December 2, 2010 – Roses

Roses

Thursday, December 2, 2010

Welcome to December! Hope you didn’t have any trouble getting here. I’m kind of breaking one of my sort-of quasi rules today, in that I’m already posting another picture of some roses from across the street, when I already just posted one a couple weeks ago.

But!! There’s a reason for it. Somebody asked me recently about mounting non-Canon lenses on a modern Canon dSLR. It’s true that I talked about it the last time I posted a shot from this particular camera/lens combination (as well as a couple other times over the years), but it never hurts to cover it again. To recap: this was taken with an old Kiron 105mm macro lens that was built with an old Minolta mount. When I say “old”, I mean really old, back when they used actual physical actuators to control the aperture, none of this electronic craziness. I mean GOSH.

I won’t bore you with the full description of why that’s interesting again, especially when I already linked to a whole post talking about it. BUT, I whipped up a little illustration of some of the points I was talking about when I was talking to the reader that was asking, so I figured that was of general enough interest that I should share it here as well. I was talking about how lenses that are built for different camera mounts are expecting to have different distances between the rear end of the lens and the sensor or film. But that’s the kind of thing that is much easier to visualize if you’re looking at a picture of it. So, I made a picture of it. The first section shows the normal situation, using a lens designed for the mount that your camera uses. The next section shows what happens when you use a lens that expects a LONGER lens-to-sensor distance (ie, Nikon lens on Canon mount), and when you attach a mount adapter to it. And, the last section shows a lens that wants a SHORTER distance (ie, Minolta lens on Canon mount), using an adaptor either with or without glass. When I shrunk the image down to a reasonable size, some of the text became too small to read, but the labels for the adapters say “Adapter (no glass)” and “Adapter (cheap glass)”.

Nikon and Minolta lenses on Canon mount

Nikon and Minolta lenses on Canon mount

So, there you go. Now you all get it, right? Yay!

Notes: Canon EOS Rebel T1i, Kiron 105mm macro lens. 1/250s, ISO 200. Aperture unknown.

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