sigma17-70 or 24-70

[zmohie]

hi all pentaxian
need your advice,iam going to buy a wide angle lens for pentax,which one is the best choic sigma 17-70 mm f2,8 to 5,6 or 24-70 mm f2,8
thanks

[dwvarch]

Personally, I own the 17-70 from Sigma.  I have found it to be a fairly good lens.  At 17 you will be able to shoot at f2.8, however, as you zoom out your aperture will change to 4.0.  The question as always is what is most important to you, a constant f stop rating throughout the zoom or the ability to shoot wide angle at 17 mm (or 25 mm equivalent).

I am beginning to lean more towards the constant f stop throughout the zoom range.  If you shoot manual quite often, having the ability to shoot low light levels with a constant wide open apperture simplifies the process somewhat in trying to calculate for proper exposure with your ISO and shutter speed. 

However, as I mentioned I am quite happy with the 17 to 70 as it allows me to shoot interior architectural work, and the zoom range is broad enough to use with portraits as well.  It is a versatile lens.

Good luck.
Darrell

[calsan]

Pentax 17-70 SDM F4 is now available and would be a lot faster in focusing than either of those two.   It's worth checking that out, as it's meant to be very sharp.  I find f2.8 not that useful in a wide angle - how many times do you need to take a wide angle shot with a limited depth of field?  I normally leave mine between f5.6 and f11!   Just my two cents...

[JAZZer]

If you need wide angle lens, 24-70 will be little bit short on wide side, 17-70 (Sigma/Pentax) have better range for wide shooting.

[zmohie]

Pentax 17-70 SDM F4 is now available and would be a lot faster in focusing than either of those two.   It's worth checking that out, as it's meant to be very sharp.  I find f2.8 not that useful in a wide angle - how many times do you need to take a wide angle shot with a limited depth of field?  I normally leave mine between f5.6 and f11!   Just my two cents...

thanks calsan
would you please tell me the price of pentax 17-70.

[zmohie]

Dwvarch,JAZZER
THANKS SO MUCH FOR ADVICE

[calsan]

thanks calsan
would you please tell me the price of pentax 17-70.

Arrgh! don't ask me! The Australian dollar has fallen so far down this past year that I can't look at prices of anything made in Japan right now!

Anyway, while f2.8 is always desirable in a wide zoom, it's just not as useful as having a sharp lens that focuses quickly.
In a tele lens, a fast / big aperture is more important as it helps you hand-hold it and increase your shutter speed (for birding, cars, etc...)

[philstaff]

I have the sigma 17/70 and have been very happy with it good luck with your choice.
Ian

[hinioman]

I have settled my walk-around lens with Sigma 17-70mm f/2.8-4.5.  It is not as sleek with constant speed  but it gains on close up with 1:2.3 and a more usable range for walk-around.  I chose it over the Pentax DA 17-70mm f/4.0 as I find it cheaper to own as I bought it used for $300.00.  And the SR works as advocated with all shots hand-held

1/3 sec, f/5.6, 53mm, iso 400, 0 Ev


1/5 sec, f/6.3, 17mm, iso 500, 0 Ev



1/40 sec, f/4.0, 40mm, iso 400, 0 Ev



1/2000 sec, f/7.1, 70mm, iso 400, 0 Ev

I don't have direct experience with Sigma 24-70mm f/2.8, you have to check on the weight as I recall the lens to be heavier and bigger.  The Sigma 17-70mm is small and lightweight in my book when compared to Tamron 28-75mm f/2.8 and it is always my go-to lens in traveling.  IQ is good for a zoom, bokeh is reasonable for a zoom but I will pick the Tamron 28-75mm f/2.8 for better bokeh, sharpness and color.  But the Sigma is not that far behind and it scores big time especially for the wider end and very good close up for a zoom.  Portraits are very decent in the 70mm range in good lighting.

Thanks,
Hin

[wtlwdwgn]

You've got a few choices in that range of lenses. These are listed at Adorama and B&H in NY.

Pentax

DA 16-45 f/4               $405.
DA* 16-50 f/2.8 SDM     744.
DA 17-70 f/4 SDM          498.

Sigma

17-50mm f/2.8 EX DC OS HSM              $630.
17-70mm f/2.8-4 DC Macro OS HSM        449.
18-50mm f/2.8 EX DC Macro                   419.

Having f/2.8 on the wide end indoors will give you a brighter viewfinder for composing. The longer end will most likely be used outdoors and f/4 will be fine there. I hope this helps.

[Frogfish]

You can add the Tamron 17-50/2.8 (US$449 from B&H) to the W man's list above.  Superb value for money lens, very sharp and most often listed as the main competition to the very expensive Pentax DA*16-50 (along with the newest, but more expensive, Sigma 17-50/2.8 ).

[Rick Clark]

I have the Pentax 17-70 as a walk around on my K5 in day light hand held is just fine and indoors I use my monopod and 99% are keepers. I do think I will buy the 15mm for my outdoor landscape and for indoors when wide is when you need too. And this year I will get the 14mm f/2.8 for when a flash can not be used indoors.

[blackcloudbrew]

This is kind of an old thread at this point. I'm with you Rick on the Pentax DA 17-70. I have really liked mine for outdoor work and hiked many a mile with it. The Sigma is supposed to be a bit better but it's not constant aperture like the Pentax.