Lenses not focused at infinity when set at the infinity mark
Oct 25, 2017 11:26:34 #
TheDman
Loc: USA
Pochon53 wrote:
I don't understand any of this. If there are, say, mountains filling in the background of your shot, then the mountains are infinity; if the sun is disappearing into the water at the beach, then the sun is infinity, and so on, ad infinitum, to be corny.
Sounds like you understand it perfectly.
Oct 25, 2017 11:37:05 #
PGHphoto
Loc: Pittsburgh, PA
cytafex wrote:
Pet peeve, modern lenses I've purchased don't seem... (show quote)
As mborn already stated, a well adopted practice for auto focus is to set focus before darkness, switch to manual and tape the focus ring with a small strip of gaff tape (never use duct tape !) so it can't move. You can do that with manual focus lenses as well at twilight, focus on the farthest object and tape the lens down. Better than guessing if you are in focus based on lens markings !
Infinity doesn't mean you are focused on an infinite point, it means that all subjects/areas beyond the front focus point with be sharp. Good place to talk about hyperfocal distance but no time !!!
Oct 25, 2017 11:40:14 #
Check out telescopes and mirror lenses. They all focus way past visual infinity. That is to compensate for temperature and viewfinder changes. Always pre focus in manual and use tape to hold that point unless you have a wide temperature shift. Then you have to refocus on a flash light or something shivering in the cold. Option number two is to use a Polaroid SX70 camera. It uses sound to determine focus. Happy Shooting
Oct 25, 2017 11:57:24 #
cytafex wrote:
Pet peeve, modern lenses I've purchased don't seem... (show quote)
The Infinity setting of a lens was never meant to be exact; just a rough indication of infinity focus...
Rely on the Infinity mark and you'll always be a little out of focus!
bwa
Oct 25, 2017 12:02:35 #
In the heat of the moment not having a hard stop at infinity caused my eclipse shots to be off. Bummer!
Oct 25, 2017 12:24:49 #
cytafex
Loc: Clarksburg MA
I realize that I can view the image on lcd and zoom to check focus. I also prefer to set up the shot when it's light, but it often doesn't work out that way. Daylight into darkness is a favorite time to look for images and why I'm not able to set up before. I'm spoiled with the 24mm Nikkor and lenses for Hasselblad focusing at infinity at the hard stop, unfortunately the coma distortion lens performance not up to Samyang 24mm f1.4. Can the point of hard stop be changed?
Oct 25, 2017 12:46:42 #
cytafex wrote:
...Can the point of hard stop be changed?
Yes, it is quite easy with all Samyang lenses. There are instructions online. I've adjusted infinity focus on both a Samyang 24 and 85mm lens; not because the infinity mark was off but because neither would reach infinity focus out of the box!
bwa
Oct 25, 2017 12:49:32 #
Jerry, the inspiration for my reply.
https://www.youtube.com/watch?v=KOO5S4vxi0o
--Bob
https://www.youtube.com/watch?v=KOO5S4vxi0o
--Bob
jerryc41 wrote:
I'd like to 1-10 rating systems raised to 11. 
Oct 25, 2017 12:51:13 #
...and chicken, the dino's descendents, still peck at grit.
Oct 25, 2017 13:27:31 #
jerryc41 wrote:
That's not unusual, and it's nothing to be concerned about. How often have you been an infinite distance away from something?
And why would you want to focus on infinity anyway. You really want the hyperfocal point.
Oct 25, 2017 13:33:19 #
cytafex
Loc: Clarksburg MA
John Howard wrote:
And why would you want to focus on infinity anyway. You really want the hyperfocal point.
To make images like these...
Oct 25, 2017 13:41:07 #
Good answer. But don’t you use manual and zoom
In to see rather than allowing the gauge to measure?
In to see rather than allowing the gauge to measure?
Oct 25, 2017 13:49:58 #
TheDman
Loc: USA
John Howard wrote:
And why would you want to focus on infinity anyway. You really want the hyperfocal point.
I'd rather focus on what I'm trying to get in focus.
Oct 25, 2017 14:01:32 #
That's another issue. Zoom lenses don't always hold focus through their zooming range.
John Howard wrote:
Good answer. But don’t you use manual and zoom
In to see rather than allowing the gauge to measure?
In to see rather than allowing the gauge to measure?
Oct 25, 2017 14:10:51 #
Sorry I did not really mean zoom. I meant using the focus assist enlargement so you can see better to sharpen focus.
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