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What’s a lens cone?

I believe they are off an aerial camera (or possibly a fixed focus macro system of some kind) – they’re used to fit large format lenses of different focal lengths at a fixed extension in a system where focusing isn’t required.

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Obviously, you should use them to store your lens cones…

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Punctuation and URLs don’t mix well.

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Nice! You can get the HTML for a link to that size under Share This > Grab the HTML if you turn on the new-style page

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Macro magnification isn’t the same thing as magnification for a telescope at all, I don’t believe. Basically, if the lens focal length is 100mm then if the lens-sensor distance is 100mm you’re focused at infinity. If the distance is 200mm you’re focused at 1:1 magnification. Aperture is irrelevant to this, as is sensor size.

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Yeah, for a simple lens, to get to 1:1 you need extension of 2x the focal length from the imaging plane (infinity is at 1x)

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Ironically the companion lens isn’t much better than green glass (complete with tiny bubbles) but, in tandem, they work beautifully.

Are you sure the second lens was in the optical path of the projected slide? It sounds might be a modifier for the light source rather than part of the actual projection.

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I use Adorama and Mpix. Print quality is comparable, and adorama is a bit cheaper, but they tend to be significantly slower.

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Best thing to do for starters if a shutter is slow is just run it a bunch of times (like 20 or so) and see if that helps, sometimes it just needs to get moving a bit. Flushing with solvents like lighter fluid can help but it can also make things worse (free up gunk and carry it into places it shouldn’t go). For something like a C3, where the shutter mechanism is pretty basic it’s probably fine, but I would avoid it for anything rare/valuable.

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Here, a manual: http://www.butkus.org/chinon/argus/argus_c-3/argus_c-3.htm

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>>>>though for the life of me I’m unsure how you advance the frame, unless you just guestimate it manually. There’s some sort of dark green window on the backside.

That window is how you advance the film – 828 was ~35mm sized rollfilm with backing paper on a spool (like 120). The frame numbers were printed on the backing paper and visible through the window.

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I think that thing at the top is a projector – early “Magic lantern” slides were on 3″ or so glass plates rather than film. It might be missing the slide holder though?

The Argus cameras are C3s – that was one of the first really popular mass market 35mm cameras in the US. They actually have interchangeable lenses, there’s a 35mm and 100mm available as well as the 50.

http://en.wikipedia.org/wiki/Argus_C3

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there’s no glass, so image quality is as good as good as the lens you’re using.

This tends to depend on the lens, actually. You may find that some of them don’t work well for this at all, because they aren’t well corrected for closeup work (e.g. field curvature will be exaggerated a great deal as you increase extension). Also, if you’re using a lens which has some degree of optical correction for close focusing, you’ll only get the maximum benefit at the closest focusing distances (which means you won’t get the best results if you try to use the lens’s focusing mechanism to focus on extension).

with the probable exception of wide angle lenses where depending on the tube length you’re using, you might be moving the focus distance to some place *inside* the lens 😆 ).

If the filter diameter is small enough to do it conveniently you can usually fix that with a reversing ring. With some lenses that may also improve the image quality, particularly as your magnification gets up beyond 1:1 (at that point the the sensor – lens distance is becoming greater than the lens – subject distance, so they tend to be optically corrected better backwards at that point)

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/how many cars will I need to sell before I can even breathe in the same room as a nikon equivalent.

None. There isn’t a Nikon equivalent 🙁

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Well hm..on further reading of that lens review, it mentions the effective apperture is quite a bit smaller than stated aperture. I’m not sure how that works, or how that works without introducing a boatload of diffraction softening by f/5.6 or f/8. Damn all this math…

Yeah, the thing is that people talk about changes to “effective aperture” when talking about macro lenses, but that can actually be quite misleading. When you focus closer by moving the lens further away from the camera, you lose light due to extension (the lens is projecting a bigger image circle, so there’s more light getting lost inside the lens, and less light falling on the sensor/film). People tend to call this a change in the aperture because they’re used to dealing with exposure in terms of three variables and it clearly doesn’t fit into shutter speed or ISO, but it’s not actually affecting your DOF or diffraction the way an actual change of aperture would, it’s really just light loss due to extension (it’s called “bellows factor” in large format shooting: www-unix.oit.umass.edu/~rbhome/bellows15.pdf).

This doesn’t necessarily apply to internal focusing lenses though. They’re focusing by changing the optical formula of the lens which can alter the effective aperture (as well as shortening the effective focal length in many cases).

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