Clackers' Beginners Tip 14: Focusing on a subject

**clackers** · 03-24-2022, 04:52 PM - **14 Likes**

Some bad news to begin with this week, I broke-up with my cross-eyed girlfriend. She was seeing someone on the side.

That's on top of a debate I had with a flat earther, he got so mad he vowed to walk to the edge to prove it. But he'll come round eventually.

This week's beginners' tip is about lines, edges, and how to focus a camera. I know it's very sad to encounter photographers who after decades, don't know how to take a photo, but there are plenty!

There is no such thing as when we read a post about someone complaining 'I focused on my child, but couldn't get sharp pictures...'.

To a PDAF focus system, there are no children, there are no dogs, no cups of coffee, just distinct lines. All PDAF sensors from every camera brand need a line to split like the rangefinders some of our oldest members may remember. Mirrorless cameras are limited in that they cannot use both horizontal and vertical lines, Pentaxes have cross points to do that.

We think before we shoot, so we find a distinct line on the subject as in the picture below. It's not backlit, we're shooting from the correct side, so this won't be a problem. Backlighting may force you into focusing on the subject's outline against the background, which may or may not be what you want.

Obviously, coffee cups don't move, so for action photographers, the game is to keep the chosen (usually central) point on a line on the subject as they go about their business. But more on sports photography in future tips, since I definitely enjoy doing that, but for today, the cup is enough. If you're buying, a latte with an extra shot but no sugar, thanks!

To end this week, there's the story of a woman on vacation who calls home. She asks her husband, "How’s my cat doing?"

The husband says, "The cat’s dead."

The woman’s upset and points out: "Well, you could have broken the news to me when I got home. I can’t enjoy my vacation now. You could’ve just said a little white lie, like the cat’s on the roof and you can’t get her down."

"Okay, I’m sorry," says the husband, "I’ll remember that."

The woman says, "Anyway, how’s my mother doing?"

The husband pauses, then cheerfully announces, "Your mother’s on the roof and we can’t get her down."

The rest of the series here: Clackers' Beginners Tips (Collected) - PentaxForums.com

Attached Images

Last edited by clackers; 04-14-2022 at 09:26 PM.

**ProfessorBuzz** · 03-24-2022, 05:01 PM - **1 Like**

PDAF = Pretty Dumb Auto Focus ?

**clackers** · 03-24-2022, 05:18 PM - **3 Likes**

Originally posted by ProfessorBuzz

PDAF = Pretty Dumb Auto Focus ?

Way better than the alternative ... CDAF, IMHO.

That algorithm looks for high contrast and *assumes* that's where focus is found.

You can put your Pentax into CDAF by using Live View. You'll get sick of it after a while.

telum · 03-25-2022, 12:38 AM - **1 Like**

Thanks for the post, known knowledge for me but being reminded over and over is how it will eventually become second nature I guess

And dad-jokes are obviously always appreciated

**Joetitch** · 03-25-2022, 12:54 AM - **4 Likes**

I call them groan-up jokes because the children aren't mine. Either way just as appreciated as the tips.

kypfer · 03-25-2022, 02:21 AM - **2 Likes**

Ha Ha … the old ones are the best

Horizontal horizons next .. or have we already got that lined up?

gatorguy · 03-25-2022, 05:18 AM - **2 Likes**

IMO, this is the most useful beginners tip thread you've done yet Clackers. Even some of of our more experienced members may not completely understand that, and the visual makes the focus intent eminently clear (groan)Thanks for taking the time to continually offer these insights from an old shooter who's been there and done that.

Last edited by gatorguy; 03-26-2022 at 03:27 AM.

35mmfilmfan · 03-25-2022, 02:05 PM - **1 Like**

Great tip (as usual) - now, just how do I explain to a swimming duck that going behind vertical reed stems does not make it easy to focus on it ?

**clackers** · 03-26-2022, 03:28 AM - **2 Likes**

Originally posted by 35mmfilmfan

Great tip (as usual) - now, just how do I explain to a swimming duck that going behind vertical reed stems does not make it easy to focus on it ?

That's what the hold function is all about ... more of that in a later tip, 35mmff!

**ProfessorBuzz** · 03-26-2022, 05:24 AM - **1 Like**

Originally posted by clackers

Way better than the alternative ... CDAF, IMHO.

That algorithm looks for high contrast and *assumes* that's where focus is found.

You can put your Pentax into CDAF by using Live View. You'll get sick of it after a while.

Ah yes, Completely Dumb Auto Focus.
But seriously... as a beginner tip, probably best to skip the TLAs and FLAs.
Four Letter Acronyms... and spell it out... Phase Detection Auto Focus and Contrast Detection Auto Focus.
And FLA is a TLA.

**clackers** · 03-26-2022, 08:17 PM - **1 Like**

Originally posted by ProfessorBuzz

Ah yes, Completely Dumb Auto Focus.
But seriously... as a beginner tip, probably best to skip the TLAs and FLAs.
Four Letter Acronyms... and spell it out... Phase Detection Auto Focus and Contrast Detection Auto Focus.
And FLA is a TLA.

I won't dumb down to beginners, PB, not my style. On this forum, they're likely to be forty years old rather than fourteen.

Acronyms are part of the photography game, they have to learn and use them to participate in discussions, and they can Google to discover what they actually stand for if they want, I'm more interested in telling them what they do.

**Joetitch** · 03-26-2022, 11:13 PM

Originally posted by clackers

I won't dumb down to beginners, PB, not my style. On this forum, they're likely to be forty years old rather than fourteen.

Acronyms are part of the photography game, they have to learn and use them to participate in discussions, and they can Google to discover what they actually stand for if they want, I'm more interested in telling them what they do.

The acronyms or the photographers?😊

MarkJerling · 03-27-2022, 02:02 AM

Originally posted by clackers

"Your mother’s on the roof and we can’t get her down."

That was a tea out the nose moment Ian. Thanks!

gatorguy · 03-27-2022, 03:03 AM

Originally posted by clackers

I won't dumb down to beginners, PB, not my style. On this forum, they're likely to be forty years old rather than fourteen.

Acronyms are part of the photography game, they have to learn and use them to participate in discussions, and they can Google to discover what they actually stand for if they want, I'm more interested in telling them what they do.

I've lost count of the number of times I've had to Google some acronym or shorthand sent to me in a text message from far younger family and friends. It won't hurt if once in awhile they have to do the same with what we old guys write.

**Kerrowdown** · 03-27-2022, 07:39 AM - **2 Likes**

Originally posted by clackers

how to focus a camera

I'm just glad my "Ladies" don't have these sort of issues.

03-24-2022, 04:52 PM - 14 Likes	#1
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Clackers' Beginners Tip 14: Focusing on a subject Some bad news to begin with this week, I broke-up with my cross-eyed girlfriend. She was seeing someone on the side. That's on top of a debate I had with a flat earther, he got so mad he vowed to walk to the edge to prove it. But he'll come round eventually. This week's beginners' tip is about lines, edges, and how to focus a camera. I know it's very sad to encounter photographers who after decades, don't know how to take a photo, but there are plenty! There is no such thing as when we read a post about someone complaining 'I focused on my child, but couldn't get sharp pictures...'. To a PDAF focus system, there are no children, there are no dogs, no cups of coffee, just distinct lines. All PDAF sensors from every camera brand need a line to split like the rangefinders some of our oldest members may remember. Mirrorless cameras are limited in that they cannot use both horizontal and vertical lines, Pentaxes have cross points to do that. We think before we shoot, so we find a distinct line on the subject as in the picture below. It's not backlit, we're shooting from the correct side, so this won't be a problem. Backlighting may force you into focusing on the subject's outline against the background, which may or may not be what you want. Obviously, coffee cups don't move, so for action photographers, the game is to keep the chosen (usually central) point on a line on the subject as they go about their business. But more on sports photography in future tips, since I definitely enjoy doing that, but for today, the cup is enough. If you're buying, a latte with an extra shot but no sugar, thanks! To end this week, there's the story of a woman on vacation who calls home. She asks her husband, "How’s my cat doing?" The husband says, "The cat’s dead." The woman’s upset and points out: "Well, you could have broken the news to me when I got home. I can’t enjoy my vacation now. You could’ve just said a little white lie, like the cat’s on the roof and you can’t get her down." "Okay, I’m sorry," says the husband, "I’ll remember that." The woman says, "Anyway, how’s my mother doing?" The husband pauses, then cheerfully announces, "Your mother’s on the roof and we can’t get her down." The rest of the series here: Clackers' Beginners Tips (Collected) - PentaxForums.com Attached Images Last edited by clackers; 04-14-2022 at 09:26 PM.

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03-24-2022, 05:01 PM - 1 Like	#2
ProfessorBuzz Loyal Site Supporter Join Date: Feb 2018 Posts: 1,903	PDAF = Pretty Dumb Auto Focus ?

03-24-2022, 05:18 PM - 3 Likes	#3
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397 Original Poster	Originally posted by ProfessorBuzz PDAF = Pretty Dumb Auto Focus ? Way better than the alternative ... CDAF, IMHO. That algorithm looks for high contrast and assumes that's where focus is found. You can put your Pentax into CDAF by using Live View. You'll get sick of it after a while.

03-25-2022, 12:38 AM - 1 Like	#4
telum Junior Member Join Date: Feb 2015 Posts: 45	Thanks for the post, known knowledge for me but being reminded over and over is how it will eventually become second nature I guess And dad-jokes are obviously always appreciated

03-25-2022, 12:54 AM - 4 Likes	#5
Joetitch Site Supporter Join Date: Aug 2016 Location: Leura NSW Posts: 502	I call them groan-up jokes because the children aren't mine. Either way just as appreciated as the tips.

03-25-2022, 02:21 AM - 2 Likes	#6
kypfer Pentaxian Join Date: Jan 2018 Location: Jersey C.I. Posts: 3,600	Ha Ha … the old ones are the best Horizontal horizons next .. or have we already got that lined up?

03-25-2022, 05:18 AM - 2 Likes	#7
gatorguy Moderator Join Date: Feb 2015 Location: Central Florida Photos: Gallery Posts: 6,094	IMO, this is the most useful beginners tip thread you've done yet Clackers. Even some of of our more experienced members may not completely understand that, and the visual makes the focus intent eminently clear (groan)Thanks for taking the time to continually offer these insights from an old shooter who's been there and done that. Last edited by gatorguy; 03-26-2022 at 03:27 AM.

03-25-2022, 02:05 PM - 1 Like	#8
35mmfilmfan Pentaxian Join Date: Oct 2016 Location: Norfolk, UK Posts: 4,342	Great tip (as usual) - now, just how do I explain to a swimming duck that going behind vertical reed stems does not make it easy to focus on it ?

03-26-2022, 03:28 AM - 2 Likes	#9
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397 Original Poster	Originally posted by 35mmfilmfan Great tip (as usual) - now, just how do I explain to a swimming duck that going behind vertical reed stems does not make it easy to focus on it ? That's what the hold function is all about ... more of that in a later tip, 35mmff!

03-26-2022, 05:24 AM - 1 Like	#10
ProfessorBuzz Loyal Site Supporter Join Date: Feb 2018 Posts: 1,903	Originally posted by clackers Way better than the alternative ... CDAF, IMHO. That algorithm looks for high contrast and assumes that's where focus is found. You can put your Pentax into CDAF by using Live View. You'll get sick of it after a while. Ah yes, Completely Dumb Auto Focus. But seriously... as a beginner tip, probably best to skip the TLAs and FLAs. Four Letter Acronyms... and spell it out... Phase Detection Auto Focus and Contrast Detection Auto Focus. And FLA is a TLA.

03-26-2022, 08:17 PM - 1 Like	#11
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397 Original Poster	Originally posted by ProfessorBuzz Ah yes, Completely Dumb Auto Focus. But seriously... as a beginner tip, probably best to skip the TLAs and FLAs. Four Letter Acronyms... and spell it out... Phase Detection Auto Focus and Contrast Detection Auto Focus. And FLA is a TLA. I won't dumb down to beginners, PB, not my style. On this forum, they're likely to be forty years old rather than fourteen. Acronyms are part of the photography game, they have to learn and use them to participate in discussions, and they can Google to discover what they actually stand for if they want, I'm more interested in telling them what they do.

03-26-2022, 11:13 PM	#12
Joetitch Site Supporter Join Date: Aug 2016 Location: Leura NSW Posts: 502	Originally posted by clackers I won't dumb down to beginners, PB, not my style. On this forum, they're likely to be forty years old rather than fourteen. Acronyms are part of the photography game, they have to learn and use them to participate in discussions, and they can Google to discover what they actually stand for if they want, I'm more interested in telling them what they do. The acronyms or the photographers?😊

03-27-2022, 02:02 AM	#13
MarkJerling Moderator Site Supporter Join Date: May 2012 Location: Wairarapa, New Zealand Photos: Gallery \| Albums Posts: 20,423	Originally posted by clackers "Your mother’s on the roof and we can’t get her down." That was a tea out the nose moment Ian. Thanks!

03-27-2022, 03:03 AM	#14
gatorguy Moderator Join Date: Feb 2015 Location: Central Florida Photos: Gallery Posts: 6,094	Originally posted by clackers I won't dumb down to beginners, PB, not my style. On this forum, they're likely to be forty years old rather than fourteen. Acronyms are part of the photography game, they have to learn and use them to participate in discussions, and they can Google to discover what they actually stand for if they want, I'm more interested in telling them what they do. I've lost count of the number of times I've had to Google some acronym or shorthand sent to me in a text message from far younger family and friends. It won't hurt if once in awhile they have to do the same with what we old guys write.

03-27-2022, 07:39 AM - 2 Likes	#15
Kerrowdown PEG Moderator Join Date: Aug 2008 Location: Highlands of Scotland... "Hold Infinity in the palm of your hand" - William Blake Photos: Gallery Posts: 57,867	Originally posted by clackers how to focus a camera I'm just glad my "Ladies" don't have these sort of issues.