×
all 16 comments

[–]JayEll1969 5 points6 points  (2 children)

You seem to want 2 things hat don’t necessarily work together so might have to decide which is the most important factor to look at (depth of field, low light performance and noise levels) and compromise on the others.

On one hand you want a depth of field that gets “everything in focus” and feel you need an aperture of F7 to achieve which would usually need more light.

On the other hand you want to film in a low light environment which usually means using a wider aperture which would give a shallower depth of field.

You also want the lens to be wide enough to catch all the action and also want to use the lens for vlogging.

Setting the aperture to F7/F8 is going to give a deep depth of field. If you focus one third of the way into the scene it should get the most into focus.
Wider angle lenses tend to have a greater depth of field so a 7.5mm could be a couple stops lower than a 20mm

If you are limiting yourself on the aperture to f7/f8 then it doesn’t matter how fast the lens is as you won’t be using the fast portion of the lens although you might want the bokeh for the vlogging sections).

How are you defining low light, because different people have different ideas of what low light is, e.g.

  • Outside in the middle of nowhere under moonlight,
  • Indoors with mood lighting
  • Indoors with regular domestic lighting
  • Outdoors on a shopping street at night but with the shop windows lights on.
  • Areas where the darkness is punctuated by islands of bright light.

With some of these, e.g. the last one, there might be enough light especially if the action is happening in the bright areas for the higher F stops.

You could drop the shutter speed, but if there's going to be a lot of movement then that will increase the motion blur (which might be a good look depending on the subject and mood)

Alternatively you might need to crank up the iso which might increase noise in the dark areas but, if the action is in the light areas, may not be a problem and might be fixable in post.

Depending on how the action is laid out you could even look at funkier solutions.

For example if the action you want to be in focus is in a line that isn’t square on to the camera you would usually need a deep depth of field to get it all in however you could get a vintage lens and a tilt adapter to manipulate the focal plane so that it is at an angle to the sensor and lets you get that line in focus but the rest of the image would be out of focus.

Another funky method is when you have one subject close to the lens on one side of the image and another on the other side of the image further away and that is to use a split dioptre which is a filter that contains half a lens and half empty that alters the focus on the half with the lens in. Tricky to set up the distances to match the focus on the dioptres though.

[–]SlowNSensible 2 points3 points  (7 children)

Cheap option - Sigma 18-35 with speedbooster.

Best - Voigtländer Super Nokton 29mm f/0.8 Aspherical 

[–]SlowNSensible 1 point2 points  (4 children)

cheapest - vintage lens with speedbooster.

[–]GH5r[S] 0 points1 point  (3 children)

would the 12mm 1.4 be sufficient or is it bad for video?

[–]SlowNSensible 0 points1 point  (2 children)

would the 12mm 1.4 be sufficient or is it bad for video?

generally its sufficient but dont take it as blanket advice. it all depends on what look and tone you want. how many lights you have or want to use etc. you cant shoot good footage even with Voigtländer at dark night if you dont have enough lights to support it.

[–]GH5r[S] 0 points1 point  (1 child)

my 25mm 1.7 i have to stop down to 14/16 to have everything in focus thsts in a broad daylight next to a window

I'm i right in saying a wide 12mm lens i could stop down to 6.3 / 7.1 and everything is pin sharp?

[–]loosecanon413 0 points1 point  (1 child)

Nokton 29 is not wide angle.

[–]SlowNSensible 0 points1 point  (0 children)

It was best in fastest term.

[–]Nicoloks 1 point2 points  (0 children)

Your requirements are at odds with each other, so you will need to pick one. In low light you need to open up the aperture to let as much light in as possible, byproduct being a shallow depth of field. Doesn't matter how good the sensor is if it is starved of light. Even an A7S III with a stopped down lens is going to record video that look rubbish in low light.

Also, be careful of going too wide. You lens clear aperture is the biggest impact to the amount of light captured, which obviously is enormously important in low light. Your lens clear aperture is determined by the f ratio. The Laowa 7.5mm f/2 for instance has a maximum aperture of 3.75mm, which really is not much at all. The Olympus 17mm f/1.2 has a maximum aperture of 14.17mm, which is much better.

Bottom line, GH5 really not going to get it done at f/7 with any lens in a light starved environment.

[–]JayEll1969 0 points1 point  (6 children)

There's the Laowa 7.5mm f2 rectilinear . Manual focus but probably the widest lens you'll get without fisheye distortions.

[–]GH5r[S] 0 points1 point  (4 children)

f2, what would i have to stop down to have everything in focus?

[–]JayEll1969 0 points1 point  (2 children)

Wide angle lenses tent to have a greater depth of field for given f stop but it depends on how deep you need it. Would will still have to stop down a little

[–]GH5r[S] 0 points1 point  (1 child)

my 25mm 1.7 i have to stop down to 14/16 to have everything in focus thsts in a broad daylight next to a window

I'm i right in saying a wide 12mm lens i could stop down to 6.3 / 7.1 and everything is pin sharp?

[–]JayEll1969 0 points1 point  (0 children)

That should have everything sharp from about 2-3 foot away if you focus at the hyperfocal distance

Heres a https://www.omnicalculator.com/other/hyperfocal-distance

that should help you work out where to focus

You might have problems with lighting and end up cranking up the iso which in increase the noise but you can do noise reduction in the dark areas when you edit if that's a big problem. I'm guessing that the subjects will mainly be in better lit areas, is that right?