Serious G1 Deficiency Overlooked by Product Reviews

Diane B · Aug 7, 2001

Bob Williams wrote:
. Talk to me right after I try

Member said:
to capture a show quality red rose, and I might throw the camera
at you

Bob, I don't know if this is possible with your camera, but this morning I decided to try various things with the exposure and a RED Cardinal flower. I had gotten a quite nice shot of it the other day by standing in front of the morning sun (I guess that's the equivalent of a black umbrella that some use for these shots) keeping it from blowing out (-1/3 EV also)--it was also a macro shot and lots of machinations with my tripod also LOL. Still, the red was not 'right on'--to other's eyes they thought so, but I'm a 'colorist' and knew it was not--just visually beautiful but not an accurate depiction of the red.

This morning I played with the AE button, other things. I finally got the red by dropping the EV a LOT. I went down a full -1, used spot and got it with Av. I also got an excellent one--maybe the better, with a manual mode shot (which is what I usually use). I also used the flash whitepoint which was fine--I could have set my whitepoint with a grey card also, but the quite considerable -1 seemed to be the answer--in this light.

I also tried using no EV for a number of shots as others mentioned (I had had -1/3 set as default) and found that 60% seemed good with no EV, some needed that -1/3 and then that Cardinal flower needed a big compensation. So--that tells me that I'll just have to pay attention. I hadn't even tried anything more than -2/3 before.

Diane

Diane B · Aug 7, 2001

Diane B Fields said:
Diane B said:

to capture a show quality red rose, and I might throw the camera
at you

Click to expand...

This morning I played with the AE button, other things. I finally
got the red by dropping the EV a LOT. I went down a full -1, used
spot and got it with Av. I also got an excellent one--maybe the
better, with a manual mode shot (which is what I usually use). I
also used the flash whitepoint which was fine--

Oh, meant to add that I was able to get the same 'true' red in Photopaint for the earlier photo with not too much trouble. After listening to an hour long NPR (local--we have an Ansel Adams 100th Anniversary exhibit at Charlotte MInt Museum) program on Ansel Adam's philosophies, ways of working/printing, etc.--I felt more comfortable with processing the photo to meet my own visual/creative ideas. Being a visual arts person, I'm very comfortable with the idea of the original being the start of the creative process.

Diane

Peter T44178 · Aug 7, 2001

I conducted the following experiment. I printed a light gray box on white and placed it 22" from the lens. I printed a dark gray box on white and placed it 52" from the lens and to the side. I shot at f2.5 and zoomed out about halfway to minimize depth of field.

I centered the light gray box in the center and since there was no contrast it was not in focus. The dark gray box was in focus.

Then I centered the edge between the light gray box and the white paper(I used the focusing light for this). Even though the dark gray box in the background presented higher contrast, the camera focused on the light gray box because it presented sufficient contrast.

I think that in the first case it only appeared that the camera focused on the dark gray box. I think what actually happens is that when the camera can't find focus it focuses long which ends up being the background.

Mike Flaherty · Aug 7, 2001

Say, Whaaaaaaaaaaaat ?????

Mike Flaherty

Bob Williams said:
Don T said:

I am embarrassed to admit that after owning my G1 or more than six
months it is only now that I have come to realize the G1’s
autofocus deficiency. This is no minor problem, unlike the magenta
overcast, which is easily fixed with an editing program. There is
no easy fix for a camera that has a very weak autofocus system.

Rather than explain the problem in my own words, please read the
exert that I have extracted from Kevin Bjorkes discussion on G1
autofocus (botzilla.com):
Autofocus
“The G1 appears to use a contrast-based AF system. It also
appears to use the entire frame to measure contrast. In other
words, the contrast of pixels along the edges and in the corners
are given just as much importance by the AF system as pixels near
the center.
This uncentered approach has serious consequences for autofocus use
on real scenes. While it's fine for landscapes and may even do well
for group shots, what about a head-and-shoulders portrait?

Canon's G1 manual mentions "autofocus crosshairs" on page 38, but
this is simply wrong they're in the optical finder and clearly have
nothing to do with the Autofocus. What's more, they may give you
the impression that the AF is concentrating on the area of the
crosshairs (like the "target marks" did on the previous Canon
design, the Pro 70) and that's simply not true

The Pro 90 also has a "target bracket" area, which might actually
do something (it's part of the EVF and LCD, not the optical
finder). But both the G1 and Pro 90 manuals claim weakness to
"Subjects with extremely low contrast to the surroundings." Even
the A20 has AF brackets why does the G1 have this crippled system?
Is it some failed prototype of the A20's AiAF ?”

If Kevin is correct in his evaluation of the G1 system, and I for
one have no reason to doubt him, the G1 has one major flaw that has
not been picked up by the various experts who have published
extensive reviews of the G1.
Had I known this at the time I was ready to buy I would have bought
a different camera. (Probably a Nikon 990/995)
One might ask why didn’t I notice this “flaw”
earlier? I have taken many in-focus pictures with the G1 because
the autofocus works adequately for many conditions considering the
very generous depth of fields associated with short focal length
lenses. In fact the focal length of most digital camera lenses are
so short, you could get by with fixed focus for many of your
routine shots. It is in those difficult shots where you most need
the autofocus as for example macros or views with both foreground
and distant objects in the field of view.
There are workarounds using contrast targets or switching between
digital zoom and manual focus (see discussion on botzilla.com ) but
these shouldn’t be needed with a camera of this quality.

Conclusion:
For most of us who have invested so much in the G1 it is a little
too late to do much about it. We will just have to learn how to
live with it and hope Canon will fix the problem on a subsequent
update. I doubt if it can be fixed without some hardware changes.
First Canon has to acknowledge that a problem even exists.
For those considering a G1, give this some thought before you buy.
There are cameras with better auto focus systems.
Don T

--
Donald T

Click to expand...

BryanS · Aug 7, 2001

Peter T said:
I think that in the first case it only appeared that the camera
focused on the dark gray box. I think what actually happens is that
when the camera can't find focus it focuses long which ends up
being the background.

This also could be a possibility. Without some sort of focus confirmation, it could definitely be happening this way.

On my EOS 630, I always know when I'm not getting focus, and in those cases, I recompose and get it to work properly. Without the green light and beep on the G1, I may squeeze off a picture when there isn't a focus and the imaginary crosshairs are pointed to a large patch of bare skin or something.

Bryan

BryanS · Aug 7, 2001

Kevin Bjorke said:
In fact, the page in question bears a typical photo. After many
struggles with the AF, not only in closeup but a variety of ranges,
that is the conclusion I reached.
http://www.botzilla.com/photo/G1focus.html

No intentions to flame, Kevin. In fact, I meant to add the smiley to the "he's full of it," but apparently those high characters don't appear in subjects.

Anyway, you have to expect some challenge to such a radical conclusion. Heck, trained monkeys would not design an auto-focus system that behaved the way you describe.

I looked at your photos, and have experienced the same thing in many frustrating situations. In fact, I've come to understand my autofocus target as being a little above center and slightly to the left. It appears yours may be the same.

It's frustrating even if it were in the absolute center without the ability to actually "see" focus as in an SLR. So many times for good photographers who know composition, no part of the primary subject may be in the center, and you have to remember to half-click, then recompose.

I'll look through my photos at home and will find a couple that demonstrate my problems just as you have. My opinion is that the greatest shortcomings of the G1 are that with it I can't tell which part of the image is in proper focus on the LCD and that I'm not warned when no focus could be found. The first isn't really a fault of the camera... and I could always buy a D30 to solve that one.

The second could be corrected in firmware, I would think, and would be a welcome change indeed... as would having a focus target that appears in the center of the LCD like on the EOS focus screens.

Bryan

nahau · Aug 7, 2001

Hi Peter,

I also took a bank of shots last night. I had no problem shooting macros in P mode, auto focus, but then many of my subjects were high contrast except for one which was an old yellow magic marker pen that had it's label wiped clean. The camera still captured the pen though. Just as an experiment for myself, I guess I will eventually have to shoot more flower type macros as it seems to be the most difficult for people to capture (from what I've read). I really don't have strong interest in macros although I do really like the many photos I've seen posted.

I like your theory of the camera focusing long. I wonder how true it is and if it can be proven. Don't know exactly how knowing that would help anything, but it is interesting. The next time my camera misses focus, I will look for what you describe. Maybe if enough people could read their EXIF data on missed focus shots, we could come up with some kind of conclusion on this. Again, I don't know how it would help anything though.
nahau

Peter T said:
I conducted the following experiment. I printed a light gray box on
white and placed it 22" from the lens. I printed a dark gray box on
white and placed it 52" from the lens and to the side. I shot at
f2.5 and zoomed out about halfway to minimize depth of field.

I centered the light gray box in the center and since there was no
contrast it was not in focus. The dark gray box was in focus.

Then I centered the edge between the light gray box and the white
paper(I used the focusing light for this). Even though the dark
gray box in the background presented higher contrast, the camera
focused on the light gray box because it presented sufficient
contrast.

I think that in the first case it only appeared that the camera
focused on the dark gray box. I think what actually happens is that
when the camera can't find focus it focuses long which ends up
being the background.

Peter T44178 · Aug 7, 2001

Try this: focus on something 2 or 3 feet away. Then quickly tap the shutter release so that autofocus starts but doesn't lock on. Press MF and you'll see that it is focused long every time.

For me the conclusion of my experiment is this. The G1 autofocuses pretty much like any camera. It requires good contrast. But it doesn't search the entire image looking for the area of greatest contrast. It only uses the middle of the image in trying to achieve focus.

If the G1 doesn't autofocus as well as some cameras then it is probably only because it requires more contrast to achieve focus.

nahau said:
I like your theory of the camera focusing long. I wonder how true
it is and if it can be proven. Don't know exactly how knowing that
would help anything, but it is interesting. The next time my
camera misses focus, I will look for what you describe. Maybe if
enough people could read their EXIF data on missed focus shots, we
could come up with some kind of conclusion on this. Again, I don't
know how it would help anything though.

Donald b Terrana · Aug 7, 2001

Peter T said:
How small a portion are you talking about? I did some tests and
didn't notice this.

It is not critical, but the object should not dominate the view. The idea is to see if the autofocus system will be able to differentiate between the the background and the object you want it to focus on. To do that it must limit its field of view to a small portion of the center of the view.

Peter T44178 said:
What did fake me out was that the G1 doesn't initiate autofocus
like other cameras I'm used to. With those cameras only a tap of
the shutter is required. Tapping the shutter on the G1 sets focus to infinity

I was not aware of this. I presume you mean to the hyperfocal point.
How did you come by this information?
.

With the G1 you have to keep the

Peter T44178 said:
shutter depressed for autofocus to work. And you have to use macro
mode when focusing really close.

You can avoid holding down the shutter release by pushing the manual focus button, read the manual for more info.

Regards,
Don T

Donald b Terrana · Aug 7, 2001

Peter T said:
Try this: focus on something 2 or 3 feet away. Then quickly tap the
shutter release so that autofocus starts but doesn't lock on. Press
MF and you'll see that it is focused long every time.

For me the conclusion of my experiment is this. The G1 autofocuses
pretty much like any camera. It requires good contrast. But it
doesn't search the entire image looking for the area of greatest
contrast. It only uses the middle of the image in trying to achieve
focus.
Peter,

Your description of how the G1 focuses is exactly what is being challanged. Keven , and many of us also, believe that the G1 has no capbility to narrow the field of view for the autofocus system, the way it does for the metering system.

The only way one can prove that the G1 does in fact limit its view of what to focus on is to show some examples of its ability focus tightly on a near by subject standing in front of an equally contrasty background.

All the good SLR film cameras can do this and one Canon SLR can actually use the takers eyeball to shift the area to focus on.

Regards,
Don T

Peter T44178 said:
If the G1 doesn't autofocus as well as some cameras then it is
probably only because it requires more contrast to achieve focus.

nahau said:

I like your theory of the camera focusing long. I wonder how true
it is and if it can be proven. Don't know exactly how knowing that
would help anything, but it is interesting. The next time my
camera misses focus, I will look for what you describe. Maybe if
enough people could read their EXIF data on missed focus shots, we
could come up with some kind of conclusion on this. Again, I don't
know how it would help anything though.

Click to expand...

Peter T44178 · Aug 7, 2001

Don T said:
Peter T said:

How small a portion are you talking about? I did some tests and
didn't notice this.

Click to expand...

It is not critical, but the object should not dominate the view.
The idea is to see if the autofocus system will be able to
differentiate between the the background and the object you want it
to focus on. To do that it must limit its field of view to a small
portion of the center of the view.

Did you see my message on the results of my autofocusing experiment?:
http://www.dpreview.com/forums/read.asp?forum=1010&page=1&message=1373026

Donald b Terrana said:
Donald b Terrana said:

What did fake me out was that the G1 doesn't initiate autofocus
like other cameras I'm used to. With those cameras only a tap of
the shutter is required. Tapping the shutter on the G1 sets focus to infinity

Click to expand...

I was not aware of this. I presume you mean to the hyperfocal point.
How did you come by this information?

It's just something I noticed. See this:
http://www.dpreview.com/forums/read.asp?forum=1010&page=1&message=1373476

Donald b Terrana said:
With the G1 you have to keep the

Donald b Terrana said:

shutter depressed for autofocus to work. And you have to use macro
mode when focusing really close.

Click to expand...

You can avoid holding down the shutter release by pushing the
manual focus button, read the manual for more info.

My point was that if you are used to another camera that only requires a tap of the shutter to establish autofocus and you then use that method on the G1 you won't get autofocus. And since there is no focus confirmation you won't necessarily know this.

Neal55306 · Aug 7, 2001

What problem are you talking about? The G-1 is the best digital camera made. You are either blind or just stupid if you think the G-1 has any focus deficiencies. There will never be a "G-2" because the G-1 is as good as it gets.

My advise: get glasses or just shut-up and live with it. You are the one with the problem. Don't bother us geniuses with your whining and complaints about an innocent piece of metal. Boy, what a 'tard you are.

Don T said:
I am embarrassed to admit that after owning my G1 or more than six
months it is only now that I have come to realize the G1’s
autofocus deficiency. This is no minor problem, unlike the magenta
overcast, which is easily fixed with an editing program. There is
no easy fix for a camera that has a very weak autofocus system.

Rather than explain the problem in my own words, please read the
exert that I have extracted from Kevin Bjorkes discussion on G1
autofocus (botzilla.com):
Autofocus
“The G1 appears to use a contrast-based AF system. It also
appears to use the entire frame to measure contrast. In other
words, the contrast of pixels along the edges and in the corners
are given just as much importance by the AF system as pixels near
the center.
This uncentered approach has serious consequences for autofocus use
on real scenes. While it's fine for landscapes and may even do well
for group shots, what about a head-and-shoulders portrait?

Canon's G1 manual mentions "autofocus crosshairs" on page 38, but
this is simply wrong they're in the optical finder and clearly have
nothing to do with the Autofocus. What's more, they may give you
the impression that the AF is concentrating on the area of the
crosshairs (like the "target marks" did on the previous Canon
design, the Pro 70) and that's simply not true

The Pro 90 also has a "target bracket" area, which might actually
do something (it's part of the EVF and LCD, not the optical
finder). But both the G1 and Pro 90 manuals claim weakness to
"Subjects with extremely low contrast to the surroundings." Even
the A20 has AF brackets why does the G1 have this crippled system?
Is it some failed prototype of the A20's AiAF ?”

If Kevin is correct in his evaluation of the G1 system, and I for
one have no reason to doubt him, the G1 has one major flaw that has
not been picked up by the various experts who have published
extensive reviews of the G1.
Had I known this at the time I was ready to buy I would have bought
a different camera. (Probably a Nikon 990/995)
One might ask why didn’t I notice this “flaw”
earlier? I have taken many in-focus pictures with the G1 because
the autofocus works adequately for many conditions considering the
very generous depth of fields associated with short focal length
lenses. In fact the focal length of most digital camera lenses are
so short, you could get by with fixed focus for many of your
routine shots. It is in those difficult shots where you most need
the autofocus as for example macros or views with both foreground
and distant objects in the field of view.
There are workarounds using contrast targets or switching between
digital zoom and manual focus (see discussion on botzilla.com ) but
these shouldn’t be needed with a camera of this quality.

Conclusion:
For most of us who have invested so much in the G1 it is a little
too late to do much about it. We will just have to learn how to
live with it and hope Canon will fix the problem on a subsequent
update. I doubt if it can be fixed without some hardware changes.
First Canon has to acknowledge that a problem even exists.
For those considering a G1, give this some thought before you buy.
There are cameras with better auto focus systems.
Don T

--
Donald T

Donald b Terrana · Aug 7, 2001

Peter T said:
Don T said:

Peter T said:

How small a portion are you talking about? I did some tests and
didn't notice this.

Click to expand...

It is not critical, but the object should not dominate the view.
The idea is to see if the autofocus system will be able to
differentiate between the the background and the object you want it
to focus on. To do that it must limit its field of view to a small
portion of the center of the view.

Click to expand...

Did you see my message on the results of my autofocusing experiment?:
http://www.dpreview.com/forums/read.asp?forum=1010&page=1&message=1373026
Peter,

Yes I saw this post and reread it several times , but am having difficulty understanding you setup and or your conclusions.

It is too bad we are not able to add simple sketches to our posts which would easily clearup issues like this.

Regards,
Don T

Peter T44178 said:
Peter T44178 said:

Peter T44178 said:

What did fake me out was that the G1 doesn't initiate autofocus
like other cameras I'm used to. With those cameras only a tap of
the shutter is required. Tapping the shutter on the G1 sets focus to infinity

Click to expand...

I was not aware of this. I presume you mean to the hyperfocal point.
How did you come by this information?

Click to expand...

It's just something I noticed. See this:
http://www.dpreview.com/forums/read.asp?forum=1010&page=1&message=1373476

Peter T44178 said:

With the G1 you have to keep the

Peter T44178 said:

shutter depressed for autofocus to work. And you have to use macro
mode when focusing really close.

Click to expand...

You can avoid holding down the shutter release by pushing the
manual focus button, read the manual for more info.

Click to expand...

My point was that if you are used to another camera that only
requires a tap of the shutter to establish autofocus and you then
use that method on the G1 you won't get autofocus. And since there
is no focus confirmation you won't necessarily know this.

BryanS · Aug 7, 2001

Neal said:
My advise: get glasses or just shut-up and live with it. You are
the one with the problem. Don't bother us geniuses with your
whining and complaints about an innocent piece of metal. Boy, what
a 'tard you are.

Oh, joy... Neal is back.

Peter T44178 · Aug 7, 2001

Don T said:
The only way one can prove that the G1 does in fact limit its view
of what to focus on is to show some examples of its ability focus
tightly on a near by subject standing in front of an equally
contrasty background.

Does this example work for you?

Bob H · Aug 7, 2001

Don T said:
I am embarrassed to admit that after owning my G1 or more than six
months it is only now that I have come to realize the G1’s
autofocus deficiency. This is no minor problem, unlike the magenta
overcast, which is easily fixed with an editing program. There is
no easy fix for a camera that has a very weak autofocus system.

Hi Don! Please forgive me if I am speaking "out of school" here, I am relatively new to photography (digital or otherwise) and may not really understand your concerns.

Some previewers of the G1 have pointed out the problems with it's metering system and Canon should address those concerns in future upgrades. However, the G1 can now be had for under $600 US dollars and I suspect under $500 very soon. Digital camera technology is expanding almost exponentially it seems and yesterday's wonder camera is viewed as mediocre today.

All that said, I think the G1 is an excellent camera for the price; even with it's inherent flaws (chromatic aberration included).

I guess my point is, (and maybe it's because I havn't developed enough of a discrimenating eye yet), but this may be "plenty" of camera for those like myself and as the price continues to drop, it may seem even more attractive in the future.

Bob Williams · Aug 7, 2001

Diane, excuse this bloom, as I was shooting trying to get a
good exposure, not trying to capture a good rose. This is
Mirandy. This is taken right at dark with a -2 EV. The color
is pretty good with minimal blooming of magenta. Levels
and USM applied. I can get deep pinks repeatedly now,
but the reds are still a challenge. I post them to a forum full
of rose nuts, so the colors have to be right. I did not adjust the
color at all, I just recovered a little light as the image was pretty
dark. After over 300 experimental shots, this is the best. When
the reds are blooming again, I will go back to the experiment.
This was also shot using the UV filter.

I suspect that the reason shade/lowlight and extreme -EV values
are needed is an IR problem, but I don't have an IR cut filter to
play with yet.

Diane B Fields said:
Diane B Fields said:

Diane B said:

to capture a show quality red rose, and I might throw the camera
at you

Click to expand...

This morning I played with the AE button, other things. I finally
got the red by dropping the EV a LOT. I went down a full -1, used
spot and got it with Av. I also got an excellent one--maybe the
better, with a manual mode shot (which is what I usually use). I
also used the flash whitepoint which was fine--

Click to expand...

Oh, meant to add that I was able to get the same 'true' red in
Photopaint for the earlier photo with not too much trouble. After
listening to an hour long NPR (local--we have an Ansel Adams 100th
Anniversary exhibit at Charlotte MInt Museum) program on Ansel
Adam's philosophies, ways of working/printing, etc.--I felt more
comfortable with processing the photo to meet my own
visual/creative ideas. Being a visual arts person, I'm very
comfortable with the idea of the original being the start of the
creative process.

Diane

Bob Williams · Aug 7, 2001

I deleted all of the really bad image where the mulch was the
focus point 5 feet behind the bloom. This one shows the same
effect, but it is not as bad, since it focused on the leaf, not the
bloom. I also have shots of this one where the focus worked on
a bud, and the same shot where the next shot did not work,
but focused eleswhere. All shots taken with a tripod, timer, and
care was taken to make sure the camera had the subject framed
properly. The camera consistantly focuses at the edges on things
that are darker and have more contrast. This is easily tested, and
the results are easily repeatable, at least with my camera. I can
repeat the same effect where it locks five feet behind the central
subject, using the contrast in the mulch to lock on to. I mean
sharp focus on the mulch. It is a known fault, and it is easy to
work around once you know it and start to watch for it, but the
problem does exist. I will shoot some good examples tomorrow.
I can't believe that so many people are arguing whether or not
this happens. I would have shot examples toady, but I had not
read these answers yet.

If you look at the red rose shot I posted for Diane, you will see the
same effect there, but that image had a mild unsharp mask applied.

Bob H said:
Don T said:

I am embarrassed to admit that after owning my G1 or more than six
months it is only now that I have come to realize the G1’s
autofocus deficiency. This is no minor problem, unlike the magenta
overcast, which is easily fixed with an editing program. There is
no easy fix for a camera that has a very weak autofocus system.

Hi Don! Please forgive me if I am speaking "out of school" here, I am relatively new to photography (digital or otherwise) and may not really understand your concerns.

Click to expand...

Some previewers of the G1 have pointed out the problems with it's
metering system and Canon should address those concerns in future
upgrades. However, the G1 can now be had for under $600 US dollars
and I suspect under $500 very soon. Digital camera technology is
expanding almost exponentially it seems and yesterday's wonder
camera is viewed as mediocre today.
All that said, I think the G1 is an excellent camera for the price;
even with it's inherent flaws (chromatic aberration included).
I guess my point is, (and maybe it's because I havn't developed
enough of a discrimenating eye yet), but this may be "plenty" of
camera for those like myself and as the price continues to drop, it
may seem even more attractive in the future.

Peter T44178 · Aug 7, 2001

Member said:
Member said:

I can repeat the same effect where it locks five feet behind the central

Click to expand...

subject, using the contrast in the mulch to lock on to.

That will only happen if the flower and the mulch are both in the center of the image. I suggest initially framing the shot so that you only see the flower and then lock focus with MF. Then reframe to get the composition you want.

BryanS · Aug 7, 2001

Bob Williams said:
I will shoot some good examples tomorrow.
I can't believe that so many people are arguing whether or not
this happens. I would have shot examples toady, but I had not
read these answers yet.

Gee, I can hardly wait to see more of your "samples." One wonders why your G1 didn't focus on the most contrasty part of the scene... the bud in the background, if it behaves the way you suggest. In fact, the leaf in the foreground had to be the lowest contrast area of the photo.

Bryan

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