>>3413531You don't have to make any manual adjustments to your exposure--the teleconverter steals its light before that light hits your meter, assuming you're using a relatively modern SLR (I.e., anything made since the 1960s or so). If you have an external meter of some sort that's not looking through your actual lens system, then yeah, adjust it two stops down. But I just noticed you said you were shooting a Minolta SR-mount cameras, so no problem.
>>3413566>I wasn't aware it was 2 steps for the 2x tcQuick intro to aperture math, since a lot of people just sort of accept the weird list of f/stop numbers without wondering why they are.
An f/stop is actually the ratio of your focal length (f) to the diameter of the entrance pupil of your lens (more or less. Actual modern lens designs are way more complex than that, but we don't need to give a shit for the purposes of this explanation).
Which means that, for instance, a 50mm f/1.0 would have an aperture 50mm in diameter.
What they discovered a century or so ago is that a ratio of the square root of 2 halves or doubles the light. We usually round that down to 1.4 because sqrt(2) is actually an irrational number and writing an infinite, non-repeating number sequence on a lens would be prohibitively expensive. But sqrt(2) * sqrt(2) = 2, which is easy.
That's why the common aperture sequence goes 1.0, 1.4, 2.0, 2.8, 4, 5.6, 8, 11, 16, 22, etc: Each of those is the previous one times sqrt(2). Easy way to remember that is start with 1 and 1.4 and alternate doubling them
That's also why the most common sizes for TCs are 1.4x and 2.0x--you're taking that focal length in the f/number formula and multiplying it by sqrt(2), one stop; or sqrt(2)^2=2, two stops. It makes the aperture math easier to do because you're adding one stop or two stops depending on whether it's 1.4x or 2.0x.
So your f/3.5 lens becomes an f/7 lens with a 2x TC, which, yeah, is gonna be dark as shit.
