and Craig - Was I ever gladLancaster, the county and CalTransdidn't man the road block closureat Ave. D and 110th Street this past Thursday. If you want to take snow pictures, there's lots only about 30 miles away from you (though its melting fast).

Craig - my SLR experience is manual focus, too - perhaps that's why I don't use the multi-focus points all that much. It's been fun trying to learn new techniques so I've really appreciated this topic and seeing what others use and why.
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Old Jan 30, 2008, 12:41 PM   #18
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Calicajun wrote:
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To all posters in this thread, thanks for clearing up a subject that has been confessing me since I unwrapped my 40D Christmas morning. Coming from manual focus SLR's this has been giving me some trouble but with this new information I should be able to work the mulit focus points in short order with a little practice.

Hi Dennis,

Nice to know I'm not the only one out here in the desert taking pictures.

Craig

Hey Craig,

I see you're just a wee bit West of me... kindred desert spirits. lol

Unfortunately, I don't find much of interest in the AV and usually head down the hill or over to the coast to release my shutter.

Since you're a manual focus kind of guy, have you looked into Katz Eye split prism focusing screens? My only other SLR was an OM-1, a totally manual beast but a great way to learn about photography becauseI made so many mistakes. I like to say that experience is the best teacher, but not the best way to learn - especially with film! My new E-510 with it's flat matte screen was very hard to manually focus, hence the Katz Eye for me. It has made a big difference and my motorizedkit lenses seem tofocus just as well as the manual OM's did. Here's a link for Katz Eye if interested.

http://www.katzeyeoptics.com/cat--Nikon-DSLRs--cat_nikon.html

Dennis
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Old Jan 30, 2008, 5:01 PM   #19
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As a general comment I'd have to say that dependence on autofocus is the one thing I loathe about digicams. Since going digital roundabout 2000, I've been though several models from shirt-pocket to prosumer, and on all of them this is the one feature that invariably sucks.

Even if autofocus were 100% reliable, it would still raise a problem for sports shots, and candid portraits. With a manual SLR you have the option to preset focus and exposure, so the camera is ready for use. You can do this without drawing too much attention to yourself. When the opportunity presents itself, you raise the camera and immediatley fire.

With autofocus, no matter how reliable, you cannot do this. An autofocus camera must be held raised for several seconds immediately prior to the shot. For sports shots, this means you cannot lower the camera once focused, so you miss seeing action outside the frame. Likewise this need to hold the camera raised makes candid portraits impossible, the subject will have noticed the camera and 'cheesed-out' long before you're ready to fire. :blah:

Most of my camera purchases have in fact been in search of a digicam that either will autofocus reliably, or else has proper film-SLR style manual focus. Short of paying several Grand (and having to carry a very bulky package) I've still not found one.

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Old Jan 30, 2008, 5:59 PM   #20
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Dennis, thanks for the link I'll take a look as I used split screen in my OM-1 and it work pretty well too on lenses shorter than 200mm.
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