Landscape mode infinty default-focus

[ga-ga]

I had to do it didn't I.........?
these shots were taken at full zoom with TL-FX9 1.5x ie 70mm FL and f2.8
(to emphasize precise focus at minimum dof)



Landscape mode default focus
The tree was paced out at 50m ....



P mode Auto Focused on tree @ 50 metres
I estimate the chevrons to be at least 5 times ie 250m+ ...

this begs a few questions .....
with regards to predictions from Dofmaster
comments invited

regards ga-ga

regards ga-ga

I seem to remember there was an article in the forum on how to set
the S602 to Infinity but cant find it anywhere. Does anyone know
how I can manually set the camera to infinity so I could set the
exposure time to say 10 seconds?

I think if I put it to landscape mode it automatically sets itself
to infinity but how would I then be able to use it on the manual
mode?

Any help will be much appreciated

Regards,

howie

 

[TomCee]

Ga-ga,

I thought that the default focus in landscape mode was about 10 meters, but it is not so easy to measure this. Your test proofs at least that it isn't infinity. BTW, did you also take the same shot at f11, to see if that gave the great dept of field everyone assumes??

--
Regards,
Tom
(FinePix S602z)
http://www.pbase.com/tomcee

S602Z FAQ:
http://www.marius.org/fuji602faq.php

 

[ga-ga]

Hi Tom,

Clearly the default in Landscape is beyond the 50meters trees I am tempted to think it is either infinty or perhaps the hyperfocal length at full zoom f2.8 which would be about 110 metres...

since posting I have checked a map which suggests the distance to the chevrons is close to 500 meters.....

according to dofmaster for a 70mm lens focused at 50m dof extends from 41m to 62m clearly 500m is well outside that yet the shot focused on the trees shows the chevrons in reasonable focus....?
turning to the second pic at default focus/landscape ...
dofmaster predicts a dof at 2.8focused on 110m from 76m to 200m
and from 247m to infinity if focusted on infinity...
I'm still not sure what to think!.....

ga-ga....again!

Ga-ga,
I thought that the default focus in landscape mode was about 10
meters, but it is not so easy to measure this. Your test proofs at
least that it isn't infinity. BTW, did you also take the same shot
at f11, to see if that gave the great dept of field everyone
assumes??

--
Regards,
Tom
(FinePix S602z)
http://www.pbase.com/tomcee

S602Z FAQ:
http://www.marius.org/fuji602faq.php

 

[Sanpete]

How do you achieve "default focus"? Do you autofocus with lenscap on first, then use a focus lock? Also, can you get f2.8 at full zoom with this camera?

 

[ga-ga]

I find the simplest way is to keep it in MF and hold my right hand over the lens and press the quick focus button with my left...

you have the setting of 2.8 available .......whether it is true 2.8 at full zom and with the converter attached is debateable - but irrelevent because TTL metering takes care of it either way!.....

ga-ga

How do you achieve "default focus"? Do you autofocus with lenscap
on first, then use a focus lock? Also, can you get f2.8 at full
zoom with this camera?

 

[Sanpete]

Thanks ga-ga. It's a small difference, but according to the specs I've seen, the max aperture at full zoom is 3.1. Is that wrong? Might affect your calculations a little (though not much, I suppose).

ga-ga

How do you achieve "default focus"? Do you autofocus with lenscap
on first, then use a focus lock? Also, can you get f2.8 at full
zoom with this camera?

 

[ga-ga]

Sanpete!....

very good point!.... you've read it on the front of the lens - its not even mentioned in the manual and doesn't show up in the camera settings. ie 2.8 is still selectable at full zoom!.....

but if we put 3.1 into the DOFmaster calc. guess what - the hyperfocal at full app full zoom is 100metres (nice round figure!) - the resultant near focus distance is 50 meters.....
so although that was begining to sound good - that ain't it!.......
with the TL on and at 70mm the dof is even at f3.1 is 68m - 195m

the trees at 50m were definitely out of focus on the default landscape shot!........
and the chevrons at 500m were close to good focus......
back to the drawing board.....?

regards ga-ga

ga-ga

How do you achieve "default focus"? Do you autofocus with lenscap
on first, then use a focus lock? Also, can you get f2.8 at full
zoom with this camera?

 

[Sanpete]

I guess you won't mind my prodding you to figure this out. Can't do it too easily myself, as I don't really know much about optics.

If I understand what you've said so far, the first shot, with default focus, is explainable if the focus is somewhere close to or beyond infinity, right? So that's OK, though it calls for more experiments to try to figure out more exactly where the default really is. By the way, I wonder if the result from the rough focus might be a little different from those using the full AF routine?

The second shot is the problematic one because it doesn't fit the predictions of the DOF calculator, in that the chevrons shouldn't be in focus if the focus point is 50 m. One variable, I gather, is the circle of confusion. If I recall rightly, there was some discussion a while back about which value should be used for that. Maybe that's part of the problem. May also be that the AF isn't exactly 50m, but something more, or good enough to catch the tree and beyond (maybe). Did you use spot focus?

Hope I'm understanding this.

• the resultant near focus distance is 50 meters.....

so although that was begining to sound good - that ain't it!.......
with the TL on and at 70mm the dof is even at f3.1 is 68m - 195m
the trees at 50m were definitely out of focus on the default
landscape shot!........
and the chevrons at 500m were close to good focus......
back to the drawing board.....?

regards ga-ga

ga-ga

How do you achieve "default focus"? Do you autofocus with lenscap
on first, then use a focus lock? Also, can you get f2.8 at full
zoom with this camera?

 

[ga-ga]

I guess you won't mind my prodding you to figure this out. Can't

I'm grateful for the company!....

do it too easily myself, as I don't really know much about optics.

If I understand what you've said so far, the first shot, with
default focus, is explainable if the focus is somewhere close to or
beyond infinity, right? So that's OK, though it calls for more
experiments to try to figure out more exactly where the default
really is.

right!......

By the way, I wonder if the result from the rough focus
might be a little different from those using the full AF routine?

I find it very dificult to find much at very llong distance to test......

in this shot the chevrons are 500 mtrs - 1/3 mile..... thats still quite a bit short of infinty on the dofmaster scale......

but its a very small opening through the trees to try to get an AF lock - the light went yesterday before I got there......

The second shot is the problematic one because it doesn't fit the
predictions of the DOF calculator, in that the chevrons shouldn't
be in focus if the focus point is 50 m.

right!........

One variable, I gather, is
the circle of confusion. If I recall rightly, there was some
discussion a while back about which value should be used for that.
Maybe that's part of the problem.

hmmmm.... the COC needs to be 0.03 to bring 500m into DOF.......

0.03 is the recommended value for 35mm according to notes on DOFmaster, who reccomends 0.007 for digital..... IanR has previouslt suggested 0.005 which gives even les DOF (don't know where he got that)

May also be that the AF isn't
exactly 50m, but something more, or good enough to catch the tree
and beyond (maybe).

I AFed on the fir tree to the left of the chevrons and got a lock.

Did you use spot focus?

you don't mean that do you....... spot is only an option for metering....!

Hope I'm understanding this.

you're doing good........!

I don't understand myself yet but I'm tempted to work with 0.03 COC and check out other situations to see if it tally's........

maybe the CCDs ability to resolve close to the size of the pixels is interfering with the expected COC value which has been obtained by saling down from 35mm......???

regards ga-ga

• the resultant near focus distance is 50 meters.....

so although that was begining to sound good - that ain't it!.......
with the TL on and at 70mm the dof is even at f3.1 is 68m - 195m
the trees at 50m were definitely out of focus on the default
landscape shot!........
and the chevrons at 500m were close to good focus......
back to the drawing board.....?

regards ga-ga

ga-ga

How do you achieve "default focus"? Do you autofocus with lenscap
on first, then use a focus lock? Also, can you get f2.8 at full
zoom with this camera?

 

[Sanpete]

No spot focus? Oh well, it's an option on some cameras (I don't have the camera, I'm just in the market). There are different AF schemes, but most focus on the most prominent object within a certain part of the field of view. With spot you can be more precise. With the Minolta 7i, for example, you can move the focus box around, and vary its size too, I think. And it can show you what point it focussed on. I think.

Anyway, I wonder if you can't get focus lock on an object without having the focus at the exact distance the object is at. That is, as long as the object is within the focus depth, it will still be in focus and able to be locked on, it seems. So the focus could be at 75 m, and the tree would still be able to provide a focus lock. Though the AF probably tries to get close to exact by splitting the difference between two OOF adjustments, moving each way from focus. Don't know. Looks like that's still wouldn't be enough fudge to make the figures work.

Here's a simpler question. Is the DOF calculater you're using set up for actual FL, or 35 mm equivalent?

I guess you won't mind my prodding you to figure this out. Can't

I'm grateful for the company!....

do it too easily myself, as I don't really know much about optics.

If I understand what you've said so far, the first shot, with
default focus, is explainable if the focus is somewhere close to or
beyond infinity, right? So that's OK, though it calls for more
experiments to try to figure out more exactly where the default
really is.

right!......

By the way, I wonder if the result from the rough focus
might be a little different from those using the full AF routine?

I find it very dificult to find much at very llong distance to
test......
in this shot the chevrons are 500 mtrs - 1/3 mile..... thats still
quite a bit short of infinty on the dofmaster scale......
but its a very small opening through the trees to try to get an AF
lock - the light went yesterday before I got there......

The second shot is the problematic one because it doesn't fit the
predictions of the DOF calculator, in that the chevrons shouldn't
be in focus if the focus point is 50 m.

right!........

One variable, I gather, is
the circle of confusion. If I recall rightly, there was some
discussion a while back about which value should be used for that.
Maybe that's part of the problem.

hmmmm.... the COC needs to be 0.03 to bring 500m into DOF.......
0.03 is the recommended value for 35mm according to notes on
DOFmaster, who reccomends 0.007 for digital..... IanR has
previouslt suggested 0.005 which gives even les DOF (don't know
where he got that)

May also be that the AF isn't
exactly 50m, but something more, or good enough to catch the tree
and beyond (maybe).

I AFed on the fir tree to the left of the chevrons and got a lock.

Did you use spot focus?

you don't mean that do you....... spot is only an option for
metering....!

Hope I'm understanding this.

you're doing good........!
I don't understand myself yet but I'm tempted to work with 0.03 COC
and check out other situations to see if it tally's........
maybe the CCDs ability to resolve close to the size of the pixels
is interfering with the expected COC value which has been obtained
by saling down from 35mm......???

regards ga-ga

• the resultant near focus distance is 50 meters.....

so although that was begining to sound good - that ain't it!.......
with the TL on and at 70mm the dof is even at f3.1 is 68m - 195m
the trees at 50m were definitely out of focus on the default
landscape shot!........
and the chevrons at 500m were close to good focus......
back to the drawing board.....?

regards ga-ga

ga-ga

How do you achieve "default focus"? Do you autofocus with lenscap
on first, then use a focus lock? Also, can you get f2.8 at full
zoom with this camera?

 

[ga-ga]

hi sanman,

No spot focus? Oh well, it's an option on some cameras (I don't
have the camera, I'm just in the market). There are different AF
schemes, but most focus on the most prominent object within a
certain part of the field of view. With spot you can be more
precise. With the Minolta 7i, for example, you can move the focus
box around, and vary its size too, I think. And it can show you
what point it focussed on. I think.

its more a case of only spot - and you can move the focus box around. and you have manual focus.

Anyway, I wonder if you can't get focus lock on an object without
having the focus at the exact distance the object is at. That is,
as long as the object is within the focus depth, it will still be
in focus and able to be locked on, it seems. So the focus could be
at 75 m, and the tree would still be able to provide a focus lock.
Though the AF probably tries to get close to exact by splitting the
difference between two OOF adjustments, moving each way from focus.
Don't know. Looks like that's still wouldn't be enough fudge to
make the figures work.

the AF works on getting the maximum contrast on the sensor.

Here's a simpler question. Is the DOF calculater you're using set
up for actual FL, or 35 mm equivalent?

try it .... http://www.dofmaster.com
its well worth it....
regards ga-ga

I guess you won't mind my prodding you to figure this out. Can't

I'm grateful for the company!....

do it too easily myself, as I don't really know much about optics.

If I understand what you've said so far, the first shot, with
default focus, is explainable if the focus is somewhere close to or
beyond infinity, right? So that's OK, though it calls for more
experiments to try to figure out more exactly where the default
really is.

right!......

By the way, I wonder if the result from the rough focus
might be a little different from those using the full AF routine?

I find it very dificult to find much at very llong distance to
test......
in this shot the chevrons are 500 mtrs - 1/3 mile..... thats still
quite a bit short of infinty on the dofmaster scale......
but its a very small opening through the trees to try to get an AF
lock - the light went yesterday before I got there......

The second shot is the problematic one because it doesn't fit the
predictions of the DOF calculator, in that the chevrons shouldn't
be in focus if the focus point is 50 m.

right!........

One variable, I gather, is
the circle of confusion. If I recall rightly, there was some
discussion a while back about which value should be used for that.
Maybe that's part of the problem.

hmmmm.... the COC needs to be 0.03 to bring 500m into DOF.......
0.03 is the recommended value for 35mm according to notes on
DOFmaster, who reccomends 0.007 for digital..... IanR has
previouslt suggested 0.005 which gives even les DOF (don't know
where he got that)

May also be that the AF isn't
exactly 50m, but something more, or good enough to catch the tree
and beyond (maybe).

I AFed on the fir tree to the left of the chevrons and got a lock.

Did you use spot focus?

you don't mean that do you....... spot is only an option for
metering....!

Hope I'm understanding this.

you're doing good........!
I don't understand myself yet but I'm tempted to work with 0.03 COC
and check out other situations to see if it tally's........
maybe the CCDs ability to resolve close to the size of the pixels
is interfering with the expected COC value which has been obtained
by saling down from 35mm......???

regards ga-ga

• the resultant near focus distance is 50 meters.....

so although that was begining to sound good - that ain't it!.......
with the TL on and at 70mm the dof is even at f3.1 is 68m - 195m
the trees at 50m were definitely out of focus on the default
landscape shot!........
and the chevrons at 500m were close to good focus......
back to the drawing board.....?

regards ga-ga

ga-ga

How do you achieve "default focus"? Do you autofocus with lenscap
on first, then use a focus lock? Also, can you get f2.8 at full
zoom with this camera?

 

[Howie Mudge]

I am pretty new to photography on a whole. So most of this what your mentioning is beyond me so maybe if I explain the two kind of shots you may be able to help.

One would be to go and shoot a seascape shot. Say some rocks some water. Ideally I would want F11 and max shutter speed of say 10-15 seconds. the next kind of shot would be a moon shot between tree's. Again if possible would it be best to use F11 and a slow shutter speed of say 10-15 seconds.

On reading this for infinity I presume I would cover the lense with my hand and switch on the camera in manual mode. Have the settings presetup. Press half way down on the manual focus setting and then remove my hand and then press completley down on the button?

Obvbiously for the moon shot I would want to zoom in as close as possible and then follow the same procedure.

If I am going wrong here in any of my simple procedures, lease can you advise if where and how to correct what is wrong. I hope my questions make sense

Howie

Thanks in advanced.

 

[ga-ga]

Hi Howie,
Sorry I misled you.....

I started out picking up on the question you asked but renamed it and started a new thread because I thought it might be of more general interest......??

We are discussing where Landscape default focus actually comes so that you can use it for just the shots you've mentioned.
It would be nice if we can prove that infinity but at the moment I'm not sure.

I've just uploaded two sets of pics focused at 50m,500m and lanscape default - with and without a 1.5x teleconverter (which makes the focusing more precise).
http://www.pbase.com/johngregson/infinity

Lets all have a look and make any observations we can see....

regards ga-ga

I am pretty new to photography on a whole. So most of this what
your mentioning is beyond me so maybe if I explain the two kind of
shots you may be able to help.

One would be to go and shoot a seascape shot. Say some rocks some
water. Ideally I would want F11 and max shutter speed of say 10-15
seconds. the next kind of shot would be a moon shot between
tree's. Again if possible would it be best to use F11 and a slow
shutter speed of say 10-15 seconds.

On reading this for infinity I presume I would cover the lense with
my hand and switch on the camera in manual mode. Have the settings
presetup. Press half way down on the manual focus setting and then
remove my hand and then press completley down on the button?

Obvbiously for the moon shot I would want to zoom in as close as
possible and then follow the same procedure.

If I am going wrong here in any of my simple procedures, lease can
you advise if where and how to correct what is wrong. I hope my
questions make sense

Howie

Thanks in advanced.

 

[Sanpete]

Well, I'm stumped. Might be fun to post your second shot in the Open Talk forum to see what people say. Or you might want to try it again with more exact measurements to back it up first. It is intriguing.

I'm not sure I'm understanding your comments on AF. If the theoretical focus point is 80 m, and the DOF goes from 45 to 200 m, say, then anything in that DOF could provide max contrast, given the practical constraints of resolution, right? So you could have an AF lock on the tree when the theoretical focus distance is actually at 80 m. Or so it seems. I think you've been assuming something like this all along, but I'm not sure.

 

[ga-ga]

Hi Sanman!...
I think your post crossed with mine to Howie -
have a look at the new shots and tell me what you think........
and if you can come to any logical deductions from them -
I have one answer in the back of my mind to this 602 Fuji funny......
but there may be others .......

and I'd like to hear anybody else's ideas first just in case there's something I havn't considered....
If I'm right you're not going to like it ..... too much!

regards ga-ga

Well, I'm stumped. Might be fun to post your second shot in the
Open Talk forum to see what people say. Or you might want to try
it again with more exact measurements to back it up first. It is
intriguing.

I'm not sure I'm understanding your comments on AF. If the
theoretical focus point is 80 m, and the DOF goes from 45 to 200 m,
say, then anything in that DOF could provide max contrast, given
the practical constraints of resolution, right? So you could have
an AF lock on the tree when the theoretical focus distance is
actually at 80 m. Or so it seems. I think you've been assuming
something like this all along, but I'm not sure.

 

[TomCee]

John,

Have you considered the possibility that covering the lens with your hand astill allows the MAIN AF system (with the two sensors underneath the flash) to do more ore less the AF job??

--
Regards,
Tom
(FinePix S602z)
http://www.pbase.com/tomcee

S602Z FAQ:
http://www.marius.org/fuji602faq.php

 

[ga-ga]

Hi Tom,
No I hadn't but
I don't think thats a possibility Tom

I don't see any way any sensor is going to beam out over 1/3 mile and catch a responce .......
I'd like to know more about that system

but best information so far is the range of that system is only about 1.5metres....
http://forums.dpreview.com/forums/read.asp?forum=1012&message=3814869

regards ga-ga

John,

Have you considered the possibility that covering the lens with
your hand astill allows the MAIN AF system (with the two sensors
underneath the flash) to do more ore less the AF job??

--
Regards,
Tom
(FinePix S602z)
http://www.pbase.com/tomcee

S602Z FAQ:
http://www.marius.org/fuji602faq.php

 

[ianR]

Hi ga-ga
Well the DOF you seem to be getting here is impossible as far as I can tell.
There must be one of those factors that is incorrect.

Either the focal length,(but by a large amount) or the F no (by a large amount) or the focusing distance, or a combination of all three. I can't imagine anything else.
Two other thoughts:

1. Perhaps the 602 is back focusing. I think you'd have noticed that but I'll say it anyway.

2. What does the 1.5x add on actually mean? It should mean 1.5x magnification but what if it just means 1.5x onto the zoom range? That would be 7.8x7.5=58.5m not 70mm.

I don't think anything so far explains it myself but I throw it in to be kicked around anyway.

I'll have a go at the same thing next week if I can, using a long fence and see if I can replicate the result.
Interesting and disturbing experiment in any case.
Ian

regards ga-ga

John,

Have you considered the possibility that covering the lens with
your hand astill allows the MAIN AF system (with the two sensors
underneath the flash) to do more ore less the AF job??

--
Regards,
Tom
(FinePix S602z)
http://www.pbase.com/tomcee

S602Z FAQ:
http://www.marius.org/fuji602faq.php

--
6900

 

[Leonardo Fornaiolo]

hi john and hi all....!!!!

I would like to ask to fuji engineers why they don't wrote a little report on the user manual regarding the "logic" of focus...little bit less fun for us, that works hard in discovering the camera, but a lot of help for people that have not the time to read the forum or perform tests...

you know...we started talking about focussing "logic" that fuji implemented on our 602 3 months ago!!! and till today, we don't have a complete reply...it puzzles me.
for Santa: a book with 602 hidden features, please!!!!

with my best wishes

Leonardo - ITALY

 

[ga-ga]

Hi leo,
Nice to see you !....
I'll drop him a line and see if he can fix up the book for you!
R ga-ga

hi john and hi all....!!!!

I would like to ask to fuji engineers why they don't wrote a little
report on the user manual regarding the "logic" of focus...little
bit less fun for us, that works hard in discovering the camera, but
a lot of help for people that have not the time to read the forum
or perform tests...
you know...we started talking about focussing "logic" that fuji
implemented on our 602 3 months ago!!! and till today, we don't
have a complete reply...it puzzles me.
for Santa: a book with 602 hidden features, please!!!!

with my best wishes

Leonardo - ITALY