Cost of High Quality Glass vs. Photos

[Aye-non Oh-non Imus]

Your completely unwarranted aggression in response to that question and your continued failure to make even the most basic attempt to answer it would seem to indicate that you are way out of your depth.

:roll:


eacemrgreen:

 

[table1349]

Your completely unwarranted aggression in response to that question and your continued failure to make even the most basic attempt to answer it would seem to indicate that you are way out of your depth.

:roll:


eacemrgreen:

Perhaps a bit of reading would be in order. Understanding Camera Lenses
» Lense tutorial, understanding camera lenses Digital photography articles » Blog Archive
Understanding Camera Lenses

 

[Derrel]

I have a hard time trusting an article written by an author who would write a web article entitled "LENSE TUTORIAL,UNDERSTANDING CAMERA LENSES".
If the author can not spell l_e_n_s correctly, I simply can not bring myself to trust in his level of education about photographic topics. Lens. Lens. Lens.

The author also plagiarized the section about Canon L lenses directly from Wikipedia,with no attribution whatsoever.

Reading through the article, if one can call it that, about all that is discussed are the various abbreviations used by manufacturers in lens model names,and not very much about anything else. Nothing about WHY ED glass or fluorite elements are used, nothing about fixed focal length lenses versus zoom lenses, nothing about the differences between "fast" lenses and "slow" lenses,and so on.

Has the original poster even checked back in with this (greatly degenerated) thread?

 

[Stosh]

What makes this discussion even more ironic is that the true (or maybe original) meaning of aperture is the physical size of the opening (or iris). It's come to be interchanged with f-number or f-ratio and apparently that's now acceptable. They are really not the same thing. The f-number or f-ratio is a ratio of aperture (physical opening) to focal length. A 50mm f/2 lens has a max f-ratio of 2, but a max aperture of 25mm. A 100mm f/2 lens has a max f-ratio of 2, but a max aperture of 50mm. A 200mm f/2 lens (an extremely expensive lens available from Canon) has a max f-ratio of 2, but a max aperture of 100mm.

So even a "constant maximum aperture zoom" lens doesn't really have a constant maximum aperture. It has a constant maximum f-ratio. Apparently that's too hard to say or too confusing.

 

[manaheim]

errrrrrrrrrrrrrrrrrrr...

There is a lens out there that literally has a constant aperture? Like forcibly 2.8 throughout... no F4 or F8 for you? Seriously?

Maybe I'm just misreading between everyone trying to piss on each other to make themselves look big.

 

[Stosh]

Sorry wasn't trying to piss on or piss off anyone. Just wanted to spread some knowledge. My first understanding of optics comes from astronomy. When you buy a large telescope you shop by physical aperture first, then f-ratio second. Unless you're doing photography through the telescope you don't really care what the focal length is unless you need to know exactly what power you happen to be looking at.
I knew pros that knew way more than I did about anything photo related and they never put 2 and 2 together that f/4 actually means something that can be calculated. They just thought is was an arbitrary number related to speed. That's why a 2x extender doubles the f-number - because the true physical aperture stays the same while the focal length doubles.

As for knowledge about the history of zooms and wide range of options today, I'm gonna stay out of that one.

 

[c.cloudwalker]

Time to add oil to the fire? :lmao:

manaheim, yes, there are lenses with a both fixed constant aperture and fixed constant f-number. Those don't even have, of course, an aperture ring.

Can anyone tell me what those are called?
:lmao:

 

[manaheim]

manaheim, yes, there are lenses with a both fixed constant aperture and fixed constant f-number. Those don't even have, of course, an aperture ring.

o rly? no wai!

Wow. That's warped. I can't even imagine why one would want such a thing, but... ok! Cool. Thanks for enlightening me.

 

[Jeffro]

I think yall ran off the Original Poster!@!! But Keep going cause I am enjoying this thread!

 

[Stosh]

Can anyone tell me what those are called?
:lmao:

Yeah, it's called "I took this lens apart to clean it, but seriously screwed up the iris blades so I left them out" I actually have one of these.

Now that you mention it Cloudwalker, I have a couple of old military aerial camera lenses and they were ALWAYS shot wide open. There was no aperture ring, only a shutter, but it wasn't a zoom obviously.

 

[Derrel]

I have two lenses with CONSTANT maximum apertures,and a fixed,constant f/number. One is a Celestron 300mm f/5.6 catdioptric lens,and the other is a 600mm f/8 Vivitar Series 1 "solid cat",made out of almost three pounds of optical glass! Most people refer to these as mirror lenses. both lenses have one aperture,and one f/number...but there's another thing underlying aperture and f/stop.....

.....and I must say I'm surprised some of the snarkier members here have not gone off on a tangential discussion about the difference between aperture,and f/stop, and T-stop...

 

[c.cloudwalker]

I have two lenses with CONSTANT maximum apertures,and a fixed,constant f/number. One is a Celestron 300mm f/5.6 catdioptric lens,and the other is a 600mm f/8 Vivitar Series 1 "solid cat",made out of almost three pounds of optical glass! Most people refer to these as mirror lenses. both lenses have one aperture,and one f/number...but there's another thing underlying aperture and f/stop.....

.....and I must say I'm surprised some of the snarkier members here have not gone off on a tangential discussion about the difference between aperture,and f/stop, and T-stop...

OK, we have a winner! Please send me your address and I'll send you a six-pack of Ramen noodles.

 

[manaheim]

^^^ oh you know I should have made the connection... telescope... mirror lenses...

 

[c.cloudwalker]

^^^ oh you know I should have made the connection... telescope... mirror lenses...

Don't know about that. Have never used a telescope and don't know the first think about them

But I did take advantage of the fact that you did not say zoom. Someone may prove me wrong but I don't think there are mirror zooms...

 

[Moglex]

Time to add oil to the fire? :lmao:

manaheim, yes, there are lenses with a both fixed constant aperture and fixed constant f-number. Those don't even have, of course, an aperture ring.

Can anyone tell me what those are called?
:lmao:

You may note that when I originally asked for a lens with a 'fixed aperture' I specifically asked for any commonly available zoom specifically to exclude the dear old mirror lens.