What's a "fixed" 2.8 lens mean?
Nov 26, 2023 09:35:59 #
Canon has a refurb RF 100MM fixed 2.8 macro lens for sale. What do they mean my fixed? Maybe I'm not up on new terminology. It wouldn't be the first time
Harry
Harry
Nov 26, 2023 09:38:18 #
Nov 26, 2023 09:41:37 #
Nov 26, 2023 09:45:22 #
foathog wrote:
Canon has a refurb RF 100MM fixed 2.8 macro lens for sale. What do they mean my fixed? Maybe I'm not up on new terminology. It wouldn't be the first time
Harry
Harry
Where do you see it posted? Can you provide a link. Generally the term fixed may be used with a zoom lens which doesn't change aperture as you zoom. Or it can be used with a lens that is not zoom and means that the focal length is fixed.
But seeing the posting we can figure it out.
Nov 26, 2023 09:51:13 #
Nov 26, 2023 09:52:08 #
To me it means that you get 2.8 and 2.8 only. who the hell would want that? LOL
Nov 26, 2023 09:53:07 #
foathog wrote:
To me it means that you get 2.8 and 2.8 only. who the hell would want that? LOL
It never means that the lens can only be used at f/2.8. I saw the listing. It's the fault of the person who wrote that listing. It does sound as if it only has 1 aperture but in fact the lens can be used at f/2.8 to f/32.
Nov 26, 2023 10:10:56 #
Nov 26, 2023 10:24:52 #
foathog wrote:
Canon has a refurb RF 100MM fixed 2.8 macro lens for sale. What do they mean my fixed? Maybe I'm not up on new terminology. It wouldn't be the first time
Harry
Harry
"With fixed aperture lenses, the aperture is not affected by the zooming mechanism of the lens, and it stays constant throughout the focal length range." (https://www.makeuseof.com/fixed-vs-variable-aperture-lens/)
Nov 26, 2023 10:27:06 #
srt101fan wrote:
"With fixed aperture lenses, the aperture is not affected by the zooming mechanism of the lens, and it stays constant throughout the focal length range." (https://www.makeuseof.com/fixed-vs-variable-aperture-lens/)
Yeah but the lens in question is a fixed focal length lens of 100mm. The writer I guess wrote so many posts for zoom lens and excited to to write that the lens as fixed aperture when uhh.. you can't zoom the lens.
Nov 26, 2023 10:30:51 #
With some zoom lenses the maximum aperture available reduces as the focal length increases. At the wide end you may have, say, f/3.3 or some such, but as you zoom in on a scene the widest aperture falls away to perhaps f/5.6 or maybe even smaller.
However, none of the above applies to a prime lens since the focal length is not variable.
However, none of the above applies to a prime lens since the focal length is not variable.
Nov 26, 2023 10:42:18 #
foathog wrote:
Canon has a refurb RF 100MM fixed 2.8 macro lens for sale. What do they mean my fixed? Maybe I'm not up on new terminology. It wouldn't be the first time
Harry
Harry
Fixed aperture zoom lenses maintain a constant aperture throughout their zoom range.
Fixed aperture prime macro lenses maintain a constant aperture throughout their focal range.
Nov 26, 2023 10:44:56 #
foathog wrote:
Canon has a refurb RF 100MM fixed 2.8 macro lens for sale. What do they mean my fixed? Maybe I'm not up on new terminology. It wouldn't be the first time
Harry
Harry
It is a poorly written sales listing. Seems to have a few errors and ambiguities and possibly unintentional non-sense. But it seems like an interesting and nice lens at what seems to me like a good price. You should buy it if it will serve your needs.
Nov 26, 2023 10:46:04 #
Nov 26, 2023 11:05:02 #
The info at the Canon posting explains what fixed means. It means that the focal length is 100mm. It says ".....fixed 100mm....." That means it is not a zoom lens with a variable focal length.
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