Fresh Dew on a Rose

by adarsha joisa

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3,148 reputation
11251
bio website fierydragonlord.com
location New York, United States
age
visits member for 3 years, 10 months
seen Jan 27 at 18:29

I'm a computer and tech enthusiast with a variety of interests, from video games to fountain pens.

I take the accuracy and correctness of my contributions very seriously. If you find any problems with my posts, feel free to edit them or let me know in chat if you have any questions or comments.

I'm also one of the resident spam fighters on Super User and can catch spam others miss. If you suspect that one or more posts are spam, bring it up in the Ask a Super User Moderator chat room, and be sure to ping me—I'm around most of the time. Don't forget to flag blatant spam—it takes just six spam flags from the community to delete it.

It sounds like flagging posts as spam isn't enough; they need to be flagged specifically to your attention (and what are the odds that you haven't already found it). —fixer1234 (source)

As an aside, I'm a bit of a photo enthusiast. I shoot with Pentax eqiuipment, and you can find me on Pentax Forums.


Gravatar derived from D&D red dragon on Wikimedia Commons, courtesy of LittleDrakon, CC BY-SA

Note that I'm not really into tabletop RPGs. I simply felt that this image suits me best.

profile for DragonLord on Stack Exchange, a network of free, community-driven Q&A sites


Oct
19
answered Is it normal for focal length to change while focusing?
Oct
19
comment Is it normal for focal length to change while focusing?
No. This is the other way around.
Oct
19
asked Is it normal for focal length to change while focusing?
Oct
17
accepted What apertures are required to enable autofocus, including cross-type or high-precision focusing, on Canon DSLR cameras?
Oct
15
comment What apertures are required to enable autofocus, including cross-type or high-precision focusing, on Canon DSLR cameras?
This is all in the manuals, but it would be more convenient if there was a comprehensive list that can easily be found. I decided to "seed" this question and answer to help Canon users with regard to what their lenses allow in terms of autofocus.
Oct
15
revised Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?
deleted 1915 characters in body
Oct
15
answered What apertures are required to enable autofocus, including cross-type or high-precision focusing, on Canon DSLR cameras?
Oct
15
asked What apertures are required to enable autofocus, including cross-type or high-precision focusing, on Canon DSLR cameras?
Oct
8
comment Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?
... which is why allowing both requires additional AF sensors, one for faster lenses and one for slower lenses. This is the approach Canon takes in its AF systems. Nikon, Olympus, and Pentax don't take this approach, which may explain why the Pentax DA* 55mm lens shows variable accuracy on different camera bodies, as noted in the conclusion of dpreview's review of this lens.
Oct
8
accepted Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?
Oct
8
comment Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?
In any case, while every phase detection AF system has a hard limit (typically around f/11 AFAIK), the fact that Canon has these limitations that are set above these hard limits means that this answer most directly answers the question.
Oct
8
comment Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?
To help understand this, I tried looking through the viewfinder of a manual focus film SLR with split prism focusing aid. I noticed that that opposite parts of each side of the split prism blackens as the lens stops down in depth-of-field preview, and that focusing with the split prism is no longer possible by f/16-22 - even with a bright flashlight aimed at the center of the lens. It seems this would explain why phase detection doesn't work past a certain aperture. Though it may still function to an extent beyond f/8, it certainly won't work at f/16.
Oct
8
comment Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?
From what I've read, the tape trick results in unreliable AF. The camera may cope in brighter conditions with high contrast, but will hunt and fail to acquire focus in low light or low contrast, depending on the camera body.
Oct
8
revised Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?
added 1 characters in body; added 68 characters in body
Oct
8
revised Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?
added 599 characters in body; added 7 characters in body
Oct
8
revised Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?
added 138 characters in body; deleted 1 characters in body
Oct
8
comment Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?
I don't have a Canon DSLR, but this is something that I don't find with Nikon, Olympus, or Pentax (the system I use). I also recognize that high-precision points truly require the specified apertures, but the fact that a certain minimum aperture is needed for AF to work at all on Canon raises this question.
Oct
8
revised Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?
added 1 characters in body; edited tags
Oct
8
asked Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?
Oct
6
accepted How should I set up a flash bracket for Pentax?