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01-12-2015, 03:46 PM   #1
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Focus

Hi guys out of interest when taking photos of people / kids how do you deal with the cameras auto focus locking on to subjects behind the subject resulting in the person being somewhat softer than you would like

01-12-2015, 04:04 PM - 1 Like   #2
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I usually use center point AF, or choose a point AF. It is usually more accurate because it is focused on one spot rather than the whole pic.
01-12-2015, 04:05 PM   #3
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QuoteOriginally posted by milesy Quote
Hi guys out of interest when taking photos of people / kids how do you deal with the cameras auto focus locking on to subjects behind the subject resulting in the person being somewhat softer than you would like
You can always stop down a little if there's enough light- that's always a good way of preventing AF inaccuracies from ruining your image.

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01-12-2015, 04:06 PM   #4
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QuoteOriginally posted by Imp Quote
I usually use center point AF, or choose a point AF. It is usually more accurate because it is focused on one spot rather than the whole pic.
+1 ^^^^ What he said. The camera cannot read your mind so either manually focus or use center point.

01-12-2015, 04:26 PM   #5
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If it is moving subjects you are shooting, then use centre point AF, plus continuous AF (C on the MF/C/AFS selector) AND stop down to F8ish and have a shutter speed of 1/200s or faster if you have enough light.

Some of the sharpness issues attributed to focus are often due to motion blur or camera shake.
01-12-2015, 05:10 PM   #6
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Thanks the ones I am talking about are people a way off and I though the focus has locked onto them until I look at the image on the PC and I can see it's actually locked onto the fence or building or something behind them I'll post an example
01-12-2015, 05:16 PM   #7
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QuoteOriginally posted by milesy Quote
Thanks the ones I am talking about are people a way off and I though the focus has locked onto them until I look at the image on the PC and I can see it's actually locked onto the fence or building or something behind them I'll post an example
DoF is your friend or enemy in those situations. As Adam said - stop down (higher f #) and you get a deeper DoF thereby rendering more in that general range in focus.
01-12-2015, 06:39 PM   #8
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http://flic.kr/p/quXYUb

01-12-2015, 06:47 PM   #9
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At f7.1, 1/1000 something in the pic should have been reasonably in focus, but in this case it seems like most everything is a bit soft almost like motion blur which doesn't make sense at 1/1000.

It could be a case that this lens at 300 may need to be shot at f11 to sharpen up, I am not that familiar with it.

This lens hasn't been dropped has it?

Are you using a filter on the end? If yes take it off and get a hood instead.

I will let others who own this lens comment if the results are typical or not. Other DAL55-300 owners?

As far as it being confused on focus point, you can calibrate it to see if it is back or front focusing. In this case it seems like the girl is the focus target but like I said it generally looks soft.
01-12-2015, 07:01 PM   #10
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Looks to me that the first photo (IMGP4933) the girl on the bogie board is coming towards you and maybe the DA L 50-300 could not keep up?
The 2nd shot (IMGP4709) looks like the shutter speed is too low and maybe combined with camera movement?
I have basically the same lense/camera combo and I struggle to get action shots with it. Even if I switch to the K3 I find the lens will not keep up so I ended up upping the iso and stopping down the lens to increase DOF as the others suggest.
01-12-2015, 07:14 PM   #11
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For sure kiwi in the first shot she was defiantly coming towards me ... I had it on afs so I guess in the split second between focus and the shot being taken there was certainly time for everything to move slightly ...I'm always a bit worried about softening the image by increasing the aperture too much ... Is this a real concern ??

The 55-300 can take some super sharp images so I'm pretty sure there is nothing 'wrong' with the lens as such I'm sure it's more operater error
01-12-2015, 08:31 PM - 1 Like   #12
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QuoteOriginally posted by milesy Quote
I'm always a bit worried about softening the image by increasing the aperture too much ... Is this a real concern ??
Well not really if you look at the figures below at 300mm from Photozone - the best resolution for 300mm focal length seem to be around f11 (figures for a K10D but you get the idea) which crewl1 mentioned also.

QuoteOriginally posted by milesy Quote
The 55-300 can take some super sharp images so I'm pretty sure there is nothing 'wrong' with the lens as such I'm sure it's more operater error
Yes the lens is quite good IQ wise and I wouldn't be too hard on yourself if you don't get the results your after - you are picking a tough shot to get exactly right.
I better "fessup" though with what I really use if I do not need the WR of my version of the the DA 50-300, see below (and I can still get blurry pics with these )
Attached Images
   

Last edited by ak_kiwi; 01-12-2015 at 08:56 PM.
01-13-2015, 07:52 AM   #13
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QuoteOriginally posted by ak_kiwi Quote
Looks to me that the first photo (IMGP4933) the girl on the bogie board is coming towards you and maybe the DA L 50-300 could not keep up?
The 2nd shot (IMGP4709) looks like the shutter speed is too low and maybe combined with camera movement?
I have basically the same lense/camera combo and I struggle to get action shots with it. Even if I switch to the K3 I find the lens will not keep up so I ended up upping the iso and stopping down the lens to increase DOF as the others suggest.
1++++ I agree

On another note I don't use the shutter for focus on my k5 lls anymore and have switched to mainly keeping it in Af.C and using back button AF for a number of reasons.
01-13-2015, 09:57 AM   #14
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QuoteOriginally posted by Oldbayrunner Quote
On another note I don't use the shutter for focus on my k5 lls anymore and have switched to mainly keeping it in Af.C and using back button AF for a number of reasons.
1+. Good point that should probably be top of the list of setting up for action. (I have this set in a sports "user mode")

QuoteOriginally posted by milesy Quote
The 55-300 can take some super sharp images so I'm pretty sure there is nothing 'wrong' with the lens
Another thing to think about is shooting closer to target with a shorter focal length and incorporate a larger field of view
This can give you the advantage of greater depth of field/more time for focusing for a given f stop and iso setting.
The disadvantage is that you lose resolution cropping to suit but this is better than having an out of focus shot.

While I jokingly posted pics of what I use for sport shooting above, the lens I use for family shots like you posted is the DA 18-135.
01-14-2015, 12:33 AM   #15
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Had another go today and set up a sports mode as suggested. ( AFC with the AF button for focus) wow what a difference that made

http://flic.kr/p/qvLoF5

By the way can I link to Flickr image like I normally do on PC while on the phone rather than the above link ?
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