# DXOMark: Sigma 24-105 f/4 DG OS Reviewed



## Canon Rumors Guy (Dec 17, 2013)

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<p><strong>From DXOMark

</strong>The folks at DXOMark have completed their review and testing of the new Sigma 24-105 f/4 DG OS Art series zoom lens.</p>
<p><strong>Says DXOMark

</strong><em>“Given its popularity, Canon has been slow to replace the EF24-105mm f4L IS USM, and it has provided rival Sigma with the opportunity to gain some leverage in this highly competitive sector. Sigma are sure to be rewarded as it’s not only a superb performer optically, at $899 it comfortably undercuts the Canon and is well worth taking a closer look.”</em></p>
<p><strong><a href="http://www.dxomark.com/Reviews/Sigma-24-105mm-F4-DG-OS-HSM-A-Canon-mount-lens-review-A-new-standard" target="_blank">Read the full review</a></strong> | <strong><a href="http://www.bhphotovideo.com/c/product/1009621-REG/sigma_635_101_24_105mm_f4_dg_os.html/bi/2466/kbid/3296" target="_blank">Sigma 24-105 f/4 DG OS at B&H Photo</a></strong></p>
<p><strong><span style="color: #ff0000;">c</span>r</strong></p>
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## Albi86 (Dec 17, 2013)

Interesting.

Seems a bit discording with the major voice claiming a "as good as but not really better".


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## Random Orbits (Dec 17, 2013)

Yeah, it only undercuts the Canon because DxO still has the 24-105 costing 1250, which is far above its current street price. It may be a slightly better than Canon's 24-105, but with the Canon version selling at 600-700, the Sigma isn't quite the bargain as when the Canon sold at 1250.


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## LetTheRightLensIn (Dec 17, 2013)

Granted I haven't used it, but count me dubious based upon sample shots and other comments and MTF charts.

DxO has also said stuff like the 70-200 2.8 IS II is the worst 200mm f/2.8 performer of all the 70-200s. That the 16-35mm is sharpest at FF edges right near wide open. That the 70-300 IS non-L is better than the 70-300L and maybe even than the 300 f/4 prime.

They also love overall ratings and for a lens the rating is based upon the focal length and aperture of peak performance, but what the heck way is that to rate a lens overall?

But I supposed it might not hurt for people to give this lens a chance. Although it costs barely less than a 24-70 f/4 IS (on sale) and weighs a lot more and is a lot larger. Heck, it's larger and heavier than the 24-70 f/2.8 II! And it costs more than what you can get the 24-105L for.


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## cliffwang (Dec 18, 2013)

Random Orbits said:


> Yeah, it only undercuts the Canon because DxO still has the 24-105 costing 1250, which is far above its current street price. It may be a slightly better than Canon's 24-105, but with the Canon version selling at 600-700, the Sigma isn't quite the bargain as when the Canon sold at 1250.


+1
That's what I thought. When you can get Canon 24-105 for 600 bulks easily, I don't really see why Canon users need to get Sigma 24-105.


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## David Hull (Dec 18, 2013)

dilbert said:


> Random Orbits said:
> 
> 
> > Yeah, it only undercuts the Canon because DxO still has the 24-105 costing 1250, which is far above its current street price. It may be a slightly better than Canon's 24-105, but with the Canon version selling at 600-700, the Sigma isn't quite the bargain as when the Canon sold at 1250.
> ...



That is somewhat irrelevant since that is not what people are paying for it. The question would be what is the actual street cost of the two lenses.


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## Jamesy (Dec 18, 2013)

Sigma are doing a great job with their new line of glass - I wonder if there has been a significant shift in their strategic direction or if they have a new heavy hitter in the Engineering department.


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## unfocused (Dec 18, 2013)

I wonder if this lens is really aimed at Nikon users.

As others have said, for Canon users this may be a nice lens, but it's not an "must have." The street price of the 24-105 "L" is less. Just about every full frame Canon user who would want this lens already has the Canon version. There are currently more than 500 in stock on the Canon refurbished store (selling for more than the street price of a new "white box" version). 

Basically, the market is flooded already, so I wonder if Sigma may have made a mistake with this lens unless they are just targeting Nikon users. 

I admire what Sigma has been doing lately and I appreciate the competition from third party manufacturers, but I'm scratching my head over this one. It runs contrary to most other recent releases from Sigma, Tamron and Tokina – where they have either been focusing on giving consumers choices that Canon and Nikon don't offer or they've been undercutting Canon and Nikon on price with staples like the 70-200 f2.8.


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## Jamesy (Dec 18, 2013)

unfocused said:


> I wonder if this lens is really aimed at Nikon users.



This makes a lot of sense - however they already have a 24-120 F4, although I am not sure how well regarded it is.


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## Random Orbits (Dec 18, 2013)

dilbert said:


> People are comparing Sigma's MSRP with Canon's street price. That seems hardly fair. A proper comparison should be between equivalent prices, so either both MSRPs or both street. If the Sigma lens is able to sustain good sales at or close to its MSRP then that's not a bad thing.



It is fair because that the order price is the MSRP for the Sigma RIGHT NOW, at the same instant in time. If I want to buy a Canon 24-105, I could have gotten one new for about 600. If I want a to order a new Sigma, it'd cost me about 900. Perhaps the Sigma's price will fall 100 in a 200 in a year and the Canon will remain at 600. If so, then that is a comparison for next year.


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## David Hull (Dec 18, 2013)

dilbert said:


> David Hull said:
> 
> 
> > dilbert said:
> ...


The only thing that matters is what you can get it for. If the Canon is selling at $700 and the Sigma is selling at $850 that is the comparison, period.


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## Frage (Dec 18, 2013)

David Hull said:


> dilbert said:
> 
> 
> > Random Orbits said:
> ...


That is somewhat relevant since not the entire world is living in the countries where the street price is the mentioned above.


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## J.R. (Dec 18, 2013)

Frage said:


> David Hull said:
> 
> 
> > dilbert said:
> ...



As a corollary, Sigma lenses aren't available in the entire world 

Even in other countries, the Canon 24-150 as part of the kit will be available for roughly equal to or less than the Sigma. 

BTW, from personal experience, Sigma's after sales support in other countries sucks big time!


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## Frage (Dec 18, 2013)

J.R. said:


> Frage said:
> 
> 
> > David Hull said:
> ...




What is your point?


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## J.R. (Dec 18, 2013)

Frage said:


> What is your point?



Only that even in other parts of the world, the Canon lens is available for substantially lower than the MRSP when it is purchased as part of a kit. So even in other parts of the world, the Canon lens is available for much less cash, as part of a kit, or used as the case may be. 

I live in India and the Canon 24-105 can be purchased for local currency that is about equivalent to $ 900 - A used lens can be had for as less as $ 650. So what I was implying was that the Canon lens is available in other countries as a cheaper price too. Sigma will be priced above the Canon lens (when it is released here) - I doubt too many will buy it over the Canon lens. 

I guess it is pretty much the same all over. but then, maybe in your country it may be different. 

PS: Photography gear in India attracts customs duty of 30%, so @ $ 900 the lens is a bargain. 

PPS: English is not my native language and I sometimes have difficulty getting my point across. 

Cheers ... J.R.


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## Zlyden (Dec 18, 2013)

Whatever it is -- retail resellers all over the world (or at least in some countries) should be happy with Sigma's decision to release its 24-105 version with that MSRP 

This should rise demand and popularity of unkitted 24-105 L. (And probably its price too.)

I can easily imagine a salesman in photo store babbling something like: 

_"Yes, this is a new Sigma 24-105! It's a great and mighty lens, just released! But... Look at this display for a second -- this is original Canon 24-105! See this red ring here? It's L-lens! Feel how small and light it is! IQ is just is as good. Do you like it? It's usual price is 3 hundreds more than Sigma. But today only for you, I can sell it for the same price as this 3rd party Sigma! And I even will add a filter and this Lowepro case for free!!! Because I see you are real 'pro' who need a lens like that!"
_
;D


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## Frage (Dec 18, 2013)

Zlyden said:


> Whatever it is -- retail resellers all over the world (or at least in some countries) should be happy with Sigma's decision to release its 24-105 version with that MSRP
> 
> This should rise demand and popularity of unkitted 24-105 L. (And probably its price too.)
> 
> ...



Yeah!

Nice speech


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## TWI by Dustin Abbott (Dec 18, 2013)

unfocused said:


> I wonder if this lens is really aimed at Nikon users.
> 
> As others have said, for Canon users this may be a nice lens, but it's not an "must have." The street price of the 24-105 "L" is less. Just about every full frame Canon user who would want this lens already has the Canon version. There are currently more than 500 in stock on the Canon refurbished store (selling for more than the street price of a new "white box" version).
> 
> ...



Big +1. As soon as this lens was announced, I felt that the only way that it would be a success is if it destroyed the 24-105L optically. It didn't seem to offer any other compelling reason to purchase: focal length the same. IS/OS. Same maximum aperture. 

Downsides included: Heavier and larger front element. Not weather sealed. Sigma's reputation for sometimes inconsistent AF accuracy. Third party lens with potential downsides that come with that.

I think the consensus out there is that in SOME ways the Sigma is better optically, but it certainly doesn't blow the 24-105L out of the water. That is going to make it a hard sell. *Just out of curiosity: a lot of you own the 24-105L - are you planning on selling it to get the Sigma?* 

I don't own the 24-105L right now. I've owned two copies in the past and liked them considerably. I own let my last copy go when I got the Tamron 24-70 VC and found that I wasn't using the Canon anymore. But if I owned the 24-105L right I certainly wouldn't be selling it to get this lens.


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## Zlyden (Dec 18, 2013)

TWI by Dustin Abbott said:


> *Just out of curiosity: a lot of you own the 24-105L - are you planning on selling it to get the Sigma?*



I definitely don't!

Any 24-105/4 is supposed to be a 'walk-about-kit-lens'. It should be small and light. Not optically perfect (this a job of 2.8 lenses). 

But if Sigma would make some extra sharp 24-105/2.8 lens (or even better for me: 24-300/4 lens) with same size, weight and price. I could consider purchasing it...


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## Zv (Dec 18, 2013)

TWI by Dustin Abbott said:


> unfocused said:
> 
> 
> > I wonder if this lens is really aimed at Nikon users.
> ...



I bought my EF 24-105L second hand. Got it fairly cheap too. I knew fine well going in that it was not going to a lens that had amazing IQ and that was fine because I just needed something to work with in the general focal range. For that it performs well, especially from 35mm onwards I'm seeing really quite sharp images. 24mm performance could be better but I can live without since I have the 17-40L and now the Samyang 14mm (on my 7D it gives an almost 24mm look). The weather sealing has came in handy when on vacation / at te beach etc. the lens isn't light by any means but a decent amount that I can handle. 

Will I change for the Sigma? Nope. The Sigma's bigger and heavier and not sealed. Don't give a damn about a tiny bit extra sharpness at the wide end. 

I think for those who don't need the extra range the 24-70 f/4 IS beats both the Sigma and 24-105L and provides a nice third option. If I was to change I'd prob go for that one, just wish it was a little cheaper though.


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## David Hull (Dec 18, 2013)

Frage said:


> David Hull said:
> 
> 
> > dilbert said:
> ...


Yea... Most of us are comparing US prices, I think. I certainly don't know about elsewhere and don't look.


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## Random Orbits (Dec 18, 2013)

dilbert said:


> Many of the cheap Canon 24-105L's are because vendors are taking it out of a kit and selling it and the camera separately. This is not a Canon approved activity but they seem to look the other way.
> 
> If you go to a proper web site for a store like B&H, then you can compare the price of the Canon and Sigma:
> 
> ...



Well, if the box the worth $500 to you, then get it for 1149. It isn't to me. And good luck selling a Canon 24-105 that you would buy for 1149 for anything close to that amount.


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## iowapipe (Dec 18, 2013)

I own the Canon lens and will not be selling it and getting the Sigma. 

Reports from those who have actually used/reviewed it do not point to any compelling reason to switch.

The Canon shares filters I already have, and the Sigma isn't a marked improvement in IQ. Slight improvement seems to be the phrase. As many have noted so far, to get a 'better' image, you will get a 'better' ($$$) lens.


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## Zlyden (Dec 18, 2013)

Random Orbits said:


> Well, if the box the worth $500 to you, then get it for 1149. It isn't to me. And good luck selling a Canon 24-105 that you would buy for 1149 for anything close to that amount.



It's not 'the box itself' but rather 'the color of the box'.

I got mine 'white boxed' 24-105 L back in 2008 for around $900 (looks like Canon ships much-much more 6Ds and 5D III kits these days than original 5Ds in early 2008). Probably the lens build quality was also more stable in those days (since I did not hear that many complains about 'unsharp' 24-105 L and 'tested 10 copies = all were bad' then). I used the lens to complement EF-S 10-22 on 400D in my traveling lens setup and always was very happy with the results.

Since now Sigma offers it's lens for around the same $900, I wonder if I would choose this lens over Canon's back in 2008. But... No. I would not: Canon's version is smaller, lighter, it uses normal 77-mm filters and lens caps (same as 10-22).


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## Eldar (Dec 18, 2013)

Zlyden said:


> Random Orbits said:
> 
> 
> > Well, if the box the worth $500 to you, then get it for 1149. It isn't to me. And good luck selling a Canon 24-105 that you would buy for 1149 for anything close to that amount.
> ...


A Rolex is more expensive than a Breitling. Is the Rolex any better?
An Armani suit is more expensive than a Bertoni suite. Is the Armani suite any better?
A Montblanc fountain pen is more expensive than a Parker fountain pen. It the Montblanc any better?
A Maserati is more expensive than a Porsche. Is the Maserati any better?
...
the world is full of items we are willing to pay more for, because it gives us some kind of value/quality/prestige/... 

A Sigma lens has a reverse engineered EF mount, a long history of AF problems, quality variations pr. copy, numerous examples of poor service etc. etc. To hope for any chunk of the Canon L-lens customer base, they have to be both better and cheaper and they have to be that over time. If they are consistently as good as Canon over time, meaning years, they can move closer to the prices Canon can charge. The only non-Canon brand that can charge as high or even higher prices than Canon is Zeiss. Because they have proved over time that they are consistently delivering absolute top class products in every department. Sigma, Tamron, Tokina and the rest have a loooong way to go before they are in the vicinity of such a position.

I have the Sigma 35/1.4. I am very happy with it, but I am a long way from joining the Sigma fan club


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## J.R. (Dec 18, 2013)

Zlyden said:


> I can easily imagine a salesman in photo store babbling something like:
> 
> _"Yes, this is a new Sigma 24-105! It's a great and mighty lens, just released! But... Look at this display for a second -- this is original Canon 24-105! See this red ring here? It's L-lens! Feel how small and light it is! IQ is just is as good. Do you like it? It's usual price is 3 hundreds more than Sigma. But today only for you, I can sell it for the same price as this 3rd party Sigma! And I even will add a filter and this Lowepro case for free!!! Because I see you are real 'pro' who need a lens like that!"
> _
> ;D



Sure if the salesman spotted a noob contemplating this lens. 

People with commonsense will be better off buying the Canon 24-105 used on CL


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## RLPhoto (Dec 18, 2013)

Not that anyone sane would buy the sigma when the 24-105L is already good/cheap. To me this reflects a change in sigma quality that they can give an equal IQ to canon. (at the moment anyway.)


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## AJ (Dec 18, 2013)

The t-stop of 5.1 for the Canon 24-105 is a bit of a shocker to me. tsk tsk Canon!

So basically the Sigma is about the same price and about the same sharpness, but half a stop brighter.


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## Zlyden (Dec 18, 2013)

J.R. said:


> Zlyden said:
> 
> 
> > I can easily imagine a salesman in photo store babbling something like:
> ...



Well, sometimes when I walk into a photo store in some big 'shopping mole' (to look at new cameras I saw only on web pictures while my wife is in next shop in search for new shoes) I do see people purchasing rather strange lenses for equally strange prices...

...looks like this is a good business still. 

My worst 'photo store' experience was back in 1996 when I decided that I want to try and buy some simple P&S camera right now (it was Canon's SureShot 80 -- and actually worked perfectly and is still alive!) After I gave to a guys behind the counter ~ $100 he wanted for this camera, he smiled and said: "And now, you know, this camera does not have a battery. But I can sell you one for just $20." -- They just did not have filters and other stuff for P&S cameras to screw on lenses and customer budget back then...

Sorry, all these is really irrelevant in this topic. If some electronic super-stores do sell lenses for their MSRPs, Sigma do has chances to sell these new 24-105 of theirs.


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## AcutancePhotography (Dec 18, 2013)

cliffwang said:


> That's what I thought. When you can get Canon 24-105 for 600 bulks easily, I don't really see why Canon users need to get Sigma 24-105.


I am not sure that Sigma is really marketing this lens toward Canon users. I think Nikon users will be more interested. There just does not seem to be a significant difference between the Canon and Sigma 24-105. Nikon, on the other hand, does not have anything with these focal lengths.


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## unfocused (Dec 18, 2013)

dilbert said:


> Or in other words, anyone that paid anything close to the MSRP when it was originally released has been screwed over and that this lens was never worth the investment when it was first released.
> 
> Says a lot for Canon "L" quality, doesn't it?



Doesn't say anything about Canon "L" quality. It just says early adopters pay a price premium for the privilege of being the first to own anything. If you want to turn this into some sort of bizarre argument over Canon quality, be my guest. But think about this:

The "white box" lenses are coming from 5DIII and 6D kits (probably more from the 5D). In order to turn a profit, they have to set a price for the split kit body-only and the lens-only that will allow them to recover their initial investment and make some money. Every dollar in value they take from one is a dollar in value they have to add to the other. So, if the lens is deeply discounted that leaves less room to discount the camera. 

A fair way to look at this is to say that Canon Cameras are highly valued on the street and can command a higher price, so that allows the sellers to offer the lens at a lower price. So, I guess this is just more proof that all the b.s. about the inferiority of Canon's bodies is just that: b.s.


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## unfocused (Dec 18, 2013)

AcutancePhotography said:


> I am not sure that Sigma is really marketing this lens toward Canon users. I think Nikon users will be more interested. There just does not seem to be a significant difference between the Canon and Sigma 24-105. Nikon, on the other hand, does not have anything with these focal lengths.



I don't follow Nikon prices as closely as Canon (no reason to), but I did notice on NikonPriceWatch that the closest Nikon equivalent is more expensive, so this could be an attractive lens for Nikon shooters from a price point as well.


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## Random Orbits (Dec 18, 2013)

dilbert said:


> Random Orbits said:
> 
> 
> > Well, if the box the worth $500 to you, then get it for 1149. It isn't to me. And good luck selling a Canon 24-105 that you would buy for 1149 for anything close to that amount.
> ...



LOL, good luck selling the Sigma 24-105 for 900 in a couple years. The S35 came out at 900 and is now discounted to less than 800. That says something about Sigma quality too, doesn't it?

The 5DIII came out at 3500, and the 24-70 II came out at 2300. Early purchases pay a premium. Kit lenses face even more pricing pressure, so what is your point? The IQ of the S35 is better than the 35L and sells for less, so it is a good value. The Sigma 24-105, whose IQ is slightly better but sells for more, is not the value winner that the S35 is.


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## Zv (Dec 18, 2013)

AJ said:


> The t-stop of 5.1 for the Canon 24-105 is a bit of a shocker to me. tsk tsk Canon!
> 
> So basically the Sigma is about the same price and about the same sharpness, but half a stop brighter.



Not surprising since it has a bigger front end! Why is that a shocker? 

An f/4 zoom lens is not one you'd expect to have optimal light transmission anyway. It has IS that easily makes up for it. Good for Sigma though for improving on the design. However that seems to have come at a price - added bulk. 

Separate note. Even though I buy in yen I always write prices in USD here on this forum because that's what most people understand. It doesn't bother me. Keeps things standardized. But the point is when we convert we all get funky numbers. I think when quoting a street price we should just use amazon.com or something.


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## Zlyden (Dec 18, 2013)

Hmmm.... two more points:

1) Why everyone here thinks that Sigma's MSRP is lower than Canon's?

It's NOT: Sigma's 24-105 official MSRP is $1260.

See: http://www.sigmaphoto.com/product/24-105mm-f4-dg-os-hsm-art






2) Why would Sigma make a lens that targets only Nikon users, while it perfectly knows that more than half of DSLR market are Canon users?


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## Sporgon (Dec 18, 2013)

Zlyden said:


> 2) Why would Sigma make a lens that targets only Nikon users, while it perfectly knows that more than half of DSLR market are Canon users?



Now _that's_ a valid question. But it looks like that is what they have done. Unless in the field the word filters out that it has some significant advantage over the Canon such as sharpness, bokeh, colour etc. But I can't see it.


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## AJ (Dec 18, 2013)

Zv said:


> An f/4 zoom lens is not one you'd expect to have optimal light transmission anyway.


Isn't the point of lens design to have optimal light transmission? And if the f-stop is four and the t-stop half a stop worse, doesn't that say something about Canon's glass elements and coatings? The Canon 24-105 is a good lens but it should not have been branded with the red ring.


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## mrsfotografie (Dec 18, 2013)

Zlyden said:


> TWI by Dustin Abbott said:
> 
> 
> > *Just out of curiosity: a lot of you own the 24-105L - are you planning on selling it to get the Sigma?*
> ...



It's my primary travel lens! The Canon is compact enough and it has weather sealing. Sorry, but the Sigma's right out.


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## atvinyard (Dec 18, 2013)

isn't 2014 supposed to be a big year for Sigma? isn't there a rumor that sigma might be releasing a new camera this year? is it possible that this might be the kit lens for that camera?


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## TWI by Dustin Abbott (Dec 18, 2013)

Reading the trend in this thread regarding light transmission reminded me of something that I read in Bryan Carnethan's review of the 35mm f/2 IS.

"The above images were identically exposed with exception of the Sigma 35 that needed a 1/3 stop longer exposure to produce a histogram equal to the other lenses in this comparison. The Canon 35 f/2 is about 1/6 stop brighter in comparison, but its exposure was not adjusted in this comparison. "

Just to provide some balance. Most manufacturers fudge a little on light transition and focal length to market lenses at certain acceptable standards. While it's not a huge deal, it is worthy to note lenses that deliver better light transmission because you may be getting slightly more bang for your buck.


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## Random Orbits (Dec 18, 2013)

AJ said:


> Zv said:
> 
> 
> > An f/4 zoom lens is not one you'd expect to have optimal light transmission anyway.
> ...



Yup, it implies that current coatings are better than something that came out in 2005. Canon's 24-70 f/4 IS has a t-stop = 4. The 24-70 II has a t-stop of 3 while the version I has a t-stop of 3.4.


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## goldencode (Dec 18, 2013)

It's heavier than the Canon 24-70 F2.8 II and its an F4 lens.
82mm filter
Optically very similar to the Canon 24-105 F4 L.

So, what is the advantage of this lens ? I don't think it really adds any " Wow " factor.


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## Random Orbits (Dec 18, 2013)

dilbert said:


> Yup, it implies that current coatings are better than something that came out in 2005. Canon's 24-70 f/4 IS has a t-stop = 4. The 24-70 II has a t-stop of 3 while the version I has a t-stop of 3.4.



It's not just coatings. The newer lenses have bigger front elements and that counts for a lot (more surface area on the front of the lens = more light gathering ability.)
[/quote]

Maybe... although it would affect some and not all a zoom's focal range. But it can also be done without changing the lens diameter. For example, the 24 f/2.8 and the f/2.8 IS both use 58mm filters. The old one has a t-stop of 3.2 while the new one is 2.8.


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## unfocused (Dec 18, 2013)

Okay, all this debate over the "true" f-stop of a lens has me scratching my head. 

Since metering is through the lens and presumably the exposure selected by the camera is going to reflect the actual light hitting the meter, what's the real world impact here?

Yes, I get that a mis-marked lens means that your f4 lens won't have as great of a light gathering power if it is really an f4.5 lens, but unless you are shooting wide open, what's the practical effect. Your images will still be properly exposed. 

Now, obviously if you bought a lens thinking it was an f2.8 and it was really an f4.5 that would be some serious fraud going on. 

While were on the topic, aren't there also some standards that must be met. After all, ISO stands for the International Order for Standardization.


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## iowapipe (Dec 18, 2013)

Random Orbits said:


> dilbert said:
> 
> 
> > Yup, it implies that current coatings are better than something that came out in 2005. Canon's 24-70 f/4 IS has a t-stop = 4. The 24-70 II has a t-stop of 3 while the version I has a t-stop of 3.4.
> ...



Maybe... although it would affect some and not all a zoom's focal range. But it can also be done without changing the lens diameter. For example, the 24 f/2.8 and the f/2.8 IS both use 58mm filters. The old one has a t-stop of 3.2 while the new one is 2.8.
[/quote]

Just as a quick question: while the filter size is the same, is the size of the front element also the same? 
I tried a quick lookup to find specs of the element size and couldn't find anything. So I can't answer my own question.


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## traveller (Dec 18, 2013)

There's a lot of Sigma hate going on in this post. I can understand that quite a few people have been burned by third party lenses in the past, I've also had mixed results, but I think that's a reason to be careful with what you buy, not to dismiss an option outright. I don't currently own any Sigma lenses, but I had the 10-20mm f/4-5.6 before moving to full frame, I enjoyed using it very much and got good results. Unlike the argument that is often put forward, I don't think that non-Canon lenses necessarily have poorer resale values, so long as you buy decent quality lenses that appeal to the (often more savvy) second hand market; the hit that I took selling my Sigma was no worse in percentage terms than the hit I would have taken selling the Canon EF-S 10-22mm. 

I currently own the Canon 24-105mm f/4L IS and while I am not in a hurry to rush out and buy this new Sigma to replace it, I am glad that people looking for a lens in this class now have another option (other than going for a 24-70 f/2.8 ). If the DXO Mark data is correct (and I am looking at the measurement data, not the silly "single number" metric), this Sigma looks quite a bit better wide open at the long end of the zoom range. This is great news, I'm often torn between the 24-105 and the 70-200 when I get to 70mm (maybe I need a second body, but I can't afford another 5D MkIII -the first one was painful enough on my bank balance!). 

For those that absolutely will not countenance owning anything but Canon branded lenses, perhaps the appearance of this new 24-105 will motivate them to produce a 24-105 f/4L IS II...


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## LetTheRightLensIn (Dec 18, 2013)

dilbert said:


> Random Orbits said:
> 
> 
> > Yeah, it only undercuts the Canon because DxO still has the 24-105 costing 1250, which is far above its current street price. It may be a slightly better than Canon's 24-105, but with the Canon version selling at 600-700, the Sigma isn't quite the bargain as when the Canon sold at 1250.
> ...



Who cares? Even years ago before the price collapsed I didn't pay close to $1149 for it. You can get them new, for $750 EASILY now, EASILY and for $600 with just a bit of effort. Real world is what counts.

$1149 is nuts! Who pays that? Heck I got a new, from a major camera store, full US warranty, 24-70 f/4 IS for $125 LESS than that, so who on Earth would actually pay $1149 for the 24-105 these days?


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## LetTheRightLensIn (Dec 18, 2013)

TWI by Dustin Abbott said:


> Reading the trend in this thread regarding light transmission reminded me of something that I read in Bryan Carnethan's review of the 35mm f/2 IS.
> 
> "The above images were identically exposed with exception of the Sigma 35 that needed a 1/3 stop longer exposure to produce a histogram equal to the other lenses in this comparison. The Canon 35 f/2 is about 1/6 stop brighter in comparison, but its exposure was not adjusted in this comparison. "
> 
> Just to provide some balance. Most manufacturers fudge a little on light transition and focal length to market lenses at certain acceptable standards. While it's not a huge deal, it is worthy to note lenses that deliver better light transmission because you may be getting slightly more bang for your buck.



Yeah it can vary. I found the sigma 120-300 2.8 non-OS to be about f/3 and 280mm if we take the 300 2.8 IS to be f/2.8 and 300mm.

And I found the 100L f/2.8 to be getting towards 1/3 stop brighter and 1/3 stop less DOF than the 100 non-L macro from Canon both at 100mm f/2.8 (and no I didn't have one in macro zone and the other out).

I forget the details but in a few cases the 70-300L, I believe, seemed to be a bit brighter than the 70-200 f/4 IS at the same aperture and focal length.

Yeah the 24-105 is kinda dim, another reason why the 24-70 f/4 IS and 24-70 II are even better in comparison than a direct aperture comparison makes it appear to be.


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## LetTheRightLensIn (Dec 18, 2013)

goldencode said:


> It's heavier than the Canon 24-70 F2.8 II and its an F4 lens.
> 82mm filter
> Optically very similar to the Canon 24-105 F4 L.
> 
> So, what is the advantage of this lens ? I don't think it really adds any " Wow " factor.



exactly. I'd rather pay $125 more and get the much smaller and lighter 24-70 f/4 IS (with macro mode) or pay less and get by with the 24-105L (or pay more and get a better Tamron 24-70 VC or really pay more and get the best 24-70 II myself since it's not like those add any size or bulk compared to the sigma, although the 24-70 iI does lack the IS, it does offer f/2.8 though).

I think this lens may look pretty good in the Nikon world though.


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## candc (Dec 19, 2013)

I have always been a bit confused about the whole f stop vs. t stop comparison. If I understand it right then a 100 mm f/2 lens has a 50mm max aperture, 100/2 = 50. The lens may pass less light, that is the t stop, an actual transmission or equivelant rating. Does the camera recognize this and make exposure calculations on a lenses light transmission capabilities or does it default to the embedded code of the lens? Is slight underexposure only an issue at max aperture?


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## Zv (Dec 19, 2013)

candc said:


> I have always been a bit confused about the whole f stop vs. t stop comparison. If I understand it right then a 100 mm f/2 lens has a 50mm max aperture, 100/2 = 50. The lens may pass less light, that is the t stop, an actual transmission or equivelant rating. Does the camera recognize this and make exposure calculations on a lenses light transmission capabilities or does it default to the embedded code of the lens? Is slight underexposure only an issue at max aperture?



If you have two lenses of similar design - one T 2.8 and other T 3 and put them both on the same camera at the same settings you would notice one is slightly brighter. With the camera in Av mode the metering system would compensate via shutter speed so they look similar. The downside being you lost speed. How important that is depends on what you're shooting - action vs landscape for example. 

Since the 24-105L isn't really known for it's action freezing abilities it's not even an issue. For low level light situations it could make a slight difference though. But then again for low light you'd use a faster lens. 

However, more light is always welcome so in the grand scheme of things better T stop values are desirable.


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## Zv (Dec 19, 2013)

candc said:


> So you attach an f/2.8 lens to the camera, the max aperture reading f2.8 you see is based on what the lens tells the camera, not what the actual light reading the camera see's based on the focal length?



Yes exactly. F stops only refer to the physical size of the aperture. It does not represent the actual amount of light the lens can transmit. 

The maximum amount of light that gets through when the lens is at f/2.8 is what the T stop refers to. By the time that light has gone through the front element, all the elements in the middle (could be several) and out the back and onto the sensor it is no longer at 100% because some of it got reflected along the way. How much got reflected depends on the quality ofthe glass and the coatings. 

Easy way to think of it. F stop is just how big the hole is. T stop is how much light is allowed to pass through the hole. If that hole is covered in spider webs not much light gonna get thru! Haha! 

Also when you stick a filter in front of the lens it also affects the T stop since the filter is essentially adding another element in the light path. 

It makes sense why prime lenses have better image quality than zooms. The zooms tend to have more glass elements thus blocking more light. 

No lens is perfect, you'll always lose a bit of light.


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## candc (Dec 19, 2013)

Okay, I think I understand how the whole lens, camera metering works. The lens tells the camera its max aperture, the camera takes a reading based on that and the light it's seeing, it's actually basing the calculation on the t stop it's seeing relative to the f stop it's given?


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## privatebydesign (Dec 19, 2013)

candc said:


> Okay, I think I understand how the whole lens, camera metering works. The lens tells the camera its max aperture, the camera takes a reading based on that and the light it's seeing, it's actually basing the calculation on the t stop it's seeing relative to the f stop it's given?



Close but not really. Forget T stop. The difference between f stop and t stop does not result in slight underexposure even at max aperture.

The camera is basing the exposure on the light it sees. The T value is one factor in that but a very minor one, of magnitudes greater importance is the luminosity of the scene. It doesn't matter to the camera if you have a low transmission efficiency, or the scene is darker, or if you put on a ND filter etc, it adds up to the same thing, longer shutter speeds.

The camera is not basing the calculation on the t stop it sees per se, it never knows what the t stop is and doesn't care, it is basing the calculation on the light it sees, that is all. The difference between the light there is (which an ETTL meter never has a way of knowing) and the light that comes through the lens (which it does), is impacted by the t stop and filters etc, but that difference is not a factor in the exposure calculation.


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## Zv (Dec 19, 2013)

candc said:


> Okay, I think I understand how the whole lens, camera metering works. The lens tells the camera its max aperture, the camera takes a reading based on that and the light it's seeing, it's actually basing the calculation on the t stop it's seeing relative to the f stop it's given?



T stop is just a theoretical (measured in a lab??) value. 

When you half press the shutter the meter is activated and the lens does nothing really, it's already wide open to allow as much light in as possible. The camera then does it's calculations based on the amount of light hitting the sensor. 

When you fully press the shutter the aperture then adjusts to the required setting and the shutter moves to achieve a correct exposure. 

The only time you might notice T stops is if you were using M mode and switching lenses for the same scene. For example lets say you set up a shot at f/2.8 1/60 ISO 100 and it looks perfect. You then switch lenses and set it to the exact same settings and notice the shot is under exposed slightly. No big deal you just crank up that ISO or adjust shutter speed and you're back on track! 

An example where you might encounter this situation is say you're using the 24-105L and shooting at 24mm and say f/8. You decide you're not a fan of the 24-105L at the wide end so you switch to your 24L or whatever and try again. Surprise surprise it looks better now! 

That's basically what this is all about. The Sigma lens would be slightly brighter and of course better. But the amount is fairly small.


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## Sporgon (Dec 19, 2013)

T stops and f stops all are pretty easy to understand in principle but....

Ever since I first started using the 24-105 in 2005 I found that if you shot from the camera's meter, or suggested exposure in manual, this lens underexposed the frame by about one third of a stop compared with say a fast lens such as the 50/1.4, so the image was slightly more 'dense' and the histogram more dense and to the left. 

Now according to DXO the 24-105 has a t stop of 5.1 against an f stop of 4, so it looses two thirds of a stop. 

Using the same source the 50/1.4 has a t stop of 1.6 against 1.4 so it is one third of a stop less; so; the difference between the two lenses actual transmission is one third and this is exactly the difference I find in exposure between the two, and this includes using a hand held incident light meter and setting the camera shutter speed and aperture manually. 

So far so good; this difference equated exactly to the t stop differences between the lenses.

However there is a problem. The 24-70 f4 IS which by the same source has a t stop of f4 against f4 _ does exactly the same thing._ Compared with a faster prime with less elements it underexposes by one third of a stop. So does complicated element lenses such as the 70-300L. Also I believe Edward Lang (eml58) found that his 200-400L underexposed on the same meter reading compared with the 400/2.8L . 

So what's going on ? By the definition of what a 't' stop is, lenses of equal t stop should expose the same, but it seems to me that the more elements that are added the more the lens is likely to underexpose. Yet this is just what t stop is supposed to measure. 

And before anyone asks, this isn't just on one copy of the lens; it is universal. 

To me it suggests that 't' stop value is not accurate in practice, or at least in this application. Any ideas ?


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## Zlyden (Dec 19, 2013)

Interesting discussion! 

Now I think I understand practical purpose of this parameter in DxO stats.

Did anyone see lenses with calculated T-stop equal to F-number on them?


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## TWI by Dustin Abbott (Dec 19, 2013)

Zlyden said:


> Interesting discussion!
> 
> Now I think I understand practical purpose of this parameter in DxO stats.
> 
> Did anyone see lenses with calculated T-stop equal to F-number on them?



Many of the better primes (particularly the new ones) are much closer. I've already mentioned the new EF 35mm f/2IS, which has both an f-number and t-stop of 2. In the past, I would say that many primes are more likely to be close than zooms (where more compromises are made), and that does speak well of the light transmission of the new Sigma 24-105. because it manages to transmit just about (almost) the amount of light that the f-stop suggests.


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## Zv (Dec 19, 2013)

TWI by Dustin Abbott said:


> Zlyden said:
> 
> 
> > Interesting discussion!
> ...



How can the T value be the same as the f number if the lens clearly vignettes wide open? Is T value only measured in the center? 

Just asking, I have no clue how the T value is actually determined.


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## TWI by Dustin Abbott (Dec 19, 2013)

Zv said:


> TWI by Dustin Abbott said:
> 
> 
> > Zlyden said:
> ...



Good question. I can't see it being anything else, as the average from almost every lens towards the periphery would bring the score down


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## privatebydesign (Dec 19, 2013)

It used to be measured as the density of the negative plus base, fb+f . In today's speak that would equate to the same charge on the sensor. It is not a spot measurement.


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## sdsr (Dec 19, 2013)

DXO gives this lens the same sharpness score (18) as the Canon 24-70 2.8 II and the Tamron 24-70 2.8 VC. Perhaps I don't understand what their sharpness scores mean, but I'm pretty sure I've not seen any other review claim or show that the Tamron, however much they may like it, is as sharp as the Canon, or that the new Sigma, while a bit sharper than the 24-105, is also as sharp as the Canon 24-70 2.8 II. What am I missing?


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## Sporgon (Dec 19, 2013)

sdsr said:


> DXO gives this lens the same sharpness score (18) as the Canon 24-70 2.8 II and the Tamron 24-70 2.8 VC. Perhaps I don't understand what their sharpness scores mean, but I'm pretty sure I've not seen any other review claim or show that the Tamron, however much they may like it, is as sharp as the Canon, or that the new Sigma, while a bit sharper than the 24-105, is also as sharp as the Canon 24-70 2.8 II. What am I missing?



Their score summaries are, in my opinion, a joke. I mean have you seen the chromatic aberration summary score they show for the 85mm 1.8 ? It's 3 mu, that's about the lowest there is. The Zeiss Otus for example is 6. 

Yet use the 85 1.8 wide open in high contrast and we _all_ know what happens.

( Well all with the exception of dxo that is ).


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## TWI by Dustin Abbott (Dec 19, 2013)

sdsr said:


> DXO gives this lens the same sharpness score (18) as the Canon 24-70 2.8 II and the Tamron 24-70 2.8 VC. Perhaps I don't understand what their sharpness scores mean, but I'm pretty sure I've not seen any other review claim or show that the Tamron, however much they may like it, is as sharp as the Canon, or that the new Sigma, while a bit sharper than the 24-105, is also as sharp as the Canon 24-70 2.8 II. What am I missing?



Roger here at Lens Rentals has the Tamron splitting the difference between the MK1 and MK2 versions the Canon both at 24mm and 70mm. http://www.lensrentals.com/blog/2013/01/canon-24-70-f4-is-resolution-tests 

Since he tested multiple copies, I would take his conclusions very strongly. Some reviews have the Tamron as good at certain focal lengths, and most conclude that stopped down they are pretty much equal, but I have never heard anyone claim that the Tamron has more resolving power. The only way that the Tamron resolves higher (according to Roger in another article) is if it is mounted on a D800E and the 24-70II is mounted on a 5DIII (in other words, just because of the difference in sensors).

http://www.lensrentals.com/blog/2013/01/a-24-70mm-system-comparison


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## candc (Dec 19, 2013)

I believe the dxo lens sharpness score is always in whole numbers. I reckon If 2 lenses are pretty close then the score gets rounded to the same number.


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## David Hull (Dec 19, 2013)

Eldar said:


> Zlyden said:
> 
> 
> > Random Orbits said:
> ...


One other thing worth mentioning is that the Canon "L" stuff seems to hold its value pretty well on the used market -- I cannot speak for Sigma since I have never tried to sell one. For the 24-105 though, if you buy one of those "white box specials" for $700 you will be able to sell it in a couple years for darn near $700. I remember paying $1850 for a 70-200 L IS and selling it after 4 years for $1550 (once the Mk II version came out). I got to use it for 4 years for $300.


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## David Hull (Dec 19, 2013)

dilbert said:


> Eldar said:
> 
> 
> > A Sigma lens has a reverse engineered EF mount, a long history of AF problems, quality variations pr. copy, numerous examples of poor service etc. etc. To hope for any chunk of the Canon L-lens customer base, they have to be both better and cheaper and they have to be that over time. If they are consistently as good as Canon over time, meaning years, they can move closer to the prices Canon can charge. The only non-Canon brand that can charge as high or even higher prices than Canon is Zeiss. Because they have proved over time that they are consistently delivering absolute top class products in every department. Sigma, Tamron, Tokina and the rest have a loooong way to go before they are in the vicinity of such a position.
> ...


1. Have you ever needed such a capability?
2. The latest Canon lenses DO have this capability but they do it through the camera body, so you don't need to buy a separate USB gizmo to do it -- Just an expensive Camera body. The last time I updated my 5DIII there was a lens FW update option in the menu.


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## David Hull (Dec 19, 2013)

LetTheRightLensIn said:


> dilbert said:
> 
> 
> > Random Orbits said:
> ...


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## Zlyden (Dec 19, 2013)

Sporgon said:


> Zlyden said:
> 
> 
> > 2) Why would Sigma make a lens that targets only Nikon users, while it perfectly knows that more than half of DSLR market are Canon users?
> ...



I do think that Sigma DID initially plan to turn this lens into a head-to-head competition against Canon's 24-105 (not as a strange product that may or may not target only Nikon users).

They just were too slow.

I do not know what time it takes to design, test and put a lens into mass production. But probably it takes few months (or rather -- more than a year).

The most drastic drop in price for 'white boxed' 24-105 L happened this year (too many unkitted 6Ds and 5D3s sold to those who already own 24-105 or do not want one) and 24-105 L price suddenly dropped to just $600-700. 

So, one or two years ago Sigma might do have reasonable plans to make a fortune selling its own version of 24-105 for $850-900. 

Now they can't. But it's too late. They could either kill the project (that's already finished) or proceed with it as it was planned...


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## K-amps (Jan 1, 2014)

I have owned a 24-105L before as well as 2 copies of the 24-70 f2.8L II. Sold all for financial reasons ... got the Sigma last week. It's not amazing but pretty darn good. Great for the price.

24mm Distortion and corner sharpness are better than the Canon 24-105L. The wide end is where I mostly use my 24 zooms.

OS is not bad either. Shot this in the evening, on a moving and bobbling Speedboat yesterday. 

This has been gently PP'ed but I have not MA'd the lens yet... it needs a little maybe but I have not done scientific tests.

F9
1/40th
ISO200



Look and feel is solid, barrel is nice and snug, feels more robust than the canon 25-105. Great finishing.


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## bholliman (Jan 1, 2014)

K-amps said:


> I have owned a 24-105L before as well as 2 copies of the 24-70 f2.8L II. Sold all for financial reasons ... got the Sigma last week. It's not amazing but pretty darn good. Great for the price.
> 
> 24mm Distortion and corner sharpness are better than the Canon 24-105L. The wide end is where I mostly use my 24 zooms.
> 
> ...



The Canon 24-105 is selling for $600-650 new, do you feel the Sigma is worth the 40-50% price premium?


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## slclick (Jan 1, 2014)

After shooting over 500 images with my new S 24-105 I am much more pleased with the wide end than I ever was with either of my 2 Canon copies. The OS and AF are great without any discernible difference to the Canon counterpart. It weighs a TON but I'm used to lugging a Tamron 24-70 around so it's ok for me on a 5D3. I was able to shoot down 4 stops at the long end without issues and it controls flare somewhat better than the Canon. Bokeh is oniony but it's no Sigma 35. 

Worth $854 anyday imho. (B&H EDU price)


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## TWI by Dustin Abbott (Jan 1, 2014)

slclick said:


> After shooting over 500 images with my new S 24-105 I am much more pleased with the wide end than I ever was with either of my 2 Canon copies. The OS and AF are great without any discernible difference to the Canon counterpart. It weighs a TON but I'm used to lugging a Tamron 24-70 around so it's ok for me on a 5D3. I was able to shoot down 4 stops at the long end without issues and it controls flare somewhat better than the Canon. Bokeh is oniony but it's no Sigma 35.
> 
> Worth $854 anyday imho. (B&H EDU price)



That is a very handsome image.


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## K-amps (Jan 2, 2014)

The Canon 24-105 is selling for $600-650 new, do you feel the Sigma is worth the 40-50% price premium?
[/quote]

Depends on your wallet... the 24-105L could go to $450 and that would not take away from what the S24-105 can still do. It's worth the money... and probably a good $200 more worth it for me. If I made money off this, I'd get a 24-70L or wait for the IS, but apart from that, I like it very much. I was on a speed boat going quite fast, snapping shots as we went along, I got almost no blurry shots... AF nailed, OS nailed. Great product.


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