Go Pro Hero 4 minimal focus distance?

[Jayson A]

Have my eye on this cam. I'd like to find out the answers to two questions:

1) What is the minimal focus distance?
2) Is the focus manually adjustable?

I desire to do 240 fps HD work, but I need close focus (1 foot or less)
and the focus has to be adjustable.

Thank you.

[David Ruether]

"Jayson A" <jayso...@ms.net> wrote in message news:
mcf0kd$uov$1...@dont-email.me:

One of several things that kept me from buying this
camera (the GoPro 4, either Silver or Black), is that
it has no lens focus. It is a fixed-focus lens of
very short focal-length, with a fixed "compromise"
focus distance which, with its great inherent DOF,
gives reasonably sharp images over a wide range of
"normally" used distances - but it's unlikely to
be as sharp as you may want it to be at 1' or less,
or to do 1080p video at greater than 80fps or 720p
at greater than 240fps. The Black's specs are here:
http://shop.gopro.com/cameras/hero4-black/CHDHX-401-master.html

If you need a super-wide fisheye view with close
focus (although the price is much higher and the
frame-rate lower - and you would need to check lens
samples to get a good one, if Samyang/Rokinon), a
Panasonic GH4 body will shoot up to 96fps at 1080p
with reasonable sharpness, and the frame rate can
be doubled in post fairly well if shot carefully
to minimize resulting visual artifacts using the
inexpensive ProDAD ReSpeeder software. An example
I shot is here, shot at 60p with a Panasonic G5
and Rokinon 7.5mm fisheye (it took six samples to
get a really good one...), and slowed it to 1/8th
speed first using Vegas to get it to 120fps
(half-speed) at 30p, then using ReSpeedr to get it
to 480fps at 1080-30p. Do read the description at:
https://www.youtube.com/watch?v=tkb0JtrN0n0
Results do show some (acceptable to me) artifacts,
but can be impressive, especially is high shutter
speeds are used.

As for usable lenses, the Samyang/Rokinon 7.5mm
f3.5 can focus fairly closely to subjects, and is
very sharp over all of its 180-degree (diagonal)
coverage (with a good sample!), and it is sharpest
around f5.6+1/2 to about f8+1/2. An alternative
that I recently discovered is the Panasonic 12-32mm
(with a good sample, although this lens is FAR less
variable in samples than the one above), used at
15mm and combined with the Panasonic GFC-1 fisheye
adapter and set at f7.1. This covers about 100-120
degrees on the diagonal, focuses very closely, and
it has a stabilizer built into the lens. More on
this lens will soon be on my website at:
http://www.david-ruether-photography.com/MFT-Lenses.htm

Have fun with Slo-Mo - it's fun to do, and it is now
possible to shoot it using reasonably-priced gear
and to process it with reasonably-priced software!;-)

--DR

[Jayson A]

On 02/23/2015 07:25 AM, David Ruether wrote:
>
>
> "Jayson A" <jayso...@ms.net> wrote in message news:
> mcf0kd$uov$1...@dont-email.me:
>
>> Have my eye on this cam. I'd like to find out the answers to two
>> questions:
>>
>> 1) What is the minimal focus distance?
>> 2) Is the focus manually adjustable?
>>
>> I desire to do 240 fps HD work, but I need close focus (1 foot or less)
>> and the focus has to be adjustable.
>>
>> Thank you.
>
> One of several things that kept me from buying this
> camera (the GoPro 4, either Silver or Black), is that
> it has no lens focus. It is a fixed-focus lens of
> very short focal-length, with a fixed "compromise"
> focus distance which, with its great inherent DOF,
> gives reasonably sharp images over a wide range of
> "normally" used distances - but it's unlikely to
> be as sharp as you may want it to be at 1' or less,
> or to do 1080p video at greater than 80fps or 720p
> at greater than 240fps. The Black's specs are here:
> http://shop.gopro.com/cameras/hero4-black/CHDHX-401-master.html

That's just what I thought, lack of manual focus and unfortunate for
what I had intended to do. I've been waiting several years for faster
consumer cameras to come on the market approaching pro standards but
more at a consumer price. This latest camera almost fit the bill except
the focus issue. If the price wasn't where it is, I'd be tempted to
replace the lens with an adjustable one, but at $500 that's a little
beyond the tinkering range for me.

> If you need a super-wide fisheye view with close
> focus (although the price is much higher and the
> frame-rate lower - and you would need to check lens
> samples to get a good one, if Samyang/Rokinon), a
> Panasonic GH4 body will shoot up to 96fps at 1080p
> with reasonable sharpness, and the frame rate can
> be doubled in post fairly well if shot carefully
> to minimize resulting visual artifacts using the
> inexpensive ProDAD ReSpeeder software. An example
> I shot is here, shot at 60p with a Panasonic G5
> and Rokinon 7.5mm fisheye (it took six samples to
> get a really good one...), and slowed it to 1/8th
> speed first using Vegas to get it to 120fps
> (half-speed) at 30p, then using ReSpeedr to get it
> to 480fps at 1080-30p. Do read the description at:
> https://www.youtube.com/watch?v=tkb0JtrN0n0
> Results do show some (acceptable to me) artifacts,
> but can be impressive, especially is high shutter
> speeds are used.

I've actually been down a similar path with the TM700 I used to own.
Record at 60 fps, then slow down in software. Pretty convincing but
having the light right was key. Still wasn't as realistic though as an
actual high speed camera.

>
> As for usable lenses, the Samyang/Rokinon 7.5mm
> f3.5 can focus fairly closely to subjects, and is
> very sharp over all of its 180-degree (diagonal)
> coverage (with a good sample!), and it is sharpest
> around f5.6+1/2 to about f8+1/2. An alternative
> that I recently discovered is the Panasonic 12-32mm
> (with a good sample, although this lens is FAR less
> variable in samples than the one above), used at
> 15mm and combined with the Panasonic GFC-1 fisheye
> adapter and set at f7.1. This covers about 100-120
> degrees on the diagonal, focuses very closely, and
> it has a stabilizer built into the lens. More on
> this lens will soon be on my website at:
> http://www.david-ruether-photography.com/MFT-Lenses.htm
>
> Have fun with Slo-Mo - it's fun to do, and it is now
> possible to shoot it using reasonably-priced gear
> and to process it with reasonably-priced software!;-)

The items you mentioned would unfortunately exceed my budget. I think
I'll just have to keep waiting for the latest high speed items to
continue to evolve and wait until the prices drop over time.

Thanks for your response.

Jayson

>
> --DR
>

[David Ruether]

"Jayson A" <jayso...@ms.net> wrote in message

news:mcf7tc$ran$1...@dont-email.me:

It can be, if shot suitably (with high shutter speeds
so that the extra frames synthesized by ReSpeedr are
also sharp...).

> > As for usable lenses, the Samyang/Rokinon 7.5mm
> > f3.5 can focus fairly closely to subjects, and is
> > very sharp over all of its 180-degree (diagonal)
> > coverage (with a good sample!), and it is sharpest
> > around f5.6+1/2 to about f8+1/2. An alternative
> > that I recently discovered is the Panasonic 12-32mm
> > (with a good sample, although this lens is FAR less
> > variable in samples than the one above), used at
> > 15mm and combined with the Panasonic GFC-1 fisheye
> > adapter and set at f7.1. This covers about 100-120
> > degrees on the diagonal, focuses very closely, and
> > it has a stabilizer built into the lens. More on
> > this lens will soon be on my website at:
> > http://www.david-ruether-photography.com/MFT-Lenses.htm
> >
> > Have fun with Slo-Mo - it's fun to do, and it is now
> > possible to shoot it using reasonably-priced gear
> > and to process it with reasonably-priced software!;-)
> >

> > --DR

> The items you mentioned would unfortunately exceed my budget. I think
> I'll just have to keep waiting for the latest high speed items to
> continue to evolve and wait until the prices drop over time.
>
> Thanks for your response.
>
> Jayson

You're welcome - but a used Panasonic G5 body is
currently about $250 and a new Rokinon 7.5mm is about
$240-250, both at Amazon. But, be prepared to check
and exchange a few of the lenses to optimize image
quality! Total: about $500 - the price of a GoPro 4
Black!;-) ReSpeedr is under $100 last I checked, so
it does add some to the total, but the combination
(with a video editor that can slow the 1080-60p to
1080-30p, increasing the fps of the video to 120 fps,
after which ReSpeedr can then take it and bump it up to
240 fps by synthesizing a new frame between each pair
of original frames). This gives you 1080p instead
of the 720p 240 fps of the GoPro, although for best
results, I stabilize the image slightly at each stage
of processing (and this helps crop out some of the most
common artifacts, which occur at the frame edges).

--DR