Horizontal and vertical lines and autofocus

[sherman_levine]

I was not previously aware of this, but at least with my FZ1000, the autofocus is sensitive to contrast which parallels the short axis of the frame (i.e. vertical lines when the camera's held in landscape position) but not contrast which parallels the long axis of the frame.

Might be worth keeping in mind when you're searching for a good focus point.

--

Sherm
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[arrow501]

It is the same with my FZ300

 

[Erik Ohlson]

I was not previously aware of this, but at least with my FZ1000, the autofocus is sensitive to contrast which parallels the short axis of the frame (i.e. vertical lines when the camera's held in landscape position) but not contrast which parallels the long axis of the frame.

Might be worth keeping in mind when you're searching for a good focus point.

To quote an old TV comedy routine:

" V e r r y. interesting !!"

I never realized that & I'd bet it applies to all Panasonics, if not all digital cameras.







--
"Measure wealth not by things you have but by things for which you would not take money"
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[sherman_levine]

I was not previously aware of this, but at least with my FZ1000, the autofocus is sensitive to contrast which parallels the short axis of the frame (i.e. vertical lines when the camera's held in landscape position) but not contrast which parallels the long axis of the frame.

Might be worth keeping in mind when you're searching for a good focus point.

To quote an old TV comedy routine:

" V e r r y. interesting !!"

I never realized that & I'd bet it applies to all Panasonics, if not all digital cameras.

Erik,

The phenomenon is well known for cameras with phase detect autofocus points. The "normal" focus points are sensitive along one axis, while the "cross-type" focus points found in larger/more sophisticated cameras will focus on lines at any axis.

I was surprised that the contrast-detect sensors in the Panasonics were also axis-dependent, but sure, why wouldn't they be.

--

Sherm
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[Rodger1943]

Hi Sherm,

Thanks for bringing this up. I've found that with the FZ200/FZ1000 and the RX10 Mk4. There have been many occasions when a bird is sitting on a branch (usually near horizontal and none of these cameras will focus. In an attempt get round it, I try to quickly focus on the trunk, which is usually near vertical and then the camera will focus, but unfortunately on many occasions, by the time I get back to the bird, the branch is empty. There doesn't seem to be an easy way out with this. I have tried One touch AF, MF, changing the focus area size, Dynamic MF on the RX10 ETC, but none seem to make any difference.

 

[sherman_levine]

Hi Sherm,

Thanks for bringing this up. I've found that with the FZ200/FZ1000 and the RX10 Mk4. There have been many occasions when a bird is sitting on a branch (usually near horizontal and none of these cameras will focus. In an attempt get round it, I try to quickly focus on the trunk, which is usually near vertical and then the camera will focus, but unfortunately on many occasions, by the time I get back to the bird, the branch is empty. There doesn't seem to be an easy way out with this. I have tried One touch AF, MF, changing the focus area size, Dynamic MF on the RX10 ETC, but none seem to make any difference.

Roger,

I don't think you can get around the sensor AF characteristics with a different focus method. Next time the issue arises, I'm going to try just rotating the camera somewhat and fixing the image in post.

--

Sherm
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[jlina]

So if you are photographing a house, the camera will focus more on the front door? Or doors and windows that are vertical across your field of view? Trying to visualize real life examples of this. Thanks!

 

[Rodger1943]

Hi Sherm,

Thanks for bringing this up. I've found that with the FZ200/FZ1000 and the RX10 Mk4. There have been many occasions when a bird is sitting on a branch (usually near horizontal and none of these cameras will focus. In an attempt get round it, I try to quickly focus on the trunk, which is usually near vertical and then the camera will focus, but unfortunately on many occasions, by the time I get back to the bird, the branch is empty. There doesn't seem to be an easy way out with this. I have tried One touch AF, MF, changing the focus area size, Dynamic MF on the RX10 ETC, but none seem to make any difference.

Roger,

I don't think you can get around the sensor AF characteristics with a different focus method. Next time the issue arises, I'm going to try just rotating the camera somewhat and fixing the image in post.

I have tried rotating the camera and it works, but in my haste to get a shot I forget to do it and instead persist in pressing the shutter button to get focus, which if course it doesn't. One day I will learn, but I appear to be a slow learner. In persisting with pressing the shutter I also fit the description of an idiot, you know the one, where its a person who keeps doing the same thing over and over and expects a different result. Ha!

 

[sherman_levine]

So if you are photographing a house, the camera will focus more on the front door? Or doors and windows that are vertical across your field of view? Trying to visualize real life examples of this. Thanks!

Roger's example is an excellent one. In landscape orientation, If you're using the small focus box the camera will have much more difficulty focusing on a horizontal branch than on a vertical branch.

If you're trying to focus on the moon in landscape orientation, focus on a vertical edge, not at the top.

I've not tried it, but I suspect the camera doesn't focus well on an ocean horizon in landscape orientation, but if you rotate it 90 degrees it'll do nicely

--

Sherm
Sherms flickr page

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[sherman_levine]

Hi Sherm,

Thanks for bringing this up. I've found that with the FZ200/FZ1000 and the RX10 Mk4. There have been many occasions when a bird is sitting on a branch (usually near horizontal and none of these cameras will focus. In an attempt get round it, I try to quickly focus on the trunk, which is usually near vertical and then the camera will focus, but unfortunately on many occasions, by the time I get back to the bird, the branch is empty. There doesn't seem to be an easy way out with this. I have tried One touch AF, MF, changing the focus area size, Dynamic MF on the RX10 ETC, but none seem to make any difference.

Roger,

I don't think you can get around the sensor AF characteristics with a different focus method. Next time the issue arises, I'm going to try just rotating the camera somewhat and fixing the image in post.

I have tried rotating the camera and it works, but in my haste to get a shot I forget to do it and instead persist in pressing the shutter button to get focus, which if course it doesn't. One day I will learn, but I appear to be a slow learner. In persisting with pressing the shutter I also fit the description of an idiot, you know the one, where its a person who keeps doing the same thing over and over and expects a different result. Ha!

although your track record in general is pretty darn good ;-)

--

Sherm
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[saudidave]

Surely then, if one follows the rule of thirds and places the subject at the intersection of horizontal and vertical lines in the EVF or the LCD, the problem will be overcome as the camera will use the vertical line of the two with which to focus?

Due to limited artistic ability I am a massive fan of the rule of thirds for composition and this may explain why I've never noticed this issue in 15 years of using well over 30 different TZ's, FZ's and G series cameras

Dave

 

[sherman_levine]

Surely then, if one follows the rule of thirds and places the subject at the intersection of horizontal and vertical lines in the EVF or the LCD, the problem will be overcome as the camera will use the vertical line of the two with which to focus?

Due to limited artistic ability I am a massive fan of the rule of thirds for composition and this may explain why I've never noticed this issue in 15 years of using well over 30 different TZ's, FZ's and G series cameras

Dave

Dave,

The observation has nothing to do with the horizontal and vertical lines on the finder. I'm referring to horizontal and vertical lines in the subject. Doesn't matter where it's placed on the display

--

Sherm
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[Jon_T]

Surely then, if one follows the rule of thirds and places the subject at the intersection of horizontal and vertical lines in the EVF or the LCD, the problem will be overcome as the camera will use the vertical line of the two with which to focus?

Due to limited artistic ability I am a massive fan of the rule of thirds for composition and this may explain why I've never noticed this issue in 15 years of using well over 30 different TZ's, FZ's and G series cameras

Dave

Dave,

The observation has nothing to do with the horizontal and vertical lines on the finder. I'm referring to horizontal and vertical lines in the subject. Doesn't matter where it's placed on the display

Yep, remember with my older film cameras would have to tilt camera to 45° or 90° to focus, then recompose to take shot.

Kinda surprised the FZ1000 "sensor contrast detect" (along with 'Depth from focus'), that focus would need 'horizontal and/ or vertical lines'.

From the articles I've read the sensor contrast detect AF:
"Contrast detection AF analyses the contrast on pixels on the camera’s sensor and pushes the lens back and forth until it finds the right focusing point. When contrast is at its highest, the subject is in focus." Excerpt from HERE (bold emphasis added by me).

I mainly use the centered single AF on all my cameras using contrast detect AF, and any subject (e.g., birds, flowers, etc.) with good lighting and with some type of pattern (contrasting edges) seldom had any AF issues.

Cheers,
Jon

 

[saudidave]

Surely then, if one follows the rule of thirds and places the subject at the intersection of horizontal and vertical lines in the EVF or the LCD, the problem will be overcome as the camera will use the vertical line of the two with which to focus?

Due to limited artistic ability I am a massive fan of the rule of thirds for composition and this may explain why I've never noticed this issue in 15 years of using well over 30 different TZ's, FZ's and G series cameras

Dave

Dave,

The observation has nothing to do with the horizontal and vertical lines on the finder. I'm referring to horizontal and vertical lines in the subject. Doesn't matter where it's placed on the display

Sherman,

Yes I appreciate that, but it would appear you have completely misunderstood my point? Maybe I didn't make it clearly enough

If the H & V lines on the finder intersect the subject matter and align with the H & V lines in the subject scene then you have perfect composition and perfect focus?

Dave

 

[sherman_levine]

Surely then, if one follows the rule of thirds and places the subject at the intersection of horizontal and vertical lines in the EVF or the LCD, the problem will be overcome as the camera will use the vertical line of the two with which to focus?

Due to limited artistic ability I am a massive fan of the rule of thirds for composition and this may explain why I've never noticed this issue in 15 years of using well over 30 different TZ's, FZ's and G series cameras

Dave

Dave,

The observation has nothing to do with the horizontal and vertical lines on the finder. I'm referring to horizontal and vertical lines in the subject. Doesn't matter where it's placed on the display

Sherman,

Yes I appreciate that, but it would appear you have completely misunderstood my point? Maybe I didn't make it clearly enough

If the H & V lines on the finder intersect the subject matter and align with the H & V lines in the subject scene then you have perfect composition and perfect focus?

Dave

Which H & V lines are you referring to?

--

Sherm
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[jlina]

Thanks Sherman! I don't know why it's printing in bold, yes I hit the b off... I had that exact thing happen last night I photographed the full moon it was very orange and I found that if I focused on the right hand edge where the craters were it was much easier to get the moon in focus! Ha talk about real life imitating art!

 

[jlina]

Hi! Yes that was my first thought as well but in practice last night before I even read Sherman's reply I noticed the edge of the moon was much easier to get in focus than the middle.... So I think he's right.

 

[sherman_levine]

Hi! Yes that was my first thought as well but in practice last night before I even read Sherman's reply I noticed the edge of the moon was much easier to get in focus than the middle.... So I think he's right.

and I think you'll notice that the sides are better focus points than the top or bottom when the camera's held in landscape orientation.

Rotate it 90 degrees and the top/bottom will be better than the sides.

(The middle is always difficult because the contrast changes are so small)

--

Sherm
Sherms flickr page

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[sherman_levine]

Surely then, if one follows the rule of thirds and places the subject at the intersection of horizontal and vertical lines in the EVF or the LCD, the problem will be overcome as the camera will use the vertical line of the two with which to focus?

Due to limited artistic ability I am a massive fan of the rule of thirds for composition and this may explain why I've never noticed this issue in 15 years of using well over 30 different TZ's, FZ's and G series cameras

Dave

Dave,

The observation has nothing to do with the horizontal and vertical lines on the finder. I'm referring to horizontal and vertical lines in the subject. Doesn't matter where it's placed on the display

Yep, remember with my older film cameras would have to tilt camera to 45° or 90° to focus, then recompose to take shot.

Kinda surprised the FZ1000 "sensor contrast detect" (along with 'Depth from focus'), that focus would need 'horizontal and/ or vertical lines'.

From the articles I've read the sensor contrast detect AF:
"Contrast detection AF analyses the contrast on pixels on the camera’s sensor and pushes the lens back and forth until it finds the right focusing point. When contrast is at its highest, the subject is in focus." Excerpt from HERE (bold emphasis added by me).

I mainly use the centered single AF on all my cameras using contrast detect AF, and any subject (e.g., birds, flowers, etc.) with good lighting and with some type of pattern (contrasting edges) seldom had any AF issues.

Cheers,
Jon

I'm a bit surprised. With phase AF, the sensor is a single pixel, but contrast AF needs to use the difference between adjacent pixels, and I guess Panasonic just compares in one direction and not the other

--

Sherm
Sherms flickr page

P950 album

P900 album RX10iv album

 

[saudidave]

Surely then, if one follows the rule of thirds and places the subject at the intersection of horizontal and vertical lines in the EVF or the LCD, the problem will be overcome as the camera will use the vertical line of the two with which to focus?

Due to limited artistic ability I am a massive fan of the rule of thirds for composition and this may explain why I've never noticed this issue in 15 years of using well over 30 different TZ's, FZ's and G series cameras

Dave

Dave,

The observation has nothing to do with the horizontal and vertical lines on the finder. I'm referring to horizontal and vertical lines in the subject. Doesn't matter where it's placed on the display

Sherman,

Yes I appreciate that, but it would appear you have completely misunderstood my point? Maybe I didn't make it clearly enough

If the H & V lines on the finder intersect the subject matter and align with the H & V lines in the subject scene then you have perfect composition and perfect focus?

Dave

Which H & V lines are you referring to?

Both the scene and the rule of thirds grid in the viewfinder. That's what my response says!