MLU lever to lens stop down lever modification, written by Luigi Cassinelli
		My name is Luigi Cassinelli. Between 1995 and 2016 I completed 345 assignments for the fashion industry, editorials and campaigns. Most of my work has been done on locations from all over the world, with no flash, and by using mainly natural light and available artificial light. I used Pentax 67/645, Leicaflex SL and SL2, Nikon F2/F3/F5/F6, Contax 645; sparingly, I worked with Hasselblad 500, Nikon FM3A, Canon eos-1 V, Leica M3/M5/M6, Mamiya 7 and RZ, Toyo 45AII and VX125. In 2025, I asked Sover Wong to modify my Nikon F2AS in a way that would allow me to view and focus at the working aperture instead at the max aperture. By design, this operation is possible by pushing the depth-of-field preview button, but such action interrupts my flow. The reason for my request is based on the following points. Of course, these are subjective preferences and evaluations, but they might help others. Premise 1. My main goal is to capture a moment while I am viewing the projected image of my chosen lens. Hence, I prefer SLRs that allow me to focus any part of the image without changing my framing. I avoid central split images, rangefinders, and autofocus systems; for my eye, these are distracting features that slow me down. I need clear matte screens. My favorite screens are the B and E type. Premise 2. Out of all the cameras I used, the Nikon F2AS optical system delivers the highest clarity. It is not as bright as the FM3A and F6, but delivers a crisp image to the eye, one that eliminates any indecision in evaluating the plane of focus. For me, this is a critical issue, even more so when I focus in the range of 2 to 3 meters. Premise 3. The other fundamental element that affects clarity in the viewfinder is the intensity and quality of light in the environment. I will divide this aspect in two situations: strong light (full sun, ocean setting, usual reading 1/500 f/8.0 with 100 ISO - EV 15) and dim light (shadow, for example below EV 8). Now, I get to the point about focusing at the working aperture. The heart of the matter is the lens I use and how it renders light. Among my set of lenses, these 4 are peerless to me: Voigtländer Ultron 40mm f/2.0 Nikkor Ai-S 50mm f/1.2 Nikkor Ai 55 f/1.2 Voigtländer Nokton 55mm f/1.2 Besides the focal differences, they all render in a unique way (once again, this is my subjective point) and I need them all. I value and use them only at f/2.0-2.8 in dim light and at 4.0 under strong light. For example, let's consider the Nikkor Ai 55 f/1.2. In the Nikon F2as viewfinder, there is no difference in brightness between the max aperture 1.2 and the aperture 2.0 (I might see a tiny change just before turning the aperture to 2.0). Even if I got 2.8, the image is extremely clear. So, for, me the 1.2 max aperture has no use. With Sover's modification, in dim light, I set the 55 at 2.0 and my negatives show precise focus and rich details; if changes in exposure are needed, I adjust the shutter speed, but I keep the wonderful rendering the lens delivers set at f/2.0 and at 2-3 meter distances (for example, full/half figure in a room or under vegetation). Under strong light, focusing at 4.0 is extremely clear, while using the 1.2 max aperture turns the matte screen "too bright" for precise, immediate evaluation. Hence, with Sover's modification I am able to follow the light, set, and view at the working aperture. There is another lens that delivers a superb performance: the Nikkor 25-50mm f/4.0 used at f/11.0. The resulting image is like no other. In this case, Sover's modification still gives me the option to use the original camera design by focusing at max aperture, f/4.0, and by closing automatically to working aperture, f/11.0, at shutter release. In a summary, this is the operation with Sover's modification: 1. By turning the mirror lock-up lever downward, I still have the mirror in viewing position, but the depth-of-field lever is completely down (so not engaging and holding the lens at max aperture); 2. I lose the option to have the mirror locked up, an option that I do not need; 3. To use a lens with the regular open aperture metering and focusing, I simply return the lock-up lever upward to regular position. Regards to all, Luigi Cassinelli Naples, FL, USA Click here for Luigi’s home page https://www.luigicassinelli.com/