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Tolerances of optical elements in lens
Ethan Brake posted a topic in Lenses & Lens AccessoriesI've been mulling what it would take to make a lens from scratch, particularly a projector lens. With proper machining equipment, I believe I could construct every part of the lens except the actual glass elements themselves. As far as designing the optics, instead of ordering custom glass elements, I could take advantage of the low cost of mass produced elements from companies like Edmund Optics. However, I'm wondering just what kind of tolerances in the glass thickness would be acceptable. For example, in an old episode of "How It's Made", they show the construction of a Canon EF 500mm F4 L IS USM lens, a $9000 lens, and they mention that the glass elements have a tolerance of +/- 0.001mm. That kind of a lens has far more precision than I would need. The cheapest elements from Edmund Optics however have a tolerance of +/- 0.1mm., something I would guess is way too low, but I'm not sure. This is for projecting Super16 film in a modified projector. Really, I don't think I would need better precision than what you would find in a $100 DSLR kit lens. My question is: What kinds of tolerances would be acceptable, and/or what kind of precision is used in mass produced kit lenses.
Hi, I am in need of some guidance concerning a lens adapter we are building. We have had some amazing success with a recent anamorphic adapter lens build that solved the minimum focus distance problem, and we have also been testing another solution for the same problem with anamorphic adapter lenses. Here is what we are trying to do: Build an adapter lens that can back-focus to the image sensor, testing at this time using a either a Micro 4/3 Camera Body Mount to the Panasonic GH5, or a Canon EF mount with a Full frame lens turbo adapter to the Micro-4/3 body. Some people have done similar things using "Stretch Adapter" on different cameras like this one in the link below: https://www.amazon.com/Fotodiox-Stretch-Adapter-Ability-Mirrorless/dp/B01E0I1UZ6 Or to get a rare focusing mount adapter usually found for B4 mount lenses with a backfocus lens like this one in the link below: https://www.ebay.com/itm/2-3-B4-Mount-Lens-to-M43-M4-3-Micro-4-3-Camera-adapter-backfocus-adjustable-BMP/183282643275?hash=item2aac7f314b:g:f9gAAOSwUKxYbaPF OR: I have been trying to utilize combinations of Enlarger Lenses mounted normal facing, or reverse facing from the rear element and mount of various Canon EF mount 35mm lenses in addition to a +10 Achromat diopter with Reverse Macro Adapter mounts. I have barely got a visible image. You may be asking, "WHAT IS YOUR OBJECTIVE?" It is the long-awaited and highly suggested REAR ANAMORPHIC ADAPTER LENS. How are you trying to do this? We bought various tiny Anamorphic Adapter lenses designed for IPHONES and IPHONE DOF ADAPTERS. Both being: 1. Moondog Labs 1.33x Anamorphic adapter lens 2. Beastgrip 1.33x Anamorphic Adapter lens This is put either forward facing or reverse facing behind the prime lens (various Canon EF mount 35mm lenses) VIA a REVERSE MACRO ADAPTER WITH ELECTRONIC COMMUNICATION TO THE 35mm Lens. The Reverse macro adapter has filter threads on either side of the adapter, (rear of prime lens, and front side of Body mount [Canon EF]) The logical way for me to see results seemed to be to put the anamorphic adapter lens on the rear side of the 35mm lens via the threads and step rings of the reverse macro adapter. Then various combinations to try and get this now blurry anamorphic adapter lens to "BACKFOCUS" to the mirrorless camera image sensor mainly trying Enlarger Lenses and +10 Achromatic Diopters. Does anyone out there know of a way to go from an anamorphic adapter lens on the rear side of a prime lens and BACKFOCUS using ANY METHODS to get a sharp and usable image on the camera? I have been trying for a while and have not got that many usable results. I am curious to any advice anyone can give. And if something works, I can share the solution with everyone. Please help, -Thank you