[englishphotographer]

4 lenses compared at 35mm; Sigma Art vs Pentax 31mm limited vs 20-35mm vs 28-105mm.

Taken with the Pentax K1 on a tripod, f8, 1/250s for every shot. Outside so the light varies slightly between shots. Shots are labelled with the lens used. I've uploaded the full DNG files; personal, pixel peeping use only please.

Pentax-28-105mm-f8-1.250s-34mm_K1_3106.DNG - Google Drive

Ben -

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Last edited by photolady95; 03-21-2017 at 04:14 PM. Reason: Personal site removed to comply with forum rules

[rawr]

I see only one un-labelled image, and a 46MB DNG to download.

[englishphotographer]

Thank you brother, here is the link to the folder with the images!

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[DeadJohn]

Do you have any comments or conclusions based on your comparison of the lenses?

[englishphotographer]

I certainly do, but I'll refrain until the other brothers have had an opportunity to draw their own conclusions, unbiased by my own.

[RGlasel]

the other brothers have had an opportunity to draw their own conclusions

I don't have the speediest Internet connection, so I only downloaded two images, one from the Pentax 28-105 and one from the Sigma Art 35. At 100% zoom, the Sigma seems to have better contrast, which makes it appear slightly sharper. When I looked at specific details, there isn't a noticeable difference in resolution (to me at least). I guess my conclusion would be that if you are going to take all of your pictures at f8, why spend money on high quality primes? The differences in image quality between lenses should be more noticeable at f4.

[englishphotographer]

I've added more photos, including a set with pixel shift. And a bonus from the 55mm Porst at f1.2 with a Tiffen gold diffusion filter.

[northcoastgreg]

I see virtually no difference across much of the frame in terms of sharpness. In the corners, however, the primes are sharper than the zooms, with the FA 20-35 being least sharp. In terms of the look of the image, I had a slight preference for the images from the FA 31 and FA 20-35. They seemed a tad brighter, with slightly more pleasing color rendering of lighter green and blue tones, and better contrast than the DFA 28-105.

[jlstrawman]

MY subjective opinion is that the FA 31 and ART 35 are quite close. I thought the D-FA 28-105 gave a good showing. I have the FA 31 and D-FA 28-105, so I am good. Very useful comparison. Thanks for sharing.

[englishphotographer]

Here are my conclusions gentlemen;

Sigma 35mm f1.4 - The sharpest lens across the frame and my preference overall. There's a big difference between f1.8 and f1.4 too so the lens gives more opportunities. Slightly cooler rendering. Quiet autofocus but not accurate.

Pentax 31mm - Similar sharpness but much smaller and lighter than the 35mm. Noisy autofocus and doesn't seem as well sealed as the sigma. Severe vignetting wide open. Smaller filters.

Pentax 28-105mm - I love this lens. It's a really good move from Pentax to provide a sharp, light, compact, weather sealed lens for a bargain price. Almost identical sharpness to the primes.

Pentax 20-35mm - This is a great lens too because it's so small and light for the focal length. It's not quite as sharp as the others and is warmer too, but it makes an excellent travel wide angle zoom. It's really so light.


I'd choose the 28-105mm if I had one lens only. But otherwise the 31mm for its large aperture relative to the size.

Ben

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[awscreo]

Sigma seems sharper at 1.4 than ltd at 1.8, very nice.

Interesting with the 28-105 shots - the first f8 shot seems sharp edge to edge, while the second one shows a bit of softness on the left side (similar to mine). I was wondering if my copy had slightly decentered optics, or that's the characteristics of the lens. I need to do some testing this weekend, haven't had a chance to properly try that lens.

Thank you for the shots, nice to have them for comparison)

[UrmoP]

Hell yeah, the D FA 28-105mm is really good lens with K-1.


Click this link. All landscape images are made with this lens. Vorming Galerii | Nature photography by Urmo Parts

[chrisfer]

4 lenses compared at 35mm; Sigma Art vs Pentax 31mm limited vs 20-35mm vs 28-105mm.

Very good comparative, thanks.
The old little 31mm is always competitive.