The autofocus speed/accuracy is quite dependant on the lens quality. Higher quality, fast lenses will focus much more quickly and accurately than slower lenses and track the focus better. I've used a 70-200 mm f2.8 with my Nikons (and in the past with an S2 pro) with exceptional results at both air shows and low light dance events. You might try experimenting with different lenses before drawing a final conclusion.Duncan Bristowhttp://www.pbase.com/duncanbristow..
Autofocus has been *there* for quite some time, especially in the DSLR's. But like all things, it works best when you understand how it works and it's limitations..
That said, not all cameras are perfect. I had a Fuji S2 and the AF was truely a pain. But knowing the limitations of the camera also made using the camera possible..
Faster lenses definately work better than slower lenses, especially in lower ligh levels..
The greatest of mankind's criminals are those who delude themselves into thinking they have done 'the right thing.'- Rayna Butler..
Understood in general- but read through the lens forums even on this board- high quality lenses with threads "this one back focuses" "this one front focuses", etc etc..
Is it really just not as simple as picking a body and a lens (a pro glass lens)?..
Image control:Zoom outZoom 100%Zoom inExpand AllOpen in new window.
How many megapixels you need from a camera:http://www.bhphotovideo.com/FrameWork/charts/resolutionChartPopup.html..
I have had a number of autofocus cameras since SLR film days; 3 x SLR, 5 x P&S, 1 x DSLR..
All worked well once you know how to use them. My guess is 99.9% of problems are with the users..
My latest, Canon 450D, works very well...
"Avoid the 450D at all costs! (nt)".
You speak from experience?..
I have used a pentax 5n film slr for yrs. about 6yrs ago switched to a pentax dslr, both with auto focus. they both worked have worked fine. the only time I manual focus is when I shoot astronomical pics(moon, etc). all in all auto focus works quite well on modern dslrs..
As for front or back focus. my view the current group of dslr users, who generall bought when digital went main stream, do not really know what front or back focus is and yell my camera is doing it all the time. I have had MANY different lenses from many makers over the last decade and a half that have been auto focusing for me and never have I had a lens that did not focus right..
The simple fact is that all lenses are supposed to front and back focus all the time. they are made that way. not to mention the laws of optical physics require it. no camera/lens focuses on a plain or point there is always a degree of focus in front and behind the subject that is in focus. the amount depends on the fstop used..
My advice is if you are about to buy a dslr, the focusing issue is a nonissue. remember that the complainers on these forums represent only a super small fraction of the total number of dslrs sold of any one model from any one maker. all the rest work fine...
Now those statements make more sense..
So the small backfocus I saw on the tests they said to do was normal and I returned thsis for nothing? ugh..
Well, I can buy it again. I DO like the camera! I have 2 other Fujis, so I am somewhat used to the menu system- and I have shot with my dad's Nikkormat with 35,50,85,105 primes...
As I said all lens/cameras front and back focus all the time. there should be an area behind the subject and in front of the subject that is in focus all the time; it is called DOF. the area behind the subject generally is larger than the area in front of the subject that is in focus. the amounts vary due to lens optics and fstop used..
The problem arises when there is an area in front of the subject and nothing is in focus behind the subject. OR there is an area behind the subject and nothing is in focus in front of the subject. THEN you have front or back focusing, and this should occur normally..
The following may be of some interest.http://www.dofmaster.com/dofjs.html..
I hate auto-focus. I have to live with it because that is the sign of times, but manual focus is far more efective and faster. On the other hand modern cameras are great and make all the decissions themselves. More professional cameras will allow you to alter some setting or another, and will make sure that the rest are changed so you get a "good" result. In the "pre-all-automatic" days taking even half decent photographs wasn't that easy...
The problem arises when there is an area in front of the subject andnothing is in focus behind the subject. OR there is an area behindthe subject and nothing is in focus in front of the subject. THEN youhave front or back focusing, and this should occur normally..
I understand the DOF- what I had was in center focus mode (just the center AF point in the middle of the frame), the object that AF pont was on was less in focus than the object off to the side and behind it about 14mm (and that AF point wasnt touching the back object in the viewfinder- it was square on the main object only.).
Shouldn't the main subject be in focus?..
What you are talking about is selective focus. in which you have say 11 spots in your viewfinder and you can select which spot is use to focus on. or use all of them and let the camera select the one that it want. or use the center spot only..
If you select a spot then the area that you want is not is focus exactly. then you coulkd have the problem of the camera moving at the moment of the shot, and this would move that spot to another area to focus. it is VERY RPT VERY RPT VERY easily for the movement and force of your finger on the shutter button to shift the spot. if you are testing this, use a tirpod and lock the camera down to be sure the selected spot and it's area does not move...
I manually focussed since I got my slr in 1970. a 1/4 centuery later I got a camera(the pentax 5n) that had autofocus, and I was so happy. NOW I could concentrate on the composition of the shot and let the camera do more of the technical stuff, like focussing..
I have since moved to a dslr and still use auto focus all the time. the only time I do not auto focus in on astronomy shots or taking panorams or HDRIs. I cannot say enough about how I little miss doing my own focussing. I did that for a 1/4 of a century and that was enough. ditto on the subject of metering. I simply leave the meter in full AUTO and let it do the metering and shutter speed selections.
If it is not I simply rotate the mode to PROGRAM and use either the shuter speed or fstop wheels to adjust them..
Meanwhile, I am doing the hard item, which is determining the composition of the shot. on 200 shots I expect 5 or less to off in exposure. that is what I have been getting since I got my dslr. any more than 5 off ashots I get very mad at my self for letting it happen. I shoot jpegs by the way and have no problems with exposure. generally, I get 100% correct exposures; this is letting the camera do the work. the only things I am adjusting is the meter area(matrix, center, or spot) and sometimes the camera mode(auto, program AV, Tv, M, and bulb) is selected.and the iso is selected before I do any of this...
And if the focus on the exact selected area is off then you have something wrong. but be sure that the area selected is suitable for focussing. if you have something that has little or no contrast then the fousser while have a heck of a time getting a good focus. for an experiment try focussing on plain white sheet of paper and see what a time you have focussing...
Not that I really have any experience in any of this, but as a kid I remember my dad had a film slr that you had to manually turn the lens to focus, and I remember it being the best part of it all. although I was just a kid, and may not remember much, or know what I was doing, but do any of you miss auto focusing sometimes. even from the sheir joy of getting it correct post click...
No way do I miss focussing manually. besides in almost all instances the camera focusses as good as I can...
What a steaming pile of BS..
If I focus on the eyes but the only the nose is in focus, if I can repeat this time and again ... it's back focusing. Same can be said for any object, not just a person prone to moving back and forth..
I have had one lens FF and 1 BF and both times I sent them in to be fixed and the lenses focused just fine afterwards..
If there was no problem then what did they fix?.
As for front or back focus. my view the current group of dslr users,who generall bought when digital went main stream, do not really knowwhat front or back focus is and yell my camera is doing it all thetime. I have had MANY different lenses from many makers over the lastdecade and a half that have been auto focusing for me and never havei had a lens that did not focus right.the simple fact is that all lenses are supposed to front and backfocus all the time. they are made that way. not to mention the lawsof optical physics require it. no camera/lens focuses on a plain orpoint there is always a degree of focus in front and behind thesubject that is in focus.
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Updated May '08..
If I focus on the eyes but the only the nose is in focus, if I canrepeat this time and again ... it's back focusing. e and never have.
Wouldn't that be "Front Focusing"?.
If you think that makes sense, then you must have read someone else's post!..