Another very basic question
After watching lot of videos I decided to put my camera on a tripod and capture pictures starting from minimum aperture - 2.4 camera supports.
However I am not seeing bokeh effect at same aperture the way I see in these videos. Almost everything stays in focus.
At the same aperture, is the effect same for every lens? I am guessing the reason why I am not getting effect is because of lens limitations.
What focal length is the lens? Youâll see more bokeh with longer lenses.
Besides focal length, the focus distance also matters, the closer you focus, the bigger the blur.
Besides aperture (expressed as an f-number), the physical (not equivalent) focal length also matters. Or, worded differently, the aperture expressed in absolute terms (e.g. millimetres). f/2.4 on a compact, with a 50 mm âequivalentâ lens (that would be 11 mm on many phones and small-sensor compacts) and a 50 mm lens on a full-frame camera will look very different.
the DOFs are in inverse proportion to the absolute aperture diameters
Image sensor format - Wikipedia
Camera is Sony RX10 IV. Focal length is listed 24mm to 600mm. For my testing I did not zoom in, just turned on the camera and left the lens at startup position. Thatâs the only position where I could get 2.4 aperture.
Hi
Iâll hazard a guess that anything beyond 2 metres, 6ft, at 24mm is gonna be in focus.
To expand on @Pizzacutter comment, keep the distance between camera and subject much smaller than subject to background.
Also bokeh effects will diminish with shorter focal lengths.
Then thereâs the lens minimum focus distance.
And the effects of sensor sizeâŚ
Hhmm, bit of a rabbit hole.
Experiment.
I shoot a 24mm on my full frame often, and blur and bokeh is not something that lens does.
200mm at f5 and focus on something close to the lens will likely give you way more blur than 24mm ever can.
A 24 mm lens at f/2.4 has an aperture diameter of 24 mm / 2.4 = 10 mm.
A simple kit lens, like my 18 - 105 Nikkor at 105 mm, f/5.6 has an aperture diameter of 105 mm / 5.6 = 18.75 mm, and has a shallower DoF (as long as both can focus on the subject, and they are the same distance from the subject). Going further, my 70 - 300 mm, when fully zoomed in, at f/5.6, has an aperture diameter of 53.57 mm. Of course it delivers a much shallower DoF than the 24 mm lens at f/2.4 (or the 18-105 at f/5.6).
DoF is a function of aperture, but in my view the true focal length of the lens is a more critical starting point. If you want a nice artistic blur (bokeh) then you must avoid short focal length lenses. In my experience I would say a 50mm lens is the shortest I would consider, but it would need an aperture of at least F1.8. A 55mm kit lens with a F 5.6 aperture would be insufficient for a nice bokeh. Even longer lens with with large enough apertures work very well.
50mm lens with F1.7 works
200mm lens with F4 works very well
As others have said, bokeh is a function of the depth of field. For a given focal lent, focal point, and aperature, there will be a range where the subject is in focus and a range where it is out of focus (both in front of and behind the subject. There are many online calculators for this such as here
https://www.cambridgeincolour.com/tutorials/dof-calculator.htm
Play around the variables to get a feel for it.
I may have missed it if someone has mentioned this, but that Sony camera has a â1 inch typeâ sensor. The wide end of the lens is something close to 9mm in real focal length. At f/2.4 that aperture is less than 4mm across.
bokeh is a function of the depth of field
I think of bokeh as a rendering result. If bokeh is a function of depth of field, there are likely more arguments to that function. Bokeh may differ significantly between lenses even if focal length, aperture and subject distance are the same.
But if all other parameters including sensor size and image crop are equal, the actual lens build affects mainly the âqualityâ of the bokeh (whatever that means â typically words such as âsoftnessâ are used), which is mainly a function of the number and shape of the aperture blades.
the actual lens build affects mainly the âqualityâ of the bokeh
As in quality of quality? I think of bokeh as âquality in out of focus areaâ not as a different way of saying âout of focusâ or âdepth of fieldâ: Bokeh - Wikipedia
Maybe I should have said âbokeh of the bokehâ? No, seriously, I think the definition of âbokehâ is flexible enough to be used in both ways, but i am OK with your definition. However, all of this discussion leads away from the key point.
What I meant was that the main impact of how the bokeh looks like is the aperture shape. This was a missing point in the discussion above, where only the influences of different parameters on the âamountâ of bokeh have been stated. But my statement is also not comprehensive, because you can influence the bokehâs look at different positions in the optical path, see e.g. https://www.instructables.com/DIY-Heart-shaped-Bokeh/. For the majority of cases, however, the simple explanation will be sufficient.
Sure, that determines the edge shape, but how the lens corrects spherical aberration determines whether the distribution of light is uniform, concentrated in the center, or in the edges.
There are even a few lenses with adjustable bokeh.
Iâm still dreaming of owning a trioplan 100/2.8 one day âŚ
There are even a few lenses with adjustable bokeh.
I do have the Nikkor âdefocus controlâ or "DC lenses (105mm and 135mm) but I think they mainly have effect on the depth of focus, not so much the bokeh. Canon may have an interesting approach using the lens coating
