I Dare You!

by peter_budo

submit your photo

Hall of Fame
View past winners from this year

Please participate in Meta
and help us grow.

Tag Info

New answers tagged


If you know the daytime brightness for a properly exposed scene, and the nighttime brightness, you can just calculate how many stops difference between the two you have and set the night aperture accordingly. Say, 2048lux day, 64lux darkness = 5 stops difference. (log2(2048)-log2(64)) I don't know how focus comes into this, though, that wouldn't change ...


It sounds like you have AI Servo selected for the AF mode. The behavior you describe is normal if that is the case. To do what you want, you need to select One Shot as the AF Mode. Please note that when shooting in one of the continuous drive (burst) modes, the camera will not refocus between each shot that is taken while you continue to hold the shutter ...


There are many settings on the Canon 5D mark III that affect what you see and when you see it in the viewfinder. The camera does have the ability to indicate when focus is achieved over a certain point during manual focus, but only if all of the correct settings that affect the display are selected. Start in the menu with AF tab 3 USM lens electronic MF ...


There are two ways I see to describe what you are asking for. One would be to simply turn on all focus points in the AF Menu, manually focus, then press on half-way on the shutter release and any points that overlap the focus points and are in focus will light up. This is the same as the 7D. What I think you are ultimately looking for is commonly referred ...


The physics... The ground glass (or plastic) screen acts as a diffuser, scattering light passing through it randomly rather than simply letting it pass through unaffected. An image can be brought to focus on the screen by adjusting the lens, and the image we perceive comes from scattered light that is traveling in the precise direction of our retinas. The ...


The ground glass, or focusing screen, is, in the simplest case, literally just a piece of glass that has been ground, so one of its sides has a rough/matte surface (see also the article Ground glass on Wikipedia. It's actually quite easy (at least for large format cameras) to make ground glass yourself, see this how-to for example. The ground glass just ...


Focusing doesn't require changing the focal length of a lens, it changes the distance of (the center of) the lens to the sensor or film.


I don't know about the focus-by-wire bit, but this photo.net discussion thread includes side-by-side images of the mounts of a 5D and an EF-M, and shows that the EF-M did indeed have all the electrical contacts of the EOS mount. My guess would be that manually focusing with focus-by-wire will probably still work, since that's more about electronic ...

Top 50 recent answers are included