Quote:
Originally Posted by Leo.G
Thank you but I soon found with the one video I found on the 85mm the lens construction was very different to the 35mm when I stripped it to try and fix it.
I haven't searched for the 14mm since I got it replaced under warranty, only the 35mm but I have just searched and found mention numerous times but haven't yet checked if any of the discussions show the fix or point to a video which does. I'll go have a look now though.
I would have thought since it focuses on the DX format D80 and the FX format Canon 5D (with adapter which may make the difference) it should focus on the D810 but no matter what I do and how long I spend playing with the focus the stars are very out of focus. At first I was blaming star drift as the problem but even a 10 second exposure produces the same results so it's definitely a focus thing.
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If your 14mm lens reaches infinity focus and gave nice sharp stars on the DX Nikon D80 it should also reach similar infinity focus on the FX Nikon D810 as they are both Nikon F-mount cameras and both have the same nominal flange focal distance of 46.5mm. Perhaps your D810 has been modified or has had a sensor change and requires adjustment{?} of the flange focal distance, or maybe it's an unfortunate stack up of tolerances between the cameras and lens.
Quote:
Originally Posted by Leo.G
Using live view I've done everything and at high magnification levels I get a lot of noise, much like a grainy video stream and it's terribly hard to pick what's in focus, even using the moon.
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Using live view is a good first option to get in the zone, but if you want to check focus more critically take a test image and zoom in.
The moon is about 1/2 a degree wide and shooting a 14mm focal length on full frame should result in an image scale around 60 to 70 arc seconds/pixel, so the Moon should be some 25 to 30 pixels wide so should be able to be discerned, depending on the screen resolution on the D810 and the image resolution you are shooting in. Perhaps instead of using the magnify feature within live view you could try an optical magnifier of some type and experiment with ISO to try and get a bright live view image.
Best
JA