Setup for ultimate bokeh (+sharpness + CA + flare) test

Started 7 months ago | Discussions
Zlik
Contributing MemberPosts: 947
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Setup for ultimate bokeh (+sharpness + CA + flare) test
7 months ago

I have been wanting to test several of my lenses at portrait distances for bokeh, flare, sharpness and chromatic aberrations for quite some time, and decided to set up a few objects to do such a test.

The idea is to keep the subject the same size in the frame and change the distance depending on focal length.

I plan to test the following Nikkor lenses:

  • 28/1.8G
  • 35/1.8G DX
  • 50/1.8G
  • 85/1.8G
  • 105/2.8 AF micro
  • 24-70/2.8G
  • 70-200/4G
  • 105/2.5 AIS
  • 20/2.8 AIS (not sure if worth testing here)

Here is how the setup looks right now, and I am looking for suggestions on how to improve it (find some objects that are challenging for smooth bokeh):

Setup.

My thoughts:

- subject will be the "Athens 2004" towel (great for judging sharpness) with the measuring tape (illuminated by a table light to produce high contrast markings for green and magenta fringing)

- Christmas tree with small lights to test the shape of highlights in bokeh

- lamp facing camera at the back on the couch to test the flare

- plant to simulate trees for testing bokeh

Examples of resulting photos at 28mm and 85mm at f/1.8, f/2.8 and f/4:

28/1.8G at f/1.8

28/1.8G at f/2.8

28/1.8G at f/4

85/1.8G at f/1.8

85/1.8G at f/2.8

85/1.8G at f/4

I will test each aperture setting from wide open to f/5.6 and then f/8, f/11 and f/16

What we already knew and can be seen here :

  • DoF is the same when the subject takes the same size in the frame between focal lengths at respective apertures
  • Elements in the background are blurred with the same radius, but due to perspective changes (with distance), the longer the focal length, the higher the magnification

Here is something interesting to illustrate both points: I took both f/2.8 photos and matched the background size:

left 28mm at f/2.8, right 85mm at f/2.8

So, before I start testing all the lenses, are there any suggestions about how to improve the test?

What would you like to see in the background ?

eajames
Regular MemberPosts: 155
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Re: Setup for ultimate bokeh (+sharpness + CA + flare) test
In reply to Zlik, 7 months ago

Consider placing some objects in front of your plane of focus, and maybe include a string of lights hung near to far.  Good luck!

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Zlik
Contributing MemberPosts: 947
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Re: Setup for ultimate bokeh (+sharpness + CA + flare) test
In reply to eajames, 7 months ago

eajames wrote:

Consider placing some objects in front of your plane of focus, and maybe include a string of lights hung near to far. Good luck!

Thanks, good idea.

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HobbiesAreFun
Senior MemberPosts: 2,420Gear list
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Re: Setup for ultimate bokeh (+sharpness + CA + flare) test
In reply to Zlik, 7 months ago

I think the more interesting test would be to compare the 135 f/2 DC with the Sony 135mm f/2.8 T4.5 STF.

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Zlik
Contributing MemberPosts: 947
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Re: Setup for ultimate bokeh (+sharpness + CA + flare) test
In reply to HobbiesAreFun, 7 months ago

HobbiesAreFun wrote:

I think the more interesting test would be to compare the 135 f/2 DC with the Sony 135mm f/2.8 T4.5 STF.

The only problem being that I don't own those

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