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Archive 2012Sigma 50-500mm at 500mm is actually shorter than 420mm
p.1 #1Sigma 50-500mm at 500mm is actually shorter than 420mm
Bought a brand new Sigma's new 50-500mm OS on 1/20/2012 from Amazon. The lens is well made and sharp. I decided to do a shoot out of this Sigma and my Nikon 300mm f4 AFS, NIKON 1.4 TC and 1.7 TC.
What a surprise when I found that the Sigma at 500mm is still much wider than Nikon 300mm f4 plus 1.4 TC ( which is only 420mm.) My subject distance s only about 7 feet, I need to move my 300f4 plus 1.4TC setup a foot or so away from the subject to match the Sigma's view.
[Corrected] Now I understood, this is the so called "focus breathing" which seems well learned by Nikon 70-200 VR II users.
Eric
Edited on Feb 05, 2012 at 11:52 PM · View previous versions
What a surprise when I found that the Sigma at 500mm is still much wider than Nikon 300mm f4 plus 1.4 TC ( which is only 420mm.) My subject distance s only about 7 feet, I need to move my 300f4 plus 1.4TC setup a foot or so away from the subject to match the Sigma's view.
[Corrected] Now I understood, this is the so called "focus breathing" which seems well learned by Nikon 70-200 VR II users.
Eric
Edited on Feb 05, 2012 at 11:52 PM · View previous versions
Feb 05, 2012 at 09:33 PM
p.1 #2Sigma 50-500mm at 500mm is actually shorter than 420mm
I'm no lens expert but wouldn't the long end be measured at infinity focus and not mid-range? The large zoom ranges tend to breath I guess, the Nikon 70-200 VR II isn't a 200mm lens at mid-range from what I've read.
Feb 05, 2012 at 09:37 PM
p.1 #3Sigma 50-500mm at 500mm is actually shorter than 420mm
Say hello to focus breathing. It may be a touch short, but it is not THAT short at infinity.
Feb 05, 2012 at 09:40 PM
p.1 #4Sigma 50-500mm at 500mm is actually shorter than 420mm
Holy crap....I bet my Tamron 28-75 is actually like an 8-15!?! 
Jokes aside, welcome to focus breathing - the near inevitable characteristic of some lenses (zooms only, or even some primes?) to exhibit shorter focal lengths at close-to-MFD ranges.
Go ask the Nikon 70-200 VR II owners about this, their "200mm" turns into around 135mm at MFD.
Just looking at your own Sigma 50-500 tells you something is up with this - their highest magnification I believe is at 200mm or so (IIRC), not 500mm. It's a very good lens for what it is, but a macro lens at 500mm it isn't.
Jokes aside, welcome to focus breathing - the near inevitable characteristic of some lenses (zooms only, or even some primes?) to exhibit shorter focal lengths at close-to-MFD ranges.
Go ask the Nikon 70-200 VR II owners about this, their "200mm" turns into around 135mm at MFD.
Just looking at your own Sigma 50-500 tells you something is up with this - their highest magnification I believe is at 200mm or so (IIRC), not 500mm. It's a very good lens for what it is, but a macro lens at 500mm it isn't.
Feb 05, 2012 at 09:43 PM
p.1 #5Sigma 50-500mm at 500mm is actually shorter than 420mm
It is nothing new; many IF zooms have been like that for decades. Measure the focal length closer to infinity.
EBH
EBH
Feb 05, 2012 at 09:47 PM
p.1 #6Sigma 50-500mm at 500mm is actually shorter than 420mm
cputeq wrote:
Holy crap....I bet my Tamron 28-75 is actually like an 8-15!?!
Jokes aside, welcome to focus breathing - the near inevitable characteristic of some lenses (zooms only, or even some primes?) to exhibit shorter focal lengths at close-to-MFD ranges.
Go ask the Nikon 70-200 VR II owners about this, their "200mm" turns into around 135mm at MFD.
Just looking at your own Sigma 50-500 tells you something is up with this - their highest magnification I believe is at 200mm or so (IIRC), not 500mm. It's a very good lens for what it is, but a macro lens at 500mm it...Show more →
Internal focusing lenses (generally) shorten approaching MFD, external focusing lenses often show a longer focal length as they approach MFD. IIRC
Holy crap....I bet my Tamron 28-75 is actually like an 8-15!?!
Jokes aside, welcome to focus breathing - the near inevitable characteristic of some lenses (zooms only, or even some primes?) to exhibit shorter focal lengths at close-to-MFD ranges.
Go ask the Nikon 70-200 VR II owners about this, their "200mm" turns into around 135mm at MFD.
Just looking at your own Sigma 50-500 tells you something is up with this - their highest magnification I believe is at 200mm or so (IIRC), not 500mm. It's a very good lens for what it is, but a macro lens at 500mm it...Show more →
Internal focusing lenses (generally) shorten approaching MFD, external focusing lenses often show a longer focal length as they approach MFD. IIRC
Feb 05, 2012 at 09:56 PM
p.1 #7Sigma 50-500mm at 500mm is actually shorter than 420mm
Anyone have some numbers on the Nikon 70-300 VR? I bought it for the extra focal length to replace my 55-220 VR which as far as i know was not internal focus. Am i not getting true 300 mm / 450mm considering 1.5 crop factor on my D90?
Feb 05, 2012 at 10:23 PM
p.1 #8Sigma 50-500mm at 500mm is actually shorter than 420mm
I would say you are way off base, not Sigma. 
Feb 05, 2012 at 10:25 PM
p.1 #9Sigma 50-500mm at 500mm is actually shorter than 420mm
Tom Kelley wrote:
Anyone have some numbers on the Nikon 70-300 VR? I bought it for the extra focal length to replace my 55-220 VR which as far as i know was not internal focus. Am i not getting true 300 mm / 450mm considering 1.5 crop factor on my D90?
55-200 max reproduction ratio = 1/3.5
70-300 max reproduction ratio = 1/4
your old lens will get you closer, but it is mostly due to the much closer min focus distance (1.1m) vs the new lens which has a close focus of (1.5m). Not sure what the effective focal lengths are at MFD, and I am way too lazy to try to calculate it.
For real world subjects your new lens will be sharper and effectively longer.
Anyone have some numbers on the Nikon 70-300 VR? I bought it for the extra focal length to replace my 55-220 VR which as far as i know was not internal focus. Am i not getting true 300 mm / 450mm considering 1.5 crop factor on my D90?
55-200 max reproduction ratio = 1/3.5
70-300 max reproduction ratio = 1/4
your old lens will get you closer, but it is mostly due to the much closer min focus distance (1.1m) vs the new lens which has a close focus of (1.5m). Not sure what the effective focal lengths are at MFD, and I am way too lazy to try to calculate it.
For real world subjects your new lens will be sharper and effectively longer.
Feb 05, 2012 at 10:29 PM
p.1 #10Sigma 50-500mm at 500mm is actually shorter than 420mm
Now I understood this is called focus breathing. I guess this is a technology limitation on zoom lens design.
Eric
Eric
Feb 05, 2012 at 11:51 PM
p.1 #11Sigma 50-500mm at 500mm is actually shorter than 420mm
penghai wrote:
Now I understood this is called focus breathing. I guess this is a technology limitation on zoom lens design.
Eric
It is not just zooms. Primes often breath quite a bit as well.
Now I understood this is called focus breathing. I guess this is a technology limitation on zoom lens design.
Eric
It is not just zooms. Primes often breath quite a bit as well.
Feb 06, 2012 at 02:21 AM
p.1 #12Sigma 50-500mm at 500mm is actually shorter than 420mm
The first time I heard about this was several years ago and it was actually with a prime, the canon 100mm 2.8 macro.
I dont't recall the exact numbers, but if memory serves me correctly it was around 60mm at MFD (I could be wrong, but I remember it was a big difference).
It was very noticeable through the viewfinder, especially at closer focusing distances, when trying to focus, as the subject magnification changed as the lens tried to focus.
Oh, and the aperture is also reduced with that lens as well as some others, something that most canon users don't know since the camera will not display that info like nikon's do.
I dont't recall the exact numbers, but if memory serves me correctly it was around 60mm at MFD (I could be wrong, but I remember it was a big difference).
It was very noticeable through the viewfinder, especially at closer focusing distances, when trying to focus, as the subject magnification changed as the lens tried to focus.
Oh, and the aperture is also reduced with that lens as well as some others, something that most canon users don't know since the camera will not display that info like nikon's do.
Feb 06, 2012 at 04:21 AM
p.1 #13Sigma 50-500mm at 500mm is actually shorter than 420mm
Edit:
Just out of curiosity, did a (very) quick google search on the canon 100mm macro and found this:
http://photo.stackexchange.com/questions/16549/is-it-normal-for-focal-length-to-change-while-focusing
Someone there claims that lens to be 70mm at MFD.
BTW, the Nikkor 28-300mm is also quite short of 300mm at or close to MFD.
Hope this helps.
Just out of curiosity, did a (very) quick google search on the canon 100mm macro and found this:
http://photo.stackexchange.com/questions/16549/is-it-normal-for-focal-length-to-change-while-focusing
Someone there claims that lens to be 70mm at MFD.
BTW, the Nikkor 28-300mm is also quite short of 300mm at or close to MFD.
Hope this helps.
Feb 06, 2012 at 04:23 AM
p.1 #14Sigma 50-500mm at 500mm is actually shorter than 420mm
penghai wrote:
Bought a brand new Sigma's new 50-500mm OS on 1/20/2012 from Amazon. The lens is well made and sharp. I decided to do a shoot out of this Sigma and my Nikon 300mm f4 AFS, NIKON 1.4 TC and 1.7 TC.
What a surprise when I found that the Sigma at 500mm is still much wider than Nikon 300mm f4 plus 1.4 TC ( which is only 420mm.) My subject distance s only about 7 feet, I need to move my 300f4 plus 1.4TC setup a foot or so away from the subject to match the Sigma's view.
[Corrected] Now I understood,...Show more →
When you get out to 50 or so feet it has been independantly tested at 485mm
Bought a brand new Sigma's new 50-500mm OS on 1/20/2012 from Amazon. The lens is well made and sharp. I decided to do a shoot out of this Sigma and my Nikon 300mm f4 AFS, NIKON 1.4 TC and 1.7 TC.
What a surprise when I found that the Sigma at 500mm is still much wider than Nikon 300mm f4 plus 1.4 TC ( which is only 420mm.) My subject distance s only about 7 feet, I need to move my 300f4 plus 1.4TC setup a foot or so away from the subject to match the Sigma's view.
[Corrected] Now I understood,...Show more →
When you get out to 50 or so feet it has been independantly tested at 485mm
Apr 26, 2012 at 10:58 AM