Sigma 18-35mm f/1.8 FX equivalent

Started 9 months ago | Discussions thread
SushiEater Forum Pro • Posts: 11,356
Re: Math

MediaArchivist wrote:

SushiEater wrote:

MediaArchivist wrote:

Not is, but is like. On a crop sensor, f/1.8 is like f/2.8 on a FF sensor. It has to do with both DoF and light gathering capability.


Wrong. I mean right. I mean "wrong" is wrong, thus in fact right.

F1.8 lens gathers over a stop more light than F2.8

All things being equal, of course. But... all things are not equal if the total area of the sensor gathering the light are not equal (or the focal length is not equal, or other things are not equal).

Get a FF and put any F2.8 lens on it. Set the exposure like aperture at F2.8 ISO, shutter speed so the exposure is right. Now take crop camera and do the same thing with F1.8 lens on it. You will notice that at the same ISO, F1.8 your shutter speed will be 2x higher.

Case closed.

-- hide signature --

If I don't respond to your post after you responded to my post with NEGATIVE remarks that means you are on my Ignore list.
Photography Director for

 SushiEater's gear list:SushiEater's gear list
Nikon D810 Nikon D500 Nikon D5 Nikon AF-S Nikkor 24-120mm F4G ED VR Nikon AF-S Nikkor 28-300mm f/3.5-5.6G ED VR +15 more
Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow