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G1 Focus Hocus Part 2: Conclusion

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I know about greater depth of field in wide angle, Peter. The difference here is that in wide my G1 will lock in focus with no hesitation with the X at the very edge, in tele and the x near edge it will lock only after 2-buz hesitation (indicating difficulty) and depending on its luck the X might or might not get in focus.

Michael
Peter T said:
Michael W. said:
At full tele the X test shows that my G1 can only focus if some of
the X is within a center area about 1/2 of the screen each way. At
full wide, however, it has no problem focusing near the edge
(confirming my #8 picture). Perhaps Canon engineers anticipated
tele is used more for portrait and wide is used more for landscape,
hence the different behavior. Whatever the reason, this disparity
is a lot easier to live with than that infamous "wide-angle
mistiming".
Click to expand...
One slight point. :)
Wide angle focusing near the edge has nothing to do with Canon
engineers and everything to do with depth of field. You are
increasing the depth of field.
Click to expand...
 
I don't think the hesitation is a reliable way of determining if the camera found focus. I have noticed that the hesitation isn't always consistent, although it usually is.
Michael W. said:
I know about greater depth of field in wide angle, Peter. The
difference here is that in wide my G1 will lock in focus with no
hesitation with the X at the very edge, in tele and the x near edge
it will lock only after 2-buz hesitation (indicating difficulty)
and depending on its luck the X might or might not get in focus.
Click to expand...
 
Ted, in the modern film SLR world just about every camera has a meter in manual mode. Sure, in manual mode you have the ultimate say but the meter serves as a baseline, or a second opinion if you will. With an SLR you can set exposure to whatever you want, but there is an indicator whether the meter thinks it's over, under, or right on. Very helpful. With the G1 the LCD display provide that 2nd opinion in a different way, but in some lighting conditions it's very hard to judge the LCD display. That's where Peter came from.

Michael
Ted B. said:
Peter T said:
Ted B. said:
Spot metering in M mode would be pointless. You have taken over
the 'metering' functions and are setting shutter speed and
aperature yourslef. Metering is used to set one or both of these
automatically, so it would be a waste of time. My guess is NO
metering takes place in M mode, spot or center weighted. What
would be the purpose?
Click to expand...
Metering is NOT used to set shutter speed and aperture
automatically. It is used to determine exposure. Any camera I've
ever seen with spot metering has it available in manual mode. It
doesn't set the exposure. It uses a scale like in exposure
compensation to let you know how close the settings are from a
correct exposure.
Click to expand...
Click to expand...
 
To find out why your link does not work, look at it. Dpreview is trying to download the page to insert inline. Copy the link and cut out everyting up to the second http and paste on address line and it loads fine.
Steve D said:
Nahau.. funny line..

here is the album. The picture I'm speaking of is the second..
butterflies.. on the Home page. it looks good to me, as i say.. I
may be far less demanding than some.

http://goin480.tripod.com/stevesphotos/

steve
Steve D said:

Steve D said:
But since there are so many people having trouble focusing,
parircularly with macros (thank god they are not my major area of
interest).. there simply must be an easier way to set focus
properly than many have discovered... or Canon would never have
sold so many G1. I think I'm lucky because i just havent had that
many way out of focus... but I'm not overly picky either. her's a
shot of some butterflies. Is this in our out of focus to most of
you? I'm curious.



steve D
Michael W. said:
First off, I don't mean to be redundant in creating this new
thread; I just though this info is so helpful to G1 users that it
shouldn't get lost in the long, long original thread.

From part 1, looks like there is no dispute that position matters,
as illustrated by the original 5 pictures of the cake I posted.

Then the debate is whether the entire frame or just the center is
used by the camera for focusing. To clear this unsettling question
I added 3 more shots to the test, please take a look.

http://www.ofoto.com/I.jsp?m=25101888103&n=569919155

Picture 8 (# sign on paper) clearly indicates that the G1 will
evaluate the entire frame and will focus on the corner if
sufficient contrast cannot be found elsewhere. Any disgreement?

Picture 6, the cake is VERY near edge causing my G1 to shift focus
to the wall. Like Bob W. noticed, the G1 actualy focuses on the
wall texture and not just arbitrarily throws long -- it's darn
sensitive!

Picture 7, the cake is also near edge but closer to center than in
pic 6, and now my G1 shifts focus back on the cake.

Evidently both the cake and the wall texture provide adequate
contrast. The cake has more contrast but is at edge, the wall
texture has less contrast but covers the center. Combining this
information with what we saw in the original 5 pictures, it is so
clear to me that the G1 indeed scans the entire frame, but it also
gives more weight to subjects which are closer to the center and/or
more contrasty. This behavior can be quite properly called
"Center-Weighed" focusing after all. The Canon Rep who talked to
Don T is correct (my personal conclusion); whether he realy knows
or just got lucky is irrelevant.

If I design an autofocus system, I probably would do the same
thing. In otherwords, the autofocus scheme is very good in my
opinion -- if you know how it works. The main problem is that Canon
does not provide adequate documentation, leading to the massive
confusion when your G1 fails to focus on the object you want it to.

One thing bothers me though: there is no spot focus in M mode!

--
Michael
Click to expand...
Click to expand...
Click to expand...
Click to expand...
 
Here's something I tried. A blank white piece of paper 3" away from the camera lens. A small target with lettering 1/4" high. In the center of the image it is clearly focused and in the corner it is clearly not. This was shot wide.
 
This test doesn't work for me, Ted. I did just that after uploading the pictures and even preview the embedding in my post, and they showed up nicely then but others couldn't see it. I think the photo service servers keep a web session ID, so since I just logged in and work on an album it allows my computer to pull those pictures but will not allow others.

Michael
Ted B. said:
Steve D said:
Nahau.. funny line..

here is the album. The picture I'm speaking of is the second..
butterflies.. on the Home page. it looks good to me, as i say.. I
may be far less demanding than some.

http://goin480.tripod.com/stevesphotos/

steve
Steve D said:

Steve D said:
But since there are so many people having trouble focusing,
parircularly with macros (thank god they are not my major area of
interest).. there simply must be an easier way to set focus
properly than many have discovered... or Canon would never have
sold so many G1. I think I'm lucky because i just havent had that
many way out of focus... but I'm not overly picky either. her's a
shot of some butterflies. Is this in our out of focus to most of
you? I'm curious.



steve D
Michael W. said:
First off, I don't mean to be redundant in creating this new
thread; I just though this info is so helpful to G1 users that it
shouldn't get lost in the long, long original thread.

From part 1, looks like there is no dispute that position matters,
as illustrated by the original 5 pictures of the cake I posted.

Then the debate is whether the entire frame or just the center is
used by the camera for focusing. To clear this unsettling question
I added 3 more shots to the test, please take a look.

http://www.ofoto.com/I.jsp?m=25101888103&n=569919155

Picture 8 (# sign on paper) clearly indicates that the G1 will
evaluate the entire frame and will focus on the corner if
sufficient contrast cannot be found elsewhere. Any disgreement?

Picture 6, the cake is VERY near edge causing my G1 to shift focus
to the wall. Like Bob W. noticed, the G1 actualy focuses on the
wall texture and not just arbitrarily throws long -- it's darn
sensitive!

Picture 7, the cake is also near edge but closer to center than in
pic 6, and now my G1 shifts focus back on the cake.

Evidently both the cake and the wall texture provide adequate
contrast. The cake has more contrast but is at edge, the wall
texture has less contrast but covers the center. Combining this
information with what we saw in the original 5 pictures, it is so
clear to me that the G1 indeed scans the entire frame, but it also
gives more weight to subjects which are closer to the center and/or
more contrasty. This behavior can be quite properly called
"Center-Weighed" focusing after all. The Canon Rep who talked to
Don T is correct (my personal conclusion); whether he realy knows
or just got lucky is irrelevant.

If I design an autofocus system, I probably would do the same
thing. In otherwords, the autofocus scheme is very good in my
opinion -- if you know how it works. The main problem is that Canon
does not provide adequate documentation, leading to the massive
confusion when your G1 fails to focus on the object you want it to.

One thing bothers me though: there is no spot focus in M mode!

--
Michael
Click to expand...
Click to expand...
Click to expand...
Click to expand...
Click to expand...
 
I re-did my experiment. Check out http://users/rcn.com/tbackher/ and tell my why the camera did not focus on the edges of the frame. The last two pics prove the border is within focus range, so why isn't it in focus in the other pics? All other pics show the camera did not focus on the edges of the frame when failing to get a lock on anything in the ever-so-obvious focus zone it uses. My inescapable conclusion is: The camera will never intentionally focus on anything not in the focus zone. If something not in the focus zone is in focus, that is an accident and it will,so far, always be background, not foreground. If you disagree, then excplain the results of my experiment, if you can. I'd be happy to hear an alternative explanation of what happened. It may seem otherwise, but I only want to discover how the camera actually works, to help clarify this issue.
nahau said:
Member said:
Steve D wrote:
Nahau.. funny line..
Click to expand...
I couldn't resist!LOL!!
Click to expand...
 
BTW, Fototime and Zing had no problem with picture embedding here :(
Michael W. said:
This test doesn't work for me, Ted. I did just that after
uploading the pictures and even preview the embedding in my post,
and they showed up nicely then but others couldn't see it. I think
the photo service servers keep a web session ID, so since I just
logged in and work on an album it allows my computer to pull those
pictures but will not allow others.

Michael
Click to expand...
 
Without being able to see the pic full screen, it looks like the edge of the wing is splitting the middle of the focus zone. The camera picked the red flower just above the edge, it appears. They are so similiar in distance from the lens, that the focus difference is minmal.
Michael W. said:
Michael
Ted B. said:
Steve D said:
Nahau.. funny line..

here is the album. The picture I'm speaking of is the second..
butterflies.. on the Home page. it looks good to me, as i say.. I
may be far less demanding than some.

http://goin480.tripod.com/stevesphotos/

steve
Steve D said:

Steve D said:
But since there are so many people having trouble focusing,
parircularly with macros (thank god they are not my major area of
interest).. there simply must be an easier way to set focus
properly than many have discovered... or Canon would never have
sold so many G1. I think I'm lucky because i just havent had that
many way out of focus... but I'm not overly picky either. her's a
shot of some butterflies. Is this in our out of focus to most of
you? I'm curious.



steve D
Michael W. said:
First off, I don't mean to be redundant in creating this new
thread; I just though this info is so helpful to G1 users that it
shouldn't get lost in the long, long original thread.

From part 1, looks like there is no dispute that position matters,
as illustrated by the original 5 pictures of the cake I posted.

Then the debate is whether the entire frame or just the center is
used by the camera for focusing. To clear this unsettling question
I added 3 more shots to the test, please take a look.

http://www.ofoto.com/I.jsp?m=25101888103&n=569919155

Picture 8 (# sign on paper) clearly indicates that the G1 will
evaluate the entire frame and will focus on the corner if
sufficient contrast cannot be found elsewhere. Any disgreement?

Picture 6, the cake is VERY near edge causing my G1 to shift focus
to the wall. Like Bob W. noticed, the G1 actualy focuses on the
wall texture and not just arbitrarily throws long -- it's darn
sensitive!

Picture 7, the cake is also near edge but closer to center than in
pic 6, and now my G1 shifts focus back on the cake.

Evidently both the cake and the wall texture provide adequate
contrast. The cake has more contrast but is at edge, the wall
texture has less contrast but covers the center. Combining this
information with what we saw in the original 5 pictures, it is so
clear to me that the G1 indeed scans the entire frame, but it also
gives more weight to subjects which are closer to the center and/or
more contrasty. This behavior can be quite properly called
"Center-Weighed" focusing after all. The Canon Rep who talked to
Don T is correct (my personal conclusion); whether he realy knows
or just got lucky is irrelevant.

If I design an autofocus system, I probably would do the same
thing. In otherwords, the autofocus scheme is very good in my
opinion -- if you know how it works. The main problem is that Canon
does not provide adequate documentation, leading to the massive
confusion when your G1 fails to focus on the object you want it to.

One thing bothers me though: there is no spot focus in M mode!

--
Michael
Click to expand...
Click to expand...
Click to expand...
Click to expand...
Click to expand...
Click to expand...
 
Ted.. thanks for your comments. I realize that the butterfly and flower are really close together and there probably was no way to precisely judge what the G1 would focus on. Is it really a "crap" shoot in many cases? I'm sure that more expereinced people can get it better.. but there doesnt seem to be any consistent was to judge how to get the "best" focus. Exposure is hard enough, but there are a number of pretty basic ways to address it. but focus.. dont know.. I just cant seem to make manual work for me on the G1.. but overall.. I'm quite pleased with most all the results I get with this camera.

In regard to the single photo link.. yep.. works fine in fototime.. but not in Lycos tripod web builder. I prefer the web browser approach, but hate to have to link to the entire album just for one pic.

Steve D
Ted B. said:
Oops, I'll try not to include so much of the original message in my
subsequent posts. Sorry.
Click to expand...
 
I would have framed up with the wing centered in the frame and locked focus, then recomposed. If the only thing in the focus zone was the wing, then that should take care of it. Using spot metering to get the square metering target would help, or use the cross hairs in the optical viewfinder. I had an olympus C2100 UZ and it had an electronic viewfinder. Focus was obvous with that camera. The LCD on the G1 needs a focus cross hair in the center weighted metering mode, if you ask me.
Steve D said:
In regard to the single photo link.. yep.. works fine in fototime..
but not in Lycos tripod web builder. I prefer the web browser
approach, but hate to have to link to the entire album just for one
pic.

Steve D
Ted B. said:
Oops, I'll try not to include so much of the original message in my
subsequent posts. Sorry.
Click to expand...
Click to expand...
 
Ted,

I think you are missing the point here. What the other posters are saying is that in manual mode, spot metering (or any other metering) is simply a useful exposure indicator and nothing else. In your example (manual mode, 1/1000 @ f8, dark object), the camera's metering system would simply warn you that the picture will be under-exposed. Similarly, if you shoot at the sun with 1 sec shutter speed, the metering would indicate over-exposure. This is just an indication and will not affect the aperture/shutter speed settings. YOU are the one to set them and the camera will totaly obey you. It is entirely up to you to use the exposure information provided by the metering system. In fact I think it is a useful feature especially to beginners who want to learn.

I'm new to the G1, and didn't know it doesn't provide metering in manual mode. But one good thing I found out is that the LCD actually simulates the final exposure, so you can assess exposure (even in manual mode) by simply looking at the LCD (or so it seems). If that's the case, the LCD serves as a real-time exposure previewer (which is amazing)!!! Can anyone confirm how accurate the LCD preview is compared to the final image?

Costas
Ted B. said:
That is why you cannot set spot metering in manual mode. You would
be contradicting yourself if you could. However, it would be nice
to have that frame there anyway, to help indicate the focus zone
accurately, in the LCD.
Peter T said:
Ted B. said:
Spot metering in M mode would be pointless. You have taken over
the 'metering' functions and are setting shutter speed and
aperature yourslef. Metering is used to set one or both of these
automatically, so it would be a waste of time. My guess is NO
metering takes place in M mode, spot or center weighted. What
would be the purpose?
Click to expand...
Metering is NOT used to set shutter speed and aperture
automatically. It is used to determine exposure. Any camera I've
ever seen with spot metering has it available in manual mode. It
doesn't set the exposure. It uses a scale like in exposure
compensation to let you know how close the settings are from a
correct exposure.
Click to expand...
Click to expand...
 
Costas,

I have found the LCD to be a good general indication of correct exposure once you get used to what angle to view it at. I think you will find it most accurate when the LCD is tilted so it is Parallel to your eye. For myself, I shoot in Raw mode always so I can determine things like white balance, saturation, contrast later on. Instead of manual mode, I use Aperature or Shutter Priority in spot mode, press shutter halfway to see what the exposure and focus will look like in the LCD, and if happy, recompose and shoot. This is where the LCD really helps out for exposure in spot mode because one can always point the spot at a different location and test various exp. in LCD, Not to mention different point of focus areas. If time permits, I will zoom in, press shutter half way to lock focus and exp. and zoom back out to recompose. So far, my only complaint is with the focus system which should have allowed a spot focus instead of some vague center weighted type of system. Hope this helps.

Tariq
Costas Vlachos said:
Ted,

I think you are missing the point here. What the other posters are
saying is that in manual mode, spot metering (or any other
metering) is simply a useful exposure indicator and nothing else.
In your example (manual mode, 1/1000 @ f8, dark object), the
camera's metering system would simply warn you that the picture
will be under-exposed. Similarly, if you shoot at the sun with 1
sec shutter speed, the metering would indicate over-exposure. This
is just an indication and will not affect the aperture/shutter
speed settings. YOU are the one to set them and the camera will
totaly obey you. It is entirely up to you to use the exposure
information provided by the metering system. In fact I think it is
a useful feature especially to beginners who want to learn.

I'm new to the G1, and didn't know it doesn't provide metering in
manual mode. But one good thing I found out is that the LCD
actually simulates the final exposure, so you can assess exposure
(even in manual mode) by simply looking at the LCD (or so it
seems). If that's the case, the LCD serves as a real-time exposure
previewer (which is amazing)!!! Can anyone confirm how accurate the
LCD preview is compared to the final image?

Costas
Click to expand...
 
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