What's causing the poor image quality?


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Mar 14, 2005
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#1
i tried taking pics of the 3/4 moon outside my place and i noticed the poor image quality even on the LCD which i confirmed on my computer. weird thing is, later images were of slightly better quality.

the only settings changed were from P to M mode and exposure settings.

first pic is an example of the bad pic

last 2 were the better ones but still bad to me...






 

deckard

New Member
Oct 13, 2006
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#5
he is most probably using a nikon camera.
 

Mar 14, 2005
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#11
it's a D70s with 70-300mm VR lens.

all images shot at 300mm
1st shot
f5.6 1/200
EV +0.7 iso 200
optimize image: vivid WB cloudy -3
color mode: mode IIIa
tone comp: auto hue adjustment: 0
saturation: normal sharpening:auto


2nd shot
f8 1/250
EV +0.7 iso 200
optimize image: vivid WB cloudy -3
color mode: mode IIIa
tone comp: auto hue adjustment: 0
saturation: normal sharpening:auto

3rd shot
f8 1/320
EV +0.7 iso 200
optimize image: vivid WB cloudy -3
color mode: mode IIIa
tone comp: auto hue adjustment: 0
saturation: normal sharpening:auto
 

Rashkae

Senior Member
Nov 28, 2005
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#12
Hmmm. Even if you're using a VR lens, did you use a tripod?

Also, 300mm is not really good enough for crisp, sharp moon shots.

I would disable your vivid color setting, as this tends to blow some highlights and is not useful for non-colorful targets like the moon.
 

dejected

New Member
Mar 26, 2006
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east!
#13
try using a tripod and a very slight faster shutter speed...
 

Mar 14, 2005
576
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#14
yeap.. i am using a tripod.

ok will try removing vivid cols.
 

RtOaNn

New Member
Mar 3, 2004
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Hougang
www.flickr.com
#15
Use the timer or the remote to minimise handshake while triggering the shutter.
Since at 300mm, any handshake is magnified.

Try shooting at smaller apertures for more DoF but when you do a 100% crop, some details are lost too. Maybe that's why you thought the image quality is poor since the moon didn't appear sharp to you.
 

Mar 14, 2005
576
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#16
Use the timer or the remote to minimise handshake while triggering the shutter.
Since at 300mm, any handshake is magnified.

Try shooting at smaller apertures for more DoF but when you do a 100% crop, some details are lost too. Maybe that's why you thought the image quality is poor since the moon didn't appear sharp to you.
100% crop as in crop the photo at 100%size ?

when viewed on the camera's lcd and on the computer's the quality was already like that before i cropped or anything.
 

PsychoV

New Member
Aug 14, 2006
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#17
it's a D70s with 70-300mm VR lens.

3rd shot
f8 1/320
EV +0.7 iso 200
optimize image: vivid WB cloudy -3
color mode: mode IIIa
tone comp: auto hue adjustment: 0
saturation: normal sharpening:auto
Maybe try using ISO100?
On a clear night, the moon is very bright, ISO100 should be enough.
 

lsisaxon

Senior Member
Nov 29, 2004
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#18
i tried taking pics of the 3/4 moon outside my place and i noticed the poor image quality even on the LCD which i confirmed on my computer. weird thing is, later images were of slightly better quality.

the only settings changed were from P to M mode and exposure settings.

first pic is an example of the bad pic

last 2 were the better ones but still bad to me...


http://img.photobucket.com/albums/v215/tarui/moon_4009.png
http://img.photobucket.com/albums/v215/tarui/moon_4018.png
http://img.photobucket.com/albums/v215/tarui/moon_4019.png
A likely reason is the presence of high clouds which you cannot see with your naked eye. This happens all the time to astrophotography especially in SG where clouds prevail.

Since you used 70-300 on D70s, your images are probably cropped and your lens may not be sharp enough to resolve the moon surface also. The difference in quality you obtained with P mode and M mode may be due to the aperture in use also. Selecting f/8 or f/11 may give you a better image since most lenses are slightly better when stopped down a couple of stops.

For example, this moon below is shot with D2X using 300/4 and resized to show the entire frame and the relative size of the moon within the frame. It's quite small.


This is the crop. As you can see, even with more megapixels from the D2X, because the magnification due to the cropping is tremendous, the image is not really sharp because the lens was not able to resolve.



This is the entire frame resized shot with D2X through a 1250mm SCT telescope around the same time. It already has so much more detail than the 300/4 because the lens is designed to give this kind of magnification.


A crop from this image would yield something like this.. you can see that the focus is not spot on and there is some camera shake also. Again, this is pushing beyond the limits of the telescope.


The absence of clouds helps in both cases, shot within minutes of each other.
 

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