Zoom in or crop?


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TroyP

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Dec 23, 2008
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#1
I have a Nikon D90 with 18-105mm lens.

I'm standing at a certain location (eg Marina Barrage) and i'm taking a distant pic of say, The Singapore Flyer...
If my desired image only occupies 1/4 of your display at 18mm, do I zoom in so the image occupies 100% of your display? Or do I leave it at 1/4 then crop on the PC/Cam?

Im just wondering if the quality is affected from lens zoom :think:
 

Anson

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Jul 31, 2006
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ansonchew.com
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#2
I have a Nikon D90 with 18-105mm lens.

I'm standing at a certain location (eg Marina Barrage) and i'm taking a distant pic of say, The Singapore Flyer...
If my desired image only occupies 1/4 of your display at 18mm, do I zoom in so the image occupies 100% of your display? Or do I leave it at 1/4 then crop on the PC/Cam?

Im just wondering if the quality is affected from lens zoom :think:
I think it would be easily to comment if we could see the photo.. :)
 

V

vince123123

Guest
#3
Generally, zooming in gives you better quality. But it also depends on what is your output requirement. If you are only going to use 1/4 of the frame anyway, then you can do away with zooming in. Zooming in on your 18-105 results in a lower f stop and thus you need mroe light.

Another side effect is perspective. 18mm gives a different perspective from 105mm. Hence, the answer may not always be that simple.

I have a Nikon D90 with 18-105mm lens.

I'm standing at a certain location (eg Marina Barrage) and i'm taking a distant pic of say, The Singapore Flyer...
If my desired image only occupies 1/4 of your display at 18mm, do I zoom in so the image occupies 100% of your display? Or do I leave it at 1/4 then crop on the PC/Cam?

Im just wondering if the quality is affected from lens zoom :think:
 

navlem

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Sep 16, 2007
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#4
If you zoom you are keeping the megapixels, when you crop you are essentially cutting out all the rest of the megapixels except for those pixels for the cropped part.

Correct me if im wrong.
 

zac08

Senior Member
Feb 21, 2005
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East
#5
Zoom... if the perspective is what you desire.
 

ahbian

Senior Member
May 23, 2006
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#6
In order of preference, if you need to fill up a frame

1) walk closer loh
2) zoom
3) crop
 

Octarine

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Jan 3, 2008
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Pasir Ris
#7
Different focal length has different effect on perspective. It not only affects the main object but also how the background and surrounding looks in relation to the main object.
 

TroyP

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Dec 23, 2008
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#8
If you zoom you are keeping the megapixels, when you crop you are essentially cutting out all the rest of the megapixels except for those pixels for the cropped part.

Correct me if im wrong.
That makes sense to me in theory, but I'm not sure if its true in the camera world LOL.
 

giantcanopy

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Feb 11, 2007
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#10
That makes sense to me in theory, but I'm not sure if its true in the camera world LOL.
If your worry is regarding IQ, we are not talking about digital zoom unlike that of point and shoot. Zooming from 18mm to 105mm is optical zoom.

Simply by just talking about image quality and resolution, a shot well taken at 105mm will be much better than cropping out that tiny bit of an 18mm and blow up to proportional size.
Ryan
 

An drew

Senior Member
May 27, 2005
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#11
Generally optical zoom will be better than digital zoom or crop.
 

Atarandas

Senior Member
Aug 19, 2008
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#12
Correct me if I am wrong . I thought simply changing focal lengths when zooming but remaining on a same spot doesnt change the persepctive ?

So technically if u stand at a spot at marina barrage and shoot with a 18-200mm at 120mm , versus u stand at same spot and shot at 24mm, the perspective of ur picture will be the same , just that the space between objects in the 24mm would sppear smaller and you can pick up more details. :think:
 

calebk

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Jul 25, 2006
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Clementi
#13
Correct me if I am wrong . I thought simply changing focal lengths when zooming but remaining on a same spot doesnt change the persepctive ?

So technically if u stand at a spot at marina barrage and shoot with a 18-200mm at 120mm , versus u stand at same spot and shot at 24mm, the perspective of ur picture will be the same , just that the space between objects in the 24mm would sppear smaller and you can pick up more details. :think:
Nope. At shorter focal lengths, you see more in the frame, and perspective is exaggerated. This means that closer elements in the frame appear much larger than objects further away in the frame.

With long focal lengths, you usually see less in the frame, and perspective is more compressed. This means to say that items of similar size but different distance do not vary that much in relative size on the final image.
 

Dec 31, 2004
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Yishun
#14
Correct me if I am wrong . I thought simply changing focal lengths when zooming but remaining on a same spot doesnt change the persepctive ?

So technically if u stand at a spot at marina barrage and shoot with a 18-200mm at 120mm , versus u stand at same spot and shot at 24mm, the perspective of ur picture will be the same , just that the space between objects in the 24mm would sppear smaller and you can pick up more details. :think:
just that the space between objects in the 24mm would sppear smaller
is this not a change in perspective? generally a telephoto lens 'compresses' the background ...
 

Anson

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Jul 31, 2006
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#16
Correct me if I am wrong . I thought simply changing focal lengths when zooming but remaining on a same spot doesnt change the persepctive ?

So technically if u stand at a spot at marina barrage and shoot with a 18-200mm at 120mm , versus u stand at same spot and shot at 24mm, the perspective of ur picture will be the same , just that the space between objects in the 24mm would sppear smaller and you can pick up more details. :think:
You may get barrel & pincushion distortion in different focal length...
 

Atarandas

Senior Member
Aug 19, 2008
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#17
Hmm because I thought the smaller spaces is purely magnification. U use a zoom , its gets magnified. The perspective remains the same untill we shift our positions. Maybe its how we define perspective heh
 

Reportage

Senior Member
Nov 24, 2008
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#18
I have a Nikon D90 with 18-105mm lens.

I'm standing at a certain location (eg Marina Barrage) and i'm taking a distant pic of say, The Singapore Flyer...
If my desired image only occupies 1/4 of your display at 18mm, do I zoom in so the image occupies 100% of your display? Or do I leave it at 1/4 then crop on the PC/Cam?

Im just wondering if the quality is affected from lens zoom :think:
zoom is easier then crop most of the time unless your megapixel count is very high for the print size you need.
 

chestertim

New Member
Feb 15, 2007
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www.pbase.com
#19
Digital zoom is effectively cropping and resizing in-camera in one step. If you are so far away from your subject that you need to do this then don't bother; go and find a worthwhile composition within range. Digital zoom is snake oil.
 

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