Author Topic: Focusing  (Read 1978 times)

garry23

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Focusing
« on: April 26, 2017, 09:08:22 AM »
In the spirit of helping fellow photographers, and because I mention ML, I thought I would share my latest post on landscape focusing: http://photography.grayheron.net/2017/04/getting-best-out-of-hyperfocal-focusing.html

DeafEyeJedi

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Focusing
« Reply #1 on: April 26, 2017, 05:47:19 PM »
Thanks for having the ability to push people like me who spend majority part of their lives as a DSLR Videographer who happens to have a deep love & hobby for Photography (especially architects & landscapes) and reading your blogs on your site have been nothing short of valuable information.

Thanks for making my dreams 'soon to become a reality' when possible as it seems I've been on the right path because of the experiences that you share, @garry23!
5D3.113 • 5D3.123 • EOSM.203 • 7D.203 • 70D.112 • 100D.101

BBA

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Re: Focusing
« Reply #2 on: April 26, 2017, 05:53:10 PM »
@Garry23
Thanks for sharing !
Very interesting to see the different curves you give.
I definitely need to get the equations of the global blur as a function of the object distance  :P.

Will you modify your focus stacking script to take a picture above the HFD, i.e. at an object distance = 2 or 3 times the HFD ?
IMHO, as for the HFD, the problem remains to translate this object distance into a known number of steps to move the focus motor towards the infinity end in the image domain.

garry23

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Re: Focusing
« Reply #3 on: April 26, 2017, 06:34:21 PM »
@BBA

Happy to share.

As for an update of my script: already done  :)

https://gist.github.com/pigeonhill/4f210b06991821b5c42c0cd76a0abb98

This version adds in what I'm calling the QHFD bracketing option, ie two focus brackets either side of the HFD.

You access this two bracket focus set (HFD/2 + (2 or 3)xHFD) under the focus bracketing. (the default is 2xHFD, change to 3 under settings).

Once you have selected the QHFD bracketing option, simply RUN the script.

You can exposure bracket at each focus bracket as well, of course  :)

And use (dark frame) bookends etc.

For the QFD bracket option the lens can be positioned anywhere. For the other focus bracketing options you need to focus at the nearest point in the focus bracket and select bracket to the HFD or infinity. I've changed HFD to mean 2 or 3 X HFD.

If using the QFD, or any focus bracketing options, make sure you maximise the quality of captured photons by choosing a sensible aperture, ie Widest + 2 Stops is a good working assumption (see my blog post at http://photography.grayheron.net/2017/04/getting-best-out-of-hyperfocal-focusing.html

Cheers

Garry