Small circle mark in 18~105 kit lens
- Thread starter bumperbees
- Start date
bumperbees
Member
Mine the same with u but when NSC put their lens which I do not know which model it show the marks, so I know it's not something that is serious.
chanjyj
New Member
Because your EYE is unable to focus on that "spot" when you are using lenses. Your eye is focusing on the image that appears at the distance the lens is focused for.To view the "spot" you have to the entire image has to be unfocused so your eye can focus on the spot (which is darned near to your eye actually). Your eye is simply not used to focusing on something 2cm infront of you.
Try using your lenses and pointing them at a white cloud. The whole viewfinder must be covered by the cloud, which is WHITE. Then bring the image OOF. You may see the "spot".
But then TS said when using the 50/1.8D, the spot is not visible. Unless the larger aperture allows enough light in to be 'blinding', thus cannot see the spot
Otherwise I'm confused
ZerocoolAstra
Senior Member
chanjyj said:
To view the "spot" you have to the entire image has to be unfocused so your eye can focus on the spot (which is darned near to your eye actually). Your eye is simply not used to focusing on something 2cm infront of you.
Try using your lenses and pointing them at a white cloud. The whole viewfinder must be covered by the cloud, which is WHITE. Then bring the image OOF. You may see the "spot".
I get what u mean.
But then the TS' point abt the spot appearing when kit lens used, can't be explained away w this.
So I am really confused
bumperbees
Member
It's alright anyway, the spot or mark does not affect the image but just that sometime when u see the spot u don't get used to it like the lens is faulty but In actual facts it's alright.
chanjyj
New Member
I get what u mean.
But then the TS' point abt the spot appearing when kit lens used, can't be explained away w this.
So I am really confused
dimmer viewfinder due to larger aperture = more contrast between viewing screen and virtual image?
It is normal.
You can see the circle here... it is very faint. http://forums.dpreview.com/forums/read.asp?forum=1034&message=34813934
My guess, it is caused by the mirror. For what purpose? I am not very sure. But the mirror in a DSLR is not just a simple mirror, parts of it is translucent for the AF to work... etc.. Here is a view of the internals.
You can see the circle here... it is very faint. http://forums.dpreview.com/forums/read.asp?forum=1034&message=34813934
My guess, it is caused by the mirror. For what purpose? I am not very sure. But the mirror in a DSLR is not just a simple mirror, parts of it is translucent for the AF to work... etc.. Here is a view of the internals.
ZerocoolAstra
Senior Member
hmmmmm :think:
eh, but larger aperture lens will give a brighter image in the VF. Noticeable difference (to me) when I mount 35/1.8G vs 18-105.
aiyoh... headache thinking about this
ZerocoolAstra
Senior Member
ok ok... sounds plausible.
hawthorne907
New Member
Sorry but that is factually incorrect. Pupils contract in bright light and dilate in dark surroundings to let more light in. Cheers!
chanjyj
New Member
Wrong way round... ah. Lack of sleep these few days lol
tsk. now that i've become aware of it ... i see it everyday!
it's right smack in the middle of the kit lens, haven't noticed before because of the AF marker set on my center focus point.
it is the same with the little faint line that connects the center AF point. not very noticeable. But once you know, you see it.
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