Experimental photography, part 1
Some more recent ventures into experimental photography... and this time I will also report on a thing I have tried which I actually haven't seen anyone else do (but I wouldn't be surprised if someone has done it before, though):
1. Round aperture modification
This was an idea I had been toying around with, and now I've tried it. The idea was to modify a lens by inserting a fixed round
aperture covering the original aperture blades. Why?
Well, the reason was to make a "better" stopped down bokeh quality (background blur) on a lens that may not have that quality originally.
First, when it comes to sharpness, most/all lenses have their sweet spot at
f-stops a couple of notches above completely open aperture. Let's say we have a lens that goes from f/1.9 (open aperture) to f/16 (max stopped down); the lens will likely be a bit softer at completely open aperture and then increase in sharpness as you stop it down to, let's say, f/2.8 or f/4.
So stopping down a lens generally gives sharper photos, but there's another effect you get by stopping down:
the bokeh (background blur) starts to get more in focus, i.e. less "creamy", which may be something you don't want if you are doing close-ups or portraits and want good subject isolation.
Furthermore, the background blur may get distracting if the aperture blades do not form a reasonably round aperture stopped down. That's why lenses with more aperture blades and/or rounded aperture blades generally give more pleasing bokeh stopped down; though some photographers sometimes like the bokeh that e.g. hexagonal apertures generate.
Example: A photo I've taken that has hexagonal bokeh balls.
The round aperture modification is an attempt to provide a "perfectly" round aperture close to the sweet spot of the f-stop that also gives better sharpness than shooting with the lens wide open. The downside with this modification is that you lose aperture control, i.e. you will not be able to shoot wide open anymore without reverting the modification.
The lens I selected for this modification was the
Chinon 50mm f/1.9 which has got six aperture blades, and the lens was manufactured in Japan during the 1970s/1980s.
Here we've got the lens disassembled. You can see in the photo that the six aperture blades form a hexagon (bottom left). Above the lens are three metal
washers I picked out as possible contenders for providing a round aperture.
Chinon 50mm f/1.9 disassembled.
After a suitable washer was selected I painted it black so there would be less internal reflections from it when it is inside the lens. When the paint had dried I put a couple of small pieces of blu tack on it so I could fix the washer inside the lens.
Left: The washer painted black. Right: The washer with some pieces of blu tack.
And then I inserted the washer inside the lens, placing it on top of the original aperture blades:
Left: Original hexagonal aperture. Right: Round aperture modification.
And here is the lens out in the sunny weather, showing the round aperture modification:
Well, does it work?
Yes, it does
.
The effect is not obvious in every photo you take, but here are two photos taken with the modified lens:
Close-up of a forget-me-not (scorpion grass) with a very blurry background.
On the next photo we can clearly see that the bokeh balls in the background are "perfectly" round:
Close-up of a forget-me-not (scorpion grass) with "perfectly" round bokeh balls.
So, all in all it was a successful modification and maybe it can be an inspiration for others to try more experimental photography
.
