manual focusing


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htthach

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Feb 26, 2006
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dover
#1
hi,

- when i do manual focusing, the image look through the view finder is sharp, but image come out blur.

- when i do auto focus, some time image through view finder blur but the image come out sharp
AND of course also, some time image through view finder sharp, image come out also sharp.

for some scene with very low light (that need long shutter), and the auto focus cannot work (too dark), these case i must use manual, but it seems that what is see not really wat i'll get.

what is the problem here? did i miss something ?
 

lsisaxon

Senior Member
Nov 29, 2004
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#3
htthach said:
hi,

- when i do manual focusing, the image look through the view finder is sharp, but image come out blur.

- when i do auto focus, some time image through view finder blur but the image come out sharp
AND of course also, some time image through view finder sharp, image come out also sharp.

for some scene with very low light (that need long shutter), and the auto focus cannot work (too dark), these case i must use manual, but it seems that what is see not really wat i'll get.

what is the problem here? did i miss something ?
Didn't someone ask this question before? There's a whole list of answers in that thread.
http://forums.clubsnap.org/showthread.php?t=180640
 

htthach

New Member
Feb 26, 2006
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#5
thanks
sorry i didn't know that

btw, i'm using canon 10D
 

#8
this problem could also be due to your poor eyesight.
if you dont have a 6/6 vision, you will focus based on what YOU think is sharp


same concept goes for microscopy
especially since it magnifies the object by so much

i notice that whenever someone comes after me to use the microscope, they will ALWAYS readjust the sharpness.

my 2 cents
 

lsisaxon

Senior Member
Nov 29, 2004
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#12
htthach said:
hi,

- when i do manual focusing, the image look through the view finder is sharp, but image come out blur.

- when i do auto focus, some time image through view finder blur but the image come out sharp
AND of course also, some time image through view finder sharp, image come out also sharp.

for some scene with very low light (that need long shutter), and the auto focus cannot work (too dark), these case i must use manual, but it seems that what is see not really wat i'll get.

what is the problem here? did i miss something ?
What you can do is this..
1) perform AF,
2) adjust the diopter adjustment until the the image is sharpest.
3) perform a MF again, see whether you are able to get it correct this time.

If still cannot, then you do these.
1) put a ruler on a table,
2) set the camera on a tripod to shoot the ruler at 45 degrees,
3) perform AF at a known marking, eg 10cm. and take a picture with aperture at max.
4) See whether you notice if somewhere else is sharp on the viewfinder instead.
5) perform MF and shoot. From the image check if the actual focus is in front or behind.

For this case, you may need to send the camera for calibration.
 

ricohflex

Senior Member
Feb 24, 2005
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#13
mirror out of alignment, easy to check, send to repairer
when sharp in VF and sharp in photo, the depth of field due to small aperture saved the day
 

lsisaxon

Senior Member
Nov 29, 2004
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#14
haagen_dazs said:
this problem could also be due to your poor eyesight.
if you dont have a 6/6 vision, you will focus based on what YOU think is sharp


same concept goes for microscopy
especially since it magnifies the object by so much

i notice that whenever someone comes after me to use the microscope, they will ALWAYS readjust the sharpness.

my 2 cents
Microscopy is different because there is no focusing screen but a direct optical path, so the eyepeice focus is also dependent on your eye. Same with telescopes. For SLR is different, the focusing screen will prevent the light from focusing at other points, so if the diopter is wrong, you should not be able to obtain any sharp image at all.
 

htthach

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Feb 26, 2006
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#16
lsisaxon said:
What you can do is this..
1) perform AF,
2) adjust the diopter adjustment until the the image is sharpest.
3) perform a MF again, see whether you are able to get it correct this time.

If still cannot, then you do these.
1) put a ruler on a table,
2) set the camera on a tripod to shoot the ruler at 45 degrees,
3) perform AF at a known marking, eg 10cm. and take a picture with aperture at max.
4) See whether you notice if somewhere else is sharp on the viewfinder instead.
5) perform MF and shoot. From the image check if the actual focus is in front or behind.

For this case, you may need to send the camera for calibration.
the diopter is set to 0
my eyes are okie, i'm not short sighted

oh no, must send for repair ? :-s just bought this second hand :-s
hopefully nothing wrong with the cam, or else maybe i'll just leave it like that, make it up to the AF :))
 

lsisaxon

Senior Member
Nov 29, 2004
11,941
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0
#17
htthach said:
the diopter is set to 0
my eyes are okie, i'm not short sighted

oh no, must send for repair ? :-s just bought this second hand :-s
hopefully nothing wrong with the cam, or else maybe i'll just leave it like that, make it up to the AF :))
It probably needs some calibration. The previous company I worked in bought a D70 about 2 years back and I had to calibrate the mirrors a little. Both the AF and focusing screen distances were a bit off the sensor. Since it was a semiconductor related establishment, I was able to use the microscopes to micro align the mirrors for the AF sensor and the focusing screen. Now the camera's focusing, both AF and MF, are spot on. Too bad the camera belongs to the company.

I was also able to verify the calibration for my own D70s which I bought later the same way. But it was good enough and I didn't have to do anything.
 

htthach

New Member
Feb 26, 2006
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#18
how to do the calibration thing?
today brought my cam to TCW. I buy a filter, and ask the guy there to check for my what happen to my cam. Try different lens also like that. The guy at first also try to adjust the diopter but also cannot. Then he also dunno how, he giv to an old man, also dunno why.
then how? how to repair the problem?
 

htthach

New Member
Feb 26, 2006
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#20
just brought to canon today
they said something inside get out of place and they fixed it
free of charge
:D
thanks you guys
 

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