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11-27-2018, 09:01 AM
Just to illustrate the effect when stopping down ... taken at f/1.2, 1.6, 2, 2.8 (from the RF 50).
Also, note the shutter effect at f/1.2 (taken at 1/4000sec).
Chief Editor - opticallimits.com
Doing all things Canon, MFT, Sony and Fuji 
11-27-2018, 11:20 AM
(This post was last modified: 11-27-2018, 11:32 AM by Brightcolours.)
Do you have an explanation for the "shutter effect"? Did you shoot with full mechanical shutter?
And the effect is called "cat's-eye", not "cat eyes" ;-)
11-27-2018, 07:23 PM
Great vignetting test. How much, 3 stops?
11-27-2018, 08:38 PM
(11-27-2018, 07:23 PM)miro Wrote: Great vignetting test. How much, 3 stops? Cat’s eyes are caused by mechanical vignetting, which is unavoidable with large aperture lenses consisting of more than 1 element fitted to some sort of barrel Optical vignetting is caused by the unavoidable light fall-off due to light rays falling in at an angle in the image projection by a lens, the cos^4 rule. Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
Regarding the weird effect at f/1.2 and 1/4000sec - thinking about it - it may not have been the shutter but a flickering effect from the (LED-)lights.
BTW, multiple "Cat's eye" as shown are surely "cat eyes" ;-)
Chief Editor - opticallimits.com
Doing all things Canon, MFT, Sony and Fuji
11-28-2018, 12:06 PM
(11-27-2018, 08:38 PM)wim Wrote: Cat’s eyes are caused by mechanical vignetting, which is unavoidable with large aperture lenses consisting of more than 1 element fitted to some sort of barrel Thank you for the explanation Wim. I was aware only for one type of vignetting https://photographylife.com/what-is-vignetting @ Klaus - Are this light dimmable. If yes - well-known Led manufacture gives the flickering factor
11-29-2018, 11:46 AM
I thought I'd give it a go ( as I was out late-ish).
all images are SOOC and taken with canon 7D mark ii + canon 50mm f 1.8 #7749 @ f1.8 1/60 ISO 400 #7689 @ f1.8 1/80 ISO 1250 #7717 @ f1.8 1/160 ISO 1250
11-29-2018, 12:17 PM
(11-28-2018, 06:34 AM)Klaus Wrote: Regarding the weird effect at f/1.2 and 1/4000sec - thinking about it - it may not have been the shutter but a flickering effect from the (LED-)lights. No! It's the "cat's eye effect"......... (cat) 's .... belonging to the cat When tested the lens produced cat's eyes towards the edges and borders of the frame..... |
