K5 question re focus point selection
Posted 02/11/2011 - 20:05
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cabstar wrote:
I used to use centre point spot focus but found I was losing shots due to out of focus. Since using selectivd focus I get a much better hit rate...
Everyone has their own preferences....
I suppose its what you've always been most used to. Its best to employ the system you are most happy with for the best results.I used to use centre point spot focus but found I was losing shots due to out of focus. Since using selectivd focus I get a much better hit rate...
Everyone has their own preferences....
David
Posted 02/11/2011 - 21:17
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Pentaxophile wrote:
It's so awkward using those buttons on the BACK of the camera! I would put some sort of toggle on the front of the grip.
I guess that shows how different we all are - I love the way the 200D does this and find it sooooo intuitive, logical and well thought out.
It's so awkward using those buttons on the BACK of the camera! I would put some sort of toggle on the front of the grip.
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Mike
Pentax K5 / Pentax K5 11/ Pentax K200D / Canon Rebel T1 i / Canon 650D / Pentax MX-1 / Fuji XF1 /Fuji X 10 / Canon EOS-M / Canon G10/ Pentax Mz-7 x 2
Mike
Pentax K5 / Pentax K5 11/ Pentax K200D / Canon Rebel T1 i / Canon 650D / Pentax MX-1 / Fuji XF1 /Fuji X 10 / Canon EOS-M / Canon G10/ Pentax Mz-7 x 2
Posted 02/11/2011 - 21:22
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Algernon wrote:
I've never used anything other than centre focus and doubt if I ever will use anything else..... it's not that accurate anyway
They did indeed - I had one chunky wrote:
I think Pentaxophile has a point.
A wee gizmo to shift focus using your forefinger would seem obvious.
Wonder why it hasn't been done either by Pentax or any of the other breeds.
Canon were supposed to have a system where the focus point moved to where your eye was looking.I think Pentaxophile has a point.
A wee gizmo to shift focus using your forefinger would seem obvious.
Wonder why it hasn't been done either by Pentax or any of the other breeds.
I've never used anything other than centre focus and doubt if I ever will use anything else..... it's not that accurate anyway
Film cameras :
EOS 50 - standard camera
EOS 50e - eye control - you had to set it up/calibrate it and from then on - three spots in a straight row across the middle and you looked at which one you wanted to be the "live" one - it worked flawlessly - thinking about it I wonder why it hasn't been implemented more recently - pretty star trek like technology IMHO.
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Mike
Pentax K5 / Pentax K5 11/ Pentax K200D / Canon Rebel T1 i / Canon 650D / Pentax MX-1 / Fuji XF1 /Fuji X 10 / Canon EOS-M / Canon G10/ Pentax Mz-7 x 2
Mike
Pentax K5 / Pentax K5 11/ Pentax K200D / Canon Rebel T1 i / Canon 650D / Pentax MX-1 / Fuji XF1 /Fuji X 10 / Canon EOS-M / Canon G10/ Pentax Mz-7 x 2
Posted 02/11/2011 - 21:24
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Pentaxophile wrote:
I don't use the focus selection much either, but I think that's more to do with it being very awkward to change the point than it not being useful! If you want to change focus point, it's so slow to change it that by the time your done, the subject has moved. n.
I couldn't possibly disagree more (though I dont tend to shoot much that moves in fairness) I always have it set to user selecting focus point, never the camera to decide and find the buttons to move to preferred focus point quick and easy to use.
I don't use the focus selection much either, but I think that's more to do with it being very awkward to change the point than it not being useful! If you want to change focus point, it's so slow to change it that by the time your done, the subject has moved. n.
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Mike
Pentax K5 / Pentax K5 11/ Pentax K200D / Canon Rebel T1 i / Canon 650D / Pentax MX-1 / Fuji XF1 /Fuji X 10 / Canon EOS-M / Canon G10/ Pentax Mz-7 x 2
Mike
Pentax K5 / Pentax K5 11/ Pentax K200D / Canon Rebel T1 i / Canon 650D / Pentax MX-1 / Fuji XF1 /Fuji X 10 / Canon EOS-M / Canon G10/ Pentax Mz-7 x 2
Posted 02/11/2011 - 21:31
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timothyw wrote:
There is a fairly sensible reason to use selectable focus points, but to understand why requires a little thought:
Camera lenses are designed so that they have a flat plane of focus. If you take a photo looking straight on at a brick wall, the whole brick wall will be in focus. That's fine.
However, if you were to take a measuring tape, and measure the distance from the camera lens to the brick wall, you'd find that the distance from lens to wall varies across the frame. At the very center of the image, the distance is at a minimum. The further you get from that center point on the wall, the longer the distance is.
So, what does this mean if you are using the center point and re-composing?
Well, what if you turn the camera to an angle, and focus on a bit of the wall off center to you, and now recompose the picture so that you're pointing straight at the wall again. You'll find that the entire wall is slightly out of focus, as the camera is now focusing behind the wall.
Compare that with the alternative- if you'd selected one of the corner focus points, while pointing straight at the wall, everything would still be in focus.
The effect is fairly subtle, and most of the time depth of field is sufficient to disguise it, but that's why it's better to compose and then focus, rather than focus and then compose.
I'm not sure I've done a great job explaining it, but this is why I use selectable focus points, rather than center focus then recompose. This is also why I'd never buy a K-X....
You've explained it perfectly and this was the view I would have expected at east 95% of folk, who have photography as a hobby - not just a way of recording life events - to have, - not for the 1st time I've been quite flabbergasted by views on this forum *shrugs* .There is a fairly sensible reason to use selectable focus points, but to understand why requires a little thought:
Camera lenses are designed so that they have a flat plane of focus. If you take a photo looking straight on at a brick wall, the whole brick wall will be in focus. That's fine.
However, if you were to take a measuring tape, and measure the distance from the camera lens to the brick wall, you'd find that the distance from lens to wall varies across the frame. At the very center of the image, the distance is at a minimum. The further you get from that center point on the wall, the longer the distance is.
So, what does this mean if you are using the center point and re-composing?
Well, what if you turn the camera to an angle, and focus on a bit of the wall off center to you, and now recompose the picture so that you're pointing straight at the wall again. You'll find that the entire wall is slightly out of focus, as the camera is now focusing behind the wall.
Compare that with the alternative- if you'd selected one of the corner focus points, while pointing straight at the wall, everything would still be in focus.
The effect is fairly subtle, and most of the time depth of field is sufficient to disguise it, but that's why it's better to compose and then focus, rather than focus and then compose.
I'm not sure I've done a great job explaining it, but this is why I use selectable focus points, rather than center focus then recompose. This is also why I'd never buy a K-X....
I am stunned, truly stunned, by the number of people saying they only ever use the central focus point !!!!
Ah well, thankfully, we're all different
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Mike
Pentax K5 / Pentax K5 11/ Pentax K200D / Canon Rebel T1 i / Canon 650D / Pentax MX-1 / Fuji XF1 /Fuji X 10 / Canon EOS-M / Canon G10/ Pentax Mz-7 x 2
Mike
Pentax K5 / Pentax K5 11/ Pentax K200D / Canon Rebel T1 i / Canon 650D / Pentax MX-1 / Fuji XF1 /Fuji X 10 / Canon EOS-M / Canon G10/ Pentax Mz-7 x 2
Posted 02/11/2011 - 23:30
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Whilst there is no doubt a theoretical point in this, in practice the technique of using centre point focus and recomposing is fast and effective. If required, Quick Shift can be applied easily and is much quicker than trying to select a focus point.
It isn't quite so clear-cut anyway as lenses do not have a flat field, with the exception of macro lenses. Which is the greater error is a moot point. In any event the effect is only apparent at quite close distances.
It isn't quite so clear-cut anyway as lenses do not have a flat field, with the exception of macro lenses. Which is the greater error is a moot point. In any event the effect is only apparent at quite close distances.
Best regards, John
Posted 02/11/2011 - 23:38
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judderman62 wrote:
I am stunned, truly stunned, by the number of people saying they only ever use the central focus point !!!!
Perhaps you'd be even more stunned at people (like me!) that use only the central point, except when they let the camera decide and set it to auto.I am stunned, truly stunned, by the number of people saying they only ever use the central focus point !!!!
Then try a bit of airshow photography and see how stunned you are
Quote:
(though I dont tend to shoot much that moves in fairness)
This is the key.(though I dont tend to shoot much that moves in fairness)
If it's big and moving, you can use the central point.
If it's small and moving, then unless you can track it very accurately (more accurately than I can, anyway, especially at long focal lengths where the angle of view is very small), chances are you'll lose it from the central AF point, and then when the focus hunts, you're basically doomed.
For airshows, I set it to auto-AF point, and it makes maintaining focus on the moving aircraft a lot easier.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Posted 02/11/2011 - 23:50
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johnriley wrote:
If required, Quick Shift can be applied easily and is much quicker than trying to select a focus point.
Not only that, I'm far from convinced that selecting the focus point will often go much of a way towards fixing the problem that Tim so lucidly explains.If required, Quick Shift can be applied easily and is much quicker than trying to select a focus point.
The focus points only go out so far anyway - only a little more than half way to the edge of the frame from the centre, and not even as far as half way to the top or bottom. Doubtless there are subjects with shapes that lend themselves to focus point selection, where frame to centre/focus/reframe really wouldn't be just as good, but they're fairly few and far between.
Most of the times that the frame/focus/reframe technique is really no good is when you're close, and with a wide angle lens - in which case the depth of field is often enormous.
I'd put money on it being camera shake that spoils most of those shots, not being focused on the wrong point.
It's usually just as easy to point the camera at something at about the right distance, rather than the actual subject, prior to reframing.
.
Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Posted 03/11/2011 - 09:37
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judderman62 wrote:
[quote:3496ace15f="Pentaxophile"]I couldn't possibly disagree more (though I dont tend to shoot much that moves in fairness) I always have it set to user selecting focus point, never the camera to decide and find the buttons to move to preferred focus point quick and easy to use.
If you are shooting a still life or a landscape on a tripod, I can see how it would help, but in reality I find getting my thumb between my face and the camera and feeling for the right button and pressing it 3 times or whatever, to be much slower than focus/recompose.[quote:3496ace15f="Pentaxophile"]I couldn't possibly disagree more (though I dont tend to shoot much that moves in fairness) I always have it set to user selecting focus point, never the camera to decide and find the buttons to move to preferred focus point quick and easy to use.
One thing I can agree on - I never let the camera decide on the focus point.
Posted 03/11/2011 - 09:45
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How on earth did we ever focus on anything with only the split screen?
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Posted 03/11/2011 - 10:37
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Pentaxophile wrote:
To be honest I'd *prefer* a decent viewfinder with split screen.
Are there people then, who don't prefer that? Difficult to imagine.To be honest I'd *prefer* a decent viewfinder with split screen.
I really wished that Pentax put it back by default. An extra option in the menus to compensate for possible side effects on the light meter so that argument is also out of the way.
Yes, please.
Pentax K10D + Vivitar 55/2.8 macro + Super Takumar 55/1.8 + SuperMultiCoated Takumar 85/1.8 + SuperMultiCoated Takumar 135/3.5 + SuperMultiCoated Takumar 200/4 + Super Takumar 300/4
Pentax K100D + DA18-55ALII + DA55-300
Pentax K5 + FA31Ltd + M50/1.7 + DFA100WR + M120/2.8 (+ DA18-55WR at occasion)
Pentax K100D + DA18-55ALII + DA55-300
Pentax K5 + FA31Ltd + M50/1.7 + DFA100WR + M120/2.8 (+ DA18-55WR at occasion)
Posted 03/11/2011 - 10:49
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sterretje wrote:
Are there people then, who don't prefer that? Difficult to imagine.
I very rarely use MF these days, so I have no particular yearning for a split screen any more. The only exception is that I take most of my classified photos using an F1.7 A-50, and I still don't really miss the split screen.Are there people then, who don't prefer that? Difficult to imagine.
I definitely would not want the microprism. I never got on with it at all.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Posted 03/11/2011 - 11:30
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I never used the split image or the microprisms when we had them. Now we have AF and it's probably more accurate than the human eye.
There have been experiments done with focusing and manual focusing was shown to be quite unpredictable. Many people cannot recognise the point of greatest sharpness and contrast.
There have been experiments done with focusing and manual focusing was shown to be quite unpredictable. Many people cannot recognise the point of greatest sharpness and contrast.
Best regards, John
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3665 posts
18 years
Grimsby,
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Everyone has their own preferences....
Concert photography
Currently on a Pentax hiatus until an FF Pentax is released