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Hot answers tagged

4

I'm surprised AF works with the 6D! That lens was discontinued at least a decade ago. Being that it does work on the 6D, though, it is disappointing that it doesn't also work on the 70D. Both the 6D and 70D use the Digic 5+ processor and were released about 9 months apart in 2012-13 around ten years after the Tokina AT-X 400 AF was last made. It would be ...


3

There are special situations where MF will be more reliable, but most of the time AF is better: Lenses that are designed for AF are usually difficult to focus manually with great precision. The internal focusing mechanism is designed for AF speed, which means that small movement of the focusing ring makes relatively large difference in the focus plane. The ...


2

Strictly, to get "crisp results" they are both exactly equal and capable. Autofocus and manual focus both do the same thing -- bring the image into focus -- and by moving the glass they both do this the same way. It's really about the user, the camera, the conditions. Try using manual focus by simply racking back and forth and you'll get nowhere. Try using ...


2

There's no definitive answer to this. It depends on what your subject is and what the situation allows. If you're shooting still life or landscape from a tripod, you can switch to Live View, zoom in and use manual focus. If you're shooting sports or live music, there will be a lot of movement involved, so it won't be easy without continuous focus (AF-C).


2

As a first-order approximation: Contrast-detection autofocus is more accurate and more flexible Phase-detection autofocus is much faster Contrast-detection always requires "hunting" back and forth to find the best focus; in ideal conditions phase-detect moves certainly to the right point Contrast-detection which uses the main sensor is likely to hurt ...


2

1600, aperture 5.6, shutter speed 1/64 is 'low light' Not dark by any means, but roughly 300 lux if I didn't do something wrong (no guarantee). (1 x 1600/100 x (5.6/1)^2 x 64/100 ~= 320) The 1/64th shutter speed may be marginal shake-wise depending on what your actual (unstated) focal length is and whether you are using an (unstated) tripod. Phase ...


2

What should I check / examine / investigate to get this working on my 70D? I'd start by cleaning the contacts on the lens. You know that the lens works because it works on a 6D. While it's certainly possible that the lens is completely incompatible with the 70D, one would expect at least some basic functionality if the lens is working at all. Dirty ...


1

Because Canon doesn't license its mount or give the internal details of the electronic communication to third parties, nearly everyone has to reverse engineer the mount communication signals. So this is the main danger of going with a 3rd party lens (particularly an old one)--that when the lens is new, it will communicate properly, but that with older ...


1

Your AF-S 18-105 VR lens has what is known as internal focusing. That means that all of the movement when the lens focuses is on the inside of the lens and nothing on the outside of the lens moves when the lens autofocuses. Your 18-55mm lens does not have an internal focus design and the front element and front barrel of the lens do move when the focus is ...


1

It is within the realm of possibility that the lens is back focusing. To confirm this and measure exactly to what degree, though, the target and distance scales need to be properly aligned with the camera. There are a couple of reasons why good alignment is needed to get a valid AF test measurement: If the camera is aimed at an angle to a target such as ...



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