gpwhite Posted February 4, 2015 Share #101 Posted February 4, 2015 Advertisement (gone after registration) The fact that you can see the blades has noting to do with the actual size of the pupil/ how the max aperture is calculated, you can't just 'open up' lenses like that. A quick way to test this is to use a point light source out of focus (a led or similar shot at 1 meter and the lens focused at infinity) and shoot the lens wide open; The OOF highlight will be pefectly round, then stop down half a stop, and the OOF will be shaped from the number of blades in the aperture. Only few Leica M lenses has round enough aperture opening to hide this effect. BTW the lens is outstanding! Thank you for the comments, but I must be thick. I am suggesting that the opening could be increased... in other words, the blades you describe would be recessed completely into the lens mount, as you see on the Elmarit-M 24mm ASPH for example. How is the pupil diameter calculated, if not as the length of the line from one side of the diaphragm to the other side at maximum opening? Link to post Share on other sites More sharing options...
Advertisement Posted February 4, 2015 Posted February 4, 2015 Hi gpwhite, Take a look here Elmar 24 mm f3.8 lens. I'm sure you'll find what you were looking for!
Erik Gunst Lund Posted February 5, 2015 Share #102 Posted February 5, 2015 What you can 'see' inside the lens and the light pasing through the lens and forming an image at the film plane are two completly different things. Edit: The aperture is calculated from the 'aparent' size of the light comming through the lens whe viewed from the front. It is not a physical measurement of the opening or the aperture blades inside the lens. The max aperture is often not restricted by the aperture blades but the rings housing the aperture blades. Link to post Share on other sites More sharing options...
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