[creoleart]

Okay I just got my sigma 17-70 today and I was disappointed to see that I lose the F2.8 as I zoom in!!! I thought it stayed at 2.8 all the way to 70. I already have the kit lens 18-55 and if it does not go down to that 2.8 aperture, is it even worth keeping it, it is not that much wider the the 18-55. I have only tried it in my studio and I like the fact that I can zoom in and out at a wider angle, but then again I have my strobe light, so lighting is not a problem. But how is it going to perform outside? Should I trade it in for a different lens? I bought it to shoot a wedding at the end of this month along with my 50mm and 70-300. Am I better off just taking my 18-55 or should I just keep it? I still have to go out with it and see how it performs outside, but I thought I would ask those of you who have one.
I was looking at the Tamron 28-75 at 2.8, I guess I lose the wider angle over the wide aperture. Can't have it all. Dilemmas dilemmas!!!
HELP! Thanks!

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Last edited by creoleart; 08-03-2009 at 05:47 PM.

[Arpe]

More research needed before purchase!

I way prefer my 17-70 Sigma, mainly because of the extra reach. And overall the Sigma is still faster at every aperture. It is widely regarded as an exceelent lens.

Maybe just sell your 18-55. Unfortunately you are right, we can't have it all!

[creoleart]

More research needed before purchase!

No kidding!!!!
But you really never really know for sure until you have it onto your camera. Good thing I can return it if I decide to get a different one!

[cwood]

variable aperture lenses are not your friend if you plan on doing weddings as you have indicated in other posts here. Any fixed aperture lens (even F4) is better although fast zooms (F2.8) are usually the best option if you plan on using a zoom.

[SOldBear]

But you really never really know for sure until you have it onto your camera.

That's not necessarily true.

You ask questions. You read reviews.

Also, most dealers (at least the good ones) list the lens as, "Sigma 17-70mm f/2.8-4.5 DC Macro Lens for Pentax." (I just did a Google-search on "sigma 17-70" to get this from mulitple places).

Back to whether you should return it....

It's up to which one is more important to you: constant F/2.8 or the extra reach to 70mm. As far as I know, if you start at 16 - 18mm and want constant F/2.8, the long end maxes out at 50mm.

I personally thing the constant F/2.8 is more important than the extra focal length. I can always crop a little bit more during post processing. But I can't always have more light during shooting.

[netuser]

I would go for the Tamron 28-75 at 2.8

[Andi Lo]

Sigma 17-70 is already an upgrade over the kit lens. If you don't notice the quality difference I guess you should return it, but really as good as the Kit lens is, it's just a Kit lens.

If you need the speed then you're right that you should spend money on something like the Tamron 28-75/2.8 or 17-50/2.8

[pop4]

Okay I just got my sigma 17-70 today and I was disappointed to see that I lose the F2.8 as I zoom in!!! I thought it stayed at 2.8 all the way to 70.

But you really never really know for sure until you have it onto your camera.

The variable maximum aperture is one thing that you could have found out for certain even if you did not have the camera or lens. The Sigma 17-70 normally has the following info "Sigma 17-70mm F2.8-4.5 DC Macro". Having F2.8-4.5, as opposed to F2.8 means that it will have a maximum aperture of F2.8 at its shortest focal length, e.g. 17mm, and it will have a maximum aperture of F4.5 at it's longest focal length of 70mm.

Picking any random lens that I don't have, say the Sigma 50-500mm. I google it, and see it is a "Sigma 50-500mm F4-6.3". I now know for sure, without having it on my camera, or even in my possession, that at 50mm, it will have a maximum aperture of F4 and at 500mm, it will have a maximum aperture of F6.3

[hinman]

As I said it on another thread, I would prefer the Tamron 28-75mm f/2.8 for event and wedding over the Sigma 17-70mm f/2.8-4.5. I used both lens for different purposes. I use the Sigma for outdoor where the wide angle serve me well in both landscape and wider shots with my kids. I use the Tamron for event such as wedding and indoor.

The caveats may lie in the missing of 17mm to 28mm, that you have to answer yourself. Assess if group shot is needed for your type of shooting. Or better assess if 28mm is good enough for your shooting.

For formal shooting, I pair up Tamron 28-75mm f/2.8 with Pentax DA* 50-135mm f/2.8. Both do well for portraits for me. And a wide angle zoom will make up the lacking as in Pentax DA 12-24, Sigma 10-20, and Pentax DA 16-45. All are good choices of gear.

The Sigma is still a wonderful lens if your focus is on outdoor, good close up with 1:2.3, lighter weight and good focal range. It is a faster lens over the kit's lens and that in DA 17-70. Though it is close, I will find the IQ and sharpness better in the Tamron 28-75mm f/2.8. The tamron is very consistent in performance if you get a good copy. I trust its performance even wide open. And it works well with the flash AF540 with a Spectra Light Diffuser for me also.

You can check my gear for reference where I use the lenses, flash, diffuser/bouncer mentioned above:

• Hin's Camera Gear
• look for Tamron 28-75, Sigma 17-70, AF540 flash and Spectra Light Diffuser

Regards,
Hin

[artistcjconrad]

If you’re on a budget, get the tamron 28-75mm f2.8 for now. The Pentax 18-55 or Sigma 17-70 will not help you much with the wedding photography, specially if you shoot inside a church. The Tammy will cover most of your focal length which gives you 42-112.5mm on a APS-C size sensor. I don’t think you’ll need wider than 42mm to take a group shot. Try to set up the group shots out side in a shaded area as much as possible which gives you plenty of space to play around. If it was me, I would use two bodies. One with the Tammy and the other with the 50mm f? . And, most probably I would be using the 50mm outfit more often than the other. You'll be surprised at how much you can cover with 50mm lens. So, yes, I would suggest you return the Sigma 17-70 and get the Tamron 28-75 if you’re going to do lots of weddings or stuff like that. You should go scouting the place in advance where the wedding is going to take place. That will give you clear idea about the available light, necessary focal length and composition. Trust me, you’ll thank yourself for doing that. I hope this helps and good luck !!

cj

[Marc Sabatella]

Note that a 17-70/2.8 is unlikely to ever be built. Such a lens would probably weigh 3-4 pounds and be the size of a roll of paper towels.

[creoleart]

The variable maximum aperture is one thing that you could have found out for certain even if you did not have the camera or lens. The Sigma 17-70 normally has the following info "Sigma 17-70mm F2.8-4.5 DC Macro". Having F2.8-4.5, as opposed to F2.8 means that it will have a maximum aperture of F2.8 at its shortest focal length, e.g. 17mm, and it will have a maximum aperture of F4.5 at it's longest focal length of 70mm.

Picking any random lens that I don't have, say the Sigma 50-500mm. I google it, and see it is a "Sigma 50-500mm F4-6.3". I now know for sure, without having it on my camera, or even in my possession, that at 50mm, it will have a maximum aperture of F4 and at 500mm, it will have a maximum aperture of F6.3

Well I am very impulsive, in every way, and this is just another example of my foolishness and not paying attention to little details like this and I am too eager to get what I "think" would work!!!

Having said that, a wider aperture is a must for me, so I will always go for that first! I can't believe I missed that 2.8-4.5 on that sigma!!!!
Now it seems like the tamrom 28-75 is a good option.

The wedding I am shooting is going to be outdoors, not too much shade, so I think the 17-70 would do okay for that one as there are not a lot of indoors shots, but if I keep shooting weddings I will not always be outdoors so I would need something like the 28-75. And I absolutely LOVE my 50 and will probably use it most of the time. I just wanted something for large group shots and a wider angle than the 50 for some bride and groom shots with a little bit more of scenery in the background.

[creoleart]

I found this one on Adorama (I bought the sigma from them) but I am not sure it'll fit my Pentax. They are currently out of stock on their Tamron 28-75 for Pentax.
Can you tell if this one would work? This is no description on it:
Tamron 28-75 2.8 Di Xr Ld-if F/maxx

[LeDave]

My Sigma 17-70 came today as a replacement to my kit lens and I'm very happy with it. It's not f2.8 all the way 'cuz it says 17-70 F2.8-4.5, that means at telephoto it can go as high as 4.5 but at its widest, highest it can go at 2.8. Hope this helps

[artistcjconrad]

I found this one on Adorama (I bought the sigma from them) but I am not sure it'll fit my Pentax. They are currently out of stock on their Tamron 28-75 for Pentax.
Can you tell if this one would work? This is no description on it:
Tamron 28-75 2.8 Di Xr Ld-if F/maxx

I don't think this would work. This one is probably for Minolta Maxxum. Try to buy a good used one. This lens has a big time focusing issue. Sometimes it takes 3-4 tries to get a good copy. On the other hand, if you buy a used lens from somebody, the seller can tell you if it has any focusing issue. Every now and then you'll see one or two for sale, for a reasonable price right here on the market place. It's much safer to buy a lens from a reputable forum member. You can also put an ad in the wanted section for the lens, I'm sure somebody will sell you one.
If you don't get any response within 3-4 days, then you can may be try at B&H.

regards
cj