Focus

milesy · 01-12-2015, 03:46 PM

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

Imp · 01-12-2015, 04:04 PM - **1 Like**

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.

Adam · 01-12-2015, 04:05 PM

Originally posted by milesy

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.

**jatrax** · 01-12-2015, 04:06 PM

Originally posted by Imp

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.

Billk · 01-12-2015, 04:26 PM

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.

milesy · 01-12-2015, 05:10 PM

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

Docrwm · 01-12-2015, 05:16 PM

Originally posted by milesy

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.

milesy · 01-12-2015, 06:39 PM

http://flic.kr/p/quXYUb

**crewl1** · 01-12-2015, 06:47 PM

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.

**ak_kiwi** · 01-12-2015, 07:01 PM

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.

milesy · 01-12-2015, 07:14 PM

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

**ak_kiwi** · 01-12-2015, 08:31 PM - **1 Like**

Originally posted by milesy

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.

Originally posted by milesy

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

)

Oldbayrunner · 01-13-2015, 07:52 AM

Originally posted by ak_kiwi

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.

**ak_kiwi** · 01-13-2015, 09:57 AM

Originally posted by Oldbayrunner

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")

Originally posted by milesy

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.

milesy · 01-14-2015, 12:33 AM

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 ?

01-12-2015, 03:46 PM	#1
milesy Veteran Member Join Date: Jan 2009 Location: Melbourne Photos: Gallery Posts: 379	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, 04:05 PM	#3
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	Originally posted by milesy 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. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

01-12-2015, 08:31 PM - 1 Like	#12
ak_kiwi Site Supporter Join Date: Jul 2011 Location: Auckland, New Zealand. Posts: 328	Originally posted by milesy 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. Originally posted by milesy 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.

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01-12-2015, 04:04 PM - 1 Like	#2
Imp Pentaxian Join Date: Nov 2014 Location: Washington, DC Photos: Gallery \| Albums Posts: 1,749	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, 04:06 PM	#4
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Originally posted by Imp 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
Billk Veteran Member Join Date: Jun 2012 Location: Melbourne, Victoria Posts: 349	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
milesy Veteran Member Join Date: Jan 2009 Location: Melbourne Photos: Gallery Posts: 379 Original Poster	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
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285	Originally posted by milesy 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
milesy Veteran Member Join Date: Jan 2009 Location: Melbourne Photos: Gallery Posts: 379 Original Poster	http://flic.kr/p/quXYUb

01-12-2015, 06:47 PM	#9
crewl1 Site Supporter Join Date: Jul 2010 Location: Los Angeles, CA Photos: Gallery \| Albums Posts: 9,807	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
ak_kiwi Site Supporter Join Date: Jul 2011 Location: Auckland, New Zealand. Posts: 328	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
milesy Veteran Member Join Date: Jan 2009 Location: Melbourne Photos: Gallery Posts: 379 Original Poster	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

01-13-2015, 07:52 AM	#13
Oldbayrunner Pentaxian Join Date: Mar 2013 Posts: 1,665	Originally posted by ak_kiwi 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
ak_kiwi Site Supporter Join Date: Jul 2011 Location: Auckland, New Zealand. Posts: 328	Originally posted by Oldbayrunner 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") Originally posted by milesy 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
milesy Veteran Member Join Date: Jan 2009 Location: Melbourne Photos: Gallery Posts: 379 Original Poster	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 ?