canon rumors FORUM

Gear Talk => Deals on Gear => Topic started by: Canon Rumors on May 30, 2013, 03:57:16 PM

Title: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: Canon Rumors on May 30, 2013, 03:57:16 PM

From B&H Photo

The new and very well regarded Sigma 120-300 f/2.8 DG OS HSM is now in stock at B&H Photo


Sigma 120-300mm f/2.8 DG OS HSM $3599 at B&H Photo


cr


Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: distant.star on May 30, 2013, 04:28:55 PM
.
Since I have no interest in such a lens, I'm sorta glad they have it priced so seemingly high.

Hope they make a ton of money with it. After my experience with their new 35mm, I'm a fan.
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: silvestography on May 30, 2013, 04:34:01 PM
Even though it doesn't seem like any optical redesign took place, I see the new build quality and WEATHER SEALING (yes, weather sealing) to be worth the price over the old version. That said, I don't have the near $4000 being asked nor the justification to want such a lens.
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: facedodge on May 30, 2013, 04:47:10 PM
The original listed for $4000 originally, and is now selling for $2,700. Give it a few months.
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: Dianoda on May 30, 2013, 05:13:22 PM
If this lens has no autofocus demons with Canon bodies (or at least none that can't be banished using the USB dock), they'll sell quite a few.  Sure, image quality of the previous version (optical formula is unchanged in the new version) wasn't perfection like the Canon IS II's, but it was good enough, and the price is a bit more down to earth than first party kit.

The weather-sealing is a nice add (about time, too).  On a related note, does anyone know if it require a filter to complete the sealing (because 105mm filters aren't cheap)?
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: meli on May 30, 2013, 05:14:32 PM
Damn that thing looks sweet though:

(http://www.sigma-global.com/en/lenses/cas/product/sports/s_120_300_28/images/outlline/detail_img01.jpg)

1200px: http://www.sigma-global.com/en/lenses/cas/product/sports/s_120_300_28/images/outlline/detail_img01.jpg (http://www.sigma-global.com/en/lenses/cas/product/sports/s_120_300_28/images/outlline/detail_img01.jpg)
the rest: http://www.sigma-global.com/en/lenses/cas/product/sports/s_120_300_28/ (http://www.sigma-global.com/en/lenses/cas/product/sports/s_120_300_28/)
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: jdramirez on May 30, 2013, 05:42:39 PM
 so where it's this in the packing order of the  Canon 70-200 is f2.8L mkii.  better,  worse,  our  just a different lens so the comparisons aren't really fair. 
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: Dianoda on May 30, 2013, 06:08:13 PM
so where it's this in the packing order of the  Canon 70-200 is f2.8L mkii.  better,  worse,  our  just a different lens so the comparisons aren't really fair.

Well, judging from TDP's IQ charts for the IS II and the previous version of the sigma 120-300mm f/2.8 OS, the canon is way better (at any aperture) in the 70-119mm range, and sharper across the frame @ f/2.8 from 120-200mm, but it just doesn't compare at 201-300mm.  Throw a 1.4x III on the IS II and @280mm the canon is sharper from mid-frame into the corners @ f/4, but the sigma is sharper in the center.  And the sigma also does f/2.8 @ 300mm - so it's got that going for it, which is nice.

Honestly, I wouldn't be surprised if the v2 sigma has better IQ than the previous edition, if for no other reason than that it seems like sigma's finally taking quality control more seriously.
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: brad-man on May 30, 2013, 06:51:30 PM

 
... Honestly, I wouldn't be surprised if the v2 sigma has better IQ than the previous edition, if for no other reason than that it seems like sigma's finally taking quality control more seriously.


This is what I would expect. If I hadn't recently picked up the Canon 70-200 v2, I would be seriously considering this lens. The thing I wonder about is the Sigma v1 weighs 6 1/2 lbs. I haven't been able to find a weight for the new version. With the improved build quality, I seriously doubt it got lighter...
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: AdamJ on May 30, 2013, 07:25:49 PM
The thing I wonder about is the Sigma v1 weighs 6 1/2 lbs. I haven't been able to find a weight for the new version. With the improved build quality, I seriously doubt it got lighter...

Et voila...

It would have been good if the new material for the casing had reduced the weight but it's actually put on 450g. Here's a comparison to give some context to its weight:

EF 70-200mm f/2.8 IS II                        1,490g
EF 300mm f/2.8 IS II                              2,400g
EF 500mm f/4 IS II                                 3,190g
Sigma 120-300mm f/2.8 OS S            3,390g
EF 400mm f/2.8 IS II                              3,850g
EF 600mm f/4 IS II                                 3,920g
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: Dylan777 on May 30, 2013, 08:19:58 PM
Look forward to see reviews
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: jdramirez on May 30, 2013, 09:23:33 PM
so where it's this in the packing order of the  Canon 70-200 is f2.8L mkii.  better,  worse,  our  just a different lens so the comparisons aren't really fair.

Well, judging from TDP's IQ charts for the IS II and the previous version of the sigma 120-300mm f/2.8 OS, the canon is way better (at any aperture) in the 70-119mm range, and sharper across the frame @ f/2.8 from 120-200mm, but it just doesn't compare at 201-300mm.  Throw a 1.4x III on the IS II and @280mm the canon is sharper from mid-frame into the corners @ f/4, but the sigma is sharper in the center.  And the sigma also does f/2.8 @ 300mm - so it's got that going for it, which is nice.

Honestly, I wouldn't be surprised if the v2 sigma has better IQ than the previous edition, if for no other reason than that it seems like sigma's finally taking quality control more seriously.

 Nice caddy shack  drop.  I have nothing in response but I appreciated it.
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: Dianoda on May 30, 2013, 09:59:22 PM
Nice caddy shack  drop.  I have nothing in response but I appreciated it.

;)
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: jhanken on May 31, 2013, 01:22:36 AM
OMG, want. 8)  As a side note, my personal transformation into a raging Sigma fanboy appears now to be complete :-[
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: Rienzphotoz on May 31, 2013, 03:07:10 AM
Nice ... but price is too steep ... for that money one can buy EF 70-200 f/2.8 L IS II + a EOS 7D (or get the 7D II when it comes out) and you have f/2.8 that goes p to 320mm. Having said that, if the price goes down to $2600-$2700 it could be a great lens for Nikon D7100 with its extra 1.3 crop, effectively giving it a 585mm at f/2.8
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: GMCPhotographics on May 31, 2013, 06:30:27 AM
Nice ... but price is too steep ... for that money one can buy EF 70-200 f/2.8 L IS II + a EOS 7D (or get the 7D II when it comes out) and you have f/2.8 that goes p to 320mm. Having said that, if the price goes down to $2600-$2700 it could be a great lens for Nikon D7100 with its extra 1.3 crop, effectively giving it a 585mm at f/2.8

The ef 70-200 and 7D combo will probably service you better too in the long run. It's lighter too, focusses better and offers more for less. Due to the crop difference, you would have an effective DOF of an f4 lens. But the Siggi isn't anywhere near a 300mm. It ranges from 240mm - 280mm depending on how close you focus. The Canon 70-200 II L is pretty much what it claims to be on the casing. On a 7D it's an effective 110-320mm f4, which will have a far better Max magnification that the Sigma. So it'll focus closer and give the point of focus a larger image and more melted background. While the Siggi 120-300/2.8 OS looks good in isolation, when compared to other lens offering, it's got a number of key deficiencies compared to the competition. It's a nice lens, 7/10 for effort but it's short of being stellar. It sure looks pretty though.
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: Chris Burch on May 31, 2013, 01:58:52 PM
Are there any reviews posted for the new version of this lens?
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: Rienzphotoz on May 31, 2013, 03:21:03 PM
Nice ... but price is too steep ... for that money one can buy EF 70-200 f/2.8 L IS II + a EOS 7D (or get the 7D II when it comes out) and you have f/2.8 that goes p to 320mm. Having said that, if the price goes down to $2600-$2700 it could be a great lens for Nikon D7100 with its extra 1.3 crop, effectively giving it a 585mm at f/2.8

The ef 70-200 and 7D combo will probably service you better too in the long run. It's lighter too, focusses better and offers more for less. Due to the crop difference, you would have an effective DOF of an f4 lens. But the Siggi isn't anywhere near a 300mm. It ranges from 240mm - 280mm depending on how close you focus. The Canon 70-200 II L is pretty much what it claims to be on the casing. On a 7D it's an effective 110-320mm f4, which will have a far better Max magnification that the Sigma. So it'll focus closer and give the point of focus a larger image and more melted background. While the Siggi 120-300/2.8 OS looks good in isolation, when compared to other lens offering, it's got a number of key deficiencies compared to the competition. It's a nice lens, 7/10 for effort but it's short of being stellar. It sure looks pretty though.
+1
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: Rudeofus on June 01, 2013, 06:44:16 AM
But the Siggi isn't anywhere near a 300mm. It ranges from 240mm - 280mm depending on how close you focus. The Canon 70-200 II L is pretty much what it claims to be on the casing.

Since I keep reading this nonsense here on CR and elsewhere I would like to take the opportunity to shed some light on this. There are basically two ways to focus a lens to a point nearer than infinity: either by moving it away from the sensor plane, or by reducing its focal length. Typical example for shifting the lens away from the sensor plane would be Canon's 85L which becomes noticeably longer as one focuses onto near points. Any lens that does "internal focusing" does the latter, which means its focal length decreases as one focuses to nearer and nearer points. From obvious geometric considerations it follows that lenses with longer focal length need more of a reduction to focus at a point at a given distance than lenses with shorter focal length,and in the same fashion lenses with shorter min focus distance "lose" more focal length.

AFAIK all current 70-200 lenses in Canon's L lineup use internal focusing, and as a result decrease their focal length as nearer points are focused on. I leave it as an exercise to the reader to search the web for information how much shorter the 70-200  F/2.8 L IS II gets at nearest focus distance. It's all there for anyone to read. Note that this does in no way excuse Sigma from selling a lens as 120-300mm which has only 280mm at infinity focus. In the same fashion one could slam Canon for selling F/1.2 lenses that are actually F/1.3 wide open.

I have no opinion whether Canon's or Sigma's lenses are better for anyone and would dare a guess that the answer to this is a very personal choice, but it would be smart to base this decision an actual facts and not on uninformed statements from people who clearly don't understand how a lens works.
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: jimmy kamballur on June 01, 2013, 10:04:58 AM
There is a review
http://camerarumors.blogspot.in/2013/05/13-sigma-120-300m-f28-dg-os-hsm-review.html (http://camerarumors.blogspot.in/2013/05/13-sigma-120-300m-f28-dg-os-hsm-review.html)
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: GMCPhotographics on June 05, 2013, 08:45:31 AM
But the Siggi isn't anywhere near a 300mm. It ranges from 240mm - 280mm depending on how close you focus. The Canon 70-200 II L is pretty much what it claims to be on the casing.

Since I keep reading this nonsense here on CR and elsewhere I would like to take the opportunity to shed some light on this. There are basically two ways to focus a lens to a point nearer than infinity: either by moving it away from the sensor plane, or by reducing its focal length. Typical example for shifting the lens away from the sensor plane would be Canon's 85L which becomes noticeably longer as one focuses onto near points. Any lens that does "internal focusing" does the latter, which means its focal length decreases as one focuses to nearer and nearer points. From obvious geometric considerations it follows that lenses with longer focal length need more of a reduction to focus at a point at a given distance than lenses with shorter focal length,and in the same fashion lenses with shorter min focus distance "lose" more focal length.

AFAIK all current 70-200 lenses in Canon's L lineup use internal focusing, and as a result decrease their focal length as nearer points are focused on. I leave it as an exercise to the reader to search the web for information how much shorter the 70-200  F/2.8 L IS II gets at nearest focus distance. It's all there for anyone to read. Note that this does in no way excuse Sigma from selling a lens as 120-300mm which has only 280mm at infinity focus. In the same fashion one could slam Canon for selling F/1.2 lenses that are actually F/1.3 wide open.

Ok here's some facts. A ef 70-200 f2.8 L IS mkII has a min focus distance of 1200mm and offers a max magnification of 0.21 at 200mm. If one focusses at 70mm and then zooms to 200mm the image is very slightly out of focus. Not a parafocus lens, but close.
A ef 70-300L IS has the same min focus distance and offers the same max magnification at 300mm. So it looses 100mm of of focal length when compared to the 70-200. Focus at 70mm and zoom to 300mm and the image is a lot more out of focus than the 70-200 was.
The Sigma 120-300 f2.8 OS's figures are really curious, MFD of 1500mm (not that far off the 70-200's) but it's max magnification is a lowly 0.12x. So there's a massive focal reduction going on there. Focus at 120mm and zoom and the image is hopelessly out of focus even by 200mm.
By my conservative estimates, this lens drops to a focal length of around 240mm at 3m or less. I compared a 120-300 (I used to own one) with a 2x TC and put it along side a 400mm lens with no converters. The Sigma should have been a 600mm f5.6, but the framing was nearly the same as my 400mm f2.8. Which indicated to me that it's lost over 100mm focal length at 3m. Where I though I was shooting in the 600mm range, I was in the 400mm range. A 400mm f5.6 is better achieved in a number of ways. 
A 300mm f4 L IS has a MFD of 1500mm and that's got a Max Mag of 0.24x so I'm sure you can see there is a lot of focal length loss with this Sigma at MFD. The whole point of a 300mm f2.8 is to diffuse the background by having the main subject fairly close and the background far away. With this lens, even a 70-200 f2.8 II L will do this better. Pop a 1.4x TC on the 70-200 and it's even easier.
So the only nonsence I see here is assumption. These figures speak for themselves.

In regards to the f stop value of the 85mm f1.2L, no it's an f1.2. F stops are a mathmatical formula and are quite abstract. T stops are a calibrated transmission of light through the optic. Generally lenses are a 1/3 of stop slower as a T- Stop (f3.2 for the Sigma btw). But to say that an f1.2 lens is wrong or a flaw show an ignorance of the science behind both scales. 
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: meenanm on June 05, 2013, 12:08:36 PM
Mine will be arriving today... It's on the FedEx truck now.  Waiting, impatiently.

I plan to use LensAlign to check it's focus accuracy.  This Saturday it looks like I will use it at the state high school softball championships. For baseball and softball I love the idea of a zoom out to 300 and maintaining the 2.8. 


I used a Canon 400 2.8 L II at the sectionals and the Indy 500. (CPS loaner)   I used the 400 as the Sigma was delayed.  I'm considering the 400 2.8 II for a future purchase.  At the softball game 400 was a bit long for some infield shots. I was using the 1Dx.

Here are some samples from the Canon 400 2.8 II (a bit off topic perhaps)...

Shortstop making play, taken between dugout and homeplate in stands.

(http://www.meenanphoto.com/Sports/LCHS/LCBears-Softball-Sectional/i-45zCV3x/0/M/IMGL8176-M.jpg)

Play at 3rd taken from 1st base side, past dugout. (slightly front focused, my fault on placement of focal point)

(http://www.meenanphoto.com/Sports/LCHS/LCBears-Softball-Sectional/i-VS6XhRk/0/M/IMGL8272-M.jpg)

Indy - car at approx 220+. I was not using a monopod at this time, hand-held. (should have slowed the shutter a bit to show more movement on pan.)

(http://www.meenanphoto.com/Sports/Racing/Indianapolis-500-2013/i-DWsNLCq/1/M/IMGL0051-M.jpg)
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: Chris Burch on June 05, 2013, 01:33:19 PM
Darn...was hoping those shots came from the Sigma lens because they are exceptionally sharp.  Oh well...please let us know how the Sig compares to the big Canon primes.
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: Rudeofus on June 06, 2013, 04:59:36 AM
A ef 70-200 f2.8 L IS mkII has a min focus distance of 1200mm and offers a max magnification of 0.21 at 200mm. If one focusses at 70mm and then zooms to 200mm the image is very slightly out of focus. Not a parafocus lens, but close.
A ef 70-300L IS has the same min focus distance and offers the same max magnification at 300mm. So it looses 100mm of of focal length when compared to the 70-200. Focus at 70mm and zoom to 300mm and the image is a lot more out of focus than the 70-200 was.
What do these "1200mm" mean? Distance from sensor? Distance from front nodal point? Distance from frontmost point of the lens? You see very quickly that the numbers you state may not say what you think they say, especially if you consider that a 300mm lens must lose more focal length to achieve near focus than a 200mm lens, and that it likely is longer and has a different internal construction.

The Sigma 120-300 f2.8 OS's figures are really curious, MFD of 1500mm (not that far off the 70-200's) but it's max magnification is a lowly 0.12x. So there's a massive focal reduction going on there. Focus at 120mm and zoom and the image is hopelessly out of focus even by 200mm.
If these 1500mm are measured from the sensor plane, and given the total length of this lens, the difference between 1200mm and 1500mm is much more substantial than it would appear to the unwashed masses.

By my conservative estimates, this lens drops to a focal length of around 240mm at 3m or less.
So what? If you look at http://www.photozone.de/canon_eos_ff/510-canon_70200_2is28, (http://www.photozone.de/canon_eos_ff/510-canon_70200_2is28,) you will see that the 70-200 L IS drops from 200mm to 161mm, that's the same relative drop (161/200 ~ 240/300). And again, nobody is trying to defraud us here, it's simply laws of optics at work here. Unless you give up internal focusing, you will have to live with loss of focal length as you focus close.

A 300mm f4 L IS has a MFD of 1500mm and that's got a Max Mag of 0.24x so I'm sure you can see there is a lot of focal length loss with this Sigma at MFD.
AFAIK the 300 F/4 doesn't have internal focusing, so it likely won't lose much focal length at MFD. If you main goal is having long focal length at MFD, stay away from lenses with internal focusing regardless of vendor.

The whole point of a 300mm f2.8 is to diffuse the background by having the main subject fairly close and the background far away. With this lens, even a 70-200 f2.8 II L will do this better. Pop a 1.4x TC on the 70-200 and it's even easier.
If blurring the far away background is your aim, the lens with the largest entrance pupil is what you want regardless of focal length. As it just so happens, this diameter is more or less the front lens diameter for most tele lenses, so you should pick accordingly. You can also estimate this number by dividing focal length by F number. No teleconverter is going to help you there in any way, shape or form!

In regards to the f stop value of the 85mm f1.2L, no it's an f1.2. F stops are a mathmatical formula and are quite abstract. T stops are a calibrated transmission of light through the optic.
I did not refer to T stops, but to real F stops. If you look at Canon patents, you will see, that stated F stop numbers are not accurate and conveniently rounded down for marketing purposes:
http://www.canonrumors.com/2011/12/canon-files-a-patent-for-a-bunch-of-lenses/ (http://www.canonrumors.com/2011/12/canon-files-a-patent-for-a-bunch-of-lenses/)

It is quite clear that a lens with 105mm filter diameter can't possibly have F/2.8 and 300mm focal length at the same time, so it's obvious that Sigma conveniently rounded the actual numbers in their favour. This discrepancy is not due to laws of physics or the like, it was simply a marketing decision and possible buyers get less than they might think they pay for.

But let's please cut this mindless drivel "I lose focal length at MFD!!!" for good.
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: Apop on June 06, 2013, 08:02:23 AM
MFD oke, but when you only get 275-280mm @ 50 feet it is a bit more worrying
I think buyers of this lens should be aware it's a 280mm f2.8 lens ( works out nicely with the 98mm diameter of the front element), and possibly around 3.4-3.5 t stop

I am still really considering this lens because it gives great flexability and a fast lens
If your willing to give up a stop when using it with 1.4 converter, it will be approx 392mm(T4.9) @f5.6 instead of f4 ,I wonder how close it comes in center performance to the nikon 200-400 f4@f4 (which is t5.1). , might be an interesting alternative even to the canon 200-400 if you dont really need 560mm.

A 70-200 with 1.4 converter should be around T-stop 4.9 ( 3.4*1.4*approx 1.03 for the light loss in the TC)
So 280mm T3.4-3.5? with the sigma will still be quite a significant advantage.

It's a shame there is no place to find the T-stops of lenses tho, the only data i found was from the older sigma 120-300(without OS), 18 elements in 16 groups, instead of the 23 in 18 groups now

that was 3.4

A ef 70-200 f2.8 L IS mkII has a min focus distance of 1200mm and offers a max magnification of 0.21 at 200mm. If one focusses at 70mm and then zooms to 200mm the image is very slightly out of focus. Not a parafocus lens, but close.
A ef 70-300L IS has the same min focus distance and offers the same max magnification at 300mm. So it looses 100mm of of focal length when compared to the 70-200. Focus at 70mm and zoom to 300mm and the image is a lot more out of focus than the 70-200 was.
What do these "1200mm" mean? Distance from sensor? Distance from front nodal point? Distance from frontmost point of the lens? You see very quickly that the numbers you state may not say what you think they say, especially if you consider that a 300mm lens must lose more focal length to achieve near focus than a 200mm lens, and that it likely is longer and has a different internal construction.

The Sigma 120-300 f2.8 OS's figures are really curious, MFD of 1500mm (not that far off the 70-200's) but it's max magnification is a lowly 0.12x. So there's a massive focal reduction going on there. Focus at 120mm and zoom and the image is hopelessly out of focus even by 200mm.
If these 1500mm are measured from the sensor plane, and given the total length of this lens, the difference between 1200mm and 1500mm is much more substantial than it would appear to the unwashed masses.

By my conservative estimates, this lens drops to a focal length of around 240mm at 3m or less.
So what? If you look at http://www.photozone.de/canon_eos_ff/510-canon_70200_2is28, (http://www.photozone.de/canon_eos_ff/510-canon_70200_2is28,) you will see that the 70-200 L IS drops from 200mm to 161mm, that's the same relative drop (161/200 ~ 240/300). And again, nobody is trying to defraud us here, it's simply laws of optics at work here. Unless you give up internal focusing, you will have to live with loss of focal length as you focus close.

A 300mm f4 L IS has a MFD of 1500mm and that's got a Max Mag of 0.24x so I'm sure you can see there is a lot of focal length loss with this Sigma at MFD.
AFAIK the 300 F/4 doesn't have internal focusing, so it likely won't lose much focal length at MFD. If you main goal is having long focal length at MFD, stay away from lenses with internal focusing regardless of vendor.

The whole point of a 300mm f2.8 is to diffuse the background by having the main subject fairly close and the background far away. With this lens, even a 70-200 f2.8 II L will do this better. Pop a 1.4x TC on the 70-200 and it's even easier.
If blurring the far away background is your aim, the lens with the largest entrance pupil is what you want regardless of focal length. As it just so happens, this diameter is more or less the front lens diameter for most tele lenses, so you should pick accordingly. You can also estimate this number by dividing focal length by F number. No teleconverter is going to help you there in any way, shape or form!

In regards to the f stop value of the 85mm f1.2L, no it's an f1.2. F stops are a mathmatical formula and are quite abstract. T stops are a calibrated transmission of light through the optic.
I did not refer to T stops, but to real F stops. If you look at Canon patents, you will see, that stated F stop numbers are not accurate and conveniently rounded down for marketing purposes:
http://www.canonrumors.com/2011/12/canon-files-a-patent-for-a-bunch-of-lenses/ (http://www.canonrumors.com/2011/12/canon-files-a-patent-for-a-bunch-of-lenses/)

It is quite clear that a lens with 105mm filter diameter can't possibly have F/2.8 and 300mm focal length at the same time, so it's obvious that Sigma conveniently rounded the actual numbers in their favour. This discrepancy is not due to laws of physics or the like, it was simply a marketing decision and possible buyers get less than they might think they pay for.

But let's please cut this mindless drivel "I lose focal length at MFD!!!" for good.
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: Rudeofus on June 06, 2013, 09:40:49 AM
MFD oke, but when you only get 275-280mm @ 50 feet it is a bit more worrying
I think buyers of this lens should be aware it's a 280mm f2.8 lens ( works out nicely with the 98mm diameter of the front element), and possibly around 3.4-3.5 t stop
Yes, this is what commenters should be calling them out for. Raving about focal length @MFD only shows that they don't know how a lens works. 275 vs. 300 is almost 10%, which means a lot less glass and big savings for the maker over what is advertised.

If your willing to give up a stop when using it with 1.4 converter, it will be approx 392mm(T4.9) @f5.6 instead of f4 ,I wonder how close it comes in center performance to the nikon 200-400 f4@f4 (which is t5.1). , might be an interesting alternative even to the canon 200-400 if you dont really need 560mm.
If you look at the cost difference, this Sigma lens with a TC most likely won't be anywhere near the 200-400 F/4 glass you suggested. There ain't no such thing as a free lunch, they say.

A 70-200 with 1.4 converter should be around T-stop 4.9 ( 3.4*1.4*approx 1.03 for the light loss in the TC)
So 280mm T3.4-3.5? with the sigma will still be quite a significant advantage.
With the same framing a 300mm (or 275mm FWIW) F/2.8 lens will give you more far distance background blur than a 200mm F/2.8 lens, period. If you add a TC, you change DOF but not far distance blur.
Title: Re: Sigma 120-300 f/2.8 DG OS HSM Now in Stock
Post by: meenanm on June 07, 2013, 08:42:42 AM
Mine arrived on Wednesday!  Unfortunately I've not been able to get it out and test it yet.
Today I am planning to do some initial testing. It's an overcast almost smoggy day here so I'm not in perfect conditions.  Oh well.

What I've seen so far about the lens:
Packaging, very similar to the previous model. Case appears to be the same.
Tripod ring is better. More sturdy and has strap mounts, similar to canon if you use that style. I typically don't but like the addition.
I've read where some feel the hood screw is flimsy. I'm not seeing that issue. It seems solid to me.
Lens build is nice, much nicer than the previous version. Focus and zoom rings are smooth.
Buttons.. nice and firm. I don't think it will adjust without my doing it intentionally. I've had times with the Canon 400 2.8 II and 70-200 II get flipped by rubbing on my leg in a sports shooting situation.
I sot a few images off hand last night, indoors, high ISO. Focus seems pretty quick and on target. Far from a real test, but initial results are good.

I'll post images later.  I will also post a full review and how I adjust (if needed) when calibrating with LensAlign.
-M
Title: Zoom orientation
Post by: clicstudio on June 14, 2013, 11:46:27 AM
Every Sigma lens I have seen has the zoom going from right to left. Even the new 18-55 1.8.
How come this lens has it the "right way"?

 :o