Sigma 17-70 at 50mm - Very Wide Images

code4code5 · 11-07-2009, 01:15 PM

Hopefully this will help others considering purchasing the Sigma 17-70 DC. Not that it's at all bad, but performance certainly does peak around f/8. This test was related to my earlier thread (https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/79196-4-lenses...tml#post802020). Here is a test of performance at all stops between f/4 and f/22.

f/4

f/5.6

f/8

f/11

f/16

f/22

All are a one inch tall 100% crop to demonstrate edge to edge sharpness. Each was processed in Bridge using default settings, manual WB and exposure in camera, on a tripod, with 3s MLU.

**Ash** · 11-07-2009, 01:46 PM

A good standardised test.
The subject is 3D no doubt? So are the corner details on the same plain as the central details?
If not it would be hard to distinguish between lens blur and gaussian (OOF) blur.

But thanks for sharing this.

code4code5 · 11-07-2009, 10:22 PM

The extreme left side was closer to the camera than it should have been in that respect... Thanks for pointing that out, Ash! It just seems as though so many "vs" threads are very subjective. I'm not an official measurbator, though.

campdog · 11-08-2009, 04:04 AM

I got the 17-70 before a trip to Samoa in may this year. Its my favorite everyday lens. I got some fantastic landscape and portrait shots.I highly recommend the lens.
John

11-07-2009, 01:15 PM	#1
code4code5 Veteran Member Join Date: Oct 2007 Location: Denver, CO Photos: Gallery Posts: 438	Sigma 17-70 at 50mm - Very Wide Images Hopefully this will help others considering purchasing the Sigma 17-70 DC. Not that it's at all bad, but performance certainly does peak around f/8. This test was related to my earlier thread (https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/79196-4-lenses...tml#post802020). Here is a test of performance at all stops between f/4 and f/22. f/4 f/5.6 f/8 f/11 f/16 f/22 All are a one inch tall 100% crop to demonstrate edge to edge sharpness. Each was processed in Bridge using default settings, manual WB and exposure in camera, on a tripod, with 3s MLU.

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11-07-2009, 01:46 PM	#2
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	A good standardised test. The subject is 3D no doubt? So are the corner details on the same plain as the central details? If not it would be hard to distinguish between lens blur and gaussian (OOF) blur. But thanks for sharing this.

11-07-2009, 10:22 PM	#3
code4code5 Veteran Member Join Date: Oct 2007 Location: Denver, CO Photos: Gallery Posts: 438 Original Poster	The extreme left side was closer to the camera than it should have been in that respect... Thanks for pointing that out, Ash! It just seems as though so many "vs" threads are very subjective. I'm not an official measurbator, though.

11-08-2009, 04:04 AM	#4
campdog Senior Member Join Date: Oct 2009 Location: Bonny Hills, NSW, Australia Photos: Gallery Posts: 202	I got the 17-70 before a trip to Samoa in may this year. Its my favorite everyday lens. I got some fantastic landscape and portrait shots.I highly recommend the lens. John