Author Topic: Focus Bracketing  (Read 4470 times)

MichaelR

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Focus Bracketing
« on: February 16, 2014, 05:36:03 PM »
First, congrats to the developers - ML is a great piece of work.

I have an issue with focus bracketing though. At present it asks me how many steps I want, but it's not as simple as that.

At present ML seems to divide distance by the no. of steps and move the focus at linear intervals - that is no good because DOF isn't linear. I have written a script in CHDK to work around this problem for my compact, so I suppose I'll have to have a go at it for ML some time for my DSLR.

It would be nice if the built in focus braketing worked properly, though, as I feel that I am reinventing the wheel! Why have a build in feature that doesn't work properly?

I'd also like to see ML split into two products - one for video users and one for photo users. I feel the interface is too complicated and many features just get in the way. I keep getting the software in a mess where instead of moving the focus box in Live View, the keys change the White Balance settings. Very annoying, because I have no idea why it does it. At present I've taken it off the camera because it just gets in the way and I haven't got time to get to the bottom of it.

Many thanks,

Michael


garry23

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Re: Focus Bracketing
« Reply #1 on: February 16, 2014, 07:03:05 PM »
Michael

Before someone else states the obvious, I would simply say that this has already been requested. You need to be aware of the effort that is put into ML by the developers and, as a stills shooter, I know the video 'stuff' gets the attention.

Having said that, we have dual ISO, extended bracketing and extended DR etc etc. in other words I'm not complaining.

BTW focus steps are linear for macro focus bracketing. It is only when you need to do focus bracketing for landscapes and architectural work that it becomes non-linear.

I for one have written a simple script in CHDK to do landscape focus bracketing.

For my 5DIII, I will wait for the script module to stabilize and then simply implement landscape focus bracketing there, ie on a lens and aperture specific basis.

Also, for wide angles, you really only need 2 or 3 focus brackets, and in this case I simply mark the lens with pre-calibrated focus distances, ie for my 24mm then use 3, 5, and 15 feet. 

Marsu42

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Re: Re: Focus Bracketing
« Reply #2 on: February 16, 2014, 07:30:42 PM »
At present ML seems to divide distance by the no. of steps and move the focus at linear intervals - that is no good because DOF isn't linear. I have written a script in CHDK to work around this problem for my compact, so I suppose I'll have to have a go at it for ML some time for my DSLR.

I'm also not using ML video features at all - but I submitted some patches to stills, for example this focus bracketing. There are a lot of ideas concerning this, prominently an algorithm to automatically calculate the required step size for the distance & dof - but no one was able to really do it yet, the only solution seemed a table for each lens.

So if you have a working script to *calculate* the step size, let's see it, and we can see if the information it needs fed is available from ML.

garry23

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Re: Re: Re: Focus Bracketing
« Reply #3 on: February 16, 2014, 08:59:40 PM »
The scripts I have used do NOT assume any knowledge from the camera. I'm afraid what I do is work out the number of streps from, say the macro or infinity end, by focusing on a fixed target at he required distances.

I use the EOS utility to drive the lens to the end stop, then to the focus targets. Thus I know how many steps to each focus distance, and I use a fixed aperture, ie F/8.

This is not as bad as it sounds, as if you wish to use focus stacking for landscapes, you normally use a wide angle. Thus, as I said before, at 24mm I use 3, 5 and 15 feet. BTW I use all of the http://www.georgedouvos.com apps, as I find they give me the best info.

engardeknave

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Re: Re: Re: Focus Bracketing
« Reply #4 on: February 16, 2014, 09:56:04 PM »
Quote
I'd also like to see ML split into two products - one for video users and one for photo users. I feel the interface is too complicated and many features just get in the way. I keep getting the software in a mess where instead of moving the focus box in Live View, the keys change the White Balance settings. Very annoying, because I have no idea why it does it. At present I've taken it off the camera because it just gets in the way and I haven't got time to get to the bottom of it.

By using bleeding-edge software like this you've not only forsaken the right to complain about unused features, you've shot it in the chest, buried it, and taken a dump on its grave. ML is somewhat convoluted. But if you don't enjoy learning complicated things, you've taken a wrong turn somewhere. You're in the wrong place.

That said, I'm pretty sure that changing the behavior of the arrow keys isn't quite as daunting as you make it out to be. In fact, I think it is a selectable item from what is a human-readable menu interface. Perhaps something containing the words "Arrow" and "key".

Audionut

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Re: Focus Bracketing
« Reply #5 on: February 17, 2014, 07:15:19 AM »
I've moved some discussion to here.

MichaelR

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Re: Focus Bracketing
« Reply #6 on: February 19, 2014, 03:17:16 PM »
Thank you for everyone who's taken the time and trouble to reply to  my post. As far as the post by engardeknave is concerned, I find your tone to be quite offensive (which was no doubt your intention) and I would suggest that you moderate your behaviour in what is a public place. You can disagree without being disagreeable.