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1

Yes, flash usages and aperture are independent of each other. I shoot weddings and 90-95% of my flash usage is with wide open or near wide open apertures. What is confusing you is specifically the case of shooting outdoors where you want the flash to fill in with power equivalent to daylight. In that situation, the shorter your shutter speed, the less ...


7

I'd say that it's common enough, since low-depth-of-field portraits are fashionable. However, you have to distinguish between two situations: in a studio or other controlled situation where flash is the primary light, vs. outdoors where you are trying to overpower the sun. As the questions you've linked suggest, the studio situation is easy, but if you ...


0

The two lenses differ by two stops wide open. That means that at a constant ISO, you can shoot with the f/1.4 at four times shorter exposure than with the f/2.8. This is commonly referred to as the exposure triangle. You get the same exposure for all combination where aperture * aperture * shutter time * ISO is constant.


1

Actually just did a ton of research on this myself and found this great article: http://www.lonelyspeck.com/lenses-for-milky-way-photography/ It give's you the run down of the different lens options and what actually goes into taking pictures of the Milky Way. Just got the lens I ordered for this the other day. Got myself a Sigma 30mm f/1.4 which, was very ...


1

One likely possibility is that the adapter ring you're using doesn't have a pin to hold the DoF preview lever on the lens in place, so that the lens actually stops down, and despite setting the aperture with the lens's aperture ring, you're still shooting wide open. You may need to hold the DoF preview button down while you take the shot to get the aperture ...


1

That said, why then pay for a lens that can work down to f/2.8 if, for example, you're going to use it regularly at f/8? (eg. at f/2.8 sometimes the depth of field can simply be too shallow - in the above example, take bird photography). If you use them at f/8, they will both allow the same amount of light, but shooting at f/8 with tele lenses is not ...


2

The hole stays wide open to let in the maximum amount of light when you're composing and focussing. The hole closes down to the specified aperture value at the moment the shot is being taken. That's a feature, not a bug.


3

The "thingy" you can turn on the lens is a focus dial. Most modern lenses don't have a separate manual aperture control, instead relying on the body for automatic aperture setting. And even if the lens supported manual aperture control, except for on very, very old lenses, the aperture diaphram stays open until you press the shutter, at which point it is ...


2

If you have browsed through the technical pages of Pierre Toscani, you probably noticed he is quite knowledgeable when it comes to geometrical optics. Although I cannot ascertain his schematics are correct, I certainly trust him on this, as this is an extremely well researched article. Concerning the maximum possible lens aperture, Toscani says that since ...


2

This is physically impossible. Without active amplification, the luminance of the image can not be more than the luminance of the subject. Otherwise you would be violating the second law of thermodynamics. If you try to focus the sun rays on a black body, it can get really hot, but not hotter than the surface of the sun itself. For a mathematical proof, read ...


11

There are two hard limits on how fast a lens can be: The first is a thermodynamic limit. If you could make a lens arbitrarily fast, then you could point it to the sun and use it to heat your sensor (not a good idea). If you then get your sensor hotter than the surface of the Sun, you are violating the second law of thermodynamics. This sets a hard limit at ...


0

A point to remember is that the camera enters live view at the currently set (or metered) aperture, then remains there no matter what changes you make, until you either exit live view or take a photo. This means that movies aren't always recorded at the currently-set aperture. Lets say you are in Aperture Priority Mode you set the camera to F5.6 and enter ...


1

The standard range is based on powers of √2 ≈ 1.4 It is 0.7, 1, 1.4, 2, 2.8, 4, 5.6, 8, 11 etc. On the low end manufacturesrs tend to be a bit more precise (1.2, 1.8, 2.5 etc are outside the standard range). Consider that a commercial issue, the practical difference between F/1.8 and F/2 is (very) small. The reason behind the √2 range is that the F ...


3

Well, it might sometimes be f/1.6, f/2.5, or other sizes (depending on the lens construction and on the exact f-stop used). Actually, f/1.8 fits in this "unusual" group. You might have noticed the canonical series goes by powers of √2. {1 ; 1.4 ; 2 ; 2.8 ; 4 ; 5.6 ; 8 ; 11 ; 16 ; 22 ; 32 ...} It's just easier to remember. What we're all calling ...


1

Technically, it still can't change aperture while recording, as the motor who flips its mirror up is the same which changes the aperture. Logically, it wouldn't make sense if it could change it while recording. As far as I know, only recent Nikon cameras have independent motors for each use, like the new D810.


7

They are flash guide numbers (in meters, for ISO 100). This is for the QL17, but see Cameraquest, and check out the manual here (page 17). Apparently many rangefinder (and point and shoot) cameras of the day used the "Flashmatic" system, where the camera automatically selects an aperture to match your focus distance and flash power. So, set the ring to the ...



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