Pentax FA 24-90/3.5-4.5 vs Sigma DC 17-70/2.8-4.5

fengwei · 2nd April 2007

Hi All,

We've seen some comparison between the Sigma DC1770 and Pentax DA1645, but I haven't seen a comparison w/ Pentax FA 2490 yet (maybe there was, but I didn't see one yet).

Happen to have these two lenses currently, I was kinda interested to see how they compare w/ each other at the same focal range. So I did a quick test over the weekend, both indoor and outdoor. It's the first time I did this kind of test, there might be something unscientific, but I guess you'd get some idea by looking at the comparison sample photos.

There are many photos on one page, so I just post a link here:

Pentax FA24-90 vs Sigma DC 17-70

Please take a look at it if interested. And your comments will be very appreciated.

fengwei · 2nd April 2007

Both lenses are similar in size/weight with the Sigma being a bit larger and heavier. The Sigma has better built quality and feels more solid. The focus and zoom rings on the Sigma is not as loose as the ones on the Pentax, but the Sigma does feel better w/ both rings. The zoom ring on the Sigma is different from most other zoom lenses I have/had, it turns clockwise instead of CCW from wide to tele end.

Overall built and feel I'd say the Sigma 1770 has the edge.

Optically, I didn't check each and every focal length, but base on what I got here, wide open or stopdown, the Pentax is sharper at the wide and tele end, while the Sigma is sharper at the middle, although the difference is too little to be a concern. I can't see any color or contrast difference, but maybe my eyes aren't well trained as most here. So please take a look at the photos (both cropped and full size ones) and let me know what you think.

My conclusion is both lenses are excellent for their focal ranges. I still haven't decided which one to keep yet, so I'm keeping both for now.

Cheers!

macrob · 2nd April 2007

Thanks for doing this.

From what I see, 24-90 is realy a good lens, and it can be used on future FF camera.

So, if I were you, will keep the 24-90.

dnaxe · 2nd April 2007

hehe. you should compare that 24-90 against a good copy of the sigma 24-135

fengwei · 2nd April 2007

Originally Posted by macrob

Thanks for doing this.

From what I see, 24-90 is realy a good lens, and it can be used on future FF camera.

So, if I were you, will keep the 24-90.

Thanks. I might keep the 24-90 eventually 'cause its focal range is more ideal to my use (family photos mostly)

fengwei · 2nd April 2007

Originally Posted by dnaxe

hehe. you should compare that 24-90 against a good copy of the sigma 24-135

I don't have a Sigma 24-135, but I had a Tamron 24-135 before. It's a very good lens optically, but it's too bulky to my like

Thanks for the suggestoin though.

I do have a Pentax 28-105/3.2-4.5 at the moment. Might compare this one against the Pentax 24-90 and see how

Cheers!

rudigunawan · 2nd April 2007

Thanks for the comparison.
I notice that although the Pentax is definitely sharper indoor, the Sigma seems to perform better outdoor. The pics from Pentax lens have this "glowing" effect.

fengwei · 2nd April 2007

Originally Posted by rudigunawan

Thanks for the comparison.
I notice that although the Pentax is definitely sharper indoor, the Sigma seems to perform better outdoor. The pics from Pentax lens have this "glowing" effect.

Yes, outdoor the Sigma does seem to work better. Probably due to it's a digital lens.

airconvent · 2nd April 2007

Hi Feng wei
I hope the owner of the underwear you took does not come after you!

BTW, oddly, I thought indoor the sigma looks better for the full picture but I could see this is not so when you cropped down to the gray card. Maybe its just my eye...

But the outdoor definitely looks better for the Sigma....
Thanks for the comparison...

fengwei · 2nd April 2007

Originally Posted by airconvent

Hi Feng wei
I hope the owner of the underwear you took does not come after you!
BTW, oddly, I thought indoor the sigma looks better for the full picture but I could see this is not so when you cropped down to the gray card. Maybe its just my eye...
But the outdoor definitely looks better for the Sigma....
Thanks for the comparison...

Thanks Richard

For indoor, the Pentax does seem better, but might due to slight BF or FF problem w/ the Sigma lens, not a problem for real shooting. For outdoor, the Sigma does look better, not just sharpness, but contrast, and less CA/flare.

I'll give the Sigma a full test during my trip to Philippines

Cheers!

2nd April 2007	#1
fengwei Moderator Join Date: Aug 2004 Location: Bukit Gombak Posts: 9,105	Pentax FA 24-90/3.5-4.5 vs Sigma DC 17-70/2.8-4.5 Hi All, We've seen some comparison between the Sigma DC1770 and Pentax DA1645, but I haven't seen a comparison w/ Pentax FA 2490 yet (maybe there was, but I didn't see one yet). Happen to have these two lenses currently, I was kinda interested to see how they compare w/ each other at the same focal range. So I did a quick test over the weekend, both indoor and outdoor. It's the first time I did this kind of test, there might be something unscientific, but I guess you'd get some idea by looking at the comparison sample photos. There are many photos on one page, so I just post a link here: Pentax FA24-90 vs Sigma DC 17-70 Please take a look at it if interested. And your comments will be very appreciated.

2nd April 2007	#2
fengwei Moderator Join Date: Aug 2004 Location: Bukit Gombak Posts: 9,105	My conclusion Both lenses are similar in size/weight with the Sigma being a bit larger and heavier. The Sigma has better built quality and feels more solid. The focus and zoom rings on the Sigma is not as loose as the ones on the Pentax, but the Sigma does feel better w/ both rings. The zoom ring on the Sigma is different from most other zoom lenses I have/had, it turns clockwise instead of CCW from wide to tele end. Overall built and feel I'd say the Sigma 1770 has the edge. Optically, I didn't check each and every focal length, but base on what I got here, wide open or stopdown, the Pentax is sharper at the wide and tele end, while the Sigma is sharper at the middle, although the difference is too little to be a concern. I can't see any color or contrast difference, but maybe my eyes aren't well trained as most here. So please take a look at the photos (both cropped and full size ones) and let me know what you think. My conclusion is both lenses are excellent for their focal ranges. I still haven't decided which one to keep yet, so I'm keeping both for now. Cheers!

2nd April 2007	#3
macrob Member Join Date: Aug 2006 Posts: 652	Re: Pentax FA 24-90/3.5-4.5 vs Sigma DC 17-70/2.8-4.5 Thanks for doing this. From what I see, 24-90 is realy a good lens, and it can be used on future FF camera. So, if I were you, will keep the 24-90.

2nd April 2007	#4
dnaxe Member Join Date: Oct 2006 Posts: 1,214	Re: Pentax FA 24-90/3.5-4.5 vs Sigma DC 17-70/2.8-4.5 hehe. you should compare that 24-90 against a good copy of the sigma 24-135

2nd April 2007	#7
rudigunawan Member Join Date: Dec 2006 Posts: 143	Re: Pentax FA 24-90/3.5-4.5 vs Sigma DC 17-70/2.8-4.5 Thanks for the comparison. I notice that although the Pentax is definitely sharper indoor, the Sigma seems to perform better outdoor. The pics from Pentax lens have this "glowing" effect.

2nd April 2007	#9
airconvent Senior Member Join Date: Apr 2005 Posts: 3,114	Re: Pentax FA 24-90/3.5-4.5 vs Sigma DC 17-70/2.8-4.5 Hi Feng wei I hope the owner of the underwear you took does not come after you! BTW, oddly, I thought indoor the sigma looks better for the full picture but I could see this is not so when you cropped down to the gray card. Maybe its just my eye... But the outdoor definitely looks better for the Sigma.... Thanks for the comparison...