Fractal lenses
Aug 23, 2019 14:55:26 #
I just purchased a set (3) of fractal prism lenses and maker advises back button focusing and use of a 50mm leans which I already have on my Canon 5D. Can anyone tell me why these instructions and limitations. I usually shoot with a 28-135,Thanks
Aug 23, 2019 15:39:02 #
Aug 23, 2019 17:43:32 #
Back button focus focuses the same as shutter button half press, it just locks the focus when you let go of the button. Same as holding a half presses shutter in one shot mode. Can't see why it would matter.
Aug 24, 2019 15:13:13 #
DTCOP wrote:
I just purchased a set (3) of fractal prism lenses and maker advises back button focusing and use of a 50mm leans which I already have on my Canon 5D. Can anyone tell me why these instructions and limitations. I usually shoot with a 28-135,Thanks
Interesting to see how AF works with all the prisms.
Aug 24, 2019 17:23:11 #
Aug 24, 2019 19:08:39 #
Rich Maher wrote:
Where did you purchase them?
Thanks
Thanks
Google is your friend.
Aug 24, 2019 21:42:01 #
Aug 25, 2019 00:57:17 #
melismus wrote:
All this talk about Fractal lenses---don't you mean Fresnel?
Right. And that may be why back button focus is recommended. If the focus target is through the grooved portion of the lens, the camera may become confused. I've not thought it all through, though.
Aug 25, 2019 13:20:33 #
Google Nikk Wong, fractal lenses
That the correct spelling of his first name. Received mine.... well constructed Will shoot with them soon
That the correct spelling of his first name. Received mine.... well constructed Will shoot with them soon
Aug 25, 2019 13:57:24 #
melismus
Loc: Chesapeake Bay Country
I am getting a sense that fractal filters and Fresnel lenses are two separate subjects.
Aug 25, 2019 14:58:43 #
Yes they are. I have a light that has a fresnel lens. Supposedly a throwback to lighthouse days where the light was not visible "way out there." A Frenchman (I believe "invented" the fresnel lens which threw the light out further
Fractal filters are made to distort images
Fractal filters are made to distort images
Aug 25, 2019 15:06:25 #
ygelman wrote:
Right. And that may be why back button focus is recommended. If the focus target is through the grooved portion of the lens, the camera may become confused. I've not thought it all through, though.
It's just that back button focusing is just a different button for the same focusing system, so maybe there is a different reason.
Aug 25, 2019 15:29:53 #
melismus
Loc: Chesapeake Bay Country
I am talking about photographic lenses with Fresnel elements, to reduce size and weight. I want to know more about these.
Aug 25, 2019 15:44:59 #
melismus wrote:
I am talking about photographic lenses with Fresnel elements, to reduce size and weight. I want to know more about these.
You could start your own topic, they are interesting lenses.
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