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07-20-2013, 07:42 AM   #1
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samyang 8mm won't focus anymore

since two years I have this 8mm fun-lens by Samyang.
However recently it will only be sharp at very close range. No matter what I try on the parameters.
I shoot with a K5, even tried resetting the camera to factory-settings.
am I missing something ?

07-20-2013, 08:18 AM   #2
Ole
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This lens is manual focus, so resetting the camera has no effect.

What happens when you turn the focusing ring on the lens? Has it somehow become lose so that it doesn't drive the focusing mechanism anymore?
07-20-2013, 08:37 AM   #3
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your guess is a good one, Ole.
However, the lens appears as solid as ever. Then there was never much (difference) to see when looking through the finder and turning the focussing wheel.
07-20-2013, 08:44 AM   #4
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You should be able to see a slight gap between the hood and focusing ring at MFD, no gap at infinity. If you're not seeing this, then the screws probably loosened up.

There are 3 very small flat head screws under the rubber ring, you can fold the rubber back on itself carefully, the screws are towards the front of the lens so fold the rubber from the front towards the back. There is also a phillips head screw, ignore that one. Since you are most likely near MFD, bring the ring to that point and try to gently tighten the screws. Make sure it is actually focusing now.

To actually calibrate it, you'll need a tripod and preferably a body with a split prism focusing screen. Put the lens at infinity, if a distant object is sharp, then you don't have to do anything. If it isn't sharp, loosen those 3 screws back up, bring the ring to somewhere in the middle and tighten them again. Now try to focus on a distant object, once you are happy that it is sharp at infinity, loosen the screws yet again, put the ring at the infinity mark and tighten the screws.

07-20-2013, 08:47 AM   #5
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I recently bought one of the variants of this lens.

I found using liveview zoomed in(push ok in LV then back wheel I think) I can see where the focus plane is. I usually set it around 5 ft mark and stop it down everything gets pretty sharp. Wide open I've gotten sharp enough shots but mine really gets sharp about f8-11
07-20-2013, 10:12 AM   #6
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I just tried tightning the three flat screws, still they seemed OK.
here's the difference, the gap that Elliot mentioned
it's rather minimal, but has always been like that , if I remember it well




however, while handling the lens I noticed a 'wobble' from within, there is actually something loose on the inside.
Where do I start best to dismantle ?
Or should I loossen the 3 flat screws and try to reset the focussing ring ?
07-20-2013, 12:39 PM   #7
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The top picture shows the gap at infinity? My hood comes much closer to the focus ring, so yours may need adjustment.
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