Tamron 17-50 or Sigma 18-50, moving from a Sigma 17-70

[drama]

Hi guys

I was using a Sigma 17-70 as my main indoor & walk around lens, my main issue with it, was that, I couldnt get a blurry background (bokeh), for love or money

Example
http://farm2.static.flickr.com/1415/651882676_8a68023a85.jpg
Shot wide open f4.5

Plus I took a series of indoor shots with flash, for a recent family function & was no too happy with the number of keepers I got

So I decided to switch to a constant f2.8 lens
I am currently testing the Tamron 17-50 f2.8, the Sigma is worth 100 $ more
Is it worth getting over the Tamron?

Macro is not a consideration, as I have a dedicated macro lens, Tamron 90

[MiqueMaus]

I have the new "Macro" version of the Sigma 18-50 and I think it does an amazing job. Contrast and sharpness are great too. However, if the Tamaron is 100 dollars less, you're better off getting that since the performance is pretty much the same IMO. I would've gone for the Tamaron but the Sigma was 40 dollars cheaper when I got it. Either way you go, you won't be disappointed.

[coldrain]

The difference in back ground blur will not be huge, at f2.8, with that focal length and distance. So do not expect miracles.

The Sigma 18-50 f2.8 EX DC macro is a tad cheaper in the US, and about the same here in Europe, a shame that where you are it is more expensive.

The Sigma has better build quality. It also has a bit better optics, and seems to be a better especially in the corners at f2.8.

If that is worth the extra money is for you to decide...

[Rooz]

Hi guys

I was using a Sigma 17-70 as my main indoor & walk around lens, my main issue with it, was that, I couldnt get a blurry background (bokeh), for love or money

Example
http://farm2.static.flickr.com/1415/651882676_8a68023a85.jpg
Shot wide open f4.5

Plus I took a series of indoor shots with flash, for a recent family function & was no too happy with the number of keepers I got

So I decided to switch to a constant f2.8 lens
I am currently testing the Tamron 17-50 f2.8, the Sigma is worth 100 $ more
Is it worth getting over the Tamron?

Macro is not a consideration, as I have a dedicated macro lens, Tamron 90

the problem with that shot you will have at 2.8 though is that not all the people will be in focus so it may not turn out as well. hard to get a blurred background from that distance away in such bright light with a 50mm max focal length. you;d need something much longer to get the DOF you are after imo. like maybe your 70-300.

i had the tam and detested the build quality although optically it was very good. i think from memory it was lighter, a bit faster focussing and the background had a nicer blur to it but the sigma is sharper, has more accurate contrast/ colour rendition and much better build quality.

btw: don;t overlook the macro feature...remember this is also about focusing distance and sometimes its has come in very handy. not necessarily for macros per se but just from the point of view of getting up close to any subject.

[GaryS]

As far as DOF goes.... The 17-70, wide open at 70mm has a shallower DOF (3.5m) than the 18-50 wide open at 50mm (4.4m), assuming your subject is about 10m away. Note: Calculated by dofmaster.com

So I don't think this lens change is going to help you with the blurred background for a shot like this one. A bit of masked guassian blur in photoshop is probably the best way to go.

In the situation you presented here, I think you have 2 options to take out the distracting fence. 1 is move your position so that the fence can't be seen. 2 is to use a longer lens and focus more on tighter shots, which would give you shallower DOF to blur the fence. Or I guess you can fix it in PS.

I like my Sigma 18-50, but I don't think it will solve this problem.

[zmikers]

That was also my question I posted in another thread. What is the auto focus like on the sigma?

[coldrain]

That was also my question I posted in another thread. What is the auto focus like on the sigma?
On Rooz' D80, it is fine, as I recall him telling.
On an XTi it is also fine, as I have seen some XTi owners tell.

On my XT I can't tell, the copy of the older 18-50 I have does not focus lock reliably always. But, that is in combination with an XT, not an XTi.

[nqjudo]

The guys are talking a lot of sense here. DOF is influenced by four factors, one of them being the focal length of your lens. In your scenario, this appears to be your biggest hurdle. Moving one or two stops using aperture will probably not help that much. I am sure if you used your 70 - 300 on the long end, you would have no problem isolating subjects. I do it all the time, usually at f/5.6, still at reasonably close distances. That's your solution at 0 cost seeing as how you already have the lens.

I am not entirely sure that you can reasonably expect to isolate subjects from the background using wide - mid lenses, especially if you are shooting from far away, distance being one other factor that determines DOF.

I don't know what camera you are using but if it is cropped sensor rather than full frame, that is another thing working against you. At a constant aperture size, the smaller the sensor (or film size), the greater the DOF. All said, changing one lens for another with similar focal length may be somewhat of a futile exercise even if the aperture can be opened up a stop or two more.

[GaryS]

That was also my question I posted in another thread. What is the auto focus like on the sigma?

I don't have much to compare it too.... But I think it works well. It seems to lock on very quickly, to the point where I don't think about it much. Its faster to find focus than my Canon 70-300.

[DonSchap]

As much as Coldrain may love the Sigma 18-50 f/2.8, after a year of toting around the TAMRON 17-50 and its brother lens, the 28-75, I can honestly say that they are lens that work and deliver clear, well-focused images.

Using it to get the f/2.8 bokeh is relatively simple, although, as was mentioned ... if your image in not too complicated, you can simulate this with the "guassian blur" filter of Photoshop, just don't push to a point of being unreal. Having some other f/2.8 images at roughly the same distance, to actively compare and refer to, keep your images looking "honest", in this regard.

Obviously, if you are going for a serious real blur, using a EF 50mm f/1.8 II or EF 50mm 1.4 USM ... or if you really have a couple of bucks to put toward the cause, the EF 35mm f/1.4L USM will deliver incredible stuff. A compromise would be using the slightly less costly EF 28mm f/1.8 USM ... getting you close to normal.

Of course, the finest fixed focal length toy is the EF 200mm f/1.8L USM.

26195


This baby isn't even produced anymore, but delivers stuff that even the pros salivate at. It was clearly designed to be shot "wide-open" (specifically, indoor sports) and is definitely worth "a rent" if you want to see and produce images you'll never get with anything else. :cool:

Here's a sample of Alan Zasi's work with the lens (mounted on a EOS 5D):

26202


and a link to other samples (http://www.pbase.com/cameras/canon/ef_200_18u) of what you can expect from this ... stellar piece of glass.

[aparmley]

Its faster to find focus than my Canon 70-300.

Thats not saying much at all, that 70-300 IS is as slow as molasses.

Drama - I agree with most everyone here. The 24-70 F2.8 L lens, at 70mm at F2.8 would not look much different than the shot you shared with us. The 18-50s won't help you out there at all. now if you moved in a lot closer, thats a different story, but at that distance no change.

[GaryS]

Thats not saying much at all, that 70-300 IS is as slow as molasses.

That made me laugh... Andy is right of course. Lets change that to "It's a TON faster than my Canon 70-300".

[nqjudo]

As soon as I saw Don's last post I completely forgot what this entire thread was about. Damned blonds get me every time.

[zmikers]

LOL, I was going to thanks everybody for more great advice, but forget that. Thanks Don for posting the blond:D

[DonSchap]

Sorry for the distraction, dudes ... women and the front end of a lens ... who knew? :eek:

Now, about that bokeh ... :o

[drama]

Thanks everyone for the great advice :)

I had a scare with the Tamron, It stopped working, it showed an aperture of 0.0, I had to remove & refix the lens for it to work again

But I went walking with it & got a lot of shots handheld
Its a lot of fun to use & I got a high rate of keepers
This is a assembled in china Tamron btw
I am alarmed by the fact that, it stopped working

I am planning to get back my 17 70

I cannot meter accurately with the 420ex, so I was thinking of upgrading to a 430 ex & sticking with the 17 70

I will try it for a couple of days & If I am not satisfied
I will get the Sigma 18 50

Don Schap
Thanks for the blonde ;)

I do have a 50 1.8 mark II, which is not getting too much action
time to change that

[Rooz]

Thanks everyone for the great advice :)

I had a scare with the Tamron, It stopped working, it showed an aperture of 0.0, I had to remove & refix the lens for it to work again

I am alarmed by the fact that, it stopped working

my first copy of the tamron stopped working aswell but it never came back to life. my second copy had similar build problems. get rid of that piece of shit before its too late.

BTW: as coldy said, the AF on both the tam and the sigma were both accurate and consistent in any reasonable lighting conditions.

[drama]

Rooz :)

done that
Got back my 17 70 & picked up a 430ex

Next need to learn how to meter accurately with the flash

[drama]

I have ordered the Sigma 2.8 18 - 50, the deciding factor for me was

1 the convenience of the tamron 17-50 as a walk around lens & the sharpness it is reputed to have at 2.8

I had a ton fo fun with the tamron , too bad about the build quality & poor dependability

2 Cold Rain's Greece pictures :)

Also picked up a EX430, I am very new to flash photography & would love some tips
I am determined to learn flash photography :)

[coldrain]

I do not have the Sigma 18-50 f2.8 EX DC Macro though... I have the older version which is not called "Macro".

And that older lens is not as nice as the one you just now ordered...

The photos I made with in in Greece are nice because Greece is nice, and it a little bit to do with the photographer ;)

Rooz has the newer version, with bigger front element.

[AdamW]

I do not have the Sigma 18-50 f2.8 EX DC Macro though... I have the older version which is not called "Macro".

And that older lens is not as nice as the one you just now ordered...

The photos I made with in in Greece are nice because Greece is nice, and it a little bit to do with the photographer ;)

Rooz has the newer version, with bigger front element.

I have the newer version too. I think it's a very nice lens. You should be very happy with it. The only drawback for me is the lack of IS, but that Canon 18-55 f/2.8 IS I'm dreaming about is twice the price!:eek:

[drama]

I was a bit reluctant to pick up the older version but the reviews on the new version have been pretty much been unambiguously positive :)

AdamW thanks for the welcome to the club, havent got it yet
The 18 55 IS would be great but too expensive for right now

Next on my list is a 70 300 IS :)