Approve the Cookies
This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies and our Privacy Policy.
OK
Index  •   • New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Guest
New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Register to forums    Log in

 
FORUMS Canon Cameras, Lenses & Accessories Canon EF and EF-S Lenses 
Thread started 09 Apr 2009 (Thursday) 17:44
Search threadPrev/next
sponsored links
(this ad will go away when you log in as a registered member)

Lenses in stops

 
joe ­ mama
Senior Member
Avatar
666 posts
Joined Oct 2005
Location: Earth
     
Apr 09, 2009 17:44 |  #1
bannedPermanent ban

We usually measure f-ratios (the quotient of the focal length and aperture) in stops, with f/1 meaning the diameter of the apparent aperture equals the effective focal length.

So, I was thinking that it would be interesting to consider the focal lengths of lenses in stops as well. For f/1, we would choose where the effective focal length of the lens equals the length of the sensor diagonal.

To that end, let me present some common focal lengths in mm and in stops, using a 35mm FF sensor:

12mm ~ -1.85 stops
14mm ~ -1.63 stops
15mm ~ -1.53 stops
16mm ~ -1.44 stops
17mm ~ -1.35 stops

24mm ~ -0.85 stops
28mm ~ -0.63 stops

35mm ~ -0.31 stops
50mm ~ 0.21 stops

70mm ~ 0.69 stops
85mm ~ 0.97 stops

100mm ~ 1.21 stops
135mm ~ 1.65 stops
150mm ~ 1.79 stops
180mm ~ 2.06 stops
200mm ~ 2.21 stops
300mm ~ 2.79 stops

400mm ~ 3.21 stops
500mm ~ 3.53 stops
600mm ~ 3.79 stops
800mm ~ 4.21 stops

The reason for the breaks is how we classify lenses:

Below -1 stops: UWA (ultra wide angle)
Between -1 and -0.5 stops: WA (wide angle)
Between -0.5 and 0.5 stops: normal
Between 0.5 stops and 1 stop: short telephoto
Between 1 and 3 stops: telephoto
Longer than 3 stops: super telephoto

And, yes, for those that are wondering, I do. : )


--joe

www.josephjamesphotogr​aphy.com (external link)
www.pbase.com/joemama (external link)

  
  LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as a registered member)
jklewer
Goldmember
Avatar
1,292 posts
Likes: 1
Joined Jan 2007
Location: 34N 118W
     
Apr 09, 2009 17:47 |  #2

Hmm, you are indeed good at math. What is the usefulness of this though?


Gear

  
  LOG IN TO REPLY
joe ­ mama
THREAD ­ STARTER
Senior Member
Avatar
666 posts
Joined Oct 2005
Location: Earth
     
Apr 09, 2009 18:03 |  #3
bannedPermanent ban

jklewer wrote in post #7700229 (external link)
Hmm, you are indeed good at math. What is the usefulness of this though?

No "usefulness" at all, that I can think of at the moment. Just interesting. Same as with my photography, save the "interesting" part. : )


--joe

www.josephjamesphotogr​aphy.com (external link)
www.pbase.com/joemama (external link)

  
  LOG IN TO REPLY
jklewer
Goldmember
Avatar
1,292 posts
Likes: 1
Joined Jan 2007
Location: 34N 118W
     
Apr 09, 2009 18:08 |  #4

joe mama wrote in post #7700300 (external link)
No "usefulness" at all, that I can think of at the moment. Just interesting. Same as with my photography, save the "interesting" part. : )

HAHA, a mathematician with a sense of humor to boot..!


Gear

  
  LOG IN TO REPLY
CameraLens
Senior Member
Avatar
414 posts
Joined Feb 2008
Location: United States
     
Apr 09, 2009 18:23 |  #5

3.14159265358979323


Canon 40D + BG-E2N + 580EX II
P
owerShot G16
EF 24-105mm f/4L IS USM, EF 70-200mm f/4L IS USM,
EF 50mm f/1.8 II, Tokina
AF 12-24mm f/4 AT-X 124AF Pro DX
Manfrotto 055XPROB Tripod + 808RC4 head

  
  LOG IN TO REPLY
TheSportsGuy
Senior Member
Avatar
359 posts
Joined Feb 2008
Location: North Carolina
     
Apr 09, 2009 18:25 |  #6

Ugh........

Math makes me cringe....... *shiver*

:D


1D Mark II_40D w/grip_16-35 L f/2.8_24-70 L f/2.8_70-200 L f/2.8_100-400 L f/4.5-5.6
http://www.flickr.com/​photos/38341050@N02/ (external link)

  
  LOG IN TO REPLY
joe ­ mama
THREAD ­ STARTER
Senior Member
Avatar
666 posts
Joined Oct 2005
Location: Earth
     
Apr 09, 2009 18:43 |  #7
bannedPermanent ban

jklewer wrote:
HAHA, a mathematician with a sense of humor to boot..!

When you look like me, your choices are limited... : )

CameraLens wrote:
3.14159265358979323


A little late to the party, no? I think they're to 4 billion digits now. : )

TheSportsGuy wrote:
---------------

Ugh........

Math makes me cringe....... *shiver*


As it does a lot of people, which is a shame. I mean, for sure you can get through life fine without it, and this thread is good evidence of that, but math is, quite literally, a language. And while it's a poor choice of languages for many things, such as love, play, and sex (wait -- did I just say the same thing three times in a row?), it's a beautiful language that let's you talk about and understand a lot of other things.

Granted, those other things may hold no appeal to you (and most), but I think it's cool to understand the things that math can talk about. I mean, going through life without understanding math is like going through life without being able to sing and dance. You can do it just fine, and most people don't feel they miss a thing, but I do. Especially 'cause I can't sing or dance. : )


--joe

www.josephjamesphotogr​aphy.com (external link)
www.pbase.com/joemama (external link)

  
  LOG IN TO REPLY
jklewer
Goldmember
Avatar
1,292 posts
Likes: 1
Joined Jan 2007
Location: 34N 118W
     
Apr 09, 2009 18:54 |  #8

joe mama wrote in post #7700509 (external link)
As it does a lot of people, which is a shame. I mean, for sure you can get through life fine without it, and this thread is good evidence of that, but math is, quite literally, a language. And while it's a poor choice of languages for many things, such as love, play, and sex (wait -- did I just say the same thing three times in a row?), it's a beautiful language that let's you talk about and understand a lot of other things.

Granted, those other things may hold no appeal to you (and most), but I think it's cool to understand the things that math can talk about. I mean, going through life without understanding math is like going through life without being able to sing and dance. You can do it just fine, and most people don't feel they miss a thing, but I do. Especially 'cause I can't sing or dance. : )

I hear ya for sure. I took many calculus classes a few years ago in school, struggled through all of them. I changed my major than realized how much more I understood because I had a good math knowledge. CHAMPION the math my friend, keep spreading the word!


Gear

  
  LOG IN TO REPLY
BrianXTi
Senior Member
Avatar
286 posts
Joined Sep 2007
Location: Grand Forks, North Dakota
     
Apr 09, 2009 19:01 |  #9

CameraLens wrote in post #7700395 (external link)
3.14159265358979323

Ever seen questions on the M-CAT (test for admission to medical school)?

for the test, pi can be assumed to be 3. :-o

and acceleration due to gravity is assumed to be 10 m/sec^2 (instead of 9.81 or 32.2 feet/sec^2 like we used in engineering classes)


2009 Red River Flooding- Grand Forks, North Dakota
https://photography-on-the.net …3177&posted=1#p​ost7613177
Canon Rebel XSi, 18-55mm IS, 55-250mm IS II, 50mm f/1.8 II
Canonet QL-17 G-III Rangefinder (40mm fixed, f/1.7-f/16) with no batteries needed!

  
  LOG IN TO REPLY
jr_senator
Goldmember
Avatar
4,861 posts
Joined Sep 2006
     
Apr 09, 2009 19:01 |  #10

I'm too damn old to learn another/different system.



  
  LOG IN TO REPLY
TheSportsGuy
Senior Member
Avatar
359 posts
Joined Feb 2008
Location: North Carolina
     
Apr 09, 2009 19:18 as a reply to  @ joe mama's post |  #11

As it does a lot of people, which is a shame. I mean, for sure you can get through life fine without it, and this thread is good evidence of that, but math is, quite literally, a language. And while it's a poor choice of languages for many things, such as love, play, and sex (wait -- did I just say the same thing three times in a row?), it's a beautiful language that let's you talk about and understand a lot of other things.

Granted, those other things may hold no appeal to you (and most), but I think it's cool to understand the things that math can talk about. I mean, going through life without understanding math is like going through life without being able to sing and dance. You can do it just fine, and most people don't feel they miss a thing, but I do. Especially 'cause I can't sing or dance. : )[/QUOTE]

That is understandable.... I am terrible, and when I mean terrible, I mean TERRIBLE at math..lol

I'm an art person, I can play instruments, draw, photograph, design, etc, but I can't do math. I guess that my reasoning side that controls math and language functions is very much lacking compared to the creative side of my brain....lol :D


1D Mark II_40D w/grip_16-35 L f/2.8_24-70 L f/2.8_70-200 L f/2.8_100-400 L f/4.5-5.6
http://www.flickr.com/​photos/38341050@N02/ (external link)

  
  LOG IN TO REPLY
wimg
Cream of the Crop
Avatar
6,896 posts
Likes: 156
Joined Jan 2007
Location: Netherlands, EU
     
Apr 09, 2009 19:22 |  #12

I think it is more useful to use magnifcation factor, both linear and area, especially as ranges of prime lenses were designed with these magnifications in mind, in the past. I reckon that is more useful because that gives an indication of how much the enlargement is, and how much of the area of a standard lens you see. The standard should actually be 50 mm, because that is what we are used to.

The word stops in this context is actually very confusing, as this indicates a link to light involved in exposure, which in your calculation doesn't compute :D.

Also, classification of lenses into categories is time dependent. F.e., in the past, 20-25 years ago or so, we considered 24 mm as UWA, 28 and 35 mm WA, and anything rectlinear beyond an AoV of 90 degrees as extreme UWA. I think nowadays these definitions have shifted a little down.

Anyway, let me make a little table too, FL, magnification factor relative to 50 mm, linear view factor relative to 50 mm (how much more or less you see in a linear fashion compared to 50mm), area magnification factor and area of view factor relative to 50 mm (which part of the frame or how much more of a frame you see compared to the field of view of a 50 mm) :D.

12mm - 0.24 - 4.17 - 0.058 - 17.36
14mm - 0.28 - 3.57 - 0.078 - 12.76
15mm - 0.30 - 3.33 - 0.090 - 11.11

16mm - 0.32 - 3.13 - 0.010 - 9.77
17mm - 0.34 - 2.94 - 0.012 - 8.65
18mm - 0.36 - 2.78 - 0.130 - 7.72
19mm - 0.38 - 2.63 - 0.144 - 6.93
20mm - 0.40 - 2.50 - 0.160 - 6.25
21mm - 0.42 - 2.38 - 0.176 - 5.67

24mm - 0.48 - 2.08 - 0.23 - 4.34
25mm - 0.50 - 2.00 - 0.25 - 4.00
28mm - 0.56 - 1.79 - 0.31 - 3.19

35mm - 0.70 - 1.43 - 0.49 - 2.04
40mm - 0.80 - 1.25 - 0.64 - 1.56
45mm - 0.90 - 1.11 - 0.81 - 1.23
50mm - 1.00 - 1.00 - 1.00 - 1.00
55mm - 1.10 - 0.91 - 1.21 - 0.83
58mm - 1.16 - 0.86 - 1.35 - 0.74
60mm - 1.20 - 0.83 - 1.44 - 0.69

70mm - 1.4 - 0.71 - 1.96 - 0.51
80mm - 1.6 - 0.63 - 2.56 - 0.39
85mm - 1.7 - 0.59 - 2.89 - 0.34
90mm - 1.8 - 0.56 - 3.24 - 0.31

100mm - 2.0 - 0.50 - 4.0 - 0.250
105mm - 2.1 - 0.48 - 4.4 - 0.227
120mm - 2.4 - 0.42 - 5.8 - 0.174
125mm - 2.5 - 0.40 - 6.3 - 0.160
135mm - 2.7 - 0.37 - 7.3 - 0.137
150mm - 3.0 - 0.33 - 9.0 - 0.111
180mm - 3.6 - 0.28 - 13.0 - 0.077
200mm - 4.0 - 0.25 - 16.0 - 0.063

240mm - 4.8 - 0.208 - 23 - 0.0434
280mm - 5.6 - 0.179 - 31 - 0.0319
300mm - 6.0 - 0.167 - 36 - 0.0278
350mm - 7.0 - 0.143 - 49 - 0.0204
400mm - 8.0 - 0.125 - 64 - 0.0156
450mm - 9.0 - 0.111 - 81 - 0.0123
480mm - 9.6 - 0.104 - 92 - 0.0109

500mm - 10.0 - 0.100 - 100 - 0.0100
560mm - 11.2 - 0.089 - 125 - 0.0080
600mm - 12.0 - 0.083 - 144 - 0.0069
700mm - 14.0 - 0.071 - 196 - 0.0051
800mm - 16.0 - 0.063 - 256 - 0.0039

1000mm - 20 - 0.050 - 400 - 0.0025
1100mm - 22 - 0.045 - 484 - 0.0021
1200mm - 24 - 0.042 - 576 - 0.0017

If you do feel like calculating something in f-stops, what about theoretical vignetting for the corners of the frame of a list of lenses, considering center is 0 stops? I would certainly find that useful, but am now too lazy to look up the formula :D.

Kind regards, Wim


EOS R & EOS 5 (analog) with a gaggle of primes & 3 zooms, OM-D E-M1 Mk II & Pen-F with 10 primes, 6 zooms, 3 Metabones adapters/speedboosters​, and an accessory plague

  
  LOG IN TO REPLY
BrianXTi
Senior Member
Avatar
286 posts
Joined Sep 2007
Location: Grand Forks, North Dakota
     
Apr 09, 2009 19:35 |  #13

Holy $h!t!


2009 Red River Flooding- Grand Forks, North Dakota
https://photography-on-the.net …3177&posted=1#p​ost7613177
Canon Rebel XSi, 18-55mm IS, 55-250mm IS II, 50mm f/1.8 II
Canonet QL-17 G-III Rangefinder (40mm fixed, f/1.7-f/16) with no batteries needed!

  
  LOG IN TO REPLY
BrianXTi
Senior Member
Avatar
286 posts
Joined Sep 2007
Location: Grand Forks, North Dakota
     
Apr 09, 2009 19:38 |  #14

also can you give titles to each group of focal lenths as you have them split? UWA, WA, normal, telephoto, etc.?


2009 Red River Flooding- Grand Forks, North Dakota
https://photography-on-the.net …3177&posted=1#p​ost7613177
Canon Rebel XSi, 18-55mm IS, 55-250mm IS II, 50mm f/1.8 II
Canonet QL-17 G-III Rangefinder (40mm fixed, f/1.7-f/16) with no batteries needed!

  
  LOG IN TO REPLY
joe ­ mama
THREAD ­ STARTER
Senior Member
Avatar
666 posts
Joined Oct 2005
Location: Earth
     
Apr 09, 2009 19:40 |  #15
bannedPermanent ban

jklewer wrote:
I hear ya for sure. I took many calculus classes a few years ago in school, struggled through all of them. I changed my major than realized how much more I understood because I had a good math knowledge. CHAMPION the math my friend, keep spreading the word!


It is cool, sometimes, though, isn't it? I mean, to see something happen and understand why? For example, my daughter just moved to second grade. Out of 85 second grade students and 21 of them from her previous class, only 3 of the kids from that class are in her new class of 17 students. What were the chances of that? Was my daughter being separated on purpose? Well, as it turns out, there's a 43% that there would be 3 or fewer, actually. : )

Brian XTi wrote:
Ever seen questions on the M-CAT (test for admission to medical school)?


Actually, that's my day job. : )

for the test, pi can be assumed to be 3.


Even worse when the politicians get into it:

http://www.straightdop​e.com …-a-law-saying-pi-equals-3 (external link)

I mean, geez, if there was ever a group of people who needed to know math, it's our "leaders".

and acceleration due to gravity is assumed to be 10 m/sec^2 (instead of 9.81 or 32.2 feet/sec^2 like we used in engineering classes)


You might be interested to know that of all the physical constants in nature, the Gravitational Constant, G, is known with the least precision:

http://en.wikipedia.or​g/wiki/Gravitational_c​onstant (external link)

due to the difficulty in accurately measuring it. So if pi, the most precisely calculated constant known, can be rounded to 3, I think we can forgive them for rounding the least precisely known of all the physical constants to the same level of precision. : )

I'm too damn old to learn another/different system.


I'm too damn old to date a young hottie. You'd be surprised what some nice clothes, a nice car, sounding smart, and a harmless lie ("I'm a doctor") will get you. If Micael Douglas wasn't too old for Katherine Zeta-Jones, then, my friend, you ain't too old to learn something useless. : )


--joe

www.josephjamesphotogr​aphy.com (external link)
www.pbase.com/joemama (external link)

  
  LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as a registered member)

6,238 views & 0 likes for this thread
Lenses in stops
FORUMS Canon Cameras, Lenses & Accessories Canon EF and EF-S Lenses 
AAA
x 1600
y 1600

Jump to forum...   •  Rules   •  Index   •  New posts   •  RTAT   •  'Best of'   •  Gallery   •  Gear   •  Reviews   •  Member list   •  Polls   •  Image rules   •  Search   •  Password reset

Not a member yet?
Register to forums
Registered members may log in to forums and access all the features: full search, image upload, follow forums, own gear list and ratings, likes, more forums, private messaging, thread follow, notifications, own gallery, all settings, view hosted photos, own reviews, see more and do more... and all is free. Don't be a stranger - register now and start posting!


COOKIES DISCLAIMER: This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies and to our privacy policy.
Privacy policy and cookie usage info.


POWERED BY AMASS forum software 2.1forum software
version 2.1 /
code and design
by Pekka Saarinen ©
for photography-on-the.net

Latest registered member is vini81
804 guests, 260 members online
Simultaneous users record so far is 15144, that happened on Nov 22, 2018

Photography-on-the.net Digital Photography Forums is the website for photographers and all who love great photos, camera and post processing techniques, gear talk, discussion and sharing. Professionals, hobbyists, newbies and those who don't even own a camera -- all are welcome regardless of skill, favourite brand, gear, gender or age. Registering and usage is free.