Aero145 From Iceland, joined Jan 2005, 3071 posts, RR: 21 Posted (8 years 1 month 3 weeks 3 days 3 hours ago) and read 6497 times:
As the Canon 100-400mm lense is now getting old, and has an old stabilizer, do you think Canon will come up with a f/2.8 version of the lense? The 100-400 is very bulky, and I'm wondering if a 2.8 version would be too big to be handhold. I'm thinking about this lense in the future; would the f/2.8 turn out to be too big and too expensive (also heavy)?
Could the lense geniuses tell me something about f/ versus size?
Aero145 From Iceland, joined Jan 2005, 3071 posts, RR: 21
Reply 10, posted (8 years 1 month 3 weeks 2 days 23 hours ago) and read 6374 times:
Quoting IL76 (Reply 6): Oh the joy of youth. So fresh and naive... Not afraid to ask silly questions.
Silly answer, especially for you, Ed.
Joy of youth. No, I am not really enjoying it.
Not afraid to ask silly questions. (Why should I be afraid of that???) Silly for you, not silly for others. I'd love to see your face when Canon comes up with a f/2.8 version of the 100-400, very sharp, only $1500. I'm not saying they WILL come with that lense, but not think you would be disappointed with a 2.8 version of the 100-400. F/4.5-5.6 is all right, but isn't it nice to have a zoom lense that reaches the Canon 400mm f/2.8L?
Quoting IL76 (Reply 6): Imagine a lens like the 100-400, twice as long, a diameter of 20cm, weighing 20kg costing $20.000. I'm sure it'll sell like hot cakes.
IL76 From Netherlands, joined Jan 2004, 2237 posts, RR: 48
Reply 20, posted (8 years 1 month 3 weeks 2 days 16 hours ago) and read 6286 times:
Quoting Glennstewart (Reply 18): But seriously....I wouldn't mind knowing the technical reason either for lens size versus aperture.
Devide the focal length by the size of your lenscap and you'll find a number pretty close to the max aperture. (Yes I was exaggerating in my previous reply. I tend to do that when I get questions like: "Can a future Hummer do 100 miles to the gallon?" and stuff like that)
StealthZ From Australia, joined Feb 2005, 5688 posts, RR: 44
Reply 22, posted (8 years 1 month 3 weeks 2 days 14 hours ago) and read 6259 times:
Quoting ChrisH (Reply 21): I've been wondering why a 600mm lens isn't 60cm+ long. Any ideas?
This is likely to be an oversimplification and some boffin may correct the details..
Basically a lens with a focal length of 600mm will require only a single(the front) element to focus a point source of light on a plane 600mm away(remember the magnifying glass you used to burn holes in paper as a kid?).
The other elements in a lens are used to further correct the light path to make the lens shorter and more compact.
Oh yes, as I said that is a gross oversimplification and photography is not about point sources of light so it is somewhat more complex than this!
If your camera sends text messages, that could explain why your photos are rubbish!