Photoclubalpha

I have been saving, and am near to purchasing the Tamron 17-50 2.8, but now I see Sigma has announced the same at PMA. I suppose I should wait and see how it reviews compared to the Tamron, but I have seen no suggested price on it. Anyone hear anything?

Rich

The Tamron sells for $630 with vibration compensation, and $450 without. The Sigma 17-50/2.8 will have not only optical stabilization, but HSM focusing, so you might expect it to be marketed toward the higher end of that spectrum, in the $600-700 range.

However, you might consider the new Sigma 17-70/2.8-4, (the old one was half a stop slower at the long end) which features both OS and HSM, and costs only $450. The big complaint against the Tamron 17-50/2.8 lens is the short range, and I must agree that it is sometimes frustrating. The Sigma was a temptation before to anyone choosing between the Tamron and the Sony 16-80 ZA, but now the new 17-70 sweetens the compromise by offering a max. aperture/focal length range that is truly exclusive to the APS-C format.

Also, the Sigma 17-70mm focuses down almost to the front element. It is an exceptional macro lens. We tested it on Pentax not Sony but it's a good bit of glass.

David

The 17-50 has been a reliable workhorse for me. However, sacrificing the constant f/2.8 for some range is a perfectly acceptable tradeoff if you're outdoors on a sunny day.

I'd be curious as to the aperture breakdown of the 17-70. If it's anything like Sigma's usual shenanigans, it's f/2.8 at 17mm, then drops to 3.5 immediately, and then probably hits f/4 around 50mm.

dvincent wrote:I'd be curious as to the aperture breakdown of the 17-70. If it's anything like Sigma's usual shenanigans, it's f/2.8 at 17mm, then drops to 3.5 immediately, and then probably hits f/4 around 50mm.

Even in this ungenerous scenario, the Sigma would still be 1/3 to 2/3 stop faster than the 16-80 throughout the overlapping range, and give up only one stop to the constant f/2.8 lenses at their longest. This is still far superior to the myriad kit lenses that quit offering f/4 after 24mm and offer only f/5.6 at 55mm.

Which camera body do you use, Rich? If it is an a700, which features the center AF sensor sensitive to f/2.8 and faster lenses, then the rest of the lenses mentioned here might mean very little next to the first two with constant f/2.8 max. aperture.

KevinBarrett wrote:

dvincent wrote:I'd be curious as to the aperture breakdown of the 17-70. If it's anything like Sigma's usual shenanigans, it's f/2.8 at 17mm, then drops to 3.5 immediately, and then probably hits f/4 around 50mm.

Even in this ungenerous scenario, the Sigma would still be 1/3 to 2/3 stop faster than the 16-80 throughout the overlapping range, and give up only one stop to the constant f/2.8 lenses at their longest. This is still far superior to the myriad kit lenses that quit offering f/4 after 24mm and offer only f/5.6 at 55mm.

No doubt about that; it is just something to be aware of.

KevinBarrett wrote:
Which camera body do you use, Rich? If it is an a700, which features the center AF sensor sensitive to f/2.8 and faster lenses, then the rest of the lenses mentioned here might mean very little next to the first two with constant f/2.8 max. aperture.

I've just picked up an a700, an upgrade from my a200.

I wonder about the Tamron 17-50/2.8 when I look at my exif data. For some reason, it shows "Max aperture: 3," which causes me to wonder if it is a true f/2.8 lens or not, and also whether the center f/2.8 AF sensor is activated when using it.

Don't skimp. Buy the sony 18-35 CZ. I SWEAR you WILL NOT regret it.

Lonnie Utah wrote:Don't skimp. Buy the sony 18-35 CZ. I SWEAR you WILL NOT regret it.

I am sure it is quite lovely, but alas, I am a poor photo gear addict, and cannot afford the cz lens. Now, if anyone wishes to donate one to me as a charitible donation, I would gladly accept.

KevinBarrett wrote:I wonder about the Tamron 17-50/2.8 when I look at my exif data. For some reason, it shows "Max aperture: 3," which causes me to wonder if it is a true f/2.8 lens or not, and also whether the center f/2.8 AF sensor is activated when using it.

Mine says 2.8. Are you using the Sony software? It shows the lens ID as blank, but clearly shows f2.8 as max (and actual) aperture. How do you see the center af sensor info? (I just have the A100.) I used to have a photo viewer that showed the sensor used, except that it never seemed correct. I tested it one time and couldn't convince myself that it was working.

When I look at my Sigma 17-70 (the older one), I see the Tamron 17-35 f/2.8-4 that I liked so much, with a 35-70 f/4.0-4.5 added by magic. Owning the 17-35 convinced me I needed more range, and that worked against the 17-50: it was too small of an increase from the 17-35 to justify. As David notes, the Sigma's close-focus ability is great, and as much fun at 17mm as at 70! It also serves well with my 1.7x TC, getting me to .83x which is plenty for what I do.

My .ARW files show as max aperture 2.8 using the Tamron on both A700 and A100?