10 stop filter focus

Started Nov 19, 2012 | Questions thread
jkjond
Veteran MemberPosts: 6,661
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Re: 10 stop filter focus
In reply to primeshooter, Nov 19, 2012

primeshooter wrote:

gl2k wrote:

primeshooter wrote:

jkjond wrote:

primeshooter wrote:

Now I am aware of what is called focus shift due to spherical abberation when a lens is focused wide open. My question is, does it matter when I am stopping down to such tiny apertures? My results seem to be sharp most of the time at 100% on the subject which I am focusing. Unless the sand moves or something...

Your camera always focuses at max aperture then stops down to take the shot whether you have a filter mounted or not.

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UK wedding photographer in the Lake District
http://www.johnleech-weddingphotography.co.uk
For my landscapes and fine art photography:
http://www.johnleechstudio.co.uk

I did wonder this. So why are people so concerned about focus shift in a lens? Does it not apply here with me focusing through the 10 stop? I always get the box turning green - confirming focus is achieved, or do this manually THEN stop down.

Nobody is really concerned about focus shift.

It is only a problem on fast lenses on rather short distances. Otherwise it's totally neglectable. It creates headache to all those weirdos doing their focus tests and having no clue how their gear behaves in real world scenarios.

Thanks to both for replying. So there is no issue really with the way I am focusing wide open through the 10 stop?

Nope, nor am I sure that the alternative is, unless you use dof preview and focus manually, which I think would be impossible with a 10 stop mounted. I'd not heard of focus shift before, but as gl2k infers, the people who worry about it don't have film in their camera anyway. At least with digital, if you check your focus after each shot using your lcd you have a chance to correct it.

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UK wedding photographer in the Lake District
http://www.johnleech-weddingphotography.co.uk
For my landscapes and fine art photography:
http://www.johnleechstudio.co.uk

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