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Author Topic: Accurately reproducing manual focus  (Read 2453 times)

trevarthan

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Accurately reproducing manual focus
« on: August 19, 2014, 07:36:50 am »

Liveview isn't so good after dark, at least on my Nikon D810. It's often difficult/impossible to tell if something is in focus.

If I have my camera on a tripod for an hour or two, is there a way to record manual focus during the day, then reproduce the settings accurately at night? The focus scales on my lenses don't seem like an incredibly accurate way to do this.

I think after the SDK comes out for the D810, digitally will be the best way to do this for lenses with AF motors, but I'm curious if there is some other trick? I was reading about how cinematographers use external focus controls sometimes?
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Iluvmycam

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Re: Accurately reproducing manual focus
« Reply #1 on: August 19, 2014, 08:28:30 am »

The almighty D810 must be having problems?  well, your lucky you got any focus scales at all. The trend of the camera fondling engineers is to 'dumb down' the lenses and not give a focus scales or apertures settings. At least that is how it is with Fuji.

If you can't focus on a tripod at night how on earth are you going to do it when on the fly? Learn how to be a (good) street photog. I shoot in partial or full darkness all the time.

https://commons.wikimedia.org/wiki/File:Gathering_of_the_Juggalos_Kiss_Copyright_2014_Daniel_D._Teoli_Jr._lr.jpg

https://commons.wikimedia.org/wiki/File:Couple_Petting_Copyright_2014_Daniel_Teoli_Jr_lr.jpg

https://commons.wikimedia.org/wiki/File:Gathering_of_the_Juggalos_Mosh_Pit_copyright_2014_Daniel_Teoli_Jr..jpg
« Last Edit: August 19, 2014, 08:33:57 am by iluvmycam »
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trevarthan

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Re: Accurately reproducing manual focus
« Reply #2 on: August 19, 2014, 08:40:35 am »

I read that the D800 had the same problem. I skipped that model, so I don't know if LiveView is better at night with the D810 or not, but there is definitely a point (usually right at a 30 second exposure or beyond) when I start having trouble focusing with the LiveView.

I'm not sure what that street photographer crack was about.
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sdwilsonsct

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Re: Accurately reproducing manual focus
« Reply #3 on: August 19, 2014, 10:15:46 am »

Stars, the moon and distant lights will give you infinity.

For closer objects I put an LED at the subject: focus, remove LED, shoot.
« Last Edit: August 19, 2014, 10:28:41 am by sdwilsonsct »
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melchiorpavone

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Re: Accurately reproducing manual focus
« Reply #4 on: August 19, 2014, 11:48:32 am »

Liveview isn't so good after dark, at least on my Nikon D810. It's often difficult/impossible to tell if something is in focus.

If I have my camera on a tripod for an hour or two, is there a way to record manual focus during the day, then reproduce the settings accurately at night? The focus scales on my lenses don't seem like an incredibly accurate way to do this.

I think after the SDK comes out for the D810, digitally will be the best way to do this for lenses with AF motors, but I'm curious if there is some other trick? I was reading about how cinematographers use external focus controls sometimes?

I don't understand the question.
« Last Edit: August 19, 2014, 01:26:48 pm by melchiorpavone »
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LesPalenik

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Re: Accurately reproducing manual focus
« Reply #5 on: August 19, 2014, 01:18:07 pm »

If the subject is relatively close, use a flashlight for focusing. If it is far, set the focus manually to infinity.
 
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trevarthan

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Re: Accurately reproducing manual focus
« Reply #6 on: August 19, 2014, 05:11:20 pm »

I guess I'm curious about medium distances. Not infinity, but not close enough for a flashlight either. I guess something like this might work, maybe with a second rubber band instead of a lever and hose clamp:

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Torbjörn Tapani

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Re: Accurately reproducing manual focus
« Reply #7 on: August 19, 2014, 09:03:13 pm »

No that will not work. As you focus to say infinity you reach a stop but not a hard stop (and past infinity even), the collar keeps turning with some resistance. So your lever will not be in the same place next time most probably.
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LesPalenik

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Re: Accurately reproducing manual focus
« Reply #8 on: August 19, 2014, 10:20:38 pm »

Quote
I guess I'm curious about medium distances. Not infinity, but not close enough for a flashlight either. I guess something like this might work, maybe with a second rubber band instead of a lever and hose clamp:

In that case, I would recommend an older MF lens with good marking lines and an extra long tape measure. If you want to go hi-tech, a laser meter would work very nicely.
The bigger problem with the long shutter speeds might be those "D810 bright spots", as reported recently and now also acknowledged by Nikon.
 
« Last Edit: August 19, 2014, 11:55:13 pm by LesPalenik »
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trevarthan

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Re: Accurately reproducing manual focus
« Reply #9 on: August 20, 2014, 07:57:51 am »

No that will not work. As you focus to say infinity you reach a stop but not a hard stop (and past infinity even), the collar keeps turning with some resistance. So your lever will not be in the same place next time most probably.

Ugh. Good point. I was thinking of my manual focus lenses, but you're right for all of the "just grab the ring to focus" AF models.
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allegretto

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Re: Accurately reproducing manual focus
« Reply #10 on: August 20, 2014, 08:03:12 am »

what type of subject are you focusing upon

is it moving (a lot) or more stable?
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trevarthan

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Re: Accurately reproducing manual focus
« Reply #11 on: August 20, 2014, 08:03:57 am »

Stable. I was thinking of using this primarily for manual focus stacking.
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allegretto

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Re: Accurately reproducing manual focus
« Reply #12 on: August 20, 2014, 09:59:09 am »

just curious... why would you have to wait such a long time between shots?

why not exposure stack as you focus stack in one sitting and be done? don't need to do full blown HDR, just a bit

perhaps you want light from different directions or sources?

even so, you can just go out at different times and have your chalk marks

maybe it's far more involved than I'm imagining.
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trevarthan

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Re: Accurately reproducing manual focus
« Reply #13 on: August 20, 2014, 10:21:38 am »

just curious... why would you have to wait such a long time between shots?

why not exposure stack as you focus stack in one sitting and be done? don't need to do full blown HDR, just a bit


Blue hour photos frequently range from 10 to 30 second exposures for the right balance of fading sunlight and human artificial lights. That's the sort of thing I enjoy shooting, I guess because it's such a fleeting moment in time, and the camera is way better at seeing it than my eyes are.

I just bought a camranger. Most likely, that will be my solution. I didn't realize they supported the D810 already (even though the SDK hasn't been released yet) AND they have an iPad app AND they support automatic focus stacking. Seems like win-win-win-win. We'll see.
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Ajoy Roy

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Re: Accurately reproducing manual focus
« Reply #14 on: August 24, 2014, 12:21:35 pm »

I think that Digicam Control will also work. You tether it to a laptop or iPad, set up the parameters and let it time lapse.

Otherwise if the distances are not large, then a long throw manual focus lense can be used after calibrating it accurately during day time.
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Herbc

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Re: Accurately reproducing manual focus
« Reply #15 on: August 24, 2014, 01:04:26 pm »

Amen to the flash light/infinitiy response.

We shot LF for many decades without any electronic stuff, you just do it.
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