nikon 50mm f1.8 problem again


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feetless

New Member
Mar 31, 2008
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#1
Hey guys! i've been using this prime for some time. but i got one issue. in f1.8. yes i know the bokeh is good.
but some part of the image that im focusing on isn't sharp because of the DOF issue.
i really need some here on how to fully utilise the f1.8 well.


here is an example i took.
im using an external flash. 1/160sec f1.8

please take a look and help me!

here's the actual size pic. sorry for posting such big pic, but the flaw can only be seen
clearly in this size.


ps. could it be im too close to the subject?
 

GadgetGod

New Member
Jan 27, 2007
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#2
I wanna know too! I've heard everyone raving about the sharpness of the 50mm F1.8 but i can never get it sharp too! I get results like you do so ur not the only one. I thought it was the ISO cuz we're generally shooting in a dark environment if we open it up to F1.8. Like you i thought it was handshake and reduced the shutter time to minimize that but still didnt work. Are you using the D80 as well?
 

kcuf2

Senior Member
Dec 29, 2005
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#3
for new users of the f1.8, such problems are commonly encountered. the problem also get worst with f1.4, f1.2 or f1.0 lens. In a sense, most people always say that fast lenses are good, but these people always never mention the difficulties of shooting with these exotic lenses.

To appreciate these lenses fully, u just have to remember one thing, always aim at the eyes of the subject. meaning, the cross hair in ur camera viewfinder should be like a missile that is locked on the eye.

When the eye is sharp and focused, the whole object would be sharp. this is the also the golden rule of shooting animals.

look at this pic:



It definitely looks like its a very sharp photo. This is because the eye of the bird is correctly focused. If u look carefully at the neck, the body and tail and legs, u will notice that the whole body is blur due to the fast apeture, but because the eyes is sharp, ppl will think the whole picture is sharp.

look at this white bird:



it doesnt look sharp at all!! BUT, if u look carefully, the whole body is sharp, only the eye head region is not sharp. BUT, human brains are always fooled by the eyes, eyes not sharp, eyes not focued = pic is not sharp!


go and shoot ur baby again, i think u know wat to do now ;p
 

JacePhoto

Senior Member
Oct 1, 2007
6,484
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www.flickr.com
#4
I have the same problem.

I think its the calibration problem. I aim at the eyes (camera confirms its sharp through its autofocus) and the hair (above the head) becomes sharp. I aim at the hair, and the eyes become sharp.

I am gg to try to calibrate the lens using the D300 feature soon. I hope it will help.

Otherwise, the 50 1.8 is truly an amazing lens, especially for low light and portraits. My fav.
 

ninelives

Senior Member
Jan 16, 2002
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#5
feetless, where did you focus on(nose, eyes, lips?)?? how far is the subject. if the subject is 1 m away, your total DOF will be 3cm, meaning anything 3cm further away from the subject will not be sharp. which also mean, if you focus on the lips, the ears and further away will be OOF.

try this calculator, it gives a rough idea to user why their photo is not sharp.

http://www.dofmaster.com/dofjs.html
 

ZerocoolAstra

Senior Member
Mar 13, 2008
9,522
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#6
Hey guys! i've been using this prime for some time. but i got one
issue. in f1.8. yes i know the bokeh is good.
but some part of the image that im focusing on isn't sharp because of the DOF issue.
i really need some here on how to fully utilise the f1.8 well.

.
.
.

ps. could it be im too close to the subject?
With f1.8, your depth-of-field is very short when your subject is within 1-3m from you. The closer you are to the subject, the shorter the DOF. Can consider stopping down (f2.8 or 3.5) or standing a little further and then cropping as necessary, if you don't want such a short DOF.
 

ninelives

Senior Member
Jan 16, 2002
3,248
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ninelives.clubsnap.org
#7
feetless, where did you focus on(nose, eyes, lips?)?? how far is the subject. if the subject is 1 m away, your total DOF will be 3cm, meaning anything 3cm further away from the subject will not be sharp. which also mean, if you focus on the lips, the ears and further away will be OOF.

try this calculator, it gives a rough idea to user why their photo is not sharp.

http://www.dofmaster.com/dofjs.html
also, you can to the battery test.

put 3 batteries 2 cm apart, :

0
---0
------0

focus on the center on, if the back battery is sharp, you are having back focus problem, if front is sharp , you are having front focus problem. if everything is soft, it could be your "prime" lens is soft a wide aperture.......
 

ymmij

New Member
Dec 4, 2005
264
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#8
this is a good discussion as i also own a 50mm 1.8 but many a times failed to get really sharp photos. they turn out to be rather soft. maybe because i did not focus well.
 

zac08

Senior Member
Feb 21, 2005
11,755
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#9
this is a good discussion as i also own a 50mm 1.8 but many a times failed to get really sharp photos. they turn out to be rather soft. maybe because i did not focus well.
DOF is very thin... you need to focus properly... just a lil miss will get the picture soft and out of focus..
 

GadgetGod

New Member
Jan 27, 2007
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#10
I am quite positive that i focused the eye too but an interesting thing to note is that i do notice the same phenomenon on my tamron 28-75 as well so maybe it might really be abt where ur focusing....
 

clioboy

New Member
May 25, 2008
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#11
Here is an example of what has been mentioned

 

#12
I wanna know too! I've heard everyone raving about the sharpness of the 50mm F1.8 but i can never get it sharp too! I get results like you do so ur not the only one. I thought it was the ISO cuz we're generally shooting in a dark environment if we open it up to F1.8. Like you i thought it was handshake and reduced the shutter time to minimize that but still didnt work. Are you using the D80 as well?
phew... good to know im not the only one. sometimes i thought my lens spoil. haha. yeah,
im using a D80 :D

for new users of the f1.8, such problems are commonly encountered. the problem also get worst with f1.4, f1.2 or f1.0 lens. In a sense, most people always say that fast lenses are good, but these people always never mention the difficulties of shooting with these exotic lenses.

To appreciate these lenses fully, u just have to remember one thing, always aim at the eyes of the subject. meaning, the cross hair in ur camera viewfinder should be like a missile that is locked on the eye.

When the eye is sharp and focused, the whole object would be sharp. this is the also the golden rule of shooting animals.

look at this pic:

-

It definitely looks like its a very sharp photo. This is because the eye of the bird is correctly focused. If u look carefully at the neck, the body and tail and legs, u will notice that the whole body is blur due to the fast apeture, but because the eyes is sharp, ppl will think the whole picture is sharp.

look at this white bird:

-

it doesnt look sharp at all!! BUT, if u look carefully, the whole body is sharp, only the eye head region is not sharp. BUT, human brains are always fooled by the eyes, eyes not sharp, eyes not focued = pic is not sharp!


go and shoot ur baby again, i think u know wat to do now ;p
thanks bro for ur effort to explain. i know what to do now. hehe, but i will have to wait till
my baby wakes up.;p will try again and post some shots again!

feetless, where did you focus on(nose, eyes, lips?)?? how far is the subject. if the subject is 1 m away, your total DOF will be 3cm, meaning anything 3cm further away from the subject will not be sharp. which also mean, if you focus on the lips, the ears and further away will be OOF.

try this calculator, it gives a rough idea to user why their photo is not sharp.

http://www.dofmaster.com/dofjs.html
hi bro, i think im within the 1m distance. i think when i'm taking the photo, my baby moved,
so i am not really sure did i focus on her eyes.;p
 

DeadEnd

New Member
Nov 24, 2006
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#14
You are taking the picture at the wide open aperture of f1.8. Most budget lens are soft at the wide open aperture. Try to stop down further if you want a sharper picture.
 

dark72

New Member
Nov 22, 2007
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#16


Taken at 1.8.

My focus was on the wire, but it is actually not really that sharp (when you see it in original file). But when i stop down to about 2.2 or 2.5 it's much better.
 

GadgetGod

New Member
Jan 27, 2007
106
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#17
My F1.8 50mm can be sharp i know it cuz if i do some perspective shot it WILL be sharp at some point but it never is when i actually use it to shoot. It doesn't help that i usually use it when i NEED the aperture (aka dark environment) which exacerbates the problem as it usually comes wth ISOs exceeding 800. Somehow whenever i do test shots with the lens it is ALWAYS sharp... it just doesnt seem to wrk when i need it to.
 

zac08

Senior Member
Feb 21, 2005
11,755
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0
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#18
My F1.8 50mm can be sharp i know it cuz if i do some perspective shot it WILL be sharp at some point but it never is when i actually use it to shoot. It doesn't help that i usually use it when i NEED the aperture (aka dark environment) which exacerbates the problem as it usually comes wth ISOs exceeding 800. Somehow whenever i do test shots with the lens it is ALWAYS sharp... it just doesnt seem to wrk when i need it to.
When testing you should be doing it in a controlled environment and you should be using it on a tripod for maximum stability.

But out in the field or actual usage, you should be encountering low light and also speedy reaction, thus the factor for getting slight movement blur is common, either from user or subject.
 

photobum

Deregistered
Apr 17, 2005
3,068
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#19
Here is my suggestion. When shooting portraiture at f1.8 or lower, switch to manual focus. Focus on the subject's eyes.
 

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