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02-24-2014, 09:37 PM   #1
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Tracking a Football (Soccer) Player - K-3 DA*60-250

Sequence of shots tracking the player who is going to head the ball. (Select center point - SEL L)

It would be nice to have software that can show us the "actual focus points" used by the K-3 on each photo to see what is really happening.

Football (Soccer) Goal Tracking - Pentax K-3 DA*60-250 - a set on Flickr

Settings
AF C
Select center point - SEL L
First frame AF C - Focus Priority
Action AF C Cont - Focus Priority
Hold AF Status - 3 medium

For this kind of shot of one player among several on the area, would you use different settings?

02-24-2014, 09:51 PM   #2
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It seems that most of the players are in focus as they are all on the same plane and far away, no?
I think the camera has a more difficult time when the players are filling the frame more.
02-24-2014, 10:11 PM   #3
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QuoteOriginally posted by crewl1 Quote
It seems that most of the players are in focus as they are all on the same plane and far away, no?
I think the camera has a more difficult time when the players are filling the frame more.
i will try closer tomorrow, thanks
02-24-2014, 10:20 PM   #4
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Check this post and thread for what I would think makes a more rigorous test.
https://www.pentaxforums.com/forums/172-pentax-k-3/242969-sports-images-k-3-a.html#post2583905

02-24-2014, 10:33 PM   #5
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QuoteOriginally posted by crewl1 Quote
It seems that most of the players are in focus as they are all on the same plane and far away, no? I think the camera has a more difficult time when the players are filling the frame more.
Took the words right off my keyboard! A shot like this is so far away that pretty much everything near enough along the line should be more or less in focus. It is much more challenging for the camera's AF system and for the photographer to have that cluster of four players, including the shooter, fill the frame about 60%.

QuoteOriginally posted by Rudy Quote
For this kind of shot of one player among several on the area, would you use different settings?
These were shot at ISO 200, 1/800. I would have bumped the ISO up to 400-800 and shot at 1/1500. That freezes action more frequently, especially on closer shots. If your shooting position is pretty typical, then I would consider obtaining a lens that reaches 400mm. With that much light, you could get some sharp shots at that focal length. If not, I'd practice taking shots closer to the mid-stripe so that the players would fill the frame. 60-250mm is a great focal range for those kind of action shots.

In addition, if you are able to get access to the end line between a goal post and the corner, shots of in box action at the goal would be excellent--your lens is ideal for that positioning.

M

---------- Post added 02-24-2014 at 09:42 PM ----------

As an example of end-line positioning, here are three from last night under extreme conditions: a driving rain storm, under lousy lights, 37 degrees F. Using a FF Canon 5DMK3, the only lens I had that was fast enough (earlier it was lighter for my slower zoom) was the 135mm f2.

Example 1



5DMK3, 135mm L f2 @ f2.8, 1/1000, ISO 12,800

Followup



5DMK3, 135mm L f2 @ f2.8, 1/750, ISO 12,800

Example 3



5DMK3, 135mm L f2 @ f2.8, 1/750, ISO 12,800

M

Last edited by Miguel; 02-24-2014 at 11:18 PM.
02-25-2014, 08:13 AM   #6
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QuoteOriginally posted by Rudy Quote
Sequence of shots tracking the player who is going to head the ball. (Select center point - SEL L)

It would be nice to have software that can show us the "actual focus points" used by the K-3 on each photo to see what is really happening.

Football (Soccer) Goal Tracking - Pentax K-3 DA*60-250 - a set on Flickr

Settings
AF C
Select center point - SEL L
First frame AF C - Focus Priority
Action AF C Cont - Focus Priority
Hold AF Status - 3 medium

For this kind of shot of one player among several on the area, would you use different settings?
It would be nice if you could also post here: https://www.pentaxforums.com/forums/172-pentax-k-3/251413-post-your-k3-af-settings-here.html
as we are trying to build a thread containing the AF settings used by K3 users.
BTW: nice job doing this here !

JP
02-25-2014, 02:29 PM   #7
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QuoteOriginally posted by Rudy Quote
It would be nice to have software that can show us the "actual focus points" used by the K-3 on each photo to see what is really happening.
You can do this textually with Exiftool. Simply:

  1. Use a text editor which does no formatting (e.g. Notepad) to create a batch file of commands. I called it EXIF_SUBSET.BAT. Since EXIFTOOL shows a lot of lines of information, I just filtered out a few interesting one. You can add, remove or rearrange search lines to suit yourself. If multiple unwanted matched are returned (e.g. ISO) extend the search string until it's unique. Save the batch file on your desktop.
  2. Get the latest Windows version of Exiftool and save it in a directory listed in your windows path. I used C:\Program Files (x86). Since recent versions of Windows have a security feature which stops you opening a folder and dropping files into this directory, I used Explorer++ to cut-&-paste it into this directory.
  3. To use: open a folder of camera image files and drag one image at a time onto the batch file icon.
Code:

@echo off
echo.
exiftool %1 | find /i "Exposure Time :"
exiftool %1 | find /i "F number"
exiftool %1 | find /i "ISO :"
exiftool %1 | find /i "Exposure Compensation"
exiftool %1 | find /i "Light Value"
exiftool %1 | find /i "lens ID"
echo.
exiftool %1 | find /i "focus mode"
exiftool %1 | find /i "AF point selected"
exiftool %1 | find /i "AF points in focus"
echo.
exiftool %1 | find /i "circle of confusion"
exiftool %1 | find /i "field of view"
exiftool %1 | find /i "focal length :"
exiftool %1 | find /i "hyperfocal distance"
echo.
echo.

pause
exit

A link to EXIF_SUBSET.BAT


A sample output:




PhotoMe used to show focus points in older Pentax DSLRs, but I think it's now out of date and no longer updated.

You could create a layer with all the focus points shown and overlay it on a image of interest. Then, based on the Exiftool info, you could see exactly what was at this focus point.

Dan.

---------- Post added 26-02-14 at 08:06 ----------

BTW, to filter out the 2nd Focal Length line which contains the term "equivalent", update the filter line to:

Code:
exiftool %1 | find /i "focal length                    :" | find /i /v "equivalent"

Dan.

Last edited by dosdan; 02-25-2014 at 02:58 PM.
02-25-2014, 06:21 PM   #8
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BTW, here's how to decode the AF point location:

Code:
     
...01 02 03 04 05
...06 07 08 09 10
26 11 12 13 14 15 27
...16 17 18 19 20
...21 22 23 24 25
Code:
01 Top Left
02 Top Near-left
03 Top
04 Top Near-right
05 Top Right

06 Upper Left
07 Upper Near-left
08 Upper Middle
09 Upper Near-right
10 Upper Right

11 Left
12 Near-left
13 Centre
14 Near-right
15 Right

16 Lower Left
17 Lower Near-left
18 Lower-middle
19 Lower Near-Right
20 Lower Right

21 Bottom Left
22 Bottom Near-left
23 Bottom
24 Bottom Near-right
25 Bottom Right

26 Far Left
27 Far Right


Extended Area
Centre; 5 27 point (L)
Centre; 3 25 point (M)
Centre; 1 9 point (S)
Centre; 0 1 point (spot)

Auto; 0 Auto 27-point
Unknown (264); 0 Auto 9-point centred on Upper Middle
Unknown (270); 0 Auto 9-point centred on Centre
Unknown (271); 0 Auto 9-point centred on Right
Unknown (276); 0 Auto 9-point centred on Lower Middle
Unknown (275); 0 Auto 9-point centred on Bottom Near-left

Dan.

02-25-2014, 10:49 PM   #9
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DOSDAN

thank you very much for sharing. this is nice. I now know which is the focus point it was used.

But can you please clarify about creating a layer to visualize the point over the image. Do you mean create a layer in Photoshop? If this is the case, how do I know where to put each of the 27 focus points of the K-3? is there a (x,y) location for each focus point? and if this is the case how do I locate (x,y) on the layer? Sorry if this is very basic but I do not know.

QuoteQuote:
=dosdan;2717037]You could create a layer with all the focus points shown and overlay it on a image of interest. Then, based on the Exiftool info, you could see exactly what was at this focus point.
02-26-2014, 02:13 AM   #10
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This is VERY interesting! :-)

The only method of visualising which AF point is used I know is by changing the layout with the info setting when viewing photo's on the camera's screen.
You'll see the grid and the AF point lights up :-)
02-26-2014, 02:32 AM   #11
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QuoteOriginally posted by Rudy Quote
But can you please clarify about creating a layer to visualize the point over the image. Do you mean create a layer in Photoshop? If this is the case, how do I know where to put each of the 27 focus points of the K-3? is there a (x,y) location for each focus point? and if this is the case how do I locate (x,y) on the layer? Sorry if this is very basic but I do not know.

I got a grid off a Pentax promo page: Feature 2?K-3 | RICOH IMAGING

http://www.ricoh-imaging.co.jp/english/products/k-3/feature/img/bod_img_02_02.jpg

I've enlarged this to 6016x4000 to match a full-size K-3 image and then saved it as a transparent-background GIF: http://users.on.net/~dosdan/K3_AF_Points_Layout.gif

I then loaded it as an overlay using "Mask from image" in PaintShop Pro X4:




On this image, the EXIF_SUBSET.BAT program tells me that the focus point was "Upper Middle" (08 on my grid map).

Dan.

Last edited by dosdan; 02-26-2014 at 04:01 AM.
02-26-2014, 02:47 AM   #12
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Now all we need is someone with some programming skills... I know that in Photoshop scripting is quite "evolved" so I see great potentional.
Unfortunatly I'm not a programmer but I think it should be possible to create script that uses the data to impose the AF point in a layer on top of the original image.
If I'm not mistaking it's even possible to use a spreadsheet as data source, so there must be a way to:
1 use the image name as id/link
2 retrieve data from the xls
3 let PS create a red square in a layer defined by the data from the spread sheet (or hide/unhide a certain layer)
4 process further...

edit: check this link

Last edited by wpompen; 02-26-2014 at 05:06 AM.
02-27-2014, 06:03 AM - 1 Like   #13
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QuoteOriginally posted by dosdan Quote
You can do this textually with Exiftool. Simply:
exiftool %1 | find /i "Exposure Time :"
exiftool %1 | find /i "F number"
exiftool %1 | find /i "ISO :"
It is much easier and much more efficient to specify the tags to extract on the command line:

exiftool %1 -exposuretime -fnumber -iso ...

- Phil
02-27-2014, 07:03 AM   #14
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Dan

Thank you for the AF Points template.

The first time I saw the picture below before I had our code, i thought that I missed the focus in the picture below. The player that it is actually in focus is the kid in green jersey [CENTER] (a goalkeeper from another team warming up outside the field) and not the player i was targeting (the player number 19 who is going to head the ball) who is in [NEAR-LEFT].

Your code and template helped me to confirm that in fact the K-3 was correct. The AF [Center] is over the player in green jersey and not over my desired target coming to head the ball. Operator error.


Exposure Time : 1/500
F Number : 4.0
ISO : 200
Exposure Compensation : 0
Light Value : 12.0
Lens ID : smc PENTAX-DA* 60-250mm F4 [IF] SDM

Focus Mode : AF-C (Focus-priority)
AF Point Selected : Center; 5
AF Points In Focus : Center

Circle Of Confusion : 0.020 mm
Field Of View : 5.5 deg
Focal Length : 250.0 mm
Focal Length : 250.0 mm (35 mm equivalent: 375.0 mm)
Hyperfocal Distance : 780.05 m


Press any key to continue . . .
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02-27-2014, 07:08 AM   #15
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At this moment I'm corresponding with a guy who's writen Photoshop scripts before and I'm trying to convince him to modify his script so an overlay is being put on top of an image to visualise the used AF point. :-)
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